Why is the quenching hardness of 45 steel plate? -The inner teeth of a 3 mm thick clutch plate were quenched at high frequency. After the temperature was 850, 2 ",it penetrated into water for 30", but the hardness started from 43 ". 1, possibly after high frequency heating. Because the workpiece is too thin, the cooling speed is fast. The temperature of the workpiece is far lower than 850℃ when the water enters, which leads to the unsatisfactory quenching effect of the workpiece.

2. Overburning leads to carbon loss, which reduces the carbon content on the surface of the workpiece and makes quenching fail to meet the ideal requirements.