Principal Design Features Mold steel H13 is one of the Hot Work, Chromium type tool steels. It also containsmolybdenum and vanadium as strengthening agents. The chromium contentassists this alloy(H13) to resist softening if used at higher temperatures. Applications H13 finds applications for hot die work, die casting and extrusion dies. Machinability Machinability of H13 is medium to good. It rates as 75% that of the W groupwater hardening tool steels which are low alloy and of generally good machinability.Hardness≦#65533;235