分段后退銲法 back step welding: 反手焊接back step welding procedure: 逐步退焊法back step welding sequence: 后退焊接順序step-back method of welding: 分段反向焊法step-back welding: 分段后退焊接; 后向分段焊接; 逆向分段焊接下載手機詞典可隨時隨地查詞查翻譯