1.前言钢铁生产的发展趋势是生产工序减少而产量提高。如果所生产的连铸坯能使工序减少则连铸方法就能得到最大的经济效果。在无缝钢管生产中,使用圆管坯具有很大的重要性。目前只有少数钢管厂用圆管坯进行生产,但是不断增长的兴趣表明了这种生产工艺的重要性。压力穿孔机可以用方坯,六边形和八边形坯作原料,而斜孔穿孔机就非用圆坯不 1. Preface The trend of steel production is to reduce production processes and increase production. If the production of slab can make the process to reduce the continuous casting method can get the maximum economic effect. In the seamless steel pipe production, the use of round tube billet is of great importance. At present, only a few steel pipe mills are producing round tubes, but growing interest shows the importance of this production process. Pressure piercing machine can use billet, hexagonal and octagonal billet as raw material, and oblique hole piercing machine on the non-use round billet