What are the main factors affecting the hardenability of 42CrMo alloy steel

The main factors affecting the hardenability of 42CrMo alloy steel are as follows:
The chemical composition of 42CrMo alloy steel, quenching and heating temperature, characteristics of cooling medium, cooling method, shape and size of parts, heating method, etc.

(1) The chemical composition of 42CrMo alloy steel is one of the most important factors affecting its hardenability. For example, the carbon content of 45# steel is similar to that of 40Cr steel, but because the former does not contain chromium and the latter contains about 1% chromium, their hardenability is obviously different under the same heat treatment conditions.

(2) The shape, size, heating temperature and cooling mode of the parts affect the hardenability of 42CrMo alloy steel in different degrees. Small size, high heating temperature and continuous cooling can improve the hardenability to a certain extent, while large size, low heating temperature and isothermal cooling can reduce the hardenability of 42CrMo alloy steel.

(3) The cooling characteristics and cooling speed of heat treatment cooling medium also have a great influence on the hardenability of 42CrMo alloy steel. If the cooling speed is fast, the hardenability will be improved; if the cooling speed is slow, the hardenability will be reduced.

(4) The heating method also affects the hardenability of 42CrMo alloy steel. Because of different heating methods, the heating effect is different. For example, the oxidation and decarburization of box type electric furnace is more serious than that of salt bath furnace, which will reduce the hardenability.