20Cr steel is China's national standard specification alloy steel. After heat treatment and ultra low temperature quenching, 20Cr steel has excellent comprehensive physical properties and excellent ultra low temperature fracture toughness. During nitriding, the crystal of steel tends 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. Relative drillability is about 65% at normalized strengths of 170-217HB.
20Cr steel has excellent electric weldability, and generally does not require heat treatment 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 steel 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. Drilling process performance is excellent under high temperature quenching or heat treatment and quenching standards, but weaker after quenching.
