Views: 11 Author: Site Editor Publish Time: 2026-04-10 Origin: Site
As pipe fittings that connect pipelines, change pipe direction, and divert or merge fluid. Stainless steel pipe fittings serve a critical function in industrial piping systems. Correct selection and application of stainless steel fittings are key factors for the safe operation of engineering projects. Stainless steel pipe fittings are indispensable connectors in piping systems. They are mainly used to change pipeline direction, connect pipes of different diameters, split or merge flow fluid, and seal pipe ends.
Made of stainless steel (e.g., 304,316, duplex steel), they offer excellent corrosion resistance, good high-temperature performance, and reliable mechanical strength. This ensures long-term stable operation of industrial pipelines in high-temperature and high-pressure environments such as petrochemical, marine engineering, and food pharmaceutical industries. Depending on the connection method and manufacturing process, stainless steel fittings are mainly divided into butt-weld fittings and forged fittings. This article details their classification and performance characteristics.
Stainless steel BW fittings connect to pipes by butt welding, providing high weld quality and low stress concentration, suitable for high-temperature and high-pressure industrial pipelines.
Main types include: 90°/45° butt-weld elbows (long radius R=1.5D, short radius R=1D), equal and reducing tees, concentric and eccentric reducers, caps, and stub ends.
The main material standard for BW fittings is ASTM A403 "Standard Specification for Wrought Austenitic Stainless Steel Piping Fittings". This is the core material standard for austenitic stainless steel fittings used in pressure piping. Common grades include WP304/304L, WP316/316L, WP321, WP31254 (6Mo), WP32205 (2205 duplex), WP32750 (2507 super duplex), etc. Chemical Composition
CHEMICAL | LIMITS | C | Mn | P | S | Si | Ni | Cr | Mo | N | Cu |
ASTM A403 WP304 | MIN | 8.0 | 18.0 | ||||||||
MAX | 0.08 | 2.00 | 0.045 | 0.030 | 1.00 | 11.0 | 20.0 | ||||
ASTM A403 WP304L | MIN | 8.0 | 18.0 | ||||||||
MAX | 0.03 | 2.00 | 0.045 | 0.030 | 1.00 | 11.0 | 20.0 | ||||
ASTM A403 WP316 | MIN | 10.00 | 16.00 | 2.00 | |||||||
MAX | 0.08 | 2.00 | 0.045 | 0.030 | 1.00 | 14.00 | 18.00 | 3.00 | |||
ASTM A403 WP316L | MIN | 10.00 | 16.00 | 2.00 | |||||||
MAX | 0.03 | 2.00 | 0.045 | 0.030 | 1.00 | 14.00 | 18.00 | 3.00 | |||
ASTM A403 WP904L | MIN | 23.00 | 19.00 | 4.00 | 1.00 | ||||||
MAX | 0.02 | 2.00 | 0.045 | 0.035 | 1.00 | 28.00 | 23.00 | 5.00 | 0.10 | 2.00 | |
ASTM A403 WP31254 | MIN | 17.50 | 19.50 | 6.00 | 0.18 | 0.50 | |||||
MAX | 0.02 | 1.00 | 0.030 | 0.010 | 0.80 | 18.50 | 20.50 | 6.50 | 0.25 | 1.0 | |
ASTM A403 WP321 | MIN | 9.00 | 17.00 | ||||||||
MAX | 0.08 | 2.00 | 0.045 | 0.030 | 1.00 | 12.00 | 19.00 | ||||
ASTM A403 WP347 | MIN | 9.00 | 17.00 | ||||||||
MAX | 0.08 | 2.00 | 0.045 | 0.030 | 1.00 | 12.00 | 19.00 |
Mechanical Properties
MATERIAL | ASTM A403 WP304 | ASTM A403 WP304L | ASTM A403 WP316 | ASTM A403 WP316L | ASTM A403 WP904L | ASTM A403 WP31254 | ASTM A403 WP321 | ASTM A403 WP347 |
T.S (MPA) | 515 min | 485 min | 515 min | 485 min | 490 min | 650-820 | 515 min | 515 min |
Y.S (MPA) | 205 min | 170 min | 205 min | 170 min | 220 min | 300 min | 205 min | 205 min |
EL % | 28 min | 28 min | 28 min | 28 min | 28 min | 28 min | 28 min | 28 min |
ASME B16.9 "Factory-Made Wrought Steel Butt-welding Fittings" specifies dimensional tolerances, end bevels, and wall thickness matching. This standard ensures interchangeability among fittings from different manufacturers. It covers sizes from NPS 1/2 to NPS 48 and matches wall thickness schedules (SCH 5S to XXS) from ASME B36.10/B36.19.
Dimension of 90Deg and 45Deg BW Elbow
BW 90 LR/SR Elbow | BW 45 LR Elbow | ||||
GB/T 12459 GB/T 13401 ASME B16.9 | |||||
Nominal Size | Outside Diameter at Bevel | Center to End | |||
90° Elbows | 45° Elbows | ||||
DN | NPS | OD | A | B | |
LR | SR | LR | |||
15 | 1/2 | 21.3 | 38 | 16 | |
20 | 3/4 | 26.7 | 38 | 19 | |
25 | 1 | 33.4 | 38 | 25 | 22 |
32 | 1 1/4 | 42.2 | 48 | 32 | 25 |
40 | 1 1/2 | 48.3 | 57 | 38 | 29 |
50 | 2 | 60.3 | 76 | 51 | 35 |
65 | 2 1/2 | 73.0 | 95 | 64 | 44 |
80 | 3 | 88.9 | 114 | 76 | 51 |
90 | 3 1/2 | 101.6 | 133 | 89 | 57 |
100 | 4 | 114.3 | 152 | 102 | 64 |
125 | 5 | 141.3 | 190 | 127 | 79 |
150 | 6 | 168.3 | 229 | 152 | 95 |
200 | 8 | 219.1 | 305 | 203 | 127 |
250 | 10 | 273.0 | 381 | 254 | 159 |
300 | 12 | 323.8 | 457 | 305 | 190 |
350 | 14 | 355.6 | 533 | 356 | 222 |
400 | 16 | 406.4 | 610 | 406 | 254 |
450 | 18 | 457.0 | 686 | 457 | 286 |
500 | 20 | 508.0 | 762 | 508 | 318 |
550 | 22 | 559.0 | 838 | 559 | 343 |
600 | 24 | 610.0 | 914 | 610 | 381 |
650 | 26 | 660.0 | 991 | 660 | 406 |
700 | 28 | 711.0 | 1067 | 711 | 438 |
750 | 30 | 762.0 | 1143 | 762 | 470 |
800 | 32 | 813.0 | 1219 | 813 | 502 |
850 | 34 | 864.0 | 1295 | 864 | 533 |
900 | 36 | 914.0 | 1372 | 914 | 565 |
950 | 38 | 965.0 | 1448 | 965 | 600 |
1000 | 40 | 1016.0 | 1524 | 1016 | 632 |
1050 | 42 | 1067.0 | 1600 | 1067 | 660 |
1100 | 44 | 1118.0 | 1676 | 1118 | 695 |
1150 | 46 | 1168.0 | 1753 | 1168 | 727 |
1200 | 48 | 1219.0 | 1829 | 1219 | 759 |
Dimension of ASME B16.9 BW Tee
Nominal Size | Outside Diameter at Bevel | Center to End | ||
DN | NPS | OD | C | M |
15 | 1/2 | 21.3 | 25 | 25 |
20 | 3/4 | 26.7 | 29 | 29 |
25 | 1 | 33.4 | 38 | 38 |
32 | 1.1/4 | 42.2 | 48 | 48 |
40 | 1.1/2 | 48.3 | 57 | 57 |
50 | 2 | 60.3 | 64 | 64 |
65 | 2.1/2 | 73.0 | 76 | 76 |
80 | 3 | 88.9 | 86 | 86 |
90 | 3.1/2 | 101.6 | 95 | 95 |
100 | 4 | 114.3 | 105 | 105 |
125 | 5 | 141.3 | 124 | 124 |
150 | 6 | 168.3 | 143 | 143 |
200 | 8 | 219.1 | 178 | 178 |
250 | 10 | 273.0 | 216 | 216 |
300 | 12 | 323.8 | 254 | 254 |
350 | 14 | 355.6 | 279 | 279 |
400 | 16 | 406.4 | 305 | 305 |
450 | 18 | 457.0 | 343 | 343 |
500 | 20 | 508.0 | 381 | 381 |
550 | 22 | 559.0 | 419 | 419 |
600 | 24 | 610.0 | 432 | 432 |
650 | 26 | 660.0 | 495 | 495 |
700 | 28 | 711.0 | 521 | 521 |
750 | 30 | 762.0 | 559 | 559 |
800 | 32 | 813.0 | 597 | 597 |
850 | 34 | 864.0 | 635 | 635 |
900 | 36 | 914.0 | 673 | 673 |
950 | 38 | 965.0 | 711 | 711 |
1000 | 40 | 1016.0 | 749 | 749 |
1050 | 42 | 1067.0 | 762 | 762 |
1100 | 44 | 1118.0 | 813 | 813 |
1150 | 46 | 1168.0 | 851 | 851 |
1200 | 48 | 1219.0 | 889 | 889 |
Tolerance of ASME B16.9 Butt Weld Fittings
ASME B16.9 defines the dimensional tolerances for stainless steel butt-welded fittings — including length, wall thickness, ID, OD, and other features. All dimensional deviations shall be within the tolerances required by the standard.
Nominal Size | 1)2) | 45°&90° Elbows | 3D Radius Elbows | Returns | ||||
DN | NPS | OD 3) 4) | ID 3) | A B C M | A B | O | K | U |
15-65 | 1/2 -21/2 | +1.6 | ± 0.8 | ± 2 | ± 3 | ± 6 | ± 6 | ± 1 |
80-90 | 3-31/2 | ± 1.6 | ± 1.6 | ± 2 | ± 3 | ± 6 | ± 6 | ± 1 |
100 | 4 | ± 1.6 | ± 1.6 | ± 2 | ± 3 | ± 6 | ± 6 | ± 1 |
125-200 | 5-8 | +2.4 | ± 1.6 | ± 2 | ± 3 | ± 6 | ± 6 | ± 1 |
250-450 | 10-18 | +4.0 | ± 3.2 | ± 2 | ± 3 | ± 10 | ± 6 | ± 2 |
500-600 | 20-24 | +6.4 | ± 4.8 | ± 2 | ± 3 | ± 10 | ± 6 | ± 2 |
650-750 | 26-30 | +6.4 | ± 4.8 | ± 3 | ± 6 | --- | --- | --- |
800-1200 | 32-48 | +6.4 | ± 4.8 | ± 5 | ± 6 | --- | --- | --- |
BW fitting manufacturing processes include: seamless push (for small to medium diameters), plate stamping and welding (for very large diameters), and hot forming. After forming, solution annealing heat treatment must be performed to eliminate work hardening and restore corrosion resistance.
Widely used in petrochemical, nuclear power, thermal power,
shipbuilding, pharmaceutical, and food industries, especially in
environments with high temperature (e.g., steam lines), high
pressure, or corrosive media.
Forged fittings mainly include socket-weld and threaded fittings. Types cover 45 deg elbows, 90 deg elbows, equal/reducing tees, couplings, caps, unions, and outlets.
Socket-weld connections insert the pipe into a socket bore and weld; threaded connections use NPT, BSPP, or BSPT threads.
ASTM A182 "Standard Specification for Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High-Temperature Service" is the core material
standard for forged fittings. Grades are prefixed with "F", such as F304/304L, F316/316L, F321, F44 (6Mo), F51 (2205 duplex), F53 (2507 super duplex).
Chemical Composition
CHEMICAL | LIMITS | C | Mn | P | S | Si | Ni | Cr | Mo | N | Cu |
ASTM A182 F304 | MIN | 8.0 | 18.0 | ||||||||
MAX | 0.08 | 2.00 | 0.045 | 0.030 | 1.00 | 11.0 | 20.0 | 0.10 | |||
ASTM A182 F316 | MIN | 10.0 | 16.0 | 2.00 | |||||||
MAX | 0.08 | 2.00 | 0.045 | 0.030 | 1.00 | 14.0 | 18.0 | 3.00 | 0.01 | ||
ASTM A182 F44 | MIN | 17.50 | 19.50 | 6.00 | 0.50 | ||||||
MAX | 0.02 | 1.00 | 0.030 | 0.010 | 0.80 | 18.50 | 20.50 | 6.50 | 1.00 | ||
ASTM A182 F51 | MIN | 4.50 | 21.00 | 2.50 | 0.08 | ||||||
MAX | 0.03 | 2.00 | 0.030 | 0.020 | 1.00 | 6.50 | 23.00 | 3.50 | 0.20 | ||
ASTM A182 F53 | MIN | 6.00 | 24.00 | 3.00 | 0.24 | ||||||
MAX | 0.03 | 1.20 | 0.035 | 0.020 | 0.80 | 8.00 | 26.00 | 5.00 | 0.32 | 0.5 |
Mechanical Properties
MATERIAL | ASTM A182 F304 | ASTM A182 F316 | ASTM A182 F44 | ASTM A182 F51 | ASTM A182 F53 | ASTM A182 F55 |
T.S (MPA) | 515 min | 515 min | 650 min | 620 min | 800 min | 750-895 |
Y.S (MPA) | 205 min | 205 min | 300 min | 450 min | 550 min | 550 min |
EL % | 30 min | 30 min | 35 min | 15 min | 25 min | 25 min |
R/A % | 50 min | 50 min | 50 min | 15 min | 45 min | |
HARDNESS | 310 max |
Forged fittings comply with several standards: ASME B16.11 "Socket-Welding and Threaded Forged Fittings" specifies dimensions and pressure classes (Class 2000/3000/6000/9000); MSS SP-83 covers Class 3000/6000 socket-weld and threaded unions; MSS SP-97 specifies integrally reinforced outlets with socket-weld, threaded, or butt-weld ends.
| SW 45° Elbow | SW 90° Elbow | SW Tee | SW Cross | ||||||||||||||||||
| ASME B16.11 | |||||||||||||||||||||
| Nominal Size | Socket Bore Dia. | Bore Dia. of Fittings | Socket Wall Thickness | Body Wall | Depth of Socket | Center to Bottom of Socket | |||||||||||||||
| DN | NPS | B | D | C | G min | J min | A | ||||||||||||||
| 3000 | 6000 | 9000 | 3000 | 6000 | 9000 | 3000 | 6000 | 9000 | 90 Elbow,Tee,Cross | 45 Elbow | |||||||||||
| ave | min | ave | min | ave | min | 3000 | 6000 | 9000 | 3000 | 6000 | 9000 | ||||||||||
| 6 | 1/8 | 10.9 | 6.1 | 3.2 | 3.18 | 3.18 | 3.96 | 3.43 | 2.41 | 3.15 | 9.5 | 11 | 11 | 8 | 8 | ||||||
| 8 | 1/4 | 14.3 | 8.5 | 5.6 | 3.78 | 3.3 | 4.6 | 4.01 | 3.02 | 3.68 | 9.5 | 11 | 13.5 | 8 | 8 | ||||||
| 10 | 3/8 | 17.7 | 11.8 | 8.4 | 4.01 | 3.5 | 5.03 | 4.37 | 3.2 | 4.01 | 9.5 | 13.5 | 15.5 | 8 | 11 | ||||||
| 15 | 1/2 | 21.9 | 15 | 11 | 5.6 | 4.67 | 4.09 | 5.97 | 5.18 | 9.53 | 8.18 | 3.73 | 4.78 | 7.47 | 9.5 | 15.5 | 19 | 25.5 | 11 | 12.5 | 15.5 |
| 20 | 3/4 | 27.3 | 20.2 | 14.8 | 10.3 | 4.9 | 4.27 | 6.96 | 6.04 | 9.78 | 8.56 | 3.91 | 5.56 | 7.82 | 12.5 | 19 | 22.5 | 28.5 | 13 | 14 | 19 |
| 25 | 1 | 34 | 25.9 | 19.9 | 14.4 | 5.69 | 4.98 | 7.92 | 6.93 | 11.38 | 9.96 | 4.55 | 6.35 | 9.09 | 12.5 | 22.5 | 27 | 32 | 14 | 17.5 | 20.5 |
| 32 | 11/4 | 42.8 | 34.3 | 28.7 | 22 | 6.07 | 5.28 | 7.92 | 6.93 | 12.14 | 10.62 | 4.85 | 6.35 | 9.7 | 12.5 | 27 | 32 | 35 | 17.5 | 20.5 | 22.5 |
| 40 | 11/2 | 48.9 | 40.1 | 33.2 | 27.2 | 6.35 | 5.54 | 8.92 | 7.8 | 12.7 | 11.12 | 5.08 | 7.14 | 10.15 | 12.5 | 32 | 38 | 38 | 20.5 | 25.5 | 25.5 |
| 50 | 2 | 61.2 | 51.7 | 42.1 | 37.4 | 6.93 | 6.04 | 10.92 | 9.5 | 13.84 | 12.12 | 5.54 | 8.74 | 11.07 | 16 | 38 | 41 | 54 | 25.5 | 28.5 | 28.5 |
| 65 | 21/2 | 73.9 | 61.2 | 8.76 | 7.62 | 7.01 | 16 | 41 | 28.5 | ||||||||||||
| 80 | 3 | 89.9 | 76.4 | 9.52 | 8.3 | 7.62 | 16 | 57 | 32 | ||||||||||||
| 100 | 4 | 115.5 | 100.7 | 10.69 | 9.35 | 8.56 | 19 | 66.5 | 41 | ||||||||||||
| SW Coupling | SW Half-Coupling | Boss | SW Cap | SW 45° Latera | ||||||||||||||||||||
| GB/T 14383 ASME B16.11 | ||||||||||||||||||||||||
| Nominal Size | Socket Bore Dia. | Bore Dia. of Fittings | Socket Wall Thickness | Body Wall | Depth of Socket | Laying Lengths | Laying Lengths | End Wall Thickness | Center to Bottom of Socket | |||||||||||||||
| DN | NPS | B | D | C | G min | J min | E | F | K min | A | H | |||||||||||||
| 3000 | 6000 | 9000 | 3000 | 6000 | 9000 | 3000 | 6000 | 9000 | 3000 | 6000 | 9000 | 3000 | 6000 | 3000 | 6000 | |||||||||
| ave | min | ave | min | ave | min | |||||||||||||||||||
| 6 | 1/8 | 10.9 | 6.1 | 3.2 | 3.18 | 3.18 | 3.96 | 3.43 | 2.41 | 3.15 | 9.5 | 6.5 | 16 | 4.8 | 6.4 | |||||||||
| 8 | 1/4 | 14.3 | 8.5 | 5.6 | 3.78 | 3.30 | 4.6 | 4.01 | 3.02 | 3.68 | 9.5 | 6.5 | 16 | 4.8 | 6.4 | |||||||||
| 10 | 3/8 | 17.7 | 11.8 | 8.4 | 4.01 | 3.50 | 5.03 | 4.37 | 3.2 | 4.01 | 9.5 | 6.5 | 17.5 | 4.8 | 6.4 | |||||||||
| 15 | 1/2 | 21.9 | 15 | 11 | 5.6 | 4.67 | 4.09 | 5.97 | 5.18 | 9.53 | 8.18 | 3.73 | 4.78 | 7.47 | 9.5 | 9.5 | 22.5 | 6.4 | 7.9 | 11.2 | 41 | 51 | 9.5 | 11 |
| 20 | 3/4 | 27.3 | 20.2 | 14.8 | 10.3 | 4.9 | 4.27 | 6.96 | 6.04 | 9.78 | 8.56 | 3.91 | 5.56 | 7.82 | 12.5 | 9.5 | 24 | 6.4 | 7.9 | 12.7 | 51 | 60 | 11 | 13 |
| 25 | 1 | 34 | 25.9 | 19.9 | 14.4 | 5.69 | 4.98 | 7.92 | 6.93 | 11.38 | 9.96 | 4.55 | 6.35 | 9.09 | 12.5 | 12.5 | 28.5 | 9.6 | 11.2 | 14.2 | 60 | 71 | 13 | 16 |
| 32 | 11/4 | 42.8 | 34.3 | 28.7 | 22 | 6.07 | 5.28 | 7.92 | 6.93 | 12.14 | 10.62 | 4.85 | 6.35 | 9.7 | 12.5 | 12.5 | 30 | 9.6 | 11.2 | 14.2 | 71 | 81 | 16 | 17 |
| 40 | 11/2 | 48.9 | 40.1 | 33.2 | 27.2 | 6.35 | 5.54 | 8.92 | 7.8 | 12.7 | 11.12 | 5.08 | 7.14 | 10.15 | 12.5 | 12.5 | 32 | 11.2 | 12.7 | 15.7 | 81 | 98 | 17 | 21 |
| 50 | 2 | 61.2 | 51.7 | 42.1 | 37.4 | 6.93 | 6.04 | 10.92 | 9.5 | 13.84 | 12.12 | 5.54 | 8.74 | 11.07 | 16 | 19.0 | 30 | 9.6 | 11.2 | 14.2 | 71 | 81 | 16 | 17 |
| 65 | 21/2 | 73.9 | 61.2 | 8.76 | 7.62 | 7.01 | 16 | 19.0 | 43 | 15.7 | 19 | 151 | 30 | |||||||||||
| 80 | 3 | 89.9 | 76.4 | 9.52 | 8.30 | 7.62 | 16 | 19.0 | 44.5 | 19.0 | 22.4 | 184 | 57 | |||||||||||
| 100 | 4 | 115.5 | 100.7 | 10.69 | 9.35 | 8.56 | 19 | 19.0 | 48 | 22.4 | 28.4 | 201 | 66 | |||||||||||
| Nominal Size | All Fittings | Elbows, Tees & Crosses | Couplings | Half- Couplings | Reducer Inserts | Unions | |||||||||||||
| Socket Bore Dia. | Bore Dia. of Fittings | Center to Bottom of Socket | Laying Lengths | Laying Lengths | Laying Length | Shank Dia. | Length | Laying Length | |||||||||||
| DN | NPS | B | D | A H | E | F | A | SD | SL | E | |||||||||
| 6~8 | 1/8~1/4 | +0.4 0 | +1.5 0 | ± 1.0 | ± 1.5 | ± 1.0 | +1.5 0 | ± 0.25 | 0 -1.5 | ± 1.5 | |||||||||
| 10~20 | 3/8~3/4 | +0.4 0 | +1.5 0 | ± 1.5 | ± 3.0 | ± 1.5 | +1.5 0 | ± 0.25 | 0 -1.5 | ± 3.0 | |||||||||
| 25~40 | 1~11/2 | +0.4 0 | +1.5 0 | ± 2.0 | ± 4.0 | ± 2.0 | +2.0 0 | ± 0.25 | 0 -2.0 | ± 4.0 | |||||||||
| 50 | 2 | +0.5 0 | +1.5 0 | ± 2.0 | ± 4.0 | ± 2.0 | +2.0 0 | ± 0.5 | 0 -2.0 | ± 4.0 | |||||||||
| 65~80 | 21/2~3 | +0.5 0 | +3.0 0 | ± 2.5 | ± 5.0 | ± 2.5 | +2.5 0 | ± 0.5 | 0 -2.5 | ± 5.0 | |||||||||
| 100 | 4 | +0.5 0 | +3.0 0 | ± 2.5 | ± 5.0 | ± 2.5 | +2.5 0 | ± 0.7 | 0 -2.5 | - | |||||||||
Threaded 45 Elbow | Threaded 45 ° Elbow | Threaded Tee | Threaded Cross | ||||||||||||
ASME B16.11 | |||||||||||||||
Nominal Size | Center-to-End | Outside Diameter of Band | Wall Thickness | Length of Thread | |||||||||||
DN | NPS | A | H | G min | L5 min | L2 min | |||||||||
90° Elbows, Tees, Crosses | 45 ° Elbows | ||||||||||||||
2000 | 3000 | 6000 | 2000 | 3000 | 6000 | 2000 | 3000 | 6000 | 2000 | 3000 | 6000 | ||||
6 | 1/8 | 21 | 21 | 25 | 17 | 17 | 19 | 22 | 22 | 25 | 3.18 | 3.18 | 6.35 | 6.4 | 6.7 |
8 | 1/4 | 21 | 25 | 28 | 17 | 19 | 22 | 22 | 25 | 33 | 3.18 | 3.30 | 6.60 | 8.1 | 10.2 |
10 | 3/8 | 25 | 28 | 33 | 19 | 22 | 25 | 25 | 33 | 38 | 3.18 | 3.51 | 6.98 | 9.1 | 10.4 |
15 | 1/2 | 28 | 33 | 38 | 22 | 25 | 28 | 33 | 38 | 46 | 3.18 | 4.09 | 8.15 | 10.9 | 13.6 |
20 | 3/4 | 33 | 38 | 44 | 25 | 28 | 33 | 38 | 46 | 56 | 3.18 | 4.32 | 8.53 | 12.7 | 13.9 |
25 | 1 | 38 | 44 | 51 | 28 | 33 | 35 | 46 | 56 | 62 | 3.68 | 4.98 | 9.93 | 14.7 | 17.3 |
32 | 1 1/4 | 44 | 51 | 60 | 33 | 35 | 43 | 56 | 62 | 75 | 3.89 | 5.28 | 10.59 | 17.0 | 18.0 |
40 | 1 1/2 | 51 | 60 | 64 | 35 | 43 | 44 | 62 | 75 | 84 | 4.01 | 5.56 | 11.07 | 17.8 | 18.4 |
50 | 2 | 60 | 64 | 53 | 43 | 44 | 52 | 75 | 84 | 102 | 4.27 | 7.14 | 12.09 | 19.0 | 19.2 |
65 | 2 1/2 | 76 | 83 | 95 | 52 | 52 | 64 | 92 | 102 | 121 | 5.61 | 7.65 | 15.29 | 23.6 | 28.9 |
80 | 3 | 86 | 95 | 106 | 64 | 64 | 79 | 109 | 121 | 146 | 5.99 | 8.84 | 16.64 | 25.9 | 30.5 |
100 | 4 | 106 | 114 | 114 | 79 | 79 | 79 | 146 | 152 | 152 | 6.55 | 11.18 | 18.67 | 27.7 | 33 |
Coupling | Half-Coupling | Boss | Cap | |||||||
Nominal Size | End-to-End | End-to-End | Outside Diameter | End Wall | Length of Thread | |||||
DN | NPS | W | P | D | G min | L5 min | L2 min | |||
3000 & 6000 | 3000 | 6000 | 3000 | 6000 | 3000 | 6000 | ||||
6 | 1/8 | 32 | 19 | 16 | 22 | 4.8 | 6.4 | 6.7 | ||
8 | 1/4 | 35 | 25 | 27 | 19 | 25 | 4.8 | 6.4 | 8.1 | 10.2 |
10 | 3/8 | 38 | 25 | 27 | 22 | 32 | 4.8 | 6.4 | 9.1 | 10.4 |
15 | 1/2 | 48 | 32 | 33 | 28 | 38 | 6.4 | 7.9 | 10.9 | 13.6 |
20 | 3/4 | 51 | 37 | 38 | 35 | 44 | 6.4 | 7.9 | 12.7 | 13.9 |
25 | 1 | 60 | 41 | 43 | 44 | 57 | 9.7 | 11.2 | 14.7 | 17.3 |
32 | 1 1/4 | 67 | 44 | 46 | 57 | 64 | 9.7 | 11.2 | 17.0 | 18.0 |
40 | 1 1/2 | 79 | 44 | 48 | 64 | 76 | 11.2 | 12.7 | 17.8 | 18.4 |
50 | 2 | 86 | 48 | 51 | 76 | 92 | 12.7 | 15.7 | 19.0 | 19.2 |
65 | 2 1/2 | 92 | 60 | 64 | 92 | 108 | 15.7 | 19.0 | 23.6 | 28.9 |
80 | 3 | 108 | 65 | 68 | 108 | 127 | 19.0 | 22.4 | 25.9 | 30.5 |
100 | 4 | 121 | 68 | 75 | 140 | 159 | 22.4 | 28.4 | 27.7 | 33.0 |
Nominal Size | Elbows,Tees & Crosses | Couplings | Half- couplings | |
Center-to-End | End-to-End | End-to-End | ||
DN | NPS | A J | W | W/ 2 |
6~8 | 1/8~1/4 | ± 1.0 | ± 1.0 | ± 1.0 |
10~20 | 3/8~3/4 | ± 1.5 | ± 1.5 | ± 1.5 |
25~50 | 1~2 | ± 2.0 | ± 2.0 | ± 2.0 |
65~100 | 21/2~4 | ± 2.5 | ± 2.5 | ± 2.5 |
ASME B16.11 specifies the pressure range for socket and threaded fittings. Pressure range of socket fittings: CLASS3000, 6000, 9000; Pressure range of threaded fittings: CLASS2000, 3000, 6000.
| Joint Type | Class | Grade of Connecting Pipes | Joint Type | Class | Grade of Connecting Pipes | ||||||||||||||
| SW | 3000 | Sch80 XS | THRD | 2000 | Sch80 XS | ||||||||||||||
| 6000 | Sch160 | 3000 | Sch160 | ||||||||||||||||
| 9000 | XXS | 6000 | XXS | ||||||||||||||||
Manufactured by die forging + precision machining: bars or sections are heated and forged in high-precision dies to obtain a dense grain flow structure, followed by heat treatment and machining to ensure dimensional accuracy and mechanical properties.
Mainly used in high-pressure piping systems such as refineries, chemical plants, and power stations, as well as in pharmaceutical and food applications requiring high cleanliness. Socket-weld construction is suitable for non-vibrating, low thermal fatigue conditions; threaded connections allow easy disassembly for maintenance.
Product | Butt-Weld Fittings | Forged Fittings |
Connection type | Butt weld | Socket weld / Threaded |
Nominal size | 1/2″ – 48″ | ≤ 4″ |
Pressure rating | Schedule-based(SCH 5S–XXS) | Class-based (2000–9000) |
Manufacturing | Seamless push / stamped & welded | Forged + machined |
Internal surface | Smooth, continuous | Small gaps at socket |
Service condition | High temp / high pressure / critical | High pressure / small bore / non-critical |
ASTM A403 is often used with:
- ASME B16.9: Dimensions and tolerances for BW fittings
- ASME B36.10/B36.19: Wall thickness schedules for fitting ends
- ASTM A960: General testing and requirements for fittings
- ASME Boiler and Pressure Vessel Code: Allowable stresses for pressure equipment
Supporting standards for ASTM A182 forged products include:
- ASME B16.11: Dimensional standard for socket-weld and threaded forged fittings
- MSS SP-83: Union standard
- MSS SP-97: Branch outlet standard
- ASME B1.20.1: NPT pipe thread standard
- ASTM A962: Material standard for high-temperature fasteners (bolts, nuts, etc.)
With a complete supply chain and technical expertise, we offer a full range of stainless steel pipe fittings:
Butt-Weld Fittings: Sizes 1/2" to 48"; materials ASTM A403 WP304/304L, WP316/316L, WP321, WP31254 (6Mo), WP32205 (2205), WP32750 (2507); seamless or welded construction; meets various pressure ratings.
Forged Fittings: Sizes 1/8" to 4"; pressure classes Class 2000, 3000, 6000, 9000; socket-weld and threaded types; materials ASTM A182 F304/304L, F316/316L, F321, F44 (6Mo), F51
(2205), F53 (2507).
Our products strictly follow ASTM, ASME, and MSS standard. We provide full material certificates and quality test reports. Suitable for oil, chemical, power, marine, pharmaceutical, and food industries. Custom solutions available.
