液压支架用无缝钢管轧制开裂原因分析

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.

Analysis on cracking of seamless steel tubes for hydraulic supports in the rolling process

During the rolling process,there is cracking in the some parts of 27SiMn seamless steel tubes for hydraulic supports.The chemical composition of the steel tube was checked,and the microcosmic analysis was conducted by metallurgical microscope and electric scanning microscopy.It is concluded that nonmetal inclusions in the continuous casting billet destroyed the structural succession of the material,and microcracks formed in this zone because of uneven stress during the rolling process.The high-speed of elevated temperature during the reheating process,increases the temperature gradient in the radial direction,tangential pulling stress forms at the outer surface because of the volume contract produced by the microstructure transform,and microcrack propagation leads to the local cracking of the tube.The paper qualitatively analyzed the inclusions,traced back to the source and provided appropriate measures for improvement.