2016 Volume 88 Issue 5 Pages 276-281
This study aims to investigate the influence of tempering temperature on strength, hardness, and wear characteristics of alloy tool steel casting. Test samples added with 0.5mass%Ti with lower C and Cr contents than those in SKD11 (JIS G4404) were manufactured by the investment casting process, and tempered at temperatures 453K, 573K, 673K, 773K, and 873K after quenching from 1293K. The amount of M7C3 type Cr carbides decreased, and continuity of the carbides was greatly reduced with the decrease of C and Cr contents. In addition MC type Ti carbides were observed in the matrix microstructure. Carbide structure did not change with varying tempering temperature. Although hardness tended to decrease with increasing tempering temperature, the hardness increased by secondary hardening at temperature of 773K and significantly decreased at 873K. Bending strength did not change largely with tempering temperature and showed maximum value at 453K. Fraction of wear loss did not change during tempering temperature from 473K to 773K but it increased significantly at 873K. The optimum tempering temperature for this alloy steel was found to be 453K from experimental results of strength, hardness, and wear characteristics.
