Abstract
The deformation due to heat treatments for five kinds of self-hardening tool steel, such as, Cr steel, Cr-Mn steel, two Cr-W steels and Cr-V steel, were investigated. In high C high Cr steel with an addition of about 3% of Mn,owing to the increase in its selfhardening property, a remarkable decrease in length takes place by the air-hardening from 1000° upwards, where as the hardening-deformation is very small on air-cooling from a comparatively low temperature, e.g. 950°. The addition of about 0.8% of W, gives a slight influence upon the hardening-deformation in high C high Cr steel,although a resistance against softening due to tempering increases. In steels containing about 2%C, 12%Cr, 1%V and about 1%C, 3%Cr, 9%W, the hardening-deformation is slight, when the specimens are air-cooled from comparatively high temperatures, e.g. 1050° for the former and 1130° for the latter respectively. In all steels studied, the retained austenite transforms into martensite during cooling from the tempering temperature, resulting in the increase in volume.
