In the field of high-temperature industry, metallurgical heat-resistant steel has become a key material in the energy, chemical, aerospace and other industries due to its excellent high-temperature strength, oxidation resistance and creep resistance. With the advancement of technology, the types and performance of heat-resistant steel are constantly optimized. This article will introduce its main materials and their application characteristics.
Common metallurgical heat-resistant steel materials
1. Low alloy heat-resistant steel
Low alloy heat-resistant steel uses chromium and molybdenum as the main alloying elements, and typical grades include 12CrMo, 15CrMo, etc. This type of steel has a low cost and is suitable for medium-temperature environments (about 500°C or less). It is widely used in boiler pipes, pressure vessels, etc. It is characterized by good welding performance, but limited high-temperature strength, and needs to be improved through heat treatment.
2. High chromium heat-resistant steel
High chromium heat-resistant steel (chromium content ≥12%) such as Cr13, Cr25, etc., relies on chromium oxide to form a dense protective film, which significantly improves oxidation resistance. This type of steel is suitable for high-temperature environments of 600℃~900℃ and is commonly found in petrochemical cracking furnaces, heat exchangers, etc. The disadvantage of high-chromium steel is that it may become brittle after long-term high-temperature use, and the composition and heat treatment process need to be strictly controlled.
3. Austenitic heat-resistant steel
Austenitic heat-resistant steel (such as 309S, 310S) with nickel and chromium as the main alloying elements has excellent high-temperature strength and corrosion resistance, and the operating temperature can reach above 1000℃. This type of steel is widely used in high-end fields such as gas turbines and aircraft engines. Its disadvantages are high cost and susceptibility to sulfide corrosion, and the performance needs to be improved by adding rare earth elements.
4. High-temperature alloy steel
High-temperature alloy steel (such as GH series) achieves stable performance under extreme high temperatures (above 1100℃) by adding elements such as cobalt, molybdenum, and titanium. This type of material is mostly used in cutting-edge fields such as spacecraft combustion chambers and nuclear power plant steam generators, but it is expensive and has a complex production process.
Application Trends and Challenges
With the advancement of the "dual carbon" goal, heat-resistant steel is developing towards higher efficiency and lower emissions. For example, the new composite heat-resistant steel takes into account both strength and economy through a multi-layer structure design. However, the problem of material aging in high temperature environments is still the focus of the industry. In the future, the research and development of heat-resistant steel will pay more attention to the combination of environmental protection and intelligent performance monitoring technology.
The diverse materials of metallurgical heat-resistant steel provide reliable protection for high-temperature industries. The selection of suitable materials requires comprehensive consideration of temperature, medium and cost factors to achieve the best benefits.
