并从结构设计及铸造工艺设计两方面提出了防止球铁井盖上表面缩凹的措施，这些方法在生产实践中已得到检验。

Some prevention methods were proposed from two aspects of structural design and casting processing which has been verified by production practice.

youdao

并从结构设计及铸造工艺设计两方面提出了防止球铁井盖上表面缩凹的措施，这些方法在生产实践中已得到检验。

Some prevention methods were proposed from two aspects of structural design and casting processing which has been verified by production practice.

youdao