Development of Cu-bearing bake-hardenable steel sheets for automotive exposed panels

被引:10
作者
Hong, Moon-Hi [1 ]
Cho, Noi-Ha [1 ]
Kim, Sung-Il [2 ]
Kwon, Ohjoon [3 ]
Lim, Sung-Hwan [4 ]
Moon, Won-Jin [5 ]
机构
[1] POSCO Gwangyang Steelworks, Jeonnam 545700, South Korea
[2] POSCO Tech Res Lab, Gwangyang 545090, Jeonnam, South Korea
[3] Res Inst Ind Sci & Technol, Pohang Si 790600, Gyeongbuk, South Korea
[4] Kangwon Natl Univ, Dept Adv Mat Sci & Engn, Chuncheon Si 200701, Gangwon, South Korea
[5] Korea Basic Sci Inst, Kwangju 500575, South Korea
关键词
metals; deformation; precipitation; strain aging; transmission electron microscopy (TEM); LOW-CARBON STEEL; MECHANICAL-PROPERTIES; COPPER SULFIDE; ALUMINUM;
D O I
10.1007/s12540-010-1205-2
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
Recently, newly developed bake-hardenable (BH) steel sheets strengthened by copper sulfide (CuS) have been successfully employed in commercial production lines that supply automotive outer panels. The metallurgical concepts governing fabrication of these new BH steel sheets require keeping carbon content as low as 0.0015 wt.% without any additional amount of titanium and/or niobium for solute carbon scavenging. The role of CuS precipitates has turned out to raise the yield strength acting as a barrier against dislocation movement. In this paper, we studied the effects of chemical compositions and manufacturing process variables on the microstructure and mechanical properties of newly developed BH steel sheets. We found that the control of carbon and nitrogen showed a good balance between bake-hardenability (BH) and yield point elongation (YP-El). We identified the crystallographic relationship between the nano-size CuS precipitates and the ferrite matrix of (001)(sulfide)//(001)(alpha-Fe) and [001](sulfide)//[001](alpha-Fe). We also found that the BH and YP-El were affected by the formation of aluminium nitride (AlN) and the annealing temperature.
引用
收藏
页码:883 / 890
页数:8
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