surface hardening

例句：

1. 1. The steel plate needs to be surface hardened before it can be used in the construction.
   钢板在用于建筑之前需要先进行表面硬化处理。
2. 2.The engineer decided to use a new surface hardening process for the project.
   工程师决定使用一种新的表面硬化工艺来处理这个项目。
3. 3. During the manufacturing process, the material is subjected to surface hardening to improve its strength and durability.
   在制造过程中，材料受到表面硬化处理以增强其强度和耐用性。