Variation of Elastic Constants of Hardened 1 per cent Carbon Steels on Tempering

Abstract

IT was shown some years ago that changes in elastic constants accompany the hardening process in steel¹ and can be measured by ultrasonic techniques. More detailed experiments have been made recently on two commercial steels containing about 1 per cent carbon. The steels were quenched in oil from 780° C. and then tempered for one hour at temperatures between 100° C. and 650° C., in steps of 50° C. Young's modulus, E, and the rigidity modulus, G, were measured after each heat treatment by the ultrasonic-pulse method. The rigidity modulus was also measured by static loading, the same specimens being used.