Influence of tool microstructure on galling resistance

In sheet metal forming, different types of tool steels are used depending on sheet quality. In the present work, influence of amount, and type, of primary carbides and carbo-nitrides was investigated regarding tool galling resistance against austenitic stainless steel. A significant impact of amount of carbides on galling resistance was observed and tool performance was improved as volume fraction increased. However, no influence of carbide type was distinguished. Alloying by nitrogen further improved the galling resistance and best tool performance was observed for a tool steel comprising only carbo-nitride M(C,N) particles. Besides transfer of sheet material, several other tool damage mechanisms were observed such as cracking, micro-chipping and abrasive scratching.