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Pipe Elbow

What are pipe elbows?

Pipe elbows are fitting accessories which are usd widely in various industrial sectors in pipe fittings. A pipe elbow is frequently used in pressurized applications and is available in various shapes and sizes for use in different applications. They are mainly used to connect two pipes or tubes, allowing a change of direction.

What is Pipe Elbow Radius?

Pipe elbow radius, also known as pipe elbow curve, is the distance between a pipe elbow’s center and its edge of curvature.
The curvature is measured by taking an arc from the center point that extends outwards and then back in. The radius size is determined by your specifications, which will be based on your piping system needs. All bends are manufactured to meet client specifications that refer to either short radius (SR) or long radius (LR). Bend’s radius is calculated by measuring the distance from the center to its edge of curvature; according to ASME B16.9, it should equal 1D, 1.5D, 2D or 5D or 3x thickness of the pipe wall depending on your specifications and calculations.
The elbow’s shape varies depending on whether it connects to a vertical line or horizontal line.

 Radius of S.R. Elbow Radius of L.R. Elbow

Here below, for example, you will find the center to face distance of NPS 4 elbows (The distance from the center of the elbow to the end face is indicated by the letter H).

• 90°-LR : = 1½ x 4(NPS) x 25.4, H=152.4 mm
• 180°-LR : = 2 times the 90° LR elbow, H=304.8 mm
• 90°-SR : = 4(NPS) x 25.4, H=101.6 mm
• 180°-SR : = 2 times the 90° SR elbow, H=203.2 mm

The center to face distance for a “long” radius elbow, abbreviated LR always is “1.5 x Nominal Pipe Size (NPS) (1.5D)”, while the center to face distance for a “short” radius elbow, abbreviated SR even is to nominal pipe size.

What are the different types of elbows?

Elbow could be ranged from direction angle, connection types, length and radius, material types.

Types of Elbows based on Direction Angle

In fluid flow, elbows can be divided into different degrees, such as 30 degree, 45 degree, 60 degree,90 degree, 120 degree,180 degree. The degree is just an representation of the angle by which the fluid flow is going to change after flowing through the said elbow.

 30° elbow 45° elbow 60° elbow 90° elbow 120° elbow 180° elbow

What is a 30 degree elbow?

30° elbow: It is a pipe fitting having an elbow angle of 30 degree. The flow direction changes by 30 degree when it passes through this elbow.

What is a 45 degree elbow?

45° elbow: It is a pipe fitting having an elbow angle of 45 degrees. The flow direction changes by 45 degrees when it passes through this elbow.

What is a 60 degree elbow?

60° elbow: It is a pipe fitting having an elbow angle of 60 degrees. The flow direction changes by 60 degrees when it passes through this elbow.

What is a 90 degree elbow?

90° elbow: It is a pipe fitting having an elbow angle of 90 degrees. The flow direction changes by 90 degrees when it passes through this elbow.

What is a 120 degree elbow?

120° elbow: It is a pipe fitting having an elbow angle of 120 degrees. The flow direction changes by 120 degrees when it passes through this elbow.

What is a 180 degree elbow?

180° elbow: It is a pipe fitting having an elbow angle of 180 degrees, which means that the fluid enters into the same opening from where it exits from and hence called as “return”.

Types of Elbows based on Length and Radius

Depending on the standards, the standards that apply to the application of elbows are the long radius elbow and the short radius elbow. The difference between these two types of elbows is their radii.

What is a short radius elbow (SR elbow)?

The centerline radius of a short radius elbow is 1.0 times the pipe diameter or less. The short radius elbow has a smaller centre line radius; therefore, this type of elbow is used where space is limited and where there is no possibility of increasing the size of the pipe.

What is a long radius elbow (LR elbow)?

The difference between these two types of elbows is their radii. The radius of a long radius elbow is at least 1.5 times the pipe diameter. The long radius elbow has a larger radius and can be used in situations where there is more space to accommodate the longer radius.

Depending on the standards, the standards that apply to the application of elbows are long radius elbow and short radius elbow. The long radius elbow is used in most cases, while short radius elbows are used when space is limited or when there is a need for more than one bend in a pipe run (for example, 90° with 45°).

Types of Elbows based on Connection with Pipe

When elbows are connected to pipes, they can be classified as Butt Welded Elbow, Socket Welded Elbow and Threaded Elbow.

 Butt Welded Elbow Socket Welded Elbow Threaded Elbow

What is a butt welded elbow?

Butt Welded Elbow: A butt welded elbow is a pipe fitting used to join two pipes at an angle. It is made by welding the ends of the elbows together.

45°-90° LR and 3D ASME B16.9 Dimensions

 NPS O.D. D 90° LR A 45° LR B 90° 3D A 45° 3D B 1/2 21.3 38 16 3/4 26.7 38 19 57 24 1 33.4 38 22 76 31 1.1/4 42.2 48 25 95 39 1.1/2 48.3 57 29 114 47 2 60.3 76 35 152 63 2.1/2 73 95 44 190 79 3 88.9 114 51 229 95 3.1/2 101.6 133 57 267 111 4 114.3 152 64 305 127 5 141.3 190 79 381 157 6 168.3 229 95 457 189 8 219.1 305 127 610 252 10 273 381 159 762 316 12 323.8 457 190 914 378 14 355.6 533 222 1067 441 16 406.4 610 254 1219 505 18 457 686 286 1372 568 20 508 762 318 1524 632 22 559 838 343 1676 694 24 610 914 381 1829 757 26 660 991 406 1981 821 28 711 1067 438 2134 883 30 762 1143 470 2286 946 32 813 1219 502 2438 1010 34 864 1295 533 2591 1073 36 914 1372 565 2743 1135 38 965 1448 600 2896 1200 40 1016 1524 632 3048 1264 42 1067 1600 660 3200 1326 44 1118 1676 695 3353 1389 46 1168 1753 727 3505 1453 48 1219 1829 759 3658 1516

Dimensions are in millimeters unless otherwise indicated. Wall thickness (t) must be specified by customer. A & B are Center to End dimensions

Dimensional Tolerances of Butt Weld Elbows 45° & 90° LR & 3D ASME B16.9

 Nominal Pipe Size 1/2 to 2.1/2 3 to 3.1/2 4 5 to 8 Outside Diameter at Bevel (D) + 1.6 – 0.8 1.6 1.6 + 2.4 – 1.6 Inside Diameter at End 0.8 1.6 1.6 1.6 Center to End LR (A/B) 2 2 2 2 Center to End 3D (A/B) 3 3 3 3 Nominal Pipe Size 10 to 18 20 to 24 26 to 30 32 to 48 Outside Diameter at Bevel (D) + 4 – 3.2 + 6.4 – 4.8 + 6.4 – 4.8 + 6.4 – 4.8 Inside Diameter at End 3.2 4.8 + 6.4 – 4.8 + 6.4 – 4.8 Center to End LR (A/B) 2 2 3 5 Center to End 3D (A/B) 3 3 6 6 Wall Thickness (t) Not less than 87.5% of Nominal Wall Thickness

Dimensional tolerances are in millimeters unless otherwise indicated and are equal ± except as noted.

90°-SR- ASME B16.9 Dimensions

 NPS O.D. D cte A NPS O.D. D cte A 1 33.4 25 8 219.1 203 1.1/4 42.2 32 10 273 254 1.1/2 48.3 38 12 323.8 305 2 60.3 51 14 355.6 356 2.1/2 73 64 16 406.4 406 3 88.9 76 18 457 457 3.1/2 101.6 89 20 508 508 4 114.3 102 22 559 559 5 141.3 127 24 610 610 6 168.3 152 – – –

Dimensions are in millimeters unless otherwise indicated. Wall thickness (t) must be specified by customer.

*cte means Center to End dimensions.

Dimensional Tolerances of Butt Weld Elbows Short Radius 90° ASME B16.9

 Nominal Pipe Size 1/2 to 2.1/2 3 to 3.1/2 4 5 to 8 Outside Diameter at Bevel (D) + 1.6 – 0.8 1.6 1.6 + 2.4 – 1.6 Inside Diameter at End 0.8 1.6 1.6 1.6 cte (A) 2 2 2 2 Nominal Pipe Size 10 to 18 20 to 24 26 to 30 32 to 48 Outside Diameter at Bevel (D) + 4 – 3.2 + 6.4 – 4.8 + 6.4 – 4.8 + 6.4 – 4.8 Inside Diameter at End 3.2 4.8 + 6.4 – 4.8 + 6.4 – 4.8 cte (A) 2 2 3 5 Wall Thickness (t) Not less than 87.5% of Nominal Wall Thickness

180° LR & SR ASME B16.9 Dimensions

 NPS O.D. D 180° LR 180° SR Center to Center O Back to Face K Center to Center O Back to Face K 1/2 21.3 76 48 3/4 26.7 76 51 1 33.4 76 56 51 41 1.1/4 42.2 95 70 64 52 1.1/2 48.3 114 83 76 62 2 60.3 152 106 102 81 2.1/2 73 190 132 127 100 3 88.9 229 159 152 121 3.1/2 101.6 267 184 178 140 4 114.3 305 210 203 159 5 141.3 381 262 254 197 6 168.3 457 313 305 237 8 219.1 610 414 406 313 10 273 762 518 508 391 12 323.8 914 619 610 467 14 355.6 1067 711 711 533 16 406.4 1219 813 813 610 18 457 1372 914 914 686 20 508 1524 1016 1016 762 22 559 1676 1118 1118 838 24 610 1829 1219 1219 914

Dimensions are in millimeters unless otherwise indicated.
Wall thickness (t) must be specified by customer.

Dimensional Tolerances of Butt Weld Elbows 180° LR & SR ASME B16.9

 Nominal Pipe Size 1/2 to 2.1/2 3 to 3.1/2 4 Outside Diameter at Bevel (D) + 1.6 – 0.8 1.6 1.6 Inside Diameter at End 0.8 1.6 1.6 Center to Center (O) 6 6 6 Back to Face (K) 6 6 6 Nominal Pipe Size 5 to 8 10 to 18 20 to 24 Outside Diameter at Bevel (D) + 2.4 – 1.6 + 4 – 3.2 + 6.4 – 4.8 Inside Diameter at End 1.6 3.2 4.8 Center to Center (O) 6 10 10 Back to Face (K) 6 6 6 Wall Thickness (t) Not less than 87.5% of Nominal Wall Thickness

Dimensional tolerances are in millimeters unless otherwise indicated and are equal ± except as noted.

Dimensions Butt Weld Reducing Elbows 90° LR ASME B16.9

 NPS Outside Diameter at bevel Center to End A Large End Small End 4 – 3 114,3 88,9 152 4 – 2.1/2 114,3 73 152 4 – 2 114,3 60,3 152 5 – 4 141,3 114,3 190 5 – 3.1/2 141,3 101,6 190 5 – 3 141,3 88,9 190 5 – 2.1/2 141,3 73 190 6 – 5 168,3 141,3 229 6 – 4 168,3 114,3 229 6 – 3.1/2 168,3 101,6 229 6 – 3 168,3 88,9 229 8 – 6 219,1 168,3 305 8 – 5 219,1 141,3 305 8 – 4 219,1 114,3 305 10 – 8 273 219,1 381 10 – 6 273 168,3 381 10 – 5 273 141,3 381 12 – 10 323,8 273 457 12 – 8 323,8 219,1 457 12 – 6 323,8 168,3 457 14 – 12 355,6 323,8 533 14 – 10 355,6 273 533 14 – 8 355,6 219,1 533 16 – 14 406,4 355,6 610 16 – 12 406,4 323,8 610 16 – 10 406,4 273 610 18 – 16 457 406,4 686 18 – 14 457 355,6 686 18 – 12 457 323,8 686 18 – 10 457 273 686 20 – 18 508 457 762 20 – 16 508 406,4 762 20 – 14 508 355,6 762 20 – 12 508 323,8 762 20 – 10 508 273 762 24 – 22 610 559 914 24 – 20 610 508 914 24 – 18 610 457 914 24 – 16 610 406,4 914 24 – 14 610 355,6 914 24 – 12 610 323,8 914

All dimensions are in millimeters unless otherwise indicated.
Wall thickness (T) must be specified by customer.

Dimensional Tolerances of Butt Weld Red Elbows 90° LR ASME B16.9

 Nominal Pipe Size 1/2 to 2.1/2 3 to 3.1/2 4 Outside Diameter at Bevel + 1.6 – 0.8 1.6 1.6 Inside Diameter at End 0.8 1.6 1.6 Center to End LR (A) 2 2 2 Nominal Pipe Size 5 to 8 10 to 18 20 to 24 Outside Diameter at Bevel + 2.4 – 1.6 + 4 – 3.2 + 6.4 – 4.8 Inside Diameter at End 1.6 3.2 4.8 Center to End LR (A) 2 2 2 Wall Thickness (t) Not less than 87.5% of Nominal Wall Thickness

Note..
MSS SP-43 only covers stainless steel buttweld fittings made for use with Schedule 5S and 10S pipe and Stub Ends suitable for use with Schedule 40S pipe, as defined in ASME B36.19. The dimensions and dimensional tolerances defined in MSS SP-43 are substantially the same as those in ASME B16.9 specifications from NPS 1/2 – NPS 24. Except with regard to the outside diameter at the bevel.

What is a socket welded elbow?

Socket Welded Elbow: Socket welded elbow is used to join two pipes together at an angle. It is made by using socket welding machines which creates a socket on one end of a pipe and a plug on the other end of another pipe and then welds them together at an angle.

Dimensions Socket Weld Elbows ASME B16.11

Class 3000

 NPS Socket Bore Depth Socket Bore DIA Socket WT Body WT B J D C G 1/2 21.95 21.70 10 16.6 15 4.65 4.10 3.75 3/4 27.30 27.05 13 21.7 20.2 4.90 4.25 3.90 1 34.05 33.80 13 27.4 25.9 5.70 5.00 4.55 1.1/4 42.80 42.55 13 35.8 34.3 6.05 5.30 4.85 1.1/2 48.90 48.65 13 41.7 40.1 6.35 5.55 5.10 2 61.35 61.10 16 53.5 51.7 6.95 6.05 5.55 2.1/2 74.20 73.80 16 64.2 61.2 8.75 7.65 7.00 3 90.15 89.80 16 79.5 46.4 9.50 8.30 7.60 4 115.80 115.45 19 103.8 100.7 10.70 9.35 8.55 NPS Center to bottom of socket A 90° 45° 1/2 15.5 11.5 3/4 19.5 12.5 1 22 14 1.1/4 27 17 1.1/2 32 21 2 38 25 2.1/2 41.5 29 3 57.5 31.5 4 66.5 41.5
 Class 6000 NPS Socket Bore Depth Socket Bore DIA Socket WT Body WT B J D C G 1/2 21.95 21.70 10 12.5 11 5.95 5.20 4.80 3/4 27.30 27.05 13 16.3 14.8 6.95 6.05 5.55 1 34.05 33.80 13 21.5 19.9 7.90 6.95 6.35 1.1/4 42.80 42.55 13 30.2 28.7 7.90 6.95 6.35 1.1/2 48.90 48.65 13 34.7 33.2 8.90 7.80 7.15 2 61.35 61.10 16 43.6 42.1 10.90 9.50 8.75 NPS Center to bottom of socket A 90° 45° 1/2 19.5 12.5 3/4 22.5 14.5 1 27 17 1.1/4 32 21 1.1/2 38 25 2 41 29

General notes..

• Dimensions are in millimeters unless otherwise indicated.
• Socket Bore (B) – Maximum and minimum dimensions.
• Bore Diameter (D) – Maximum and minimum dimensions.
• Socket wall thickness – (C) – Average of Socket wall thickness.
• Dimensional tolerances center to bottom of socket – (A)
NPS 1/2 and NPS 3/4 = +/- 1.5 mm
NPS 1 to NPS 2 = +/- 2 mm
NPS 2.1/2 to NPS 4 = +/- 2.5 mm

What is a threaded elbow?

Threaded Elbow: Threaded elbows can be found in industry where pipes are needed to be threaded together for joining purposes. These types of elbows are commonly used for making connections between two pipes with different diameters or for reducing the flow rate through large diameter pipes.

Dimensions Threaded Elbows 90°/45° ASME B16.11

 Class 2000 NPS Min Thread Length Outside Dia Min WT Center to End B J D G 90° A 45° C 1/2 10.9 13.6 33 3.18 28 22 3/4 12.7 13.9 38 3.18 33 25 1 14.7 17.3 46 3.68 38 28 1.1/4 17 18 56 3.89 44 33 1.1/2 17.8 18.4 62 4.01 51 35 2 19 19.2 75 4.27 60 43 2.1/2 23.6 28.9 92 5.61 76 52 3 25.9 30.5 109 5.99 86 64 4 27.7 33 146 6.55 106 79
 Class 3000 NPS Min Thread Length Outside Dia Min WT Center to End B J D G 90° A 45° C 1/2 10.9 13.6 38 4.09 33 25 3/4 12.7 13.9 46 4.32 38 28 1 14.7 17.3 56 4.98 44 33 1.1/4 17 18 62 5.28 51 35 1.1/2 17.8 18.4 75 5.56 60 43 2 19 19.2 84 7.14 64 44 2.1/2 23.6 28.9 102 7.65 83 52 3 25.9 30.5 121 8.84 95 64 4 27.7 33 152 11.18 114 79
 Class 6000 NPS Min Thread Length Outside Dia Min WT Center to End B J D G 90° A 45° C 1/2 10.9 13.6 46 8.15 38 28 3/4 12.7 13.9 56 8.53 44 33 1 14.7 17.3 62 9.93 51 35 1.1/4 17 18 75 10.59 60 43 1.1/2 17.8 18.4 84 11.07 64 44 2 19 19.2 102 12.09 83 52 2.1/2 23.6 28.9 121 15.29 95 64 3 25.9 30.5 146 16.64 106 79 4 27.7 33 152 18.67 114 79

General notes..

• Dimensions are in millimeters unless otherwise indicated.
• Dimension (B) is minimum length of perfect thread.
The length of useful thread (B plus threads with fully formed roots and flat crests) shall not be less than J. from: wermac.org

Types of Elbows based on Material of Construction

Materials used to make elbows are divided into two main groups: carbon steel and stainless steel. Carbon steel is the most common material used in elbow manufacturing, followed by stainless steel. Each type of elbow has its own advantages and disadvantages, however each one can be manufactured to meet all your requirements and specifications.
The material of construction is a vital factor when choosing an elbow. The quality of the material used to construct pipes plays a large role in the overall durability and lifespan of the pipe. High quality materials can be used to construct elbows which last longer and require less frequent replacement than their counterparts made from lower quality materials.

•  ASTM A403 WP Gr. 304, 304H, 309, 310, 316, 316L, 317L, 321, 347, 904L.
• Carbon Steel Elbow : ASTM A 234 WPB , WPBW, WPHY 42, WPHY 46, WPHY 52, WPH 60, WPHY 65 & WPHY 70.
• Low Temperature Carbon Steel Elbow : ASTM A420 WPL3, A420 WPL6.
• Alloy Steel Elbow : ASTM / ASME A/SA 234 Gr. WP 1, WP 5, WP 9, WP 11, WP 12, WP 22, WP 91.
• ASTM A 815, ASME SA 815 UNS NO S31803, S32205. Werkstoff No. 1.4462.
•  ASTM / ASME SB 336 UNS 2200 ( NICKEL 200 ), UNS 2201 (NICKEL 201 ), UNS 4400 (MONEL 400 ), UNS 8020 ( ALLOY 20 / 20 CB 3, UNS 8825 INCONEL (825), UNS 6600 (INCONEL 600 ), UNS 6601 ( INCONEL 601 ), UNS 6625 (INCONEL 625), UNS 10276 ( HASTELLOY C 276).
• Copper Alloy Elbow: ASTM / ASME SB 111 UNS NO. C 10100 , C 10200 , C 10300 , C 10800 , C 12000, C 12200, C 70600 C 71500, ASTM / ASME SB 466 UNS NO. C 70600 ( CU -NI- 90/10) , C 71500 ( CU -NI- 70/30)

Special Elbows

When special elbows are connected to pipes, they can be classified as Reducing Elbow, Male Pipe Elbow and Female Pipe Elbow.

 Reducing Elbow Male Pipe Elbow Female Pipe Elbow

What is a reducing elbow?

Reducing elbows are used to connect pipes of different sizes, or for connecting a pipe with a fitting on it to another straight pipe. Reducing elbows are also used to turn 90 degrees within the piping system.

What is a male pipe elbows?

Male pipe elbows are used to connect two pipes of the same diameter. They have one outlet and one inlet, making them useful for joining pipes at a 90-degree angle.
Male pipe elbows can also be used to join two pipes of different diameters in order to create an unequal flow rate through each section of the pipe system, which is called a branch connection.

What is a female pipe elbow?

Female elbows are used to connect two pipes of the same size. They’re also used to change the direction of a pipe, and can be used between pipes of different sizes.
The most common type of female elbow is called an NPT female elbow, which stands for National Pipe Thread Standard and refers to the method of sealing onto a pipe or fitting with a nut (also known as tapping). This type of connection has three openings: two on the sides and one at the bottom, where it connects with another pipe or fitting.

Wall Thickness of Pipe Elbows

The wall thickness of a pipe elbow is important to ensure that it can withstand the pressure rating and temperature rating required for your application. The wall thickness of a pipe elbow is determined by the diameter and pressure rating required, as well as any other factors such as code requirements or regulatory standards that might be applicable for your situation. For example, if you’re working with a low-pressure application within an industrial plant, there may be specific codes and regulations you have to follow; in this case you’ll want to be sure that your elbows are up to code or else they may not pass inspection at all!

The wall thickness of pipe elbows is a critical factor in determining the size and capacity of a pipe elbow. In many cases, the wall thickness will determine if your product will be able to meet your requirements or not.

Manufacturing standard of pipe elbow

Japanese Standards

• JIS B2311 General purpose steel butt welded pipe fittings
• JIS B2312 Steel Butt Welding Pipe Fittings
• JIS B2313 Steel Plate Butt Welding Pipe Fittings
• JIS B2316 Steel Socket Welding Pipe Fittings

American Standards

• ASME/ANSI B16.9 Factory Made Wrought Steel Butt Welding Fittings
• ASME/ANSI B16.11 Forged Fittings, Socket Welding and Threaded
• ASME/ANSI B16.28 Steel Butt Welding Small Radius Elbow and Turnback Bend
• ASME B16.5 Pipe Flanges and Flanged Fittings
• MSS SP-43 Forged Stainless Steel Butt Welding Pipe Fittings
• MSS SP-79 Socket Weld Reducing Inserts
• MSS SP-83 Socket Welding and Threaded Union
• MSS SP-97 Integral Reinforced Socket, Threaded and Butt Welding Ends

Chinese Standards

• HGJ514 Carbon Steel, Low Alloy Steel Seamless Butt Welding Pipe Fittings
• HGJ528 steel butt welded pipe fittings
• HGJ10 forged steel socket welding pipe fittings
• HGJ529 Forged steel socket welding, threaded and butt welding pipe stand
• HGJ-44-76-91 Steel Pipe Flange, Gasket and Fastener
• HG20592-20635 Steel Pipe Flange, Gasket and Fastener

Manufacturing processes of pipe elbows

How to make pipe elbow? The manufacturing of elbow is divided into the manufacturing of seamless elbow and the manufacturing of slotted elbow.

Manufacturing method of seamless elbow

Elbow is a kind of pipe fitting used for pipe turning. The proportion of all pipe fittings used in the pipe system is about 80%. Generally, different forming processes are selected for elbows with different materials or wall thicknesses. The forming process of seamless elbow commonly used by manufacturers includes hot pushing, stamping, extrusion, etc.

Seamless elbow manufacturing method I: hot pushing

The hot push elbow forming process is a process that uses a special elbow pusher, a core die and a heating device to make the blank sheathed on the die move forward under the push of the pusher, and is heated, expanded and bent during the movement. The deformation feature of hot push elbow is to determine the diameter of tube blank according to the rule that the volume of metal material remains unchanged before and after plastic deformation. The diameter of tube blank used is smaller than the diameter of elbow. The deformation process of the blank is controlled by the core mold, so that the compressed metal at the inner arc flows and is compensated to other parts that are thinner due to expanding, so as to obtain an elbow with uniform wall thickness.

The hot push elbow forming process has the characteristics of beautiful appearance, uniform wall thickness and continuous operation, which is suitable for mass production. Therefore, it has become the main forming method of carbon steel and alloy steel elbows, and also used in the forming of certain specifications of stainless steel elbows.
The heating methods in the forming process include medium frequency or high frequency induction heating (the heating ring can be multi ring or single ring), flame heating and reverberatory furnace heating. The heating method used depends on the requirements of the formed products and the energy situation.

Seamless elbow manufacturing method II: stamping

Stamping elbow is the earliest forming process applied to batch production of seamless elbow. It has been replaced by hot pushing method or other forming processes in the production of elbow with common specifications. However, in some elbow specifications, the production quantity is small, the wall thickness is too thick or too thin.
The product is still used in case of special requirements. The pipe blank with the same outer diameter as the elbow shall be used for the stamping forming of the elbow, and the press shall be used for direct pressing in the die.
Before stamping, the tube blank is placed on the lower die, the inner core and end die are installed into the tube blank, the upper die moves downward and starts to press, and the elbow is formed by the constraint of the outer die and the support of the inner die.
Compared with the hot extrusion process, the appearance quality of stamping is not as good as the former; The outer arc of the stamping elbow is in tension during forming, and there is no excess 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, stamping elbow process is mostly used for the manufacturing of small batch and thick wall elbows.
Stamping elbow is divided into cold stamping and hot stamping, which are usually selected according to material properties and equipment capacity.

Seamless elbow production method III: cold extrusion

The forming process of cold extruded elbow is to use a special elbow forming machine to put the tube blank into the external mold. After the upper and lower molds are closed, the tube blank moves along the gap reserved between the internal mold and the external mold with the push rod to complete the forming process.

The elbows manufactured by the internal and external cold extrusion process are beautiful in appearance, uniform in wall thickness and small in size deviation. Therefore, stainless steel elbows, especially thin-walled stainless steel elbows, are mostly manufactured by this process. The internal and external molds used in this process require high precision; The requirements for wall thickness deviation of tube blank are also strict.
In addition to the above three common forming processes, the seamless elbow is also formed by extruding the tube blank to the external mold and then shaping the tube blank through the ball. However, this process is relatively complex and difficult to operate, and the forming quality is not as good as the aforementioned process, so it is rarely used.

Manufacturing method of seamed elbow

Seam elbow manufacturing method I: butt welding

Butt welding elbows are made of steel plates. Draw the expansion diagram of butt welding elbows, then cut the materials by gas cutting, then heat them and press them into shape on a press, and then two and a half elbows are produced, followed by cutting, then splicing and welding. The butt welding elbows are formed, and finally take photos of the elbows. Butt welding elbow is mainly used for making elbow above DN700. Large diameter elbow can also be pushed and punched, but the process cost of butt welding elbow is lower than that of those two kinds.

Seam elbow manufacturing method II: split elbow

Draw the side projection and seam line of the elbow according to the actual size. Divide each closed wireframe shape into independent shapes. Draw two parallel horizontal lines along the height of the pattern, perpendicular to the centerline, and the length is the circumference of the pattern diameter. The vertical direction of the drawing shall be divided equally and marked. The bisector shall be vertically expanded into the rectangle. The expanded icon shall mark the coordinates corresponding to the coordinates of the projected drawing. The diagonal line of the drawing is divided into equal lines along the horizontal direction. The parallel line is pulled to the original drawing standard, corresponding to the corresponding coordinates. The intersection points of the unfolded sample are smoothly connected to obtain the unfolded curve. The mitre elbow is finished. This process is applicable to manufacturing large elbows of any specification with elbows larger than 1.5D.

Applications of Steel Elbow

Elbows are widely used in different industries, working conditions and applications. The general application categories are as follows:
Elbows are mainly used in steel industry, cement industry, smelting industry, machinery industry, coal industry, petrochemical industry, mining industry, chemical industry, thermal power industry, dredging industry, silicone industry, lithium battery industry, coal chemical industry, ports and wharfs, coal washing plants, commercial concrete stations, machine-made sand and other pipeline diversion places where the material transportation system is seriously worn.

How do you calculate elbow pipe length?

Piping systems are fairly easy to design and install. However, there are times when you need to make a special cut or add an elbow to your piping project. You may even need to replace an elbow because it’s no longer functioning properly. When this happens, it’s important that you know how long the pipe needs to be for the new elbow. The length of elbow pipe needed depends on several factors such as:

• Length of pipe before the elbow (from corner) (inches)

• Radius of old and new elbows (inches)

• Angle between old and new elbows (degrees).

Finding the elbow center line length

Finding the elbow center line length is simple. You can use a protractor to find the angle of the elbow, then measure its length.

Divide the elbow radius by the sine of 90 degrees to find the center line length.

The center line length is found by dividing the elbow radius by the sine of 90 degrees. The elbow radius is the distance between two points on an elbow pipe, which can be calculated using trigonometry. The sine of 90 degrees is a trigonometric function that gives you a ratio for any angle in degrees; this represents how much shorter or longer one side of an angle is compared to another line segment at that same angle.

The calculation for determining centerline length from elbows involves converting angles into ratios, then multiplying them together. To do this, use:

• Centerline length = (Elbow Radius) / (Sine of 90)

Determining how long it will take for a pipe to reach an elbow.

The pipe length is the distance between the elbow and outlet.

The elbow radius is equal to twice the radius of a pipe fitting, so this can be used to determine how long it will take for a pipe to reach an elbow.

The following equation can be used in order to determine how long it will take for a fluid to reach an elbow:

• Pipe Length = Radius of Elbow + Radius of Elbow

Find the time it takes for the water to reach the elbow.

To calculate the time it takes for water to reach the elbow, you need to first find the distance that water will travel. The equation for this is: time = distance / speed

The formula works by dividing both sides of the equation by distance, which gives you: time/distance = speed

When you need to calculate the length of an elbow pipe, it’s important to know exactly what information you need and how to get it. You can use these calculations as part of a larger plumbing project or on their own. The formulas are easy enough for anyone with basic math skills and knowledge of sines, cosines and tangents (all covered in school).

What is the difference between a pipe elbow and a pipe bend?

Bend has a larger radius than elbows. Generally, the most basic difference is the radius of curvature.
Usually, a pipe elbow is of a specific angle but some variations can also be found in high-end pipes and fittings suppliers.
Unlike a pipe bend, the angle of a pipe elbow is predetermined. Usually, a pipe elbow is of a specific angle but some variations can also be found in high-end pipes and fittings suppliers. Elbows radiuses are 1D, 1.5D, 2D and can be purchased as standard or heavy duty versions depending on your application and requirements.
Pipe bends usually have a bending radius more than 2 times of the pipe diameter.
A pipe bend is the name given to a piece of pipe that is bent into a curve in order to make changes in direction. The amount of curvature on a pipe bend will vary depending on the size and construction of the pipe being bent.

How to purchase the right pipe elbow?

A pipe elbow is an important part of piping system, and it’s indispensable in any home or business. These elbows connect pipes at various angles, allowing you to direct water flow as needed. They are available in a wide range of sizes, materials, and types. However, with so many options on the market today it can be difficult to know which one is right for your needs. To help you find the perfect elbow for your job, we’ll cover some key topics below:
Know the dimensions.
The first thing you’ll need to do is figure out the size of your pipe. The most common sizes for industrially use are 4″, 6″, and 8″. You’ll also need to know the size of elbow you’re looking for, which are measured in inches. For example, a 90-degree elbow will have an angle of 45 degrees; a 45-degree elbow will have an angle of 22.5 degrees; and so on.
Once you have these measurements, it’s time to decide what length elbow you want. You can choose between short or long elbows depends on how much space is available between the pipes.
Understand the types of elbows.
An elbow is a pipe fitting that allows you to connect two pipes of different diameters. There are three types of elbows: 90 degree elbows, 180 degree elbows and 45 degree elbows.
If you are planning to buy a pipe elbow, there are a few things you need to know before purchasing.
First, what do you need? Do you want the pipe elbow for a piping system or something else? Will it be used indoors or outdoors? Does it have to be made of specific materials such as plastic or metal? Is there a brand that makes certain types of elbows better than others? These are all questions that will help narrow down your search and avoid buying an incorrect product.
Second, how much will this material cost me? If you’re shopping online then prices may vary depending on where they come from as well as how many units are available at once (because sometimes there might not be any left!). If this isn’t an option then try calling up some local hardware stores; they might offer lower prices because they don’t charge sales tax! Either way check out our recommendations below before making any decisions so that nothing goes wrong later down line when installing them into place.
Look at pipe material.
If you’re looking to buy a pipe elbow, it is important to consider the type of material that it is made of. The two main types of materials are stainless steel and carbon steel. Carbon steel pipes are cheaper than stainless steel pipes but they are less resistant to corrosion and can’t be used in situations where there is a lot of moisture or water. Stainless steel is more expensive than carbon steel but it is more durable and will last longer if you need it for a specific use.
Know your location’s temperature range.
When you are purchasing a pipe elbow for your business or home, it is important to know the temperature range of your location. This is because the temperature range determines which material should be used and also what pressure rating will be needed on your pipe elbow. If you have an application where large amounts of water are going to pass through the pipe elbow, then it may need to have a higher pressure rating than if smaller amounts were passing through it.
Choose a pressure rating.
The next step is to determine the pressure rating of your pipe elbow. This can be a little confusing, so let’s take it one step at a time.

• First, you’ll need to know what kind of pipe you’re using and how much pressure it can withstand. Pressure ratings are based on the material used—for example, steel pipes have different pressure ratings than copper pipes.
• Next, find out if your elbow will be used in pressurized situations or not. For example: if you live in an area prone to earthquakes or floods and would like extra protection from burst water lines when they occur, then a higher-pressure rating may be right for you!
• Finally, consider whether this elbow will come into contact with any other fittings or valves along its path before reaching its destination point (i.e., “the end” of where our story ends). If so—and if those fittings/valves are made from similar materials as well—then this could affect how well they hold up over time together under high pressures (or lack thereof).

Use the right pipes.
When using a pipe elbow, you should make sure that it matches your needs. You wouldn’t use a pipe elbow to connect two pieces of PVC or copper plumbing, for example; this is because these materials are incompatible and there would be no way for them to effectively join together. If you’re connecting different types of piping, then an adapter can be used instead; this will allow the two pipes to work properly together but won’t let any chemicals get through from one side to another.
If you know what to look for, buying a pipe elbow isn’t hard! You can find the right one for your needs by doing some research and asking questions. By knowing the dimensions, types of elbows, material used and more, you’ll have no problem finding the right pipe fitting for your project.

Source:  – Yaang Pipe Industry (www.epowermetals.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.)

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