方矩形客车骨架钢管用超高强度钢带开发

为了实现汽车的轻量化生产，开发了车身骨架用高延伸率热轧超高强度钢带。对汽车车身骨架的受力分析及其减重计算分析说明，采用超高强度QStE700TM替代20钢、Q235、510L等传统材料可以实现车身骨架减重32.5%，整体减重7%的目的。通过优化思路，设计了TMCP控轧+多段冷却控冷工艺，试制了高延伸率超高强度热轧钢带，将该钢带经“圆变方”成型工艺制成方矩形焊管，并对其力学性能进行了检测。结果表明，设计的钢带轧制工艺可靠，生产的钢带质量稳定，方矩形管的力学性能达到了客车骨架用QStE700TM的性能要求。

Development of Ultra High Strength Steel Strip for Rectangular Bus Frame Tubes

In order to realize lightweight production of car, high elongation hot rolling ultra high strength steel(UHSS) strip was developed. The force analysis of car-body frame and its weight reduction computational analysis showed that ultra high strength QStE700TM replacing traditional materials, such as 20 steel, Q235, 510L and so on, could realize 32.5% weight reduction of car-body frame and 7% weight reduction of full vehicle. By optimized approaches, thermo mechanical control process(TMCP) combined with multi-section cooling control process was designed, high elongation UHSS strip was trial-produced, the strip was trial-produced to rectangular steel tube by the process which became square from round, and its mechanical properties were tested. The results indicated that the designed steel strip rolling technology was reliable, the quality was stable, and the mechanical properties of rectangular steel tube could meet the performance requirements of QStE700TM for bus frame.