Process analysis of heat treatment of wire drawing knife using high frequency induction heating machine

Rifling is a key process in the manufacture of artillery rifling. In order to ensure the processing quality and processing efficiency of rifling, the rifling knife must have sufficient durability. We all know that the only way to improve durability and hardness is to quench the workpiece, and the wire drawing knife is no exception. We usually use a high-frequency induction annealing machine to quench and heat treat it.

With the improvement of the performance of modern artillery, the strength of the materials used in the barrel is getting higher and higher, and the processing difficulty is also increasing. Even if high-performance high-speed steel M42, CO5Si, etc. are used to make wire drawing knives, the processing efficiency and tool durability are still not high enough. Meet daily processing requirements. For this reason, after experimental research, CF3 type powder high-speed steel was selected to make the wire drawing knife to process the gun barrel rifling. After field testing, satisfactory results were achieved.

Judging from the chemical composition of CF3 powder high-speed steel, CF3 is a high-carbon, high-cobalt, and high-vanadium powder high-speed steel. The hardness after annealing is 280-310HBW, and the hardness after quenching and tempering can reach 68-70HRC. Its density It is 8.25-8.33g/cm3, the flexural strength is 3.34-3.92GPa, and the impact toughness is 0.25-0.34MJ/m2. The heat treatment process is introduced as follows.

1) Preheat. A high-frequency induction heating machine is used for two preheatings of 600°C and 850°C.

2) Heating. Induction heating at 1170-1180℃x20s/mm, the grain size is controlled at 10.5-11 levels.

3) Cool down. After grading neutral salt at 600-620℃, transfer to 240-260℃ nitrate salt isotherm for 30-45min.

4) Straighten. Hot calibrate immediately after isothermal release, cool to room temperature, wash and then cold calibrate.

5) Tempering. A high-frequency induction heating machine is used for tempering at 550-560℃xlhx4 times to control the hardness within the range of 66.5-67.5HRC. If it exceeds 67.5HRC, increase the tempering temperature and temper again.

Well, this article briefly introduces the high-frequency heat treatment process of wire drawing knife. I hope it will be helpful to your work. However, this article only gives a rough introduction. As for the specific conditions and some details of its heat treatment process, you need to explore it yourself.