Effect of tempering temperature on microstructure and strength-toughness of high-strength wear-resistant steel was studied in the tempering temperature range of 200-700 ℃.The results show that the martensite lath degenerates after tempering at 500-700 ℃,resulting in a significant decrease in tensile strength,yield strength,and hardness.The impact absorbed energys of V-notch and U-notch are both less than 12 J.After tempering at 200-400 ℃,the impact properties of the specimens are significantly improved.The tempering temperatures corresponding to the impact absorbed energy peak of V-notch and U-notch are 250℃ and 300 ℃,respectively.The yield strength and tensile strength are maintained at more than 1340 MPa and 1660 MPa,respectively,and the elongation exceeds 10％.The tested steel achieves the best comprehensive mechanical properties after tempering at 250 ℃,with V-notch and U-notch impact absorbed energy of 40 J and 59 J,respectively,the yield strength of 1374 MPa,the yield ratio of 0.80 and the strength-toughness product of 92 269 MPa·J·cm-2.Based on the hindering effect of Si on the precipitation of cementite,the higher Si content in the steel increases the temper brittleness range.The tempering temperature brittleness range of the tested steel is 450-700 ℃.
维普
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