INFLUENCE OF TEMPERING TEMPERATURE ON THE MICROSTRUCTURE AND ULTIMATE TENSILE STRENGTH OF 28Cr3SiNiMoWV STEEL

In this research, the influences of the tempering temperature on the microstructure and ultimate tensile strength of 28Cr3SiNiMoWV steel were studied. The microstructure and ultimate tensile strength were investigated after tempering 28Cr3SiNiMoWV steel at different temperatures, ranging from 280 °C to 440 °C for 2 h. The results show that after tempering it at different temperatures, the microstructure of 28Cr3SiNiMoWV steel was tempered martensite. During the tempering process, the alloy carbides precipitated in the martensite matrix. Precipitation of alloy carbides in the microstructures of different specimens is the cause for an increase in the ultimate tensile strength. With the increasing tempering temperature, the ultimate tensile strength initially increases from 1390 MPa to 1601 MPa, and then decreases to 1466 MPa, with its maximum value at 280 °C.