Effect of single and double cold-rolling reductions on the planar anisotropy of r-value in sheet steels

The planer anisotropy of r-value (Δr) is an important property of sheet steels for two piece can use. The effects of cold rolling and temper rolling reduction on Δr are especially large. Δr has a maximum value at the ratio of about 75% single cold rolling reduction. At the higher cold reduction, Δr decreases abruptly for the low carbon steels. On the other hands, Δr become zero at the reduction about 90% for ultra low carbon steels. For the double cold rolling, Δr decrease linearly, independent of cold reduction or carbon content. The tin mill black plate is manufactured at high single cold rolling reduction because of its thin thickness of final products. It is thought that single cold rolling reduction become higher when reduction of gauge is progressed. Therefore, reduction of the carbon content is superior to the conventional ones to achieve the small anisotropy ultra-thin sheets. The r-value and its anisotropy can be explained by the texture using simple Tucker model.