Characteristics of 38CrMoAl steel;
38CrMoAl steel is a Cr-Mo-Al alloy structural steel, a kind of nitrided steel, and an ultra-high strength steel. 38CrMoAl steel is mainly used for gas nitriding, ion nitriding and soft nitriding. Al element in steel is the main alloying element to improve the hardness of nitrided layer, and forms highly dispersed aluminum nitride (AlN) with nitrogen, and the hardness is extremely high, reaching 9~ 10 Mohs hardness. Due to the interaction of Al, Mo and Cr, the surface hardness of 38CrMoAl steel after nitriding can reach1100 ~1200 HV, and the microstructure stability is good (it can be used below 500℃). At the same time, they can also refine grains and improve the strength and hardenability of steel. In addition, a small amount of Mo and Mo can also improve the thermal stability of steel and eliminate temper brittleness caused by long-term heat preservation and subsequent slow cooling at nitriding temperature.
Although 38CrMoAl steel has high fatigue strength and wear resistance, its hardenability is not high, and it can only be quenched to a size of 50mm thick. In addition, the cold deformation plasticity is low and the welding performance is almost poor. Tempered sorbite structure can be obtained after quenching and tempering of 38CrMoAl steel. During surface nitriding, a large amount of nitrogen is easily dissolved in ferrite structure to form iron nitride and aluminum nitride with extremely high hardness, thus enhancing the fatigue strength, surface hardness, wear resistance, corrosion resistance, heat resistance and seizure resistance of steel surface. Quenching treatment is generally not needed after nitriding, so there is no quenching deformation problem.
Chemical composition of 38CrMoAl steel;