quenched and tempered steel

例句：

1. 1.This type of steel is used for building heavy machinery.
   这种类型的钢材用于建造重型机械。
2. 2.The steel was quenched to harden it before being tempered.
   这种钢材在被硬化之前进行了淬火处理。
3. 3. Steelmakers use this method to produce high-quality steel products.
   钢铁制造商使用这种方法生产高质量的钢铁产品。