hollow casting

例句：

1. 1. Hollow casting is a technique used in the production of lightweight metal parts.
   空心铸造是一种用于生产轻质金属部件的技术。
2. 2.In the hollow casting process, molten metal is poured into a mold and allowed to solidify.
   在空心铸造过程中，熔融金属被倒入模具中并允许凝固。
3. 3. The hollow casting process reduces the weight of the final product, making it more energy-efficient.
   空心铸造过程减少了最终产品的体重，使其更加节能。