论文部分内容阅读
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.
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 (drdn). A mathematical model (12 r 0.345 () enddr 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.