| 摘要 |
PURPOSE: To provide excellent bulging press fomability by specifying a composition. CONSTITUTION: This steel sheet has a composition which contains, by weight ratio, 0.01-0.10% C, 0.01-0.15% N, <=2.0% Mn, 3.0-5.5% Ni, 15.0-20.0% Cr, and 0.5-3.0% Cu and in which the value of >=Ni represented by the equation is regulated to -6 to -4%. TheΔNi represented by the equation is a value of determining the stabiility of austenite and take a value of -3 to -2% in the case of general purpose SUS 3-4 and -4 to -2% in the case o SUS 301. The elongation of the material at room temp. (20 deg.C) can be maximized by the above-mentioned component deign. However, elongation in a wide temp. range between 40 and 80 deg.C rather than that at room temp. is required in the case of extremely severe bulging because material temp. rises in the course of this working. Accordingly, in order to obtain the required elongation at 40 to 80 deg.C, the composition is regulated andΔNi is regulated to -6 to -4%.
|
