Subzero treatment of P/M Vanadis 6 ledeburitic tool steel

The Cr–V ledeburitic steel Vanadis 6 was vacuum austenitised, nitrogen gas quenched and double tempered under various combinations of heat treatment regimes. For selected samples, a subzero period was inserted between quenching and tempering. The results obtained infer that: (1) the as quenched microstructure consisted of martensite, retained austenite and undissolved carbides; (2) the subzero processing reduced the amount of the retained austenite and increased the tetragonality of the martensitic lattice; (3) the as quenched hardness of the steel was higher by 2–3 HRC due to subzero processing; (4) the as tempered hardness increased with increasing austenitising temperature, but it decreased slightly during the subzero period; (5) no negative impact of subzero processing on toughness was recorded; (6) the wear resistance increased with subzero period when a 100Cr6 steel was used as a counterpart.