| 摘要 |
PROBLEM TO BE SOLVED: To provide a steel sheet for nitriding treatment, excellent in strength and low temperature brittleness after nitriding and further excellent in press formability and surface characteristic, and its production. SOLUTION: The steel sheet has a composition which consists of, by weight, <=0.010% C, <=0.05% Si, 0.1-1% Mn, <=0.1% P, <=0.02% S, 0.01-0.10% Sol.Al, <=0.1% Cu, <=0.003% N, Ti in an amount in the range where the value of Ti*, defined by equation Ti*=Ti%-48/14×N%-48/12×C%-48/32×S%, is regulated to -0.01 to 0.08%, and the balance Fe with inevitable impurities, and further, the average crystal grain size of ferrite is regulated to <=15μm.
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