短语词组短语powder submerged -arc 粉末埋弧焊submerged -arc smelting 埋弧冶炼Submerged -arc welding power 埋弧焊接电源double submerged -arc welding 双丝埋弧焊multiplewire submerged -arc welding 多丝埋弧焊 返回 submerged arc