Heat-resistant steel is a special type of steel that can maintain strength, oxidation resistance and creep resistance in high temperature environments. It is widely used in energy, chemical industry, aerospace and other fields. According to different chemical composition and performance, heat-resistant steel can be divided into many types, each type is suitable for different working conditions. Understanding the classification of heat-resistant steel helps companies accurately select materials and improve the service life and safety of equipment.
According to chemical composition, heat-resistant steel is mainly divided into three categories: chromium-molybdenum steel, austenitic heat-resistant steel and ferritic heat-resistant steel. Chromium-molybdenum steel is the most common type of heat-resistant steel. It contains high chromium and molybdenum elements, has good high-temperature strength and oxidation resistance, and is suitable for medium-temperature environments such as boilers and pressure vessels. Austenitic heat-resistant steel uses nickel and chromium as the main alloying elements, such as 310S, 309S and other grades. It has excellent high-temperature oxidation resistance and corrosion resistance and is often used in high-temperature furnace tubes, heat exchangers and other equipment. Ferritic heat-resistant steel has a high chromium content, but a low nickel content, and is relatively low in cost. It is suitable for heating furnaces and combustion chamber components at lower temperatures.
According to the use temperature and performance characteristics, heat-resistant steel can also be subdivided into low-alloy heat-resistant steel, medium-alloy heat-resistant steel and high-alloy heat-resistant steel. Low-alloy heat-resistant steel is usually used in working conditions below 500℃, such as 15CrMo, 12Cr1MoV, etc., and is mainly used for medium-temperature pipelines in the petrochemical and power industries. Medium-alloy heat-resistant steel is suitable for high-temperature environments of 600-800℃, such as 2.25Cr-1Mo steel, which is widely used in hydrogenation reactors and petrochemical equipment. High-alloy heat-resistant steels such as Inconel series (such as Inconel 600, 625) and Hastelloy series can maintain stable performance in high-temperature environments above 1000℃, and are mainly used in high-end fields such as aircraft engines and gas turbines.
In addition, heat-resistant steel can also be divided into pearlite heat-resistant steel, martensite heat-resistant steel and austenite heat-resistant steel according to the microstructure. Pearlite heat-resistant steel is mainly used in medium-temperature environments, while martensite heat-resistant steel improves strength through heat treatment and is suitable for high-temperature fasteners and other components.
The classification of heat-resistant steel is complex and diverse. Enterprises need to select appropriate materials according to specific operating temperature, corrosion environment and cost requirements. Correct material selection can not only improve equipment performance, but also reduce maintenance costs, creating greater economic benefits for enterprises.
