grinding hardness

例句：

1. 1. The steel is very hard and can withstand heavy loads.
   这种钢非常硬，能够承受重载。
2. 2. The grinding process requires a high degree of precision to achieve the desired hardness.
   磨削过程需要高度的精确度以达到所需的硬度。
3. 3.The engineer used a special alloy to increase the hardness of the material.
   工程师使用了一种特殊的合金来增加材料的硬度。