鋼の燒入硬化に及す特殊元素の影響(I)

抄録

The influence of several elements on the quench-hardening of steel was studied and in this paper the effects of Ni, Cr and Co were described. The specimens were made by adding about 0.5, 1.0, 1.5 and 2.0% of these elements into the molten carbon steel with eutectoid composition and finished into a cylinder of 30mm in diameter and 30mm in high. The specimens were quenched from 750°, 800°, 850°, 900° and 950° into water and oil. The hardness was measured in 1mm distance along a diameter on a section which was ground off 5mm from the surface, using the Vickers' hardness tester. The transformation points of these steels were determined by means of a differential dilatometer. The microstructure was also examined. From the hardness distribution on the sectional surface the following conclusions were deduced: -Nickel increases the quench-hardening effect of steel; Chromium increases the effect very markedly; Cobalt rather decreases the effect.