TOOL STEEL FOR HOT WORKING HAVING SUPERIOR HEAT CRACK RESISTANCE AND SOFTENING RESISTANCE

摘要

PURPOSE:To manufacture a tool steel for hot working having superior heat crack resistance and softening resistance at high temp. by incorporating regulated amts. of specified elements into a tool steel having a specified compsn. CONSTITUTION:The compsn. of a tool steel is composed of, by weight, 0.05-0.3% C, 0.1-1.0% Si, 0.1-3.0% Mn, 1-3% Ni, 1-4% Cr, 0.2-1.5% Mo, 0.01-0.3%, in total, of Ti and/or Nb and the balance Fe with inevitable impurities. The tool steel has superior heat crack resistance and softening resistance at high temp., a tool made of the steel does, therefore, not crack over a long period of time and has a remarkably prolonged service life.