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为了克服传统辊弯工艺和设备对室温下高强钢的影响,提出弯角局部感应加热辊压成形工艺制备高强钢方管,并通过单向拉伸试验、断口形貌观察、微观组织扫描电镜观察和X射线衍射分析研究热辊压成形温度对高强钢方管弯角处组织及力学性能的影响.结果表明,随着温度的升高,弯角力学性能得到明显的改善,断口形貌由室温下解理断裂逐渐过渡为韧性断裂,弯角处微观组织由板条状贝氏体向粒状贝氏体发展且多边形铁素体晶粒开始长大,方管外表面周向和纵向残余应力都明显降低且分布更加合理.综合实验分析,高强钢方管热辊压成形工艺的最佳温度为650℃.
In order to overcome the influence of conventional roll bending process and equipment on high strength steel at room temperature, a corner induction induction heating roll forming process was proposed to prepare high strength steel square tube. Through uniaxial tensile test, fracture morphology observation and microstructure scanning electron microscope observation And X-ray diffraction (XRD) were used to study the effect of hot roll forming temperature on the microstructure and mechanical properties of high-strength steel square tube.The results show that with the increase of temperature, the mechanical properties of bending angle are obviously improved, The lower cleavage fracture gradually transitions to ductile fracture, the microstructure at the corner is developed from lath-shaped bainite to granular bainite, and the polygonal ferrite grains begin to grow up. Both the circumferential and longitudinal residual stress on the outer surface of the square tube are Obviously lower and more reasonable distribution.According to the comprehensive experimental analysis, the optimum temperature of high-strength steel tube hot roll forming process is 650 ℃.