Casting structure analysis of an austenitic heat-resistant and wear-resistant steel

    
    Austenitic heat-resistant and wear-resistant steel is widely used in the manufacture of valves, pumps, and other components operating in high pressure and temperature conditions. The alloy's ability to maintain its mechanical and structural integrity even when exposed to extremely high temperatures makes it the ideal choice for applications that require strength and corrosion resistance. This paper discusses the composition, microstructure, and mechanical properties of austenitic heat-resistant and wear-resistant steel.
    
    Composition
    
    Austenitic heat-resistant and wear-resistant steel (AHRWS) is composed of iron, chromium, nickel, and other alloying elements. The most common alloys of AHRWS contain 15-17% chromium, 8-10% nickel, and a small amount of elements such as manganese, silicon, and aluminum to enhance strength and corrosion resistance. The chromium and nickel give the alloy its heat-resistance and austenitic nature, while the other elements are beneficial in maintaining the steel’s mechanical and chemical properties.
    
    Microstructure
    
    The microstructure of AHRWS is composed of an austenitic matrix, a ferrite phase, and dispersed carbides of MC and M23C6. The austenite matrix is the primary component, forming the lattice that provides strength and toughness to the steel. It consists of a face-centered cubic (FCC) structure, and is composed of atoms of iron and chromium arranged in a non-magnetic, crystalline form. The ferrite phase makes up about 5-10% of the microstructure and consists of iron atoms arranged in a body-centered cubic (BCC) form. These atoms are ferromagnetic, which increases the steel’s toughness and yield strength. In addition, MC and M23C6 carbides are dispersed throughout the austenitic matrix and provide wear-resistance to the steel.
    
    Mechanical Properties
    
    AHRWS has excellent mechanical properties due to its high strength-to-weight ratio, wear-resistance, and corrosion-resistance. Its corrosion-resistance is the result of the alloy’s high chromium content, which gives it excellent resistance to both oxidizing and reducing acids. Additionally, the elements within the alloy’s microstructure allow it to maintain its mechanical properties even when subjected to extreme temperatures. Its yield strength, ultimate tensile strength, and elongation are all very high and remain consistent even when exposed to temperatures up to 1200°C.
    
    Figure 1: Microstructure of Austenitic Heat-Resistant and Wear-Resistant Steel [1]
    
    Conclusion
    
    Austenitic heat-resistant and wear-resistant steel is an alloy of iron, chromium, and nickel that provides high strength, corrosion-resistance, and wear-resistance, even when exposed to extreme temperatures. It has an austenitic matrix, a ferrite phase, and is enriched with dispersed carbides of MC and M23C6 to add wear-resistance. The mechanical properties of AHRWS, such as its yield strength, ultimate tensile strength, and elongation, are excellent and maintain their integrity when exposed to temperatures up to 1200°C. The alloy’s corrosion-resistance, wear-resistance, and high-temperature strength make it ideal for use in the production of valves, pumps and other components operating in a wide range of conditions.

---