Effects of Rolling Parameters on Texture and Formability of High Strength Ultra-Low Carbon BH Steel

The effects of hot rolling and cold rolling parameters on texture and r (plastic strain ratio) value of high strength ultra low carbon bake hardening (ULC-BH) steels are studied with orientation distribution function (ODF) structural analysis method. After hot rolling, the high strength ULC-BH steel sheet has weak gamma-fiber with uniform orientation distributions, and weak alpha-fiber, of which {445}< 110 > component forms a high intensity peak at coiling temperature of 750 degrees C. After cold rolling, both {111}< 110 > {111}< 112 > intensity on the gamma-fiber and {111}-{112}< 110 > intensity on the alpha-fiber enhanced. As a result of substitutional solute elements Mn and P being added to the steel, strong {112}< 110 > deformation texture component is observed on alpha-fiber, especially at 80% cold rolling reduction, and this leads to the strong {111} < 112 > recrystallization texture after annealing. The increase of cold rolling reduction shift's the maximum intensity on the gamma-fiber from {111}< 112 > to {111}< 113 >. After annealing, a very strong gamma-fiber is obtained, with intensity peak at {111}< 112 > component when cold rolling reduction reaches 80%. Increasing coiling temperature and cold rolling reduction improve gamma-fiber intensity and r value, resulting in good deep drawability.