Rockwell hardness number

例句：

1. 1. The Rockwell hardness number of the material is 60.
   该材料的洛氏硬度数为60。
2. 2.The Rockwell hardness number is an important parameter in determining the quality of steel.
   洛氏硬度数是决定钢材质量的重要参数。
3. 3. The Rockwell hardness number can be used to measure the resistance of materials to wear and tear.
   洛氏硬度数可以用于测量材料抵抗磨损和疲劳的能力。