TA2钛管表面横向轧制裂纹研究

Study on transverse rolling cracks of tube TA2

针对使用LG轧机轧制TA2钛管时外表面出现横向裂纹的现象,分析了轧前管坯的内外表面质量、化学成分、力学性能,对轧制后管材横向裂纹的断口形貌进行SEM观察,并对轧制工艺和轧制参数进行分析,结果显示,管坯质量良好,轧制工艺及参数合理,以上均不是造成横向裂纹的原因。通过测量轧辊轧槽的开口度,发现轧辊的开口度为1.12,比正常情况的1.01-1.07偏大,结合轧后管材壁厚偏差较大的现象,认为轧辊开口度过大,使得金属轧制变形不均匀,是造成管材表面产生横向裂纹的原因。基于以上分析,采用辊槽开口度正常的轧辊对管坯继续进行轧制,结果显示,管材外表面横向裂纹消失。

For the phenomenon of transverse cracks on the outside surface of titanium tubes TA2 rolled by LG cold-rolling mill, the out- side and inside surface quality, chemical composition and mechanical property of the original tube blank were analyzed, and the fracture feature of transverse cracks was observed by SEM. Furthermore, the roiling technology and parameters were analyzed, the result shows that the tube blank has good quality, and the rolling technology and parameters are reasonable, which are not the reasons of transverse crack. The rolling width 1.12 is measured, which is bigger than the normal value 1.03 - 1.07. Considering the phenomenon of bigger wall thickness deviation of cold-rolled tube, it is concluded that a bigger rolling width will bring non-uniform metal deformation, which is the reason of transverse crack on the outside surface of tubes. Based on the above analysis, tubes are rolled with normal roiling width, and no transverse cracks on the outside surface are found.