| 摘要 |
PURPOSE:To reduce the amount of secondary scale formed on the surfaces of steel products and to enhance the suitability of the scale to pickling by coating the products with a mixture of siC powder and Al2O3 powder and with an antioxidant in order before hot-rolling the products. CONSTITUTION:When steel products such as a slab and a billet are heated to 900- 1,400 deg.C and hot-rolled, fine SiC powder having <=20mum size is mixed with fine Al2O3 powder having <=7mum size so as to make the ratio of Al2O3/(SiC+ Al2O3) 0.2-0.8, and the steel products are coated with the mixture by 20- 600g/m<2> using an inorg. binder such as sodium silicate or polyphosphoric acid. They are further coated with an antioxidant, heated, and hot-rolled. Thus, secondary scale is formed by a small amount during the hot-rolling and the following process, and it can be removed thoroughly by pickling with hydrochloric acid, sulfuric acid or the like in a short time. |
