The etched section also reveals that multiple weld passes were made over the top of the original submerged arc weld pass.

 
  • 從酸蝕斷面還可以看出:在原自動(dòng)埋弧焊的上面覆蓋有多層焊道。
今日熱詞
目錄 附錄 查詞歷史
国内精品美女A∨在线播放xuan