Heat treatment and application of 42CrMo alloy steel

42CrMo alloy steel usually uses surface quenching after quenching and tempering as a heat treatment scheme:
The heating temperature is 1150-1200℃, the starting temperature is 1130-1180℃, the end temperature is > 850℃, and when φ> 50mm, slow cooling.
Normalizing temperature is 850-900℃, air-cooled; tempering temperature is 680-700℃, air-cooled;
Preheating temperature 680-700℃, quenching temperature 840-880℃, oil cooling, tempering temperature 580℃, water cooling or oil cooling, hardness ≤ 217HBW;
Quenching temperature 900℃, tempering temperature 560℃, hardness (37±1) HRC.
The quenching temperature is 900℃, the tempering temperature is 150-180℃, and the hardness is 54-60HRC.

42CrMo alloy steel application range:
42CrMo alloy steel is used to manufacture forgings that require higher strength and larger quenched and tempered sections than 35CrMo steel, such as large gears for locomotive traction, supercharger transmission gears, rear axles, connecting rods and spring clips that are heavily loaded. 42CrMo is also used for drill pipe joints and fishing tools in oil wells below 2000m.