ASTM A334 Seamless Carbon Steel Pipe
ASTM A334 is a forged seamless carbon steel pipe that is one of the standard specifications for cryogenic applications.
| Element | Composition, max, % | |
| Grade A | Grade B | |
| C | 0.25 | 0.30 |
| Mn | 0.95 | 1.20 |
| P | 0.035 | 0.035 |
| S | 0.035 | 0.035 |
*The steel from which the ASTM A135 ERW pipe is made shall conform to the chemical requirements prescribed in this table, based on heat analysis.
| ASTM A135 | Grade A | Grade B |
|---|---|---|
| Tensile Strength, min, ksi [MPa] |
48 [330] |
60 [415] |
| Yield Strength, min, ksi [MPa] |
30 [205] |
35 [240] |
| Elongation, min, % |
35 | 30 |
For ASTM A135 Grade B ERW steel pipes, the welds require heat treatment after welding. The minimum processing temperature is 1000°F (approximately 540°C), which ensures that the performance of the steel pipe meets the standard requirements. At the same time, one of the purposes of heat treatment is to prevent untempered martensite from remaining in the weld. Martensite is a hard phase in steel materials. Its presence will significantly increase the hardness of the material, but at the same time it will also reduce the plasticity and toughness of the material. Therefore, heat treatment is performed after welding to temper the martensite at the weld and become more stable, thus improving the overall performance of the steel pipe.
