ASTM A335 P11 Allowable Stress – Temperature Ratings
Piping materials of ASTM A335 P11 can be used in both process piping and power piping services. The correlation between its allowable stress and temperature must be considered. Usually, the basic allowable stress descends as the working temperature ascends. This relationship is dictated ans specified by ASME B31.1 and ASME B31.3 respectively both of which are ASME code for pressure piping. ASME B31.1 is the standard specification for power piping while ASME B31.3 is the standard specification for process piping. Generally, ASME B31.1 imposes more rigorous constraints on the limits of allowable stresses and temperatures of A335 P11 materials than ASME B31.3.
ASTM A335 P11 pipework for an Australian power plant.
1. Allowable Stress – Temperature Ratings acc. to ASME B31.1
| Allowable Stress - Temperature Ratings of ASTM A335 according to ASME B31.1 | |||||||
|---|---|---|---|---|---|---|---|
| Temp.(°F) | -20 | 400 | 500 | 600 | 650 | 700 | 750 |
| Stress(ksi) | 15.0 | 15.0 | 15.0 | 15.0 | 15.0 | 15.0 | 14.8 |
| Temp.(°F) | 800 | 850 | 900 | 950 | 1000 | 1050 | 1100 |
| Stress(ksi) | 14.4 | 14.0 | 13.6 | 9.3 | 6.3 | 4.2 | 2.8 |
*The allowable stress values given are the “maximum” while the temperature values given are the minimum(“not exceeding”).
2. Allowable Stress – Temperature Ratings acc. to ASME B31.3
| Allowable Stress - Temperature Ratings of ASM A335 P11 according to ASME B31.3 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Temp.(°F) | -20-100 | 200 | 300 | 400 | 500 | 600 | 650 | 700 | 750 |
| Stress(ksi) | 20.0 | 18.7 | 18.0 | 17.5 | 17.2 | 16.7 | 16.2 | 15.6 | 15.2 |
| Temp.(°F) | 800 | 850 | 900 | 950 | 1000 | 1050 | 1100 | 1150 | 1200 |
| Stress(ksi) | 15.0 | 14.5 | 12.8 | 9.3 | 6.3 | 4.2 | 2.8 | 1.9 | 1.2 |
*The stress values shall be treated as the “basic” allowable stresses in tension. A quality factor E shall be multiplied in pressure design.
See the chemical composition & mechanical properties of ASTM A335 P11.
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