DOUBLE-LAYERED STEEL SHEET FOR DEEP DRAWING HAVING HIGH STRENGTHENING CHARACTERISTIC BY IRRADIATION WITH HIGH-DENSITY ENERGY SOURCE AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To provide a double-layered steel sheet for deep drawing which has a layer for improving a high strengthening characteristic by irradiation with a high-density energy source on a front layer and has an inside layer excellent in high strength increasability by irradiation with the high-density energy source having a component system with excellent workability. ;SOLUTION: This double-layered steel sheet for deep drawing, which is excellent in the high strength increase by the irradiation with the high-density energy source, contains C, Si, Mn, Cr, B which are the elements to enhance the high strength increasability by the irradiation with the high-density energy source without impairing the deep drawability on the surface of the steel sheet. The inside of the steel sheet is an extra-low carbon steel which is particularly good in deep drawability. The process for producing this steel sheet is a method of exactly arranging the position of a nozzle for injecting molten steel 11 and a position for installing a static magnetic field 5 and adding the surface layer elements at the time of casting. The control of the thickness of the surface layer 10a is exectuable exactly at the pulling speed of a slab and the position where the static magnetic field 5 is installed and, therefore, the double-layered steel sheet for deep drawing which has the stable thickness of the surface layer 10a and is excellent in the high strength increase by the irradiation with the high-density energy source is produced.;COPYRIGHT: (C)1997,JPO