Abstract: Both wear and crack due to heat checking in hot work tool steel are major failure modes. It is desirable to find a method to lengthen the tool life while reducing manufacturing cost. This paper suggests a method to improve tool life for hot work tool steel (SKD6) with crack by laser-melting process. The method has been evaluated using the impact and fatigue test results. It is demonstrated that a repair of the crack by a laser-melting process is effective for life extension of the damaged tool.

Key words: Hot work tool steel, Laser-melting process, Impact test, Fatigue test, Fractography