ASTM A182 F91
UNS K90901ASTM A182 F91 material
Key Engineering Metrics
Instant specifications summary for ASTM A182 F91
General Specifications & Standard Data
ASTM A182Minimum Design Metal Temperature rules for impact testing exemption under ASME B31.3 paragraph 323.2.2.
Mechanical Properties
Room Temp (20°C / 68°F)Allowable Stress Data (ASME B31.3 Table A-1)
asme-bpvcAllowable Stress vs Temperature
ASME B31.3 / BPVC Section II Part D Reference Curve
| Temperature (°C) | Allowable Stress (MPa) | % of Room Temp Rating |
|---|---|---|
| 38 | 177.2 | 100% |
| 100 | 177.2 | 100% |
| 150 | 177.2 | 100% |
| 200 | 176.5 | 100% |
| 250 | 175.8 | 99% |
| 300 | 173.7 | 98% |
| 350 | 169.6 | 96% |
| 400 | 162.0 | 91% |
| 450 | 149.6 | 84% |
| 500 | 133.1 | 75% |
| 550 | 99.3 | 56% |
| 600 | 55.2 | 31% |
| 650 | – | – |
🛡️ ASME B16.5 Flange P-T Ratings & Calculator
Material Group 1.15 (Carbon and low-alloy steel materials)
| Temp (°C) | Class 150 | Class 300 | Class 400 | Class 600 | Class 900 | Class 1500 | Class 2500 |
|---|---|---|---|---|---|---|---|
| -29 to 38 | 20 | 51.7 | 68.9 | 103.4 | 155.1 | 258.6 | 430.9 |
| 50 | 19.5 | 51.7 | 68.9 | 103.4 | 155.1 | 258.6 | 430.9 |
| 100 | 17.7 | 51.5 | 68.7 | 103 | 154.6 | 257.6 | 429.4 |
| 150 | 15.8 | 50.3 | 66.8 | 100.3 | 150.6 | 250.8 | 418.2 |
| 200 | 13.8 | 48.6 | 64.8 | 97.2 | 145.8 | 243.4 | 405.4 |
| 250 | 12.1 | 46.3 | 61.7 | 92.7 | 139 | 231.8 | 386.2 |
| 300 | 10.2 | 42.9 | 57 | 85.7 | 128.6 | 214.4 | 357.1 |
| 325 | 9.3 | 41.4 | 55 | 82.6 | 124 | 206.6 | 344.3 |
| 350 | 8.4 | 40.3 | 53.6 | 80.4 | 120.7 | 201.1 | 335.3 |
| 375 | 7.4 | 38.9 | 51.6 | 77.6 | 116.5 | 194.1 | 323.2 |
| 400 | 6.5 | 36.5 | 48.9 | 73.3 | 109.8 | 183.1 | 304.9 |
| 425 | 5.5 | 35.2 | 46.5 | 70 | 105.1 | 175.1 | 291.6 |
| 450 | 4.6 | 33.7 | 45.1 | 67.7 | 101.4 | 169 | 281.8 |
| 475 | 3.7 | 31.7 | 42.3 | 63.4 | 95.1 | 158.2 | 263.9 |
| 500 | 2.8 | 28.2 | 37.6 | 56.5 | 84.7 | 140.9 | 235 |
| 538 | 1.4 | 25.2 | 33.4 | 50 | 75.2 | 125.5 | 208.9 |
| 550 | – | 25 | 33.3 | 49.8 | 74.8 | 124.9 | 208 |
| 575 | – | 24 | 31.9 | 47.9 | 71.8 | 119.7 | 199.5 |
| 600 | – | 18.6 | 24.8 | 37.2 | 55.9 | 93.1 | 155.1 |
| 625 | – | 12.6 | 16.8 | 25.2 | 37.9 | 63.1 | 105.1 |
| 650 | – | 8.2 | 11 | 16.5 | 24.7 | 41.1 | 68.6 |
Working pressures are in gauge (bar). Values interpolated linearly for intermediate temperatures per ASME B16.5 para. 2.3.
Chemical Composition (% Weight)
Heat & Product Analysis🛡️ Service Compatibility
Industry standard for main steam & reheat piping up to 593°C (1100°F) for P91.
Resistant to High Temperature Hydrogen Attack per API RP 941 (Nelson Curves).
High creep-rupture strength in refinery vacuum furnaces and hydrocrackers.
High weld heat-affected zone hardness; requires strict PWHT to prevent SSC.
High ductile-to-brittle transition temp; strictly high-temperature service.
🔥 Welding & Heat Treatment
Mandatory preheat: 150°C–200°C for P11/P22; 200°C–250°C for P91/C12A. Maintain preheat until PWHT or post-bake.
Mandatory post-weld heat treatment for all thicknesses: P11/P22 (650°C–700°C), P91 (730°C–760°C) per ASME B31.3 Table 331.1.1.
Impact testing required for low-temperature applications or code thickness thresholds.
Material property data provided is for preliminary engineering reference. Always verify properties against the latest ASME BPVC Section II, ASTM material specification, and Material Test Report (MTR/MTC).