under tempering

例句：

1. 1. The steel was under tempered before being used in the machine.
   钢材在用于机器之前需要经过热处理。
2. 2. The engineers were under tempering to ensure thequality of the new product.
   工程师们正在接受热处理，以确保新产品的质量。
3. 3. The car wasunder tempered to improve its durability andperformance.
   汽车进行了淬火处理，以提高其耐用性和性能。