Correlation of morphological anisotropy and Lankford value of deep drawing sheets hot-rolled by compact strip production

Shu-li Li 1),Run Wu 1),Yuan-zheng Wei 2),Zhi-fang Wu 1),Xue-jun Zhou 2),Yong-fu Zhang 1),and Guang Xu 1) 1) School of Material and Metallurgy,Wuhan University of Science and Technology,Wuhan 430081,China 2) Wuhan Iron and Steel(Group) Corporation,Wuhan 430083,China

摘 要：Cold-rolled steel sheets in automotive applications require an excellent deep draw ability,which is characterized by the Lankford value（r-value）.In this study,a correlation was identified between r-value and pancake-shaped grain flatness which is indicated as the ratio of grain diameter in the rolling direction（RD） and normal direction（ND） of sheets（d r d n）.A mathematical model（12 r 0.345（） e n d d r 12 =） was developed to calculate r-value by the microstructure of steel sheets hot-rolled by compact strip production（CSP）.It is shown that the r-value is higher,if the microstructure of steel sheet is of pancake-shaped grains elongated in the rolling direction.The calculated r-value is confirmed to fit exactly to the measured one from the large-scale production.

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