| 摘要 |
PURPOSE: To produce a chromium steel sheet excellent in formability and ductility in a weld zone by incorporating specific amounts of C, Si, Mn, P, S, N, Cr, Al, Ti, Nb, B, La, Ce, Se, and Fe. CONSTITUTION: A steel, having a composition consisting of, by weight, <=0.03% C, <=1% Si, <=1% Mn, <=0.05% P, <=0.015% S, <=0.O2% N, 5-60% Cr, =0.1% Al, 4(C+N) to O.5% Ti, 0.003-0.02% Nb, 0.0002-0.005% B, one or >=2 elements among La, Ce, and Se by the amounts in the ranges satisfying (La+Ce+20 Se)=0.01 to 0.5%, and the balance essentially Fe, is used. Deep drawability and resistance to secondary working brittleness can be improved by the combined addition of Nb, Ti and B, and ductility in a weld zone can be improved by the use of La, Ce and Se. By this method, the chromium steel sheet, in which Lankford value (r), inplane anisotropyΔr, brittle crack occurrence temp., and cracking ratio at the time of repeated bending are regulated to >=1.5, >=0.3, >=-50 deg.C, and <=10%, respectively, can be produced.
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