flame tempering

例句：

1. 1.This process is used to temper steel for cutting tools.
   这个过程用于对钢铁进行淬火，以制造切削工具。
2. 2. The engineers were experimenting with new techniques for flame tempering steel.
   工程师们正在尝试新的技术来对钢铁进行火焰淬火。
3. 3.Flame tempering is a method of heat treatment that can improve the strength and hardness of metals.
   火焰淬火是一种热处理方法，可以提高金属的强度和硬度。