double quenching

例句：

1. 1. The steel was subjected to double quenching to improve its hardness and strength.
   钢材经过双重淬火以提高其硬度和强度。
2. 2.During the manufacturing process, the metal undergoes multiple stages of double quenching to achieve optimal properties.
   在制造过程中，金属经历多重阶段的双重淬火以获得最佳性能。
3. 3. The engineers designed a new process for double quenching that significantly improved the material's durability.
   工程师们设计了一种新的双重淬火工艺，显著提高了材料的耐用性。