Effect of Secondary Tempering Temperature on the Microstructure and Mechanical Properties of GX23CrMoV12-1 Heat-resistant Steel
GX23CrMoV12-1 heat-resistant steel is used as the core castings of gas turbines.The heat treat-ment process is quenching at 1050 ℃ for 4 h followed by oil cooling and tempering at 740 ℃ for 6 h fol-lowed by fumace cooling.Secondary tempering treatment was performed on the material after the initial tempering to investigate the effects of secondary tempering temperature on the microstructure and mechani-cal properties of material.The results indicated that after the secondary tempering,the material remained similar structure to that after the initial tempering,consisting of fine plate-like martensite.After the sec-ondary tempering,the strength,hardness and elongation of the material decreased.As the secondary tem-pering temperature increased from 710 ℃ to 740 ℃,the tensile strength and yield strength of the material showed a slow decreasing trend,while the elongation increased.After secondary tempering at 720 ℃,a large amount of coarse precipitates appeared in the microstructure of the heat-resistant steel,resulting in the lowest plasticity and toughness of the material.The impact toughness of the material was significantly improved after the secondary tempering,with the impact absorption energy as high as 71.8 J after tempe-ring at 740 ℃,representing a 56％increase compared to the initial tempering state.
secondary temperingheat-resistant steelprecipitated phasestrengthimpact absorption energy
万方数据
维普
