What is 20Cr steel?

20Cr steel is Chinese's national standard specification alloy steel. 20Cr steel has excellent comprehensive physical properties after heat treatment and ultra-low temperature quenching: excellent ultra-low temperature fracture toughness and quenching ductility are not significant. During nitriding, the crystals of steel tend to grow and develop, so secondary heat treatment is necessary to improve the ductility of the core, and refrigeration and heat treatment are not suitable. When the normalized strength is 170-217HB, the relative drillability is about 65%. 20Cr steel has excellent electric welding weldability. Generally, heat treatment is not required after electric welding, but parts with a thickness of more than 15mm must be heated to 100-150°C before electric welding, and it is very likely that the quenching heat treatment process cannot be carried out after electric welding. .

Compared with 15Cr steel, 20Cr has higher compressive strength and cutting performance. The critical value in oil can be hardened with a diameter of 4-22mm, and the critical value in water can be hardened with a diameter of 11-40mm, but the ductility is poor. Under high temperature quenching or heat treatment and quenching standards, the drilling process performance is excellent, but it is weak after quenching.

Pre: Things to consider when choosing carbon steel

Next: What are the differences between 20Cr steel and 40Cr steel