DEVELOPMENT AND OPTIMIZATION OF CARBIDE-REINFORCED TOOLS AND APPLICATION TO HOT-ROLLING OF STAINLESS-STEEL

A new design philosophy was tried out on a carbide-reinforced tool for hot working of stainless steel. The carbide particle in the microstru cture of the new tool was selected so as to meet the relatively large optimum size. Attention has been focused, in the conventional tool, on the enlargement of the area fraction of fine carbide particles on the surface. The tool was made by a plasma transferred are process, and i t was found in the laboratory that an optimum mixture ratio of NbC and AISI316L powder realizes the best performance against wear and gallin g. It was also found that coating of the new tool material on the moth er metal of moderate strength, roughness, and ductility ensures the lo ngevity of the tool. The new tool was subjected to hot rolling of a st ainless-steel seamless tube by a plug mill to verify the high performa nce.