Effect of Annealing Temperature on Microstructun and Mechanical Properties of Precipitation Hardening High Nb IF Steel

摘要：

By using salt bath annealing trial,effects of annealing temperature on microstructure and mechanical properties of a precipitation hardening high Nb IF steel were investigated. Annealed in the range of 790 ~ 850℃ ,the steel shows the elongated ferrite-structure and the ferrite grain size is in the range of 5. 4 ~6. 2μm. A certain amount of bainitic ferrite occurs in the sheet annealed at 870?. For the high Nb IF steel,there is a critical annealing temperature Tc in annealing process．When annealing temperature is lower than Tc,the annealed sheets are with stable mechanical properties and yield ratios of theirs are a litfle lower than those of conventional IF steel. When annealing temperature higher than Tc,yield strength and yield ratio decrease remarkably,possibly due to re—dissolution of fine NbC particles during annealing process． The Nb／C rati0 and coiling temperature in hot rolling of the sheet have apparent influence on the temperature Tc. The optimum annealing temperature for experimental high Nb IF steel is below 830℃．Reducing contents of solid solution elements Mn and P can decrease the strength,simultaneously improving the ductility of the steel．

关键词： high strength IF steel precipitation strengthening microstructure mechanical properties

作者: Wanq Ruizhen Yang Na Cui Yan

作者单位: Institute for Structural Materials,Central Iron and Steel Research Institute,Beijing 100081,China Institute for Structural Materials,Central Iron and Steel Research Institute,Beijing 100081,China Sc

会议类型: 国际会议

会议名称: 2009 International Symposium on Automobile Steel(2009年汽车用钢生产及应用技术国际研讨会)

会议地点: 大连

会议语种:英文

页码: 252-257

在线出版日期: 2009-09-06（万方平台首次上网日期，不代表论文的发表时间）