quench-hardening

例句：

1. 1. The steel was quenched and then hardened to increase its strength.
   钢材经过淬火和硬化以提高其强度。
2. 2.In the manufacturing process, quenching is an essential step for achieving hardening.
   在制造过程中，淬火是实现硬化的关键步骤。
3. 3. The engineers had to quench the metal before it could be hardened.
   工程师们必须在金属硬化之前对其进行淬火处理。