The heat treatment process of using medium frequency induction heating machine to heat A-type center drill

Center drilling is suitable for processing center holes and positioning holes on workpieces made of cast iron, steel, copper, aluminum and other materials after being clamped by a universal fixture on machine tools such as lathes, drilling machines or machining centers. The center drill consists of a shank in the middle and working parts at both ends. The shank is used for clamping and transmitting cutting torque. The working part is divided into two parts: the small diameter cutting part at the front end plays the role of drilling centering, and the tapered cutting part at the rear end is used for expansion. hole. The cutting part of the cone surface is divided into three types according to the shape of the center hole: Type A with a 60° cone, Type B with a protective cone, and Type R. During use, all the center holes can be processed by drilling once. According to the groove type, it can be divided into two types: straight groove and spiral groove. In order to meet the needs of the work, the A-type center drill (without protective cone) needs to be heat treated. This article briefly introduces the medium-frequency heat treatment process of A-type center drill (without protective cone) using a medium-frequency induction heating machine.

1) Preheat. A medium frequency induction heating machine is used for preheating heat treatment. The preheating temperature is 850-870℃, and the preheating time is twice the heating time.

2) Heating. Medium frequency induction heating, M2 steel 1220-1225℃, 9341 steel 1225-1230℃, 4341 steel 1175-1190℃, grain size control 10 to 10.5 levels.

3) Cool down. In order to improve the toughness of the center drill, graded isothermal treatment is used, that is, after high-temperature heating, it is first graded at 580-620°C, and then treated with nitrate salt isotherm at 260-280°C for 2 hours.

4) Tempering. A medium frequency induction heating machine is used for 4 times of tempering heat treatment, and the tempering is 550℃x1.5h.

Center drilling is mainly used to process center holes and positioning holes, and its heat treatment process is quite important. This article briefly introduces the heat treatment process of the center hole. After the center drill is heat treated by the above process, the hardness is ≥64HRC, the tempering is sufficient, and there is no overheating. The effect is still good. You can also apply these heat treatment processes to your work.