| 摘要 |
PURPOSE:To improve remarkably the heat resistance of a steel sheet by providing a composition contg. N by an amount increased to the utmost and restricted amounts of Al and Si to the steel sheet and by coating both sides of the steel sheet with Al contg. a specified amount of Si by hot dipping to a specified extent of sticking. CONSTITUTION:The composition of a steel sheet is composed of, by weight, 0.005-0.02% C, 0.2-1.5% Mn, 0.003-0.03% N (expressed in terms of sol. N and measured by an internal friction method), <0.01% Si, <0.005% Al, <0.025% P, <0.01% S and the balance Fe with inevitable impurities. Both sides of the steel sheet are coated with Al contg. 3-15 Si by hot dipping by 30-120g/m<2> total extent of sticking of Al. |
