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SCM420H alloy carburizing steel
SCM420H is an alloy carburizing steel defined in the Japanese Industrial Standard (JIS G 4053), belonging to the chromium-molybdenum steel series.
Its naming follows JIS specifications: "S" represents steel, "C" represents carbon, "M" represents molybdenum, the number "420" indicates an approximate carbon content of 0.20%, and the suffix "H" specifically indicates a steel grade that guarantees a hardenability band.
The chemical composition of SCM420H steel is designed with a clear functional orientation: Carbon serves as the foundation, providing the hardness framework of martensite after quenching; the addition of chromium primarily improves hardenability and forms stable carbides on the surface, enhancing wear resistance; molybdenum refines the grain, improving the steel's strength and toughness, and suppressing temper brittleness.
Trace amounts of manganese, silicon, and other elements assist in deoxidation and solid solution strengthening.
These elements do not act in isolation; their synergistic effect ensures that the material achieves the expected performance during subsequent heat treatment.
After ideal carburizing heat treatment, the properties of SCM420H directly depend on its microstructure.
High-carbon martensite and possibly dispersed alloy carbides form on the surface of SCM420H, achieving a hardness of HRC 58-62, which is responsible for resisting wear and contact fatigue.
Its naming follows JIS specifications: "S" represents steel, "C" represents carbon, "M" represents molybdenum, the number "420" indicates an approximate carbon content of 0.20%, and the suffix "H" specifically indicates a steel grade that guarantees a hardenability band.
The chemical composition of SCM420H steel is designed with a clear functional orientation: Carbon serves as the foundation, providing the hardness framework of martensite after quenching; the addition of chromium primarily improves hardenability and forms stable carbides on the surface, enhancing wear resistance; molybdenum refines the grain, improving the steel's strength and toughness, and suppressing temper brittleness.
Trace amounts of manganese, silicon, and other elements assist in deoxidation and solid solution strengthening.
These elements do not act in isolation; their synergistic effect ensures that the material achieves the expected performance during subsequent heat treatment.
After ideal carburizing heat treatment, the properties of SCM420H directly depend on its microstructure.
High-carbon martensite and possibly dispersed alloy carbides form on the surface of SCM420H, achieving a hardness of HRC 58-62, which is responsible for resisting wear and contact fatigue.
