34CrMo4/1中厚壁蓄能器用管轧制弯曲原因分析

Analysis on Causes for Bend of 34CrMo4/1 Thick-Wall Pipe After Rolling

阐述了钢种为34CrMo4/1蓄能器用无缝管热轧后在冷床上弯曲的原因。通过分析该钢种的化学成分、金相组织,发现钢管弯曲是由于组织不均所产生的组织应力引起的。经过对比弯管和正常管的CCT曲线,发现Cr和Mo元素的微量变化对中厚壁钢管空冷组织有严重的影响。研究证实适当减少或增加Cr、Mo元素质量分数,CCT曲线向左或向右移动,钢管空冷组织完全避开贝氏体区不发生贝氏体相变或稳定进入贝氏体区,使组织均匀以消除或减小组织应力,均可以避免钢管在大冷床上弯曲。

The bending causes of 34CrMo4/1 accumulator pipe in the cold bed after hot rolling are described. Through analyzing chemical composition and microstructure of the steel, pipe bending is due to the stress for micro structure ununiformity. After comparing the CCT curves of bending pipe and non-bending pipe, it was found that the content change of Cr and Mo in the thick walled steel pipe influences air cooled microstructure. An appropriate reducing or increasing Cr or Mo elements, the CCT curves moved toward left or right can impede or stabilize bainitic transformation to avoid pipe bending for microstructure stress in cooling bed.