Study of the effect of cycle time of plasma nitriding on the service life of AISI H-13 tool steel die

Abstract

AISI H-13 tool steel is widely used as a hot-forging die for various automotive components. Usually,

to increase the die life, the dies are subjected to additional surface treatment process such as

carburizing, gas nitriding, salt bath nitriding, plasma nitriding, etc. The case depth is an important

parameter in surface treatment process. In this work, AISI H-13 tool steel hot-forging dies are

subjected to plasma nitriding. The nitriding time cycles are 8 , 12 and 24 h. The lives of plasmanitrided

dies increased largely. Highest life enhancement and surface hardness is achieved by 8 h

plasma-nitriding cycle. The effect of cycle time on life enhancement is presented with justification

with respect to the microstructure.

Keywords: Coefficient of thermal expansion, Caompound layer, die life.