What are the differences in properties of 45# 35Cr 40Cr steel

The cold plasticity of 45# steel is general. It is slightly better under annealing and normalizing than quenching and tempering. 45# steel has high strength and good machinability. After proper heat treatment, 45# steel can obtain certain toughness, plasticity and wear resistance. 45# steel is suitable for hydrogen welding and argon arc welding, but not suitable for gas welding. Preheating is required before welding, and stress relief annealing shall be conducted after welding.

35Cr steel is a medium carbon alloy quenched and tempered steel with high strength and toughness. 35Cr steel is used for manufacturing wear-resistant or impact parts, such as rollers, bolts, etc.

The hardenability of 40Cr steel is good. It can be quenched to Ф 28 - 60mm in water quenching and to Ф 15 - 40mm in oil quenching. In addition to quenching and tempering, 40Cr steel is also suitable for cyaniding and high frequency quenching. When the hardness is 174-229HB, the relative machinability is 60%. 40Cr steel is suitable for making medium-sized plastic mould.