| The purpose of the present study is to develope for producing high strength cold-rolled steel sheets having low yield strength suitable for automobile body panels. In recent years the modification of nonmetallic inclusions by a metallic calcium addition has received increasing attention. Calcium in molten steel reacts with the oxides and sulphides to form new calcium containing compounds and complex oxysulphids. As a result, the composition, shape, number and distribution of a non-metallic inclusions are changed, greatly improving the mechanical and other properties of a finished steel. In this study the addition of Ca wire and CaAl wue containing calcium and aluminum into the molten steel (0.1% C) gives the following advantages. 1) Deoxidation and desulphurization more effectively. 2) Increase of the amount of calcium residuals in the steel. 3) Change of shape and distribution of nonmetallic inclusion. 4) Increase of elongation, reduction of cross sectional area and impact values. 5) Improvement of workability and anisotropy. |
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