Effect of induction heating and tempering on properties and microstructures of quenched and tempered pipes

In this study, a C-Mn quenched steel tube was quickly tempered by induction heating, and the influence of the tempering temperature on its performance was studied and compared with that by traditiona tempering. The results show that the yield strength of both is quite strong with regula changes in the tempering temperature, but that the tensile strength of the tube tempered by induction heating is higher than that tempered by traditional tempering by about 25 MPa, and the elongation after induction tempering is significantly higher than that after traditional tempering. The diferences in the microstructures of tubes ater induction and traditional tempering were compaed by metallographic microscope, scanning electron microscopy, and transmission electron microscopy. Theoretical analysis was also performed. Compaed with traditional tempering, a fine dispersion of precipitated cabides occurs after induction tempering, which is the main reason for the performance diferences.