surface hardening

• 表面硬化

surface hardening的用法和样例：

例句

1. Where through hardness and the maxium strength associateed with it are not necessary,it may be more economical to gain the needed surface qualities by a casehardening process.
   有些不需要同时具有高的强度和硬度的地方完全可以通过表面硬化工艺进行强化使之在达到使用要求的同时又能够节约成本。