n.硬化法(增加硬度；淬火；渗碳；锻炼)

动词harden的现在分词形式.

So we find that hardening operation is made up of heating and quenching. 因此我们发现淬火工序包括加热和淬硬两个步骤。

The maximum degree of hardness obtainable in steel by direct hardening is determined largely by the carbon content. 直接淬火后的刚所能获得的最大硬度在很大程度上时由含碳量决定的。

The Super carburization process can provide outstanding performance in the surface hardening of high-alloyed steel. 过渗碳处理可以有效提升高合金工具钢的表面特性。