A335 P22 steel pipe belongs to the seamless nominal pipe of ferrite alloy steel for high temperature, and the standard is ASTM A335 / A335M.

Chemical composition of A335 P22 steel pipe: C 0.10-0.20, Mn 0.30-0.80, P ≤ 0.025, S ≤ 0.025, Si 0.10-0.50, Mo 0.44-0.65.

Mechanical properties of A335 P22 steel pipe: tensile strength: 415 MPa, yield strength: 205 MPa, elongation: 30%.

A335 P22 steel pipe is characterized by good process performance, less sensitivity to the heating temperature of heat treatment, good welding performance and good plasticity. Its disadvantage is low strength, especially its high temperature endurance strength is lower than 12Cr1MoVG steel. When used at the same temperature and stress, its wall thickness is about 30% thicker than 12Cr1MoVG steel pipe. That the wall thickness of steam water pipe is too large will not only increase the manufacturing difficulties, but also bring inconvenience to the design, installation and operation.

High temperature and high pressure pipeline material is one of the most important materials in thermal power plant. It not only plays an important role in the safe operation of the power plant, but also affects the construction investment of the power plant. In the past 600 MW unit projects, A335 P22 steel pipes were used for main steam pipe and hot section of reheat steam pipe.