hardening accelerator

例句：

1. 1. The steel is being hardened to increase its strength.
   钢材正在被硬化以提高其强度。
2. 2. The chemical was used as a hardening accelerator in the manufacturing process.
   这种化学物质在生产过程中用作硬化加速剂。
3. 3. The engineer found that the addition of this hardening accelerator could significantly improve the material's properties.
   工程师发现，加入这种硬化加速剂可以显著改善材料的物理性质。