Abstract
For the purpose of obtaining some knowledge on the effect of alloying elements upon the elevated temperature strength of low alloy heat-resisting steels, the influences of some alloying elements upon the hot hardness of low alloy steels have been investigated. The conclusions are as follows: At room temperature, the effect of dispersion of carbide on hardness is very strong, however the effect decreases rapidly above 400°C. The Cottrell effects by dissolved carbon and nitrogen show peaks of hardness at 300°C and 250°C respectively, but their contributions to hardness at 600°C are very small. The solid solution hardening by substitutional atoms is not so strong at room temperature, but the contribution to hot hardness increases slightly with increasing temperature up to 600°C. The contribution of interaction between interstitial solid solution atoms and substitutional solid solution atoms (I-S effect) to hardness appears at temperatures above 300°C, and increases with increasing temperature. The I-S effect cannot be ignored for the high temperature strength of low alloy steels.
