depth of hardening zone

例句：

1. 1.The depth of the hardening zone is crucial for the quality of the steel.
   硬化带深度对钢材的质量至关重要。
2. 2.The engineers were able to determine the depth of the hardening zone by analyzing the microstructure of the steel.
   工程师们通过分析钢的微观结构来确定硬化带深度。
3. 3. The researcher found that the depth of the hardening zone could be affected by various factors, such as temperature and pressure.
   研究者发现，硬化带深度可能受到温度和压力等多种因素的影响。