脱管机和定径机是天津钢管公司轧管厂热轧管生产线上的主要设备。脱管机、定径机轧辊孔型的加工精度直接影响钢管的外表面质量。经对轧辊加工刀具倒角刀的改进，解决了长期困扰生产的钢管表面青线缺陷问题，取得了较好的实际效果和经济效益。 Tube removing machine and sizing machine are the main equipments on the hot rolling pipe production line of Tianjin Pipe Mill. Off the machine, sizing mill roll hole machining accuracy directly affects the quality of the outer surface of the steel pipe. After the improvement of the roll processing tool chamfering knife, the long-term problem of the green line defect plagued by the steel pipe surface production has been solved and good practical and economic benefits have been achieved.