What are the main welding characteristics of 20Cr steel plate?

Compared with 15Cr steel plate, 20Cr steel plate has higher strength and hardenability, and the critical quenching diameter in oil is 4 The critical quenching diameter in water is 11-40mm, but the toughness is poor. When 20Cr steel plate is carburized, there is still a tendency of grain growth, and the impact toughness is greatly affected by direct cooling quenching. Therefore, secondary quenching is required after carburizing to improve the core toughness of 20Cr steel plate parts without tempering brittleness.

The cold strain plasticity of 20Cr steel plate is high, which can be drawn in cold state; the machinability of 20Cr steel plate is good under high temperature normalizing or quenching and tempering state, but poor after annealing.

20Cr steel plate is pearlite and has good weldability. Generally, heat treatment is not required after welding. However, parts with thickness greater than 15mm of 20Cr steel plate shall be preheated to 100-150℃ before welding, and no tempering heat treatment is required after welding.