Effect of Sub-Zero Treatment Temperatures on Hardness, Flexural Strength, and Fracture Toughness of Vanadis 6 Ledeburitic Die Steel

Abstract

Any improvement on the service life of tools reduces the tooling costs, and assists to increase labor productivity by decreasing the needs for either the tools’ re-grinding or their replacement. This requires, among others, an enhancement of the key mechanical properties of the tool materials, by newer treatment route development. The current paper describes the impact of different heat treatment regimes, including austenitizing; sub-zero treatments; and tempering on the hardness, flexural strength, and toughness of tool steel, which is demonstrated upon Vanadis 6 steel. An improvement in the hardness due to the sub-zero treatment is reported, but it is also pointed out that both the flexural strength and fracture toughness of the material cannot be inevitably deteriorated by the application of this processing. Finally, it is demonstrated that both of these properties, despite their conflicting relationship, in most cases, can be improved simultaneously when the material is treated in the proper way.

Keywords

• tool steel
• sub-zero treatment
• microstructure
• hardness
• flexural strength
• fracture toughness
• fractography