1.ASTM A335 is a standard issued by the American Society for Testing and Materials (ASTM) for high-temperature seamless ferritic alloy steel nominal pipes, including a variety of different grades of materials, corresponding to different chemical compositions and performance characteristics
2.A335 P11
Corresponding domestic materials: equivalent to the domestic 15CrMo alloy structural steel, and also equivalent to the national standard high-pressure boiler tube 15CrMoG.
Material characteristics: It belongs to low-alloy heat-resistant steel, pearlite heat-resistant steel, with high thermal strength (δb≥440MPa) and oxidation resistance at high temperatures, and has a certain resistance to hydrogen corrosion. However, due to the high content of Cr, C and other alloy elements in the steel, the hardening tendency of the steel is more obvious and the weldability is poor.
3.A335 P5
Corresponding domestic materials: corresponding to the domestic alloy steel 1Cr5Mo.
Material properties: The metal structure is martensite, which has good oxidation resistance at about 650 degrees Celsius, good thermal strength below 600 degrees Celsius, good shock absorption and thermal conductivity, and is widely used in steam turbines.
4.A335 P91
Corresponding domestic material: equivalent to the national standard 10Cr9Mo1VNb.
Material properties: The material composition (composition wt%) is C 0.08 - 0.12; Mn 0.30 - 0.60; Si 0.20 - 0.50; P ≤0.02; S ≤0.01; Cr 8.0 - 9.5; Mo 0.85 - 1.05; V 0.18 - 0.25; Nb 0.06 - 0.1; N 0.03 - 0.07; Al ≤0.04; Ni ≤0.4. It is commonly used in fields such as petroleum cracking, and has certain tensile strength (370MPa~480MPa), yield strength (700MPa) and other properties.
5. A335 P92
Corresponding domestic situation: It belongs to the American standard martensitic heat-resistant steel, and there is no completely corresponding domestic single standard grade.
Material characteristics: On the basis of P91 steel, the content of molybdenum element (0.5% Mo) is appropriately reduced, and a certain amount of tungsten (1.8% W) is added, and a trace amount of boron is also added. Compared with other chromium-molybdenum heat-resistant steels, its high-temperature corrosion and oxidation resistance are similar to those of 9%Cr steel, but the high-temperature strength and creep properties of the material have been further improved. The steel has good processing performance, very high high-temperature creep rupture strength, and good corrosion resistance. In recent years, it has been widely used in the main steam pipeline and reheat steam pipeline of thermal power plants.
