Introduction of 30CrMo alloy steel

Introduction of 30CrMo alloy steel

30CrMo alloy steel is Chromium molybdenum alloy structural steel. 30 refers to the carbon content. 30CrMo alloy steel is used to make 10.9S 8.8S high-strength bolts. But before use, 30CrMo alloy steel must be tested to confirm its composition content before it can be safely used. Chinese grade 30CrMo is equivalent to Japanese SCM430.

30CrMo alloy steel has high strength and toughness, high hardenability. Its critical hardenability diameter in oil is 15-70 mm. 30CrMo alloy steel also has good thermal strength and enough high temperature strength below 500℃. But its strength decreases significantly at 550℃. When alloy elements are at the lower limit, 30CrMo alloy steel has good weldability. But when alloy elements are near the upper limit, 30CrMo alloy steel only has medium weldability and needs to be preheated to more than 175℃ before welding. 30CrMo alloy steel has good machinability and moderate plasticity during cold deformation. 30CrMo alloy steel has the first kind of tempering brittleness in the range of 300~350℃ during heat treatment, and tends to form white spots.

30CrMo alloy steel is usually used in quenched and tempered state. When the carbon content of the steel is at lower limit, 30CrMo alloy steel can also be used as a high strength carburized steel at the center. In medium-sized machinery manufacturing industry, 30CrMo alloy steel is mainly used to manufacture quenched and tempered parts with large cross-section and working under high stress conditions, such as shafts, spindles, operating wheels, bolts, double-head bolts, gears and so on under high load; in chemical industry, 30CrMo alloy steel is used to manufacture welding parts, sheets and pipes, and welded structures.