Steel Pipe Elbow (45 and 90 degree) ASME B16.9
An elbow is a pipe fitting used to change the direction of flow in a piping system. ASME B16.9 defines the dimensional standards for factory-made wrought steel butt-welding fittings, including elbows, for seamless and welded construction.
Types of Steel Pipe Elbows
- By Angle:
- 45° Elbow: Changes direction by 45 degrees.
- 90° Elbow: Changes direction by 90 degrees.
- 180° Elbow: Changes direction by 180 degrees (used for U-turns).
- Custom Angles: Non-standard angles like 30°, 60°, etc., can be manufactured.
- By Radius:
- Short Radius (SR) Elbow: Radius = 1 × Nominal Pipe Size (NPS).
- Long Radius (LR) Elbow: Radius = 1.5 × NPS (preferred for smoother flow).
- By Material：ASME B16.9 elbows are available in various material grades, including:
- Carbon Steel: ASTM A234 WPB, WPC.
- Stainless Steel: ASTM A403 WP304, WP316.
- Alloy Steel: ASTM A234 WP11, WP22.WP5，WP91
- Duplex & Super Duplex Stainless Steel: UNS S31803, UNS S32750.
- Nickel Alloys: Inconel, Hastelloy, Monel.
Dimensions Butt Weld Elbows 45°-90° LR and 3D ASME B16.9
| 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 |
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.
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.
