EXTRA-LOW CARBON THIN STEEL SHEET FOR DEEP DRAWING AND EXTRA-LOW CARBON THIN STEEL SHEET FOR DEEP DRAWING APPLIED WITH GALVANIZING

摘要

PROBLEM TO BE SOLVED: To obtain excellent deep drawability, in an extra-low carbon thin steel sheet for deep drawing contg. C and Ti respectively by specified amounts, by controlling the concn. ratio of precipitated N expressed by (the concn. of precipitated N in the surface layer part from the surface of the steel sheet to a specified depth of the sheet thickness)/(the concn. of precipitated N in the center part of the steel sheet) to the value equal to or below the specified one. ;SOLUTION: This extra-low carbon thin steel sheet for deep drawing contains, by mass, ≤0.005% C and 0.01 to 0.1% Ti, and in which the concn. ratio of precipitated N expressed by (the concn. of precipitated N in the surface layer part from the surface of the steel sheet to 1/100 of the sheet thickness)/(the concn. of precipitated N in the center part of the steel sheet) is ≤3.0. It is also preferable that, as to the crystal grains in the position of 100 μm in the sheet thickness direction from the surface of the steel sheet, the shape ratio expressed by (the grain size in the rolling direction)/(the grain (BR) size in the sheet thickness direction) is ≤3.0. It is also suitable that the steel sheet is incorporated with at least one kind among Sn, Pb, As, Bi, Te, Se and Sb respectively by 0.001 to 0.10%.;COPYRIGHT: (C)2001,JPO