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我厂为生产石化部门需要的φ57×3.5mm×(6—7m)的1Cr18Ni9Ti 无缝钢管,在 LG55—2型冷轧管机上试进行了超规格轧制。用φ72×5.0mm 的管坯轧出了φ57×3.5mm 的成品管,超出了该设备规定的φ55mm 的上限。在该设备上进行超规格轧制之所以取得成功,是因为我们针对试轧中出现的管坯前窜现象采取了一系列对应措施,保证了试制顺利进行,并为批量生产奠定了基础。该项产品在试轧时,管坯在正行程中曾出现前窜。前窜长度达40～80mm,瞬时变形区不稳定,结果被迫停车。我们分析了造成管坯前窜的原因。从孔型各点示意(图1)可见,小于 R_w 各点的速度,同机架移动方向一致,而大于 R_w各点的速度,则与机架移动方向相反。若以 O_1 为瞬时速度中心,则 O_1 对孔型脊部
I plant for the production of petrochemical sector needs φ57 × 3.5mm × (6-7m) 1Cr18Ni9Ti seamless steel pipe, LG55-2-type cold-rolled pipe machine on a trial of the super-size rolling. The finished pipe of φ57 × 3.5 mm was rolled out of a φ72 × 5.0 mm tube blank beyond the upper limit of φ55 mm specified by the device. The reason why the ultra-standard rolling on this equipment has been successful is that we have taken a series of countermeasures against the phenomenon of pre-channeling of tube blank during trial rolling, which has ensured the successful trial production and laid the foundation for mass production. The product in the trial rolling, the tube has been in the positive stroke had channeling. Forward channeling length of 40 ~ 80mm, instantaneous deformation zone instability, the result was forced to stop. We analyzed the reasons that led to the tube before channeling. It can be seen from the points of the hole type (Fig. 1) that the speed of each point smaller than R_w is consistent with the moving direction of the rack, and the speed of each point larger than R_w is opposite to the moving direction of the rack. If O_1 is the instantaneous velocity center, then O_1 pairs of hole ridges