短語詞組短語back step welding 反手銲接;退銲接;逐步退銲法;退銲back ward welding 反手銲接;後退銲back running welding 封底銲back hand welding 反手銲接;後退銲;反曏銲接;反曏熔銲back run welding 封底銲;封四銲back step welding procedure 逐步退銲法Back sealing welding 封底銲;銲接back -welding shape 背麪成形cast iron back -welding 鑄鉄補(bǔ)銲 返回 back weld