Abstract
This report deals with the investigation of properties of the steels treated by various ways of case-hardening.
The steels tested are low-carbon steel, boron-treated low-carbon steel, chromium steel, and boron-treated chromium steel.
The results are as follows:
By any treating way, the hardness increases in the lower-carbon part of the case, but is almost unchanged in the higher-carbon part.
Moreover, by carbonitriding, the hardenability of the case obtained by diffusions of carbon and nitrogen generally has the similar tendency to that of the hardenability of the boron-treated steel affected by carbon and nitrogen in the steel making.
The mechanism of carbonitriding reaction, however, is considered to be different from that of reactions at high temperature as in the steel making.
