热处理工艺: 表面局部硬化
Heat Treatment: Selective Surface Hardening

优点:
高硬度：加热速度极快，因而转变温度提高，从而达到细化晶粒的目的，由于晶粒细小而强化了组织。
变形小：因为局部硬化，所以工件整体变形量变小。
表面耐应力：耐疲劳。

Advantages: 
High Hardness: The high rates of heating speed raise the transforming temperature to obtain the fine grains. With the fine grains, the structures will be strengthened.
Low Deformations: The hardening(s) is/are only carried out on the specific locations on the parts, so the overall deformations are low.