基于不同工艺的三种结构用方钢管材性研究*
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（1 石家庄铁道大学土木工程学院，石家庄 050043；2 南洋理工大学土木与环境工程学院，新加坡 639798）
［摘要］对强度等级为S355的方钢管的冷加工钢、热加工钢和热轧钢的物理性能、化学性能和力学性能进行了对比研究。结果表明，3种钢材均满足加工标准BS EN 10219-2∶2006 和 BS EN 10210-1∶2006的要求。虽然生产工艺不同，但3种钢材的化学成分相近，对于碳当量CE值，热加工钢最大，其次是热轧钢，冷加工钢最小。3种钢材的力学性能显著不同：冷加工钢的屈服强度最高，但塑性最差；热加工钢的屈服强度最低，但塑性最好；热轧钢介于二者之间。此外，冷加工钢的纵向残余应力最大，且在焊缝处波动明显，转角处不容忽视；而热加工钢的纵向残余应力最小，转角处不明显，大部分区域甚至受压；热轧钢的纵向残余应力分布与冷加工钢的相似，但应力值小很多。［关键词］冷加工钢; 热加工钢; 热轧钢; 方钢管; 材性中图分类号：TU393.3 文献标识码：A 文章编号：1002-848X(2015)14-0077-05
Material properties study on three types of structural square steel tubes with different manufacturing processesQiao Wentao1, Zhao Mingshan2(1 School of Civil Engineering, Shijiazhuang Tiedao University, Shijiazhuang 050043, China; 2 School of Civil and Environmental Engineering, Nanyang Technological University, Singapore 639798, Singapore)Abstract: A comparative study was carried out on the physical, chemical, and mechanical properties of the cold-formed, hot-formed and hot-finished square steel tubes with strength grade of S355. The research results indicate that the three types of steel are able to meet requirment of the production standards of BS EN 10219-2∶2006 and BS EN 10210-1∶2006. Although the manufacturing processes are different, the chemical compositions of the three types of steel are similar. The carbon equivalent (CE) value of the hot-formed steel is the biggest, followed by the hot-finished and then the hot-formed steel. The mechanical properties of the three sections are significantly different. The cold-formed steel shows the highest yield strength but the worst ductility and the hot-formed steel shows the lowest yield strength yet the best ductility, while the hot-finished steel behaves intermediately between the other two in both yield strength and ductility. Besides, the cold-formed steel has the largest residual stress, and the residual stress fluctuates distinctly in the weld seam and can not be ignored at the corners. However the hot-formed steel has the smallest residual stress which is not obvious at the corners, and most of parts are even in the state of compression. The hot-finished steel shows the similar residual stress distribution with the cold-formed steel but the values are much smaller.Keywords: cold-formed steel; hot-formed steel; hot-finished steel; square steel tube; material property
*国家自然科学基金青年基金项目（51208317），河北省高等学校科学技术研究优秀青年基金项目（Z2013037）。作者简介：乔文涛，博士，副教授，硕士生导师，Email：tottyer@126.com。
