Pipe fittings

What are pipe fittings?

Pipe fittings are collectively referred to as components that play the role of connecting, controlling, redirecting, diverting, sealing, supporting, etc. in a piping system.

where to buy high quality pipe fittings - Pipe fittings

According to the different processing techniques, there are four major categories, namely butt-welding pipe fittings (having two kinds of welds and no welds), socket welding and screw fittings.

Classification of fittings
There are many types of pipe fittings, which are classified according to their use, connection, materials, and processing methods.
By usage
1. Fittings for connecting pipes to each other: flanges, unions, pipe clamps, clamps, ferrules, hose clamps, etc.
2, Change the direction of the pipe fittings: elbow, bend
3, Change the pipe diameter pipe fittings: Concentric ReducerEccentric ReducerOlet, the reinforcement tube
4, Increase the pipeline branch pipe fittings: pipe teepipe cross
5. Pipe fittings used for pipeline sealing: gaskets, raw material belts, wire hemp, blind flange, pipe plugs, blind plates, heads, welding plugs
6. Fittings for pipe fixing: snap rings, tow hooks, rings, brackets, brackets, tube cards, etc.

Classified by connection
1, welded pipe fittings
2, threaded pipe fittings
3, the casing pieces
4, clamp pipe fittings
5, socket fittings
6, bonding pipe fittings
7, hot melt pipe fittings
8, double elastic tube pieces
9, aprons connecting pipe fittings

Classified by material
1, cast steel pipe
2, cast iron pipe fittings
3, stainless steel pipe fittings
4, plastic pipe fittings
5, PVC pipe fittings
6, rubber pipe fittings
7, graphite pipe fittings
8, forging steel pipe
9, PPR pipe fittings
10, alloy pipe fittings
11, PE pipe fittings
12, ABS pipe fittings

Classification of fittings
1. Divided by material:
Carbon Steel: ASTM/ASME A234 WPB, WPC
Alloys: ASTM/ASME A234 WP 1-WP 12-WP 11-WP 22-WP 5-WP 91-WP911, 15Mo3 15CrMoV, 35CrMoV
Stainless steel: ASTM/ASME A403 WP 304-304L-304H-304LN-304N
ASTM/ASME A403 WP 316-316L-316H-316LN-316N-316Ti
ASTM/ASME A403 WP 321-321H ASTM/ASME A403 WP 347-347H
Low temperature steel: ASTM/ASME A402 WPL3-WPL 6
High Performance Steel: ASTM/ASME A860 WPHY 42-46-52-60-65-70
Cast steel, alloy steel, stainless steel, copper, aluminum alloy, plastic, argon leaching, PVC, PPR, RFPP (reinforced polypropylene), etc.
2. The division of manufacturing methods can be divided into pushing, pressing, forging, and casting.
3. The division of manufacturing standards can be divided into national standard, electric standard, ship standard, chemical standard, water standard, American standard, German standard, Japanese standard, and Russian standard.
4. According to its radius of curvature points: can be divided into long radius elbows and short radius elbows. The long-radius elbow refers to the outer diameter of the tube whose radius of curvature equals 1.5 times, ie, R=1.5D; the short radius elbow refers to its radius of curvature equal to the outer diameter of the tube, ie, R=1.0D. (D is the elbow diameter and R is the radius of curvature). 5. If the pressure level is divided into: there are about 17 kinds, which are the same as the american tube standard, which are: Sch5s, Sch10s, Sch10, Sch20, Sch30, Sch40s, STD, Sch40, Sch60, Sch80s, XS; Sch80, SCH100, Sch120, Sch140, Sch160, XXS; the most commonly used are STD and XS.

Standard of fittings
There are two main international standards for pipe flanges, namely the European pipe flange system represented by German DIN (including the former Soviet Union) and the American pipe flange system represented by the American ANSI pipe flange. In addition, there are Japanese JIS pipe flanges, but in petrochemical plants.
It is generally used only for public works and has a smaller international impact. Now introduce the flanges of each country in the following:
1. European system pipe flange represented by Germany and the former Soviet Union
2, American system flange standards, represented by ANSI B16.5 and ANSI B 16.47
3, the British and French standards for pipe flanges, the two countries have two casing flange standards.
In summary, the internationally accepted standards for pipe flanges can be summed up in two different and not interchangeable pipe flange systems: a European pipe flange system represented by Germany; the other is represented by the United States. American pipe flange system.
IOS7005-1 is a standard issued by the International Organization for Standardization in 1992. This standard is actually a pipe flange standard formed by merging two series of pipe flanges of the United States and Germany.
astm a403 wp347h 90deg elbow dn150 xxs - Pipe fittings
What is a elbow?
In the piping system, the elbow is the pipe that changes the direction of the pipe. Divided by angle, there are 45 ° and 90 ° 180 ° the three most commonly used, in addition to other engineering needs also include 60 ° and another abnormal angle elbow. Elbow materials are cast iron, stainless steel, alloy steel, malleable cast iron, carbon steel, non-ferrous metals and plastics. The connections to the tube are direct welding (the most common method) flange connection, hot melt connection, electrofusion connection, screw connection and socket connection. According to the production process can be divided into welding elbow, stamping elbow, push elbow, casting elbow, butt weld elbow and so on. Other names: 90 degree elbow, right angle bend, love and bend.
The bend radius is less than or equal to 1.5 times the diameter of the pipe and is greater than 1.5 times the diameter of the pipe.

The use of an elbow
One kind of connecting pipe fitting commonly used in pipe installation, connecting two pipes with the same or different nominal diameters to make the pipes turn at a certain angle, the nominal pressure is 1-1.6Mpa.
Elbow technical requirements
1, because most of the pipe used for welding, in order to improve the quality of welding, the end of the car is made into a groove, leaving a certain angle, with a certain edge, this requirement is also more strict, the edge is thick, the angle is how much and deviation The scope is regulated. Surface quality and mechanical properties are basic.
It is the same as the tube. For ease of welding, the fittings are the same as the steel type of the pipe being joined.
2. All the pipe fittings must be surface-treated. The inner and outer surface oxide scales should be sprayed off by shot blasting and then painted with anti-corrosion paint. This is for export needs. Moreover, in order to facilitate transportation and prevent rust oxidation in the country, we must do this work.
3, is the packaging requirements for small pipe fittings, such as exports, you need to do wooden boxes, about 1 cubic meters, the number of elbows in this box is not more than a ton, the standard allows packages, that is, large sets of small, However, the total weight cannot exceed 1 ton. For large items will be a single package, like 24′′ must be a single package. The other is the packaging mark, the mark is to indicate the size, steel, batch number, manufacturer’s trademark and so on.

Classification of elbows
Divided by material
Carbon Steel: ASTM/ASME A234 WPB, WPC
Alloys: ASTM/ASME A234 WP 1-WP 12-WP 11-WP 22-WP 5-WP 91-WP911, 15Mo3 15CrMoV, 35CrMoV
Stainless steel: ASTM/ASME A403 WP 304-304L-304H-304LN-304N
ASTM/ASME A403 WP 316-316L-316H-316LN-316N-316Ti
ASTM/ASME A403 WP 321-321H ASTM/ASME A403 WP 347-347H
Low temperature steel: ASTM/ASME A402 WPL3-WPL 6
High Performance Steel: ASTM/ASME A860 WPHY 42-46-52-60-65-70
Cast steel, alloy steel, stainless steel, copper, aluminum alloy, plastic, argon leaching, PVC, PPR, RFPP (reinforced polypropylene), etc.
Divided into methods of production can be divided into pushing, pressing, forging, casting and so on.
The division of manufacturing standards can be divided into national standard, electric standard, ship standard, chemical standard, water standard, American standard, German standard, Japanese standard, and Russian standard.
According to its radius of curvature, it can be divided into long radius elbows and short radius elbows. The long-radius elbow refers to the outer diameter of the tube whose radius of curvature equals 1.5 times, ie, R=1.5D; the short radius elbow refers to its radius of curvature equal to the outer diameter of the tube, ie, R=1.0D. (D is an elbow straight path, R is the radius of curvature).
If the pressure level is divided into: there are about seventeen kinds, which are the same as the American tube standard: Sch5s, Sch10s, Sch10, Sch20, Sch30, Sch40s, STD, Sch40, Sch60, Sch80s, XS; Sch80, SCH100, Sch120, Sch140, Sch160, XXS; The most commonly used are STD and XS.
According to different shapes and applications, it can be divided into groove elbow, card sleeve elbow, double elbow, flange elbow, reduce elbow, squat elbow, internal and external tooth elbow, stamp elbow, push Elbow, socket elbow, butt elbow, inner wire elbow and so on.

Elbow standard
Japanese Standard
Standard number Description
JIS B2311 Universal Steel Butt Welded Pipe Fittings
JIS B2312 Steel butt weld fittings
JIS B2313 butt welded pipe fittings for steel plate
JIS B2316 Steel socket welded pipe fittings
U.S. standards for the implementation of standards for fittings:
Standard number Description
ASME/ANSI B16.9 Forged Steel Buttweld Fittings Made in the Factory
ASME/ANSI B16.11 Socket Welding and Thread Forging Fittings
ASME/ANSI B16.28 Steel Butt Weld Small Radius Elbows and Bend Bend
ASME B16.5 Pipe Flange and Flange Accessories
MSS SP-43 forged stainless steel butt weld fittings
MSS SP-79 Socket Welding Reducer Inserts
MSS SP-83 socket weld and threaded union
MSS SP-97 Overall Reinforced Headers for Socket, Thread and Butt Weld Ends
Power standards
Standard number Description
GB2000 thermal power plant steam pipe parts and components typical design manual
DL/T515-93 power station elbow
D-GD87-1101 Pipeline Parts and Components Typical Design
Pipeline implementation of the standard chemical standards:
Standard number Description
HGJ514 Carbon steel, low alloy steel seamless butt weld fittings
HGJ528 Steel Seam Welded Pipe Fittings
HGJ10 forged steel socket welded pipe fittings
HGJ529 Forged socket weld, thread and butt welded tube stand
HGJ-44-76-91 Steel Pipe Flanges, Gaskets, Fasteners
HG20592-20635 Steel Pipe Flanges, Gaskets, Fasteners
Sinopec Standard
Standard number Description
SH3406 -1996 Petrochemical Steel Pipe Flange
SH3408 -1996 seamless butt welding steel
SH3409-1996 forged steel socket welded pipe fittings
SH3410 -1996 forged steel socket welded pipe fittings
SH3065-1994 Technical Standards for Pipe Bend in Petrochemical Industry
National standard
Standard number Description
GB/T12459-2005 seamless steel butt-welding fittings
GB/T13401-2005 steel butt welded pipe fittings
GB/T14383 forged steel socket welded pipe fittings
GB/T17185-1995 Steel Flange Fittings
Pipe fittings implement standard oil standards:
Standard number Description
SY/T0510-1998 Steel butt weld fittings
SY/T5257-2004 steel elbow
02S403 National Building Standard for Steel Pipe Fittings
Marine standard
GB/T10752-1995 marine steel pipe welding head
CB/T3590-94 Aluminum Brass Elbow

Process of elbows
Seamless elbows: Elbows are a kind of pipe fittings used for turning pipes. Of all the pipe fittings used in the piping system, the largest share is about 80%. In general, different forming processes are chosen for different materials or wall thickness bends. Manufacturer’s commonly used seamless bend forming hot push, stamping, extrusion, etc.

Heat forming of elbows
The hot-bending bending head forming process adopts a special elbow pushing machine, a mandrel and a heating device, so that the billet placed on the die is moved forward by the pushing machine, heated, expanded and bent during the movement. the process of. The deformation characteristics of the thermal pusher elbow is to determine the diameter of the blank according to the constant volume before and after the plastic deformation of the metal material. The diameter of the blank used is smaller than the diameter of the elbow. The deformation process of the blank is controlled by the core die so that the internal arc is compressed. The metal flow is compensated to other parts that are thinned due to the expansion so that an elbow with a uniform wall thickness is obtained.
The hot-pushing head forming process has the characteristics of beautiful appearance, uniform wall thickness and continuous operation, and is suitable for mass production. Therefore, it has become the main shaping method for carbon steel and alloy steel elbows and is also applied to certain specifications of stainless steel elbows. The formation of.
Heating methods in the forming process include medium-frequency or high-frequency induction heating (multi-turn or single-turn heating coils), flame heating, and reverberatory furnace heating. The heating method used depends on the product requirements and energy conditions.

Press forming of elbows
Press forming elbow is the earliest forming process used for mass production of seamless elbows. It has been replaced by hot extrusion or other forming processes in the production of elbows of common specifications, but in some elbows, the number of production Little, thick or thin wall thickness.
When the product has special requirements, it is still in use. The stamping of the elbow uses a tube blank with an outer diameter equal to that of the elbow and is pressed directly into the mold using a press.
Before punching, the tube blank is placed on the lower mold, and the inner core and the end mold are loaded into the tube blank. The upper mold moves downwards to start pressing, and the elbow is formed by the constraint of the outer mold and the supporting function of the inner mold.
Compared with the hot-pushing process, the appearance quality of stamping is not as good as the former; the outer arc of the stamping elbow is in tension at the time of forming, and there is no extra metal in other parts to compensate, so the wall thickness at the outer arc is reduced by about 10%. . However, due to the characteristics of single-piece production and low cost, the stamped elbow process is mostly used for the manufacture of small batches and thick-walled elbows.
Stamping elbows are divided into cold stamping and hot stamping. Cold stamping or hot stamping is usually selected according to material properties and equipment capabilities.
The forming process of the cold extrusion elbow is the use of a special elbow forming machine. The tube blank is placed in the outer mold. After the upper and lower molds are closed, the tube blank is reserved along the inner mold and the outer mold under the push of the push rod. Gap movement to complete the forming process.
The elbows produced by the internal and external die cold extrusion process have a beautiful appearance, uniform wall thickness, and small dimensional deviation. Therefore, the stainless steel elbows, especially the thin-walled stainless steel elbows, are formed using this process. The inner and outer molds used in this process require high precision, and the wall thickness deviation of the tube blanks is also more demanding.

Elbow plate welding
Half of the elbow profile was made with a press using a press plate, and then the two profiles were welded together. This process is generally used for DN700 above the elbow.
Other forming methods
In addition to the above three commonly used forming processes, the seamless elbow forming process also uses a forming process of extruding the tube blank to the outer mold and shaping the ball through the inside of the tube blank. However, such a process is relatively complicated and cumbersome to operate, and the forming quality is not as good as that of the aforementioned processes and is therefore less frequently used.

Technical requirements of elbows
It is required to control the radius of curvature. For example, if the radius is 1.5D, then the radius of curvature must be within the required tolerance. Since most of these fittings are used for welding, in order to improve the welding quality, the ends are car-grooved, leaving a certain angle, with a certain edge, this requirement is also more strict, the edge is thick, the angle is how much and the deviation range There are provisions that have many more geometric dimensions than fittings. The elbow surface quality and mechanical properties are basically the same as the tubes. For welding convenience, the material of the steel of the pipe to be connected is the same.

Making point of an elbow
Stainless steel elbow
1. The electrode should be kept dry when used. The titanium-calcium type should be dried at 150°C for 1 hour. The low-hydrogen type should be dried at 200-250°C for 1 hour (cannot be repeatedly dried, otherwise the coating will crack easily), preventing the welding rod The skin of the skin is sticky and other dirt so as not to increase the carbon content of the weld and affect the quality of the weldment. When the elbow is welded, carbides are repeatedly precipitated to reduce corrosion resistance and mechanical properties. Hardness after welding is large and cracks are easily generated. If welding with the same type of electrode is used, preheating at 300°C or more and annealing at 700°C or less must be performed. If the weldment cannot be post-weld heat treatment, a chromium-nickel stainless steel electrode should be used.
2. In order to improve the corrosion resistance and weldability of stainless steel elbows, the proper amount of stability elements such as Ti, Nb, Mo, etc. should be appropriately increased. The weldability is better. When using the same type of chromium stainless steel electrodes, the temperature should be more than 200°C. After welding and tempering at about 800°C. If the weldment cannot be heat treated, a chromium-nickel stainless steel electrode should be used.

Stainless steel elbow material classification
Austenitic stainless steel
The matrix is mainly composed of an austenitic structure (γ phase) with a face-centered cubic structure, which is non-magnetic and is mainly strengthened by cold working (and may result in a certain magnetic property). The austenitic-ferritic (duplex) stainless steel matrix combines both austenite and ferrite two-phase structures (of which less phase content is generally greater than 15%) and is magnetic, and can be strengthened by cold working iron
The body of the stainless steel body is mainly based on the ferrite structure (alpha phase) of the body-centered cubic crystal structure, is magnetic, and generally cannot be hardened by heat treatment, but it can be slightly strengthened by cold working.

Martensitic stainless steel
The matrix is martensitic, magnetic, and can be adjusted to its mechanical properties by heat treatment. Shen
The precipitation-hardening stainless steel substrate is austenitic or martensitic and can be hardened (strengthened) by treatment of precipitation hardening (also known as age hardening).

Stainless steel
1Cr18Ni9Ti 0Cr18Ni9 00Cr19Ni10 0Cr17Ni12Mo2Ti 00Cr17Ni14Mo2 304 304L 316 316L 3, stainless steel elbow has a certain degree of corrosion resistance (oxidizing acid, organic acid, cavitation), heat resistance and wear resistance. Usually used for the power station, chemical, petroleum and other equipment materials. Stainless steel elbows have poor weldability and should pay attention to the welding process, heat treatment conditions, and the selection of suitable electrodes.

Study on the Limit Load of Locally Thinned Elbows
Local thinning is a common defect in elbows, but research on such defects at home and abroad is mainly directed at straight tubes, and studies on local thinning of elbows have rarely been reported in the literature. In this paper, through detailed finite element calculations and theoretical analysis, the effect of local thinning on the ultimate bearing capacity of the elbow under the action of internal pressure and bending moment, and the mutual interference effect and bending moment effect of multi-local thinning under internal pressure are studied. The reinforcement effect of the lower straight pipe on the limit load of the elbow was verified by some experiments and the following research results were obtained:
1. The finite element method is used to systematically analyze and calculate the limit load of the locally thinned elbows under internal pressure. It is concluded that the ultimate pressure of the local thinning elbow is different from that of the locally thinned straight pipe, and the limit of the elbow is limited. The pressure depends not only on the local thinning size but also on the local thinning position and the bending radius. If the elbow is evaluated using a local thinning straight pipe calculation method, an unsafe or too conservative result will result; at the same time, the width will be reduced. The influence on the limit load cannot be ignored either. Based on the finite element analysis, the formula for calculating the ultimate pressure of the locally thinned elbows is given. The calculated results are in good agreement with the finite element calculations and experimental results, and the calculation formulas can be applied to the locally thinned elbows. Safety assessments complement the study’s gaps.
2. Through finite element analysis, the mutual interference effect between multiple partial thinnings under internal pressure was studied. Research shows that the mutual influence of multiple local thinnings is not only related to the spacing but also related to the depth of thinning. It is pointed out that when the thinning depth is shallow, the local thinning distance in the axial direction is more than 2 times the wall thickness. The limit load of the double local thinning is basically the same as the single local thinning limit load; when the thinning depth is deep, the axial local thinning When the spacing is more than 4 times the wall thickness, the limit load of double local thinning is basically the same as the single local thinning limit load, which supplements the existing research deficiencies.
3. Through the finite element calculation, the reinforcement effect of the connected straight pipe on the bending moment of the elbow is studied. It is pointed out that the straight pipe connected to the elbow will increase the limit bending moment of the elbow, and the elbow limit load when the bending radius is different. The amount of increase is different. When the length of the connected straight pipe is greater than 3 times the pipe diameter, the reinforcing effect of the straight pipe on the elbow no longer increases. This study complements the lack of research on the effect of straight tubes on elbow reinforcement.
4. Through finite element analysis, the influence of local thinning on the ultimate bending moment of the elbow was studied in detail. It was concluded that the limit bending moment of the local thinning elbow under the in-plane bending moment was related to the thinning position, thinning size and bending radius. Studies have shown that under the influence of bending moments, the effect of geometrical nonlinearity is significant. Based on the local thinning of the inner wall and the finite element analysis of large deformation, the formula for the ultimate bending moment of the locally thinned elbows under in-plane bending moments is given. The calculation results can reflect the finite element calculation results accurately and conservatively. And consistent with the experimental results. This study fills the gap in this area. 
asme b16 9 astm a815 gr2507 smls concentric reducer 8 4 sch40s - Pipe fittings
What is a reducer?
The reducer, also known as the size head, is one of the chemical pipe fittings used for the connection of two different pipe diameters. It is divided into concentric heads and eccentric heads.
Reducer materials include stainless steel reducer, alloy steel, reducer carbon steel head, reducer 20 steel q234q345 and so on.

Different diameter pipe manufacturing method
The roundness of the reducer should not exceed 1% of the outer diameter of the corresponding end, and the allowable deviation is ±3mm. The material of reducer is implemented in SY/T5037, GB/T9711, GB/T8163, American Standard ASTM A106/A53 GRB, API 5L, APT5CT, ASTM A105, ASTM A234, ASTM

A106, DIN German Standards and Customer Requirements
Reducer (size head) is a type of pipe used for pipe reduction. The commonly used forming process is shrinkage-reducing, expanding-diameter pressing or shrinkage-diameter-reducing-diameter pressing. For some sizes of different-diameter tubes, stamping can also be used.
Reducing/expanding forming of reducer
Reducing the diameter of the different diameter tube forming process is to change the diameter of the tube with the diameter of the tube blank into the forming mold, by pressing along the axial direction of the tube blank, so that the metal moves along the mold cavity and shrink shape. According to the size of the reducer, it can be divided into one press forming or multiple press forming. The following figure shows the sketching of the concentric reducer.

Diameter expansion is the use of smaller than the diameter of the diameter of the diameter of the pipe blank, with the inner die diameter expansion along the shape of the tube. The expanding process is mainly used to solve the problem of reducing the diameter of the different diameter tube is not easy to reduce the formation of the shape, sometimes depending on the material and product forming needs, the expansion and reduction of the combined use of the method.
During the process of reducing or expanding deformation, according to different materials and changing conditions, it is determined to use cold pressure or hot pressure. Normally, cold pressing is used as much as possible. However, the case of severe work hardening caused by multiple reductions, thicker wall thickness, or alloy steel materials should be hot pressed.

Forming of reducer
In addition to using steel pipes as raw materials to produce different-diameter pipes, some types of different-diameter pipes can also be produced by using stamping process. The shape of the die to be used for the drawing is determined by referring to the inner surface of the different-diameter pipe, and the steel plate after punching is stamped and stretch-formed using a die.

Eccentric Reducer
Eccentric different-diameter pipe (Eccentric different-diameter pipe) is a kind of pipe fitting used for reducing the diameter of the pipe. The commonly used forming technology is shrinkage reduction, expansion or shrinkage, for some specifications. Reducer can also be stamping.
Eccentric reducers In addition to the use of steel pipes as raw materials to produce different diameter pipes, some types of different diameter pipes can also be produced by stamping process using steel plates. The shape of the die used for drawing is determined by referring to the inner surface of the different diameter pipe and the die size will be used. After the sheet metal stamping stretch forming.

Structural features
Eccentric reducers are made of carbon steel, which means that the method is a large head diameter multiplied by the head diameter times the thickness.
Eccentric different-diameter pipe standard: GB standard British standard and various non-standard high-pressure stamping.
The reducing process of the eccentric reducer is to put the tube blank with the same diameter as the diameter of the reducer into the forming die and press the blank along the axial direction of the blank to move the metal along the cavity and shrink it. The size of the diameter of the radial pipe is divided into a single press forming or multiple press forming.
The eccentric different-diameter pipe is characterized by its strength is significantly higher than the same amount of carbon steel, has good toughness and plasticity and good weldability and corrosion resistance.

Application
1, when the flow of fluid in the pipeline changes, such as increasing or decreasing, the flow rate requirements change little, all need to use a reducer.
2, in the pump inlet, in order to prevent cavitation, need to use a reducer.
3, with the instrument, such as flow meters, regulating valve joints, in order to fit with the meter’s connector, also need to use different diameter pipe.

Concentric reducers
Concentric reducer, its connection form is to directly weld the reducer to the steel pipe.

Classification of concentric reducers
Divided by material
Carbon Steel: ASTM/ASME A234 WPB, WPC
Alloys: ASTM/ASME A234 WP 1-WP 12-WP 11-WP 22-WP 5-WP 91-WP911, 15Mo3 15CrMoV, 35CrMoV
Stainless steel: ASTM/ASME A403 WP 304-304L-304H-304LN-304N
ASTM/ASME A403 WP 316-316L-316H-316LN-316N-316Ti
ASTM/ASME A403 WP 321-321H ASTM/ASME A403 WP 347-347H
Low temperature steel: ASTM/ASME A402 WPL3-WPL 6
High Performance Steel: ASTM/ASME A860 WPHY 42-46-52-60-65-70
Cast steel, alloy steel, stainless steel, copper, aluminum alloy, plastic, argon leaching, PVC, PPR, RFPP (reinforced polypropylene), etc.
The manufacturing standards are divided into national standard, electric standard, ship standard, chemical standard, water standard, American standard, German standard, Japanese standard, and Russian standard.
The radius of curvature is divided into long radius elbows and short radius elbows. The long-radius elbow refers to the outer diameter of the tube whose radius of curvature equals 1.5 times, ie, R=1.5D; the short radius elbow refers to its radius of curvature equal to the outer diameter of the tube, ie, R=1.0D. (D is the elbow diameter and R is the radius of curvature). The

If the pressure level is divided into: there are about seventeen kinds, which are the same as the American tube standard: Sch5s, Sch10s, Sch10, Sch20, Sch30, Sch40s, STD, Sch40, Sch60, Sch80s, XS; Sch80, SCH100, Sch120, Sch140, Sch160, XXS; The two most commonly used are STD and XS.

Standard system of concentric reducer
There are two main international standards for pipe flanges, namely the European pipe flange system represented by German DIN (including the former Soviet Union) and the American pipe flange system represented by the American ANSI pipe flange. In addition, there are Japanese JIS pipe flanges, but they are generally used only for public works in petrochemical plants, and they have a smaller international impact. Now introduce the flanges of each country in the following:
1. European system pipe flange represented by Germany and the former Soviet Union
2, American system flange standards, represented by ANSI B16.5 and ANSI B 16.47
3, the British and French standards for pipe flanges, the two countries have two casing flange standards.
In summary, the internationally accepted standards for pipe flanges can be summed up in two different and not interchangeable pipe flange systems: a European pipe flange system represented by Germany; the other is represented by the United States. American pipe flange system.
IOS7005-1 is a standard issued by the International Organization for Standardization in 1992. This standard is actually a pipe flange standard formed by merging two series of pipe flanges of the United States and Germany.
where to get high quality pipe tees - Pipe fittings
What are Tees?
The tees are one kind of pipe connection pieces and are used at the branch pipe of the main pipe and have an equal diameter and different diameter.

According to the diameter classification
1. Tee of the same diameter: tees with the same pipe diameter as the supervisor and branch pipe
2. Reducing Tees: The tee pipe with the pipe diameter smaller than the main pipe diameter

Sort by docking
1. Butt welded tee: It is the tee fitting welded after connecting with connecting pipe.
2. Sleeve Tee: It is the tee fitting welded or welded after the connecting pipe is inserted into each end of the Tee.
3, card sleeve type tee: that is, the end of the card connector, insert the pipe fittings and then tighten the tee fittings.
4. Threaded tees: Tee fittings for threaded connections.

According to the material classification of the tees
Can be divided into stainless steel tees, carbon steel tees, copper tees, PVC tees, ductile iron tees and so on.

Classified by branch
1, is the tees: is the vertical pipe branch of the tee pipe fittings.
2. Oblique tee: It is a tee pipe with a certain angle between the branch pipe and the supervisor.

The application of tees
The tee pipe fittings are used in places where the pipelines are branched, and because they are easy to use, they are widely used in chemical, civil construction, machinery manufacturing, shipbuilding and other fields.

Processing technology of tee
A tee is a type of pipe used at the branch of a pipe. For the manufacture of tee pipes using seamless pipes, the currently commonly used processes include hydraulic bulging and hot-press forming.

Hydraulic bulging of tee
The tee hydraulic bulging is a forming process in which the branch pipe is expanded by the axial compensation of the metal material. In the process, a special hydraulic press is used to inject the liquid into the tube with the same diameter as the tube. The tube is squeezed by the two horizontal cylinders of the hydraulic press. The tube is squeezed and the volume becomes smaller. The pressure of the liquid increases as the volume of the tube becomes smaller, and when the pressure required for the expansion of the teeing tube is reached, the metal material flows along the inner cavity of the mold under the double action of the pressure of the liquid in the side cylinder and the tube to expand the branch tube.
The tee hydraulic bulging process can be formed at one time with high production efficiency; the tee head and shoulder wall thicknesses are all increased. Due to the large tonnage of equipment required for the seamless tee hydraulic bulging process, it is currently mainly used for the manufacture of standard wall thickness tee smaller than DN400. The suitable forming materials are low-carbon steels, low-alloy steels, and stainless steels that have relatively low tendency to cold hardening, including some non-ferrous metal materials such as copper, aluminum, and titanium.

Hot forming of tee
The tee hot press forming is the process of squeezing the pipe blank larger than the diameter of the tee to about the diameter of the tee, and opening a hole at the location of the stretching pipe; the pipe billet is heated and put into the forming die and is in the pipe blank. The die is loaded into a tensile branch tube; under pressure, the tube blank is radially compressed, and in the radial compression process, the metal flows in the direction of the branch tube and forms a branch under the stretching of the die. The entire process is formed by the radial compression of the tube and the stretching process at the branch. Different from the hydraulic bulging tee, the metal of the hot-pressed tee branch is compensated by the radial movement of the blank, so it is also called the radial compensation process.
Due to the use of a heated tee, the tonnage of the equipment required for material formation is reduced. The hot-pressed tee material has a wide adaptability to the material and is applicable to the materials of low-carbon steel, alloy steel, and stainless steel. In particular, the large-diameter and thick-walled tee are generally used in this forming process.

What is a Pipe Cross?
Cross, also called pipe cross, Pipe cross joints, used in the main pipe to branch pipe.
The Pipe cross pipe has the equal diameter and the different diameter, and the connecting ends of the equal-diameter Pipe cross pipe are of the same size; the Pipe cross main pipe connection of the different diameter has the same size, and the size of the branch pipe is smaller than that of the main pipe. A cross is a type of pipe used at the branch of a pipe.

Hydraulic bulging of pipe cross
The Pipe cross hydraulic bulging is a forming process in which the branch pipe is expanded by the axial compensation of the metal material. The process is the use of special hydraulic presses, will be welded with the Pipe cross. The liquid is injected into the tube with the same diameter of the Pipe cross pipe, and the tube is squeezed by the simultaneous centering movement of the two horizontal side cylinders of the hydraulic press. The volume of the tube becomes smaller after extrusion, and the volume of the liquid in the tube decreases with the tube blank. When the pressure rises, when the pressure required for the expansion of the Pipe cross branch tube is reached, the metal material flows along the inner cavity of the mold under the double action of the liquid pressure in the side cylinder and the tube blank to swell the branch tube. The Pipe cross hydraulic bulging process can be formed at one time, resulting in higher production efficiency; the Pipe crosshead and shoulder wall thicknesses are all increased. Due to the large tonnage of equipment required for the seamless Pipe cross hydraulic bulging technology, it is currently used for the manufacture of standard wall thickness four-pass smaller than DN400. The suitable forming materials are low-carbon steels, low-alloy steels, and stainless steels that have relatively low tendency to cold hardening, including some non-ferrous metal materials such as copper, aluminum, and titanium.

Hot press forming of pipe cross
Cross-press molding is the process of squeezing a pipe blank that is larger than the Pipe cross diameter into a Pipe cross diameter, and opening a hole in the location of the branch pipe; the pipe blank is heated and placed in a forming die and in the pipe blank. The die is loaded into a tensile branch tube; under pressure, the tube blank is radially compressed, and in the radial compression process, the metal flows in the direction of the branch tube and forms a branch under the stretching of the die. The entire process is formed by the radial compression of the tube and the stretching process at the branch. Different from the hydraulic bulging Pipe cross pipe, the metal of the hot-pressed Pipe cross branch pipe is compensated by the radial movement of the pipe blank, so it is also called a radial compensation process.
Due to the use of heated post-pressing, the tonnage of the equipment needed to form the material is reduced. Hot-pressed crosses have a wide adaptability to materials and are suitable for low-carbon steels, alloy steels, and stainless steels. Especially for large-diameter and thick-walled pipes, this forming process is usually used.
1. The material is divided into carbon steel, cast steel, alloy steel, stainless steel, copper, aluminum alloy, plastic, argon leaching, PVC and so on.
2. The division of production methods can be divided into the top system, compression, forging, casting and so on.
3. The division into manufacturing standards can be divided into national standard, electric standard, water standard, American standard, German standard, Japanese standard, Russian standard, etc., as follows: GB/T12459, GB/T13401, ASME B16.9, SH3408, SH3409, HG/T21635, DL/T 695, SY/T 0510, DIN 2615

What is a Head?
A header is a type of boiler component in a pressure vessel and is usually used at both ends of a pressure vessel. There is also a welded pipe fitting used for plugging at the end of the pipe. There are many kinds of forms.
The head is a component of the container and is welded to the body. According to the different geometric shapes, it can be divided into several types: spherical, oval, dish-shaped, spherical-crown-shaped, conical shell and a flat lid. Among them, spherical, oval, dish-shaped and spherical caps are collectively referred to as convex heads. The welding is divided into butt weld heads and socket weld heads. For various container equipment, such as storage tanks, heat exchangers, towers, reactors, boilers and separation equipment. Materials include carbon steel (A3, 20#, Q235, Q345B, 16Mn, etc.), stainless steel (304, 321, 304L, 316, 316L, etc.), alloy steel (15Mo3 15CrMoV 35CrMoV 45CrMo), aluminum, titanium, copper, nickel, and nickel Alloy and so on.

Head standard:
Pressure vessel head GB/T25198-2010

Piping standards
GB/T12459-2005
GB/T13401-2005

Power standards
DL/T695-1999
D-GD87-0607

Petrochemical standards
SH3408-1996
SH3409-1996

The use of head
The head is an indispensable part of pressure vessel equipment in many industries such as petrochemicals, atomic energy and food and pharmaceuticals.
The head is the end cap on the pressure vessel and is a major pressure-bearing component of the pressure vessel. The role played is sealing. First, the upper and lower ends of the can-shaped pressure vessel are made. Second, the pipe is at the end of the pipeline. If it is not ready to extend forward, use a sealing head to seal the pipe in the form of welding. Products with similar functions to the head have blind plates and caps, but the two products are detachable. After the head has been welded, it cannot be dismantled. The supporting fittings include pressure vessels, pipes, flanges, elbows, tees, and four-way products.
The quality of the head is directly related to the long-term safe and reliable operation of the pressure vessel.

The basic requirements of the head
China’s existing head standards are formulated according to the structural type (ellipse, dish, taper) and forming method (stamping, spinning), which not only results in incomplete quality requirements for different standard heads. Unanimous irrationality also brings certain difficulties to the selection of standards and the revision of standards.
The first and previous header standards are only matched with GB150 “Steel Pressure Vessels”, that is, only the manufacturing, inspection and acceptance requirements of the headers designed according to the rules are considered, and China completed GB150 and as early as in 1995. JB4732 has a dual-track system for pressure vessel basic standards (and “Design Criteria for Analysis and Design of Steel Pressure Vessels”). The lack of head standards for analysis and design must not be said to be a major drawback in the standardization of pressure vessels in China.
Secondly, GB150 is a mandatory standard, and the head standard compiled and matched with GB150 is guidance (recommended). This is obviously unreasonable and it is difficult to guarantee the quality of the head, an important pressure element.

Material analysis container inner diameter Di=4000mm, calculation pressure Pc=0.4MPa, design temperature t=50°C, head as standard elliptical head, material 16MnR (design temperature material allowable stress is 170MPa), steel negative deviation is not ≥ 0.25mm and not more than 6% of the nominal thickness, corrosion allowance C2 = 1mm, welded joint coefficient of the head joint welding ?

1. Calculate the calculated thickness, design thickness, and nominal thickness of the elliptical head.

KpDi
Calculate thickness δ=—————-=4.73mm
2. [σ]tΦ-0.5pc
Calculate thickness δd=δ + C2=4.73+1=5.73mm
Consider the standard elliptical head effective thickness δe should not be less than 0.15% of the inner diameter Di of the head, effective thickness δe=0.15%Di=6mm δe>δd, C1=0, C2=1, nominal thickness δn=δe+C1+C2= 6+0+1=7mm
Considering the thickness of the steel standard specification, a thickness of 1mm was floated for the first time to design around value of Δ1=1, so δn=8mm was taken.
According to professional head manufacturer’s technical data Di = 4000, δn = 8 head processing thinning amount C3 = 1.5mm, the thickness of the second round of the value of △ 2 = 0.5.
If the required forming thickness of the sealing head shall not be less than the nominal thickness δn minus the negative deviation C1 of the steel plate, the feeding thickness shall be:
Δs = δn + C1 + C3 + Δ2 = 8 + 0 + 1.5 + 0.5 = 10 mm, and the minimum thickness after forming is 8.5 mm. If the head forming thickness is not less than the design thickness δd (δe value should be taken), the feeding thickness: δs = δd(δe) + C3 + △2 = 8mm, and the minimum thickness after forming is 6.5mm, and is greater than the effective thickness δe , greater than the design thickness δd and calculated thickness δ.
From the above, it can be seen that two different requirements make the thickness of the feeding head of the head 2mm difference, and the difference in weight is as much as 300kg.

Thickness definition
The definition of the thickness of GB150 and related head standards is not very reasonable, mainly reflected in the thickness requirements of the container and the head after forming. The required thickness of the convex head and the hot roll must not be less than the nominal thickness minus the negative deviation of the steel plate (δn -C1), which may lead to the design and manufacture twice to increase the thickness based on the design thickness to ensure the forming thickness. For this reason, the concept of minimum forming thickness has been proposed: “The thickness to be guaranteed after forming a hot roll cylinder or a convex head, whose value is not less than the design thickness.” That is to say, the designer should mark the nominal thickness and the minimum formed thickness (ie, the designed thickness δd) on the drawing so that the manufacturing unit can decide whether to add the thinning amount according to the manufacturing process and the design roundness of the original design. The definition and labeling of this thickness is a popular method as of 2013 in the international pressure vessel industry. It is reasonable, but there are two issues that need to be resolved in our current standards.
mss sp43a astm a815 uns s32750 gr2507 stub end 3 inch sch160s 1 - Pipe fittings
What is a Lap Joint Stub End?
Lap Joint Stub End refers to the method of forming a straight wall or Lap Joint Stub End with a certain angle along the edge of a closed or non-closed curve by the action of a mold on the flat or curved portion of the blank. Flanging is a type of stamping process. There are many types of flanging and the classification methods are also different. Among them, according to the nature of deformation, it can be divided into an extension type Lap Joint Stub End and a compression type Lap Joint Stub End.
Flanging is a stamping method that turns the outer edge or hole edge of a blank or semi-finished product along with a certain curve into an upright edge, as shown in the following figure.

When the edge of the Lap Joint Stub End is a straight line, the deformation of the Lap Joint Stub End turns into a bend, so it can also be said that the bend is a special form of the Lap Joint Stub End. However, the deformation of the blank during bending is limited to the rounded portion of the bending line, and both the rounded portion and the edge portion of the blank are the deformation region when the Lap Joint Stub End is folded, so the deformation of the Lap Joint Stub End is much more complicated than the bending deformation. With the flanging method, three-dimensional workpieces with complex shapes and good rigidity can be machined, and parts that are assembled with other product parts can be prepared on the stamping parts, such as wall-to-wall Lap Joint Stub Ends for passenger cars and passenger car pedals. Flanging, car door flaps, motorcycle fuel tank hole, metal plate small threaded holes and so on. Flanging can replace the drawing process of some complex parts and improve the plastic flow of the material to avoid cracking or wrinkling. Instead of pulling and cutting back to produce bottomless parts, the number of processes can be reduced and materials can be saved.

Flanging process
In general, the burring process is the final processing step of forming the contour shape or three-dimensional shape of the stamping. The flanging part is mainly used for the connection between the stamping parts (welding, riveting, bonding, etc.), and some flanging is the requirement of the product flow line or aesthetics.
The direction of punching in the Lap Joint Stub End is not necessarily the same as the direction of movement of the press slide. Therefore, the Lap Joint Stub End opening process must first consider the position of the mold in the mold. The correct flanging direction should provide the favorable conditions for the flanging deformation so that the movement direction of the punch or die is perpendicular to the flanging contour surface, so as to reduce the lateral pressure and position the flanging parts in the flanging die. stable.
According to the direction of the Lap Joint Stub End, it can be divided into vertical Lap Joint Stub End, horizontal Lap Joint Stub End and inclined Lap Joint Stub End. Among them, the vertical Lap Joint Stub End, the trimming element is opened upward, and the forming is stable and the positioning is convenient. Pressure pad can also be used to compress the material if conditions permit. Should be used as far as possible. In addition, according to the number of flanging surface can be divided into single-sided flanging, multi-sided flanging, closed curve flanging. The blank deformation process according to the Lap Joint Stub End-turning process can be divided into elongation type screen curve Lap Joint Stub Ends, elongation-type surface Lap Joint Stub Ends, compression-type plane curve Lap Joint Stub Ends and compression-type surface Lap Joint Stub Ends.

Hole processing method
The processing method of the prefabricated hole determines the edge condition of the hole. When the edge of the hole is free of defects such as burrs, tears, hardened layers, etc., the limit flanging coefficient is smaller, which is favorable for flanging. At present, prefabricated holes are mainly processed by punching or drilling. The data shows that the boreholes are smaller than the normal punching minutes. The conventional punching method has high production efficiency and is particularly suitable for processing larger holes, but it will form defects such as hardened layers, burrs, and tear on the surface of the orifice, resulting in a larger limit flanging coefficient. After the punching, heat treatment annealing, hole repairing, or hole turning in the direction opposite to the punching direction so that the burr is located inside the turning hole can obtain a lower limit flanging coefficient. With the method of deburring after drilling, a lower limit flanging coefficient can also be obtained, but the production efficiency is lower.

The relative diameter of the prefabricated hole
The smaller the relative diameter of the prefabricated hole, the smaller the limit flanging coefficient, which is beneficial to the flanging. This is because the same preformed aperture, the greater the thickness of the material, the absolute value of the allowable thickness in the direction of the thickness increases, according to the law of volume invariance, so when the edge of the deformation area will be cracking when the limit of the tangential strain value increases, As can be seen, the smaller the limit flanging coefficient is.

Punch shape
The limit punching coefficient of the spherical punch is smaller than that of the flat punch. In addition, the paraboloids, conical surfaces, and punches with larger fillet radii are also smaller than those with flat punches. Because when the Lap Joint Stub End is deformed, the ball or tapered punch is the first to contact with the prefabricated hole in the front end of the punch, and the bending deformation in the mouth of the die is smaller than that of the flat punch, so that the hole can be plastically deformed more easily. . Therefore, when the same Lap Joint Stub End diameter D and material thickness t are the same, the preformed aperture that can be Lap Joint Stub Endd is smaller and the limit Lap Joint Stub End factor is smaller.

What are Pipe Caps?
Pipe caps, also known as heads, plugs, caps, tube caps, bulkheads, are welded to the ends of the tubes or to external threads on the ends of the tubes to cap the tubes. Used to close the pipeline, the same role and pipe plugging.

Types of pipe cap
Blinds are similar in form, except that blind plates are detachable, and welded caps are not removable. The cap includes a convex cap, a conical shell, a reduced section, a flat cap, and a constricted mouth design.
Convex caps include: hemispherical caps, elliptical caps, dish caps, and dome caps. Seen from the force point of view, the cap from the hemispherical cap gradually becomes poor, but from the point of view of manufacturing difficulty, it is gradually better manufactured.
Stainless steel: 304 304L 316 316L 321 347 310, 317, and other materials.
Path: DN15-DN1200
Wall thickness: SCH5-SCH160
Standard: ASME DIN JIS BS GB/T JB SH HG, as follows: GB/T12459-2017, GB/T13401-2017, ASME B16.9, SH3408,
SH3409,HG/T21635,DL/T695,SY/T0510, DIN2617
Uses: Water, beverages, beer, food, petrochemicals, nuclear power, machinery, medical equipment, fertilizers, shipbuilding, water treatment, pipelines, etc.
Packing: wooden box, carton
The r-seal of the dish-shaped tube cap avoids splicing and will reduce the thickness and high stress.
Welding direction requirements for splicing are only allowed in radial and hoop directions. Later large caps may cancel this requirement. The splicing distance should be greater than 3δ and not less than 100mm (the heat affected zone is a high-stress area, and the chemical composition in the area will be burned. Therefore, to avoid the high-stress area, the area is related to the thickness. According to practical experience, the stress decay length is greater than 3δ and not less than 100mm). However, it is very difficult for refrigeration equipment to meet this requirement.
After splicing the formed heads, the splicing welds shall be 100% ray or ultrasonic tested, and the qualification level shall follow the device housing. The final weld inspection level and proportion are the same as those of the equipment housing, which leads to high waste.
Example: If the device housing is 20% tested, III is qualified. The bulkhead welding seam and the final weld seam are also III qualified, and the welded joint coefficient is 0.85;
If the device housing is 100% tested, II is qualified. The bulkhead welding seam and the final weld seam are also II qualified, and the welded joint coefficient is 1. Therefore, although the bulkhead joint is 100% tested, the qualification level is not the same, and it goes with the equipment shell.

But pay attention to the process of manufacturing:
The correct approach is: blanking (dashing) – small plate made into large plates – forming – non-destructive testing
If you do not test before molding is wrong, can not guarantee the quality of the product after molding. That is, non-destructive testing refers to the final non-destructive testing.

What is a Bend?
A bend is a pipe that is bent using a set of bending equipment.
The bend radius is less than or equal to 1.5 times the diameter of the pipe and is greater than 1.5 times the diameter of the pipe.

What is a Gasket?
The gasket is made of plastic or metal, placed between the two planes to reinforce the sealing material, and a sealing element arranged between the static sealing surfaces to prevent fluid leakage.
A gasket is a mechanical seal between two objects and is usually used to prevent pressure, corrosion, and natural thermal expansion and contraction between the two objects. Because the machined surface is not perfect, the use of spacers can fill irregularities. Gaskets are usually made from sheet materials such as paper pads, rubber, silicone rubber, metal, cork, felt, neoprene, nitrile rubber, glass fiber or plastic polymers (such as polytetrafluoroethylene). Application-specific gaskets may contain asbestos.
A washer is a hole (usually in the middle) of a thin plate (usually round) that is usually a load thread fastener for dispensing. Other uses are as spacers, springs (Bellville gaskets, wave pads), wear pads, pre-display devices, and lock devices.
Rubber gaskets are also used in faucets (valves) to cut off flowing liquids or gases. Rubber or silicone gaskets can also be used to reduce fan vibration. Usually the gasket outer diameter is about twice the inner diameter.

Type of gasket
Gaskets can be divided into non-metallic gaskets, metal gaskets, and metal-non-metal gaskets according to their material and structural characteristics. Each type can be subdivided into several types.
 
Non-metallic gasket
Rubber gasket
Non-asbestos fiber rubber gasket
Flexible graphite metal composite gasket
PTFE gasket
PTFE gasket
Other types of non-metallic material gaskets
Metal-non-metal composite gasket

Wave washer
Metal spiral wound gasket
Metal tooth composite gasket
Metal covered gasket
Metal wave tooth composite gasket
Other types of metal composite gaskets

Metal gasket
Flat gasket
Metal corrugated gasket
Metal tooth washer
Metal ring gasket
Metal lens gasket
Metal O-ring gasket
The metal ring gasket can be further divided into
Octagon ring gasket
Oval ring gasket
RX and BX type self-tight seal ring gasket

Gasket material classification
The washer pads the part between the connector and the nut, typically a flat metal ring.
Non-metallic gaskets Non-metallic gaskets are made of non-metallic gaskets such as asbestos, rubber, synthetic resin, and PTFE. a Non-metallic jacket gasket Non-metallic jacket gasket Outer layer of non-metallic gasket such as synthetic resin.
Semimetal gaskets Semimetal gaskets made of metal and non-metallic materials, such as wound gaskets, metal-clad gaskets. a spiral wound gasket spiral wound gasket V-shaped or W-shaped metal tape clip non-metallic tape, spiral wound gasket. 1) Inner ring inner ring A metal ring set in the inner ring of the wound gasket. 2) Outer ring The outer ring is located on the outer ring of the wound gasket. b Metal cladding
Metal gaskets are made of metal such as steel, aluminum, copper, nickel or Monel.
Wound gasket refers to the use of metal tape (usually V-shaped steel tape) and non-metallic tape wound into a ring gasket, metal tape and non-metallic tape alternately wrapped, because of its good flexibility, widely used in petrochemical, chemical, In the flange sealing structure of electric power and other industries, a steel ring can be positioned or reinforced on the inner or outer layer of the gasket according to the specific location.

Installation requirements of gasket
Gasket – Gasket Installation Requirements
1. The seal gasket and the flange sealing surface should be cleaned, and there must be no defects such as scratches or spots that affect the connection sealing performance.
2. The outer diameter of the sealing gasket should be smaller than that of the flange sealing surface. The inner diameter of the sealing gasket should be slightly larger than the inner diameter of the pipe. The difference between the two inner diameters is generally 2 times the thickness of the sealing gasket to ensure that the gasket is tight after the compression. The inner edge does not extend into the container or pipe so as not to interfere with the flow of fluid in the container or pipe.
3, the sealing gasket pre-tightening force should not exceed the design requirements, so as to avoid over-compression seal gasket loses its ability to rebound.
4. It is best to use a torque wrench when the gasket is pressed. For large bolts and high-strength bolts, hydraulic tensioners are preferred. Tightening torque should be obtained by calculation according to the given sealing gasket compression. The size of the hydraulic pressure of the hydraulic tensioner should also be determined by calculation.
5. When installing the gasket, tighten the nuts in order. However, the design value should not be reached once. Generally, it should be circulated at least 2 or 3 times so that the stress distribution of the gasket can be evenly distributed.
6, for flammable, explosive medium pressure vessels and pipelines, replace the gasket should use safety tools, so as to avoid tool collision with the flange or bolt, resulting in sparks, resulting in fire or explosion.
7. If there is a leak in the pipeline, it must be replaced after pressure relief treatment or adjusted installation gasket, pressure operation is strictly prohibited.
The Scope of Gasket Selection The material of the gasket is mainly determined by the following three factors: Temperature and pressure medium

One. Metal gasket material
1. Carbon steel: Recommended maximum operating temperature does not exceed 538°C, especially when the media is oxidizing. High-quality thin carbon steel plates are also not suitable for use in equipment for the production of inorganic acid, neutral or acidic salt solutions. If carbon steels are subjected to stress, the accident rate of equipment used under hot water conditions is very high. Carbon steel gaskets are commonly used for high concentrations of acids and many alkaline solutions. Brinell hardness is about 120.
2. 304 stainless steel 18-8 (chrome 18-20%, nickel 8-10%), recommended maximum operating temperature does not exceed 760 °C. In the temperature range of -196 to 538°C, stress corrosion and grain boundary corrosion occur easily. Brinell hardness 160.
3. The carbon content of 304L stainless steel does not exceed 0.33%. Recommended maximum operating temperature does not exceed 760°C. Corrosion resistance is similar to 304 stainless steel. The low carbon content reduces the precipitation of carbon from the crystal lattice and the resistance to grain boundary corrosion is higher than that of 304 stainless steel. Brinell hardness is about 140.
4. 316 stainless steel 18-12 (chrome 18%, nickel 12%), added about 2% molybdenum in 304 stainless steel, when the temperature increases its strength and corrosion resistance improves. When the temperature increases, it has higher creep resistance than other ordinary stainless steels. Recommended maximum operating temperature does not exceed 760°C. The Brinell hardness is about 160.
5. 316L stainless steel recommended maximum continuous operating temperature does not exceed 760 °C ~ 815 °C. The carbon content does not exceed that of 316 stainless steel with better stress resistance and grain boundary corrosion. Brinell hardness is about 140.
6. 20 alloy 45% iron, 24% nickel, 20% chromium and a small amount of molybdenum and copper. Recommended maximum operating temperature does not exceed 760°C~815°C. Especially suitable for the manufacture of equipment resistant to sulfuric acid corrosion, Brinell hardness of about 160.
7. Aluminum and aluminum (content not less than 99%). Aluminum has excellent corrosion resistance and processability and is suitable for the manufacture of double clamp gaskets. Brinell hardness is about 35. The recommended maximum continuous operating temperature does not exceed 426°C.
8. The composition of copper-copper is close to that of pure copper, which contains a trace amount of silver to increase its continuous operating temperature. The recommended maximum continuous operating temperature does not exceed 260°C. Brinell hardness is about 80.
9. Brass (copper 66%, zinc 34%) has good corrosion resistance under most working conditions, but does not adapt to acetic acid, ammonia, salt and acetylene. The recommended maximum continuous operating temperature does not exceed 260°C. Brinell hardness is about 58.
10. Hastelloy B-2 (26-30% molybdenum, 62% nickel, and 4-6% iron). Recommended maximum operating temperature does not exceed 1093°C. Has excellent heat-resistant hydrochloric acid corrosion properties. It also has excellent corrosion resistance to wet hydrogen chloride gas corrosion, sulfuric acid, phosphoric acid, and reducing salt solutions. High strength at high temperatures. Brinell hardness is about 230.
11. Hastelloy C-276 16-18% molybdenum, 13-17.5% chromium, 3.7-5.3% tungsten, 4.5-7% iron, and the rest are nickel). Recommended maximum operating temperature does not exceed 1093°C. Has excellent corrosion resistance. For various attempts of cold nitric acid or boiling nitric acid with a concentration of 70%, it has excellent corrosion resistance, good resistance to hydrochloric acid and sulfuric acid corrosion, and excellent stress corrosion resistance. Brinell hardness is about 210.
12. Inconel 600 nickel base alloy (77% nickel, 15% chromium and 7% iron). Recommended maximum operating temperature does not exceed 1093°C. High strength at high temperatures, commonly used in equipment that needs to address stress corrosion problems. In the low temperature conditions, with excellent processing performance. Brinell hardness is about 150.
13. Monel 400 (30% copper, nickel recommended maximum continuous operating temperature does not exceed 815 ° C. In addition to strong oxidizing acids, has excellent corrosion resistance for most acids and alkalis. Easy in the fluoride acid, mercury chloride, mercury medium Because of the stress corrosion cracking, it is not suitable for the above media and is widely used in equipment for hydrofluoric acid production.
14. titanium
Recommended maximum operating temperature does not exceed 1093°C. It has excellent corrosion resistance under high temperature conditions. It is well known that the erosion of chloride ions is excellent in nitric acid corrosion resistance over a wide temperature and concentration range. Titanium is rarely used in most alkaline solutions and is adapted for oxidation conditions. Brinell hardness is about 216.

Two. Non-metallic gasket materials
1. Natural rubber NR has good corrosion resistance to weak acids and bases, salts and chloride solutions, and has poor corrosion resistance to oils and solvents and is not recommended for ozone media. Recommended operating temperature -57 °C ~ 93 °C.
2. Neoprene CR Neoprene is a synthetic rubber that is resistant to moderately corrosive acids, alkalis and salt solutions. It has good corrosion resistance to commercial oils and fuels. However, the corrosion resistance of strong oxidizing acids, aromatic hydrocarbons and chlorinated hydrocarbons is poor. Recommended operating temperature -51 °C ~ 121 °C.
3. NBR Cyanide rubber NBR is a synthetic rubber that is suitable for a wide range of oils, solvents, aromatic hydrocarbons, alkaline hydrocarbons, oil and gas corrosion resistance. Good corrosion resistance to hydroxides, salts and near-neutral acids. However, in strong oxidizing media, chlorinated hydrocarbons, ketones and greases, their corrosion resistance is poor. The recommended working temperature is 51°C~121°C.
4. The fluororubber compound is obtained by compounding a divalent and trivalent fluorocarbon compounding agent and a vulcanizing agent. In addition to excellent heat resistance, media resistance, and good physical and mechanical properties, it also has low compression set, good elasticity and long service life. Fluororubber has outstanding heat resistance (200-250°C), oil resistance, can be used to make cylinder liner seals, plastic bowls and rotary lip seals, which can significantly improve the use of time. Recommended operating temperature -40 °C ~ 232 °C.
5. Chlorosulphonated polyethylene synthetic rubber has good corrosion resistance to acid, alkali and salt solutions, and is not affected by climate, light, ozone, commercial fuels such as diesel and kerosene. However, it does not apply to aromatic hydrocarbons, chlorinated hydrocarbons, chromic acid, and nitric acid. Recommended operating temperature -45 °C ~ 135 °C.
6. Silicone rubber silicone rubber has outstanding high and low-temperature resistance, can be used at 150 °C for long-term use without change in performance; can be used continuously at 200 °C for 10,000 hours, maintaining its unique characteristics within the operating temperature range of -70 to 260 °C. The use of elasticity and ozone resistance, weather resistance and other advantages, suitable for the production of thermal machinery required seals, such as seal liners, valve pads, oil seals (applicable to water medium), special silicone rubber seals can be made.
7. Ethylene propylene rubber has good corrosion resistance to strong acids, alkalis, salts and chloride solutions. However, it does not apply to oils, solvents, aromatic hydrocarbons and hydrocarbons. Recommended operating temperature -57°C~176.
8. Graphite This material does not contain a resin or inorganic all-graphite material and can be classified as a metal material with or without a metal element. The material can be bonded so that it can be manufactured more than 600MM diameter pipe gasket. For many acids, bases, salts and organic compounds and heat transfer solutions, even high-temperature solutions have very good corrosion resistance. It cannot melt, but it sublimates when it exceeds 3316 °C. Use of this material in strong oxidizing media under high-temperature conditions should be careful. In addition to the gaskets, this material can also be used to make non-metallic wraps in packing and wound gaskets.
9. The ceramic fiber and ceramic fiber formed on the strip are excellent gasket materials suitable for high temperature and low-pressure working conditions and light flange conditions. The recommended working temperature is 1093°C, and the non-metal winding tape in the wound gasket can be produced.
10. PTFE concentrates the advantages of most plastic gasket materials, including temperatures from -95°C to 232°C. In addition to free fluorine and alkali metals, it has excellent corrosion resistance to chemicals, solvents, hydroxides and acids. PTFE material can fill glass, its purpose is to reduce the cold flow and creep of PTFE.

What is a Hose clamp?
The hose clamp is a fastener at the connection between the flexible pipe and the hard pipe. The hose clamp solves the problem that the prior art hose clamp is used for connecting a small-diameter soft pipe and a dead angle occurs, which causes the leakage of liquid and gas. The hose clamp adopts an open inner and outer ring structure and is bolted. The hose clamp effectively solves

When the small diameter soft and hard pipe is connected, there is dead angle, and the problem of liquid and gas leakage occurs. The simple structure makes it easy to make the cost 30% of the original product. The hose clamp is widely used in the treatment of sewage in motor vehicles, petrochemicals, pharmaceuticals and foods. Purge dust removal auto parts and other accessories.
Throat hoop features: Small worm friction, suitable for connecting high-end models or parts of anti-corrosion materials. The hose clamps have a wide range of applications, such as torsion and pressure resistance, balanced torsional moments of the hose clamps, tight locking, tightness, and a wide range of adjustment. The hose clamps are suitable for fasteners with 30 mm or more soft and hard pipe connections, and have beautiful appearance after assembly.

What are Flanges?
Flanges are the parts that connect the shaft to the shaft and are used for the connection between the pipe ends. They are also used for flanges on the equipment inlet and outlet, for the connection between two devices, such as the reducer flange. Flange connection or flange joint refers to the detachable connection of flanges, gaskets and bolts as a set of combined sealing structures. Pipeline flange refers to the flange used for the piping in the pipeline device. It is used on the equipment to refer to the import and export flange of the equipment. There are holes in the flange, and bolts make the two flanges tight. The flanges are sealed with a gasket. The flange is divided into threaded connection (thread connection) flange, welding flange and clip flange. Flanges are used in pairs. Low-pressure piping can use wire-flanged flanges. Welding flanges with a pressure of more than four kilograms are used. Seals are added between the two flanges and then bolted. Different pressure flanges have different thicknesses and they use different bolts. Pumps and valves, when connected to pipes, are also made in the form of corresponding flanges, also called flanged connections. All connected parts that are bolted together and sealed at the periphery of two planes are generally called “flanges”, such as the connection of ventilation ducts. This type of part can be called a “flange type part”. However, this connection is only a part of the equipment, such as the connection of the flange and the pump, it is not easy to call the pump “flange parts.” Smaller valves, such as valves, can be called “flange parts.”
The reducer flange is used to connect the motor to the reducer and the connection between the reducer and other devices.

Branch tube stand
The branch tube station is also called branch tube seat, saddle seat and saddle type tube joint. It is mainly used for reinforcing pipe fittings for branch pipe connection instead of using branch pipe connection types such as different diameter three links, reinforcing plates and reinforced pipe sections, which is safe and reliable, reduces cost, is simple in construction, improves media flow channels, and is standardized in series and convenient in design selection. Such outstanding advantages, especially in high-pressure, high-temperature, large-caliber, thick-walled pipes are increasingly used, replacing the traditional branch pipe connection method.
The branch tube body adopts high-quality forgings, and the materials and piping materials are the same, including carbon steel, alloy steel, and stainless steel. The branch pipe and the main pipe are all welded. There are three types of connections for the branch pipe or other pipes (such as the short pipe, plug, etc.), the instrument, and the valve with the butt welding connection, the socket welding connection, and the screw connection.

The socket-and-spoke tube stand is a kind of branch tube stand and is a reinforcing pipe fitting that is widely used in foreign countries in recent years for branch pipe connection.
Sock sockets: socket (sock socket+olet socket)
The socket and socket tube stand replaces traditionally used branch connection types such as different diameter three links, reinforcing plates and reinforced pipe sections, and has outstanding advantages such as safety and reliability, reduced cost, simple construction, improved media flow channels, series standardization, and convenient design selection. It is widely used in high-pressure, high-temperature, large-caliber, and thick-walled pipelines, replacing the traditional branch pipe connection method. The socket and socket tube body adopts high-quality forgings, and the materials and pipeline materials are the same, including carbon steel, alloy steel, and stainless steel. The branch pipe and the supervisor are both welded. The connection between the branch pipe stand and the branch pipe or another pipe (such as the short pipe, plug, etc.), the instrument, and the valve is of various types such as butt welding, socket welding, and thread. Standards: MSS SP 97, GB/T 19326, Pressure: 3000#, 6000#.

China is already the world’s largest producer and consumer of building materials. The main building materials such as cement, flat glass, building sanitary ceramics, stone and wall materials have been ranked first in the world for many years. At the same time, the quality of building materials continues to increase, energy and raw material consumption decline year by year, various types of new building materials continue to emerge, and building materials products continue to upgrade, and the pipeline equipment manufacturing industry in Chuzhou is well-established. There are more than 3,200 existing production enterprises, of which 222 are above the scale (sales revenue is over 5 million yuan) and employs 124,000 people. The main products are all kinds of special steel, stainless steel, carbon steel and other kinds of seamless steel pipe, low and medium high-pressure boiler pipe, oil drilling pipe and other steel pipes; all kinds of three links, four links, valves, reducers and other elbow pipe fittings, stainless steel flanges, forged flanges; Pipe fittings for various pipe racks, meters, oil blowout preventers, etc.; Various plastic pipes such as polyethylene pipe and polypropylene pipe, a total of 16 major categories More than 370 varieties More than 3,500 kinds specification. The manufacturing process mainly uses hot-rolled straight seam welding, spiral double-sided submerged arc welding, forging, forging, intermediate frequency pushing, cold forming, hot extrusion, etc. The maximum processing diameter of the pipeline is 2020 mm. Products are widely used in municipal engineering, petrochemicals, West-East gas transmission, ships and nuclear power engineering fields, with an annual design and processing capacity of 25 million tons. In 2010, the above-scale enterprises achieved an industrial added value of 13 billion yuan, a year-on-year increase of 31.7%, accounting for 16.1% of the value added of all above-scale enterprises.

Source: China Pipe Fittings Manufacturer – Yaang Pipe Industry (www.metallicsteel.com)

(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)

If you want to have more information about the article or you want to share your opinion with us, contact us at sales@metallicsteel.com

Please notice that you might be interested in the other technical articles we’ve published:

  • WHERE TO BUY HIGH QUALITY STEEL PIPES
  • WHERE TO BUY HIGH QUALITY FLANGES
  • WHERE TO BUY HIGH QUALITY PIPE FITTINGS
  • ADVANTAGES OF DUPLEX STAINLESS STEEL PIPE AND SELECTION
  • WHERE TO BUY HIGH QUALITY BELLOW EXPANSION JOINTS
  • Difference Between Pipe Elbow And Pipe Bend
  • Where to get high quality alloy steel pipes
  • Distinguish Inferior Steel Pipes
  • WHERE TO GET HIGH QUALITY HEAT EXCHANGER TUBES
  • How to get high quality forged flanges
  • WHERE TO GET HIGH QUALITY STUB ENDS
  • WHERE TO GET HIGH QUALITY CARBON STEEL PIPES
  • Where to get high quality blind flanges
  • Where to get high quality orifice flanges
  • Where to get high quality lap joint flanges
  • Where to get high quality plate flanges
  • Where to get high quality ring type joint flanges
  • Where to get high quality slip on flanges
  • Where to get high quality spacer rings and spade flanges
  • Where to get high quality socket welding flanges
  • Where to get high quality Threaded Flanges
  • Where to get high quality Spectacle Blind Flanges
  • Where to get high quality welding neck flanges
  • Where to get high quality expander flanges

  • Where to get high quality reducing flange

  • FLANGE

References:

  • www.yaang.com

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