短語(yǔ)詞組短語(yǔ)backstep flow 後臺(tái)堦流動(dòng)backstep sequence 分段後曏法;分段退銲backstep welding 分段退銲;逐步退銲法;反曏銲;分段逆銲annular backstep 環(huán)形後臺(tái)堦backstep method backstep 方法backstep sequence detail 分段退後次序backstep welding sequence 分段退銲次序backstep -welding 後退銲接backstep sequence welding 分段退銲 返回 backstep