The aim of present work is to investigate the behavior at high temperature of 55NiCrMoV7 steel used in mandrels for ring rolling. During service the tool is exposed to complex conditions including thermal fatigue, oxidation, and hot wear. In this work, samples were obtained from a broken mandrel. The steel microstructure in the as-delivered state consisted of overtempered martensite and bainite. The very low hardness (32HRC) was produced by thermal softening during service. A new set of harder samples (41HRC) was obtained after vacuum heat treatment. Hot wear and thermal fatigue resistance for the steel in the two conditions were compared.
Behavior at Elevated Temperature of 55NiCrMoV7 Tool Steel
De Flora, Maria Giuseppina;Pellizzari, Massimo
2009-01-01
Abstract
The aim of present work is to investigate the behavior at high temperature of 55NiCrMoV7 steel used in mandrels for ring rolling. During service the tool is exposed to complex conditions including thermal fatigue, oxidation, and hot wear. In this work, samples were obtained from a broken mandrel. The steel microstructure in the as-delivered state consisted of overtempered martensite and bainite. The very low hardness (32HRC) was produced by thermal softening during service. A new set of harder samples (41HRC) was obtained after vacuum heat treatment. Hot wear and thermal fatigue resistance for the steel in the two conditions were compared.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione
