Influences of Manufacturing‐Related Microstructural Variations on Fatigue in Carbide‐Rich Tool Steels

In cold-work applications, tool steels with high carbide contents are used as cutting and stamping tools. The service life is limited by wear resistance fatigue strength. relationship between manufacturing-related microstructural influences strengths of has not yet been adequately investigated. To investigate these on high-cycle (HCF) strength (NG = 107), rotating bending tests performed AISI D2 M2/M3. Raw materials produced conventional ingot casting subsequent hot working (HW) well in a powder metallurgy (PM) process isostatic pressing (HIP) forging. Herein, statistically validated correlation process-related defect size the resulting presented. Both PM show significantly higher HCF than HW steels. Critical defects appear to be exclusively small oxide inclusions. contrast, cracks typically initiated fracture large, blocky eutectic carbides. main factor influencing size. Other critical features microstructure include matrix hardness, circularity, type. Improvements can obtained reducing mechanical defects, inclusions for PM, carbides microstructures.