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在轧制27SiMn液压支架用无缝钢管的过程中,管体出现局部开裂,对管体的化学成分进行了检验,利用金相显微镜和扫描电镜对其进行微观分析.分析结果表明,连铸坯中存在较多的非金属夹杂物,破坏了钢基体组织的连续性,在轧制过程中,该部位的金属受力不均产生显微裂纹.再加热过程的快速升温,增大钢管沿壁厚方向的温度梯度,外表面由于相变收缩而产生切向拉应力,显微裂纹进一步扩展从而导致局部开裂.对夹杂物做定性分析,找出其来源,并提出相应的技术改进措施.
In the process of rolling seamless steel pipe for 27SiMn hydraulic support, local crack occurred in the pipe body, chemical composition of the pipe body was inspected, and its microstructure was analyzed by metallographic microscope and scanning electron microscope.The results showed that the slab In the presence of more non-metallic inclusions, destruction of the continuity of the steel matrix, in the rolling process, the parts of the metal uneven micro-cracks generated by the force. Reheating the process of rapid heating, increasing the pipe along the wall The temperature gradient in the thickness direction, the tangential tensile stress on the outer surface due to the phase transformation and shrinkage, and the further increase of the microcrack to cause local cracking. The qualitative analysis of the inclusions is made, the source is found, and the corresponding technical improvement measures are put forward.