1966年，北京金属构造厂开辟出了使被焊球体扭转的埋弧主动焊。

In 1966, Beijing metal structure factory developed by rotating sphere of the submerged arc welding automatic welding.

youdao

1966年，北京金属构造厂开辟出了使被焊球体扭转的埋弧主动焊。

In 1966, Beijing metal structure factory developed by rotating sphere of the submerged arc welding automatic welding.

youdao