| abstract |
A method for producing a formed member (10, 20,n30, 50, 50', 60, 70, 80, FR, F4) made of a steel sheetnaccording to the present invention is characterized bynpreparing a steel sheet material having tensile strengthnof 500 MPa or less and containing a nitriding element;nforming a formed member (10', 20, 30', 50, 50', 60, 70,n80, FR, F3) having a predetermined shape by performing anplastic forming on the steel sheet material; andnperforming a nitriding treatment on the formed member sonthat an average hardness in the sheet thickness directionnof the resultant steel sheet member is Hv 300 or more bynVickers hardness, and further characterized in that thendifference in hardness between the surface part and theninside center part in the thickness direction of thensteel sheet member of the formed member is Hv 200 or lessnby Vickers hardness, thereby it is possible to reliablynobtain a formed member having a sufficiently highnstrength after a nitriding treatment while ensuring anplastic formability of a steel sheet in obtaining anformed member made of a steel sheet member of highnstrength by performing a nitriding treatment afternsubjecting a steel sheet material to a plastic forming. |