Types Of Heat-resistant Steel

According to the alloy composition and use temperature, heat-resistant steel can be divided into the following categories:

Low alloy heat-resistant steel: mainly by adding alloy elements such as Cr, Mo, V, Ti to ordinary carbon steel to improve the creep strength and structural stability of steel. This type of steel shows good strength and toughness at high temperatures and is suitable for various industrial fields.

Medium alloy heat-resistant steel: the main alloying element is Cr. With the increase of Cr content, high temperature resistance and oxidation resistance are enhanced. In order to improve creep strength and reduce temper brittleness, elements such as Mo are usually added. This type of steel performs well in medium and high temperature environments and is widely used in petrochemical and power industries.

High alloy heat-resistant steel: has high mechanical properties and oxidation resistance at temperatures above 600℃. According to its basic alloy system, it can be divided into chromium-nickel type and high chromium type. Elements such as Ti, Nb, Al, W, V, Mo, B, Si, Mn and Cu are often added to improve performance. This type of steel is suitable for extreme high temperature environments, such as aircraft engines and nuclear reactors.

‌Austenitic heat-resistant steel‌: It is mainly composed of austenite-forming elements such as nickel, manganese, and nitrogen. It has good toughness, machinability, and weldability, and is suitable for high-temperature environments above 600°C‌.

‌Martensitic heat-resistant steel‌: The chromium content is generally 7-13%. It has high high-temperature strength and water vapor corrosion resistance below 650°C, but poor weldability‌.

‌Ferritic heat-resistant steel‌: It is rich in chromium, aluminum, silicon and other elements, forming a single-phase ferrite structure, with good oxidation resistance and high-temperature gas corrosion resistance, but relatively low high-temperature strength and poor weldability‌.

‌Pearlite heat-resistant steel‌: It is mainly composed of chromium and molybdenum, and the total amount generally does not exceed 5%. It has good high-temperature strength and process performance in the temperature range of 500-600°C, and is widely used in the manufacture of heat-resistant parts below 600°C‌.

These classification methods help us better understand the performance characteristics and application scope of heat-resistant steel in different application scenarios.