DEVELOPMENT OF LOW CARBON NIOBIUM BEARING HIGH STRENGTH F-B DUAL PHASE STEEL WITH HIGH HOLE EXPANSION PROPERTY
(0) In the study a low carbon niobium bearing high strength F-B dual phase automobile steel with high hole expansion property has been investigated.Steels of different chemical composition have been investigated by simulation experiments of controlled rolling and cooling process to study the influences of chemical elements,especially for C,Nb and Ti,and cooling pattern on the mechanical properties,flangeability and microstructure of strips.So-called 3-stages cooling pattern was adopted in simulation experiments,combining ultra fast cooling in first stage,air cooling in middle stage and fast cooling in the last stage,and at the end of run-out table the temperature of rolled pieces drop to below Bs point.Optical microstructure and SEM morphology have been observed.Results indicate that it is possible to obtain dual phase microstructure of polygonal ferrite plus bainite in adopting 3-stages cooling pattern.The low temperature coiling method using 3-step controlled cooling pattern after hot rolling is effective to produce low carbon Nb bearing steel with high balance of strength-ductility-flangeability,in addition,higher carbon content of steel tend to be detrimental to flangeability of steel,due to much carbide precipitation at ferrite boundary.Based on the results of simulation experiments mill trial has been carried out and hot rolled high strength steel with tensile strength higher as 600Mpa and hole expansion ratio higher as 100%has been developed successfully.
F-B steel dual phase steel bainite hole expansion ratio niobium
Lin ZHANG Ming-sheng XIA Zi-liu XIONG Yan-bing DU Zhi-ming Qiao Hong-bo ZHANG
Tangshan Iron and Steel Group Co.,Ltd,Tangshan,Hebei Province,China Central research institute of HeBei Iron and Steel Group,ShiJiaZhuang,Hebei Province,China
国内会议
杭州
英文
677-681
2015-11-11（万方平台首次上网日期，不代表论文的发表时间）