1. The blacksmith used a special technique to case harden the metal, making it more resistant to wear and tear.
铁匠使用了一种特殊技术对金属进行表面硬化，使其更耐磨。

2. It is important to case harden the outer layer of the material to protect it from corrosion.
对材料的外层进行表面硬化以防止腐蚀是很重要的。

3. The manufacturer decided to case harden the components of the machinery to prolong their lifespan.
制造商决定对机器的部件进行表面硬化以延长其使用寿命。

4. The process of case hardening involves heating the metal and then rapidly cooling it to create a hardened outer layer.
表面硬化的过程包括加热金属然后迅速冷却以形成硬化的外层。

5. The swordsmith used a traditional method to case harden the blade, giving it strength and durability.
剑匠使用传统方法对刀刃进行表面硬化，使其更坚固耐用。

6. It is essential to properly control the temperature and cooling process when attempting to case harden a material.
在尝试对材料进行表面硬化时，正确控制温度和冷却过程是必要的。