HIGH-STRENGTH COLD-ROLLED STEEL SHEET WITH EXCELLENT STRETCH FLANGEABILITY AND PRECISION PUNCHABILITY, AND PROCESS FOR PRODUCING SAME

摘要

A high-strength cold-rolled steel sheet having excellent stretch flangeability and precision punchability which contains given components, with the remainder comprising iron and incidental impurities. In mass%, containing: C: greater than 0.01% and less than 0.4%, Si: 0.001% or more and less than 2.5%, Mn: 0.001% or more and less than 4%, P: 0.001 to 0.15% or less, S:0.0005 to 0.03% or less, Al: 0.001% or more and less than 2%, and N: 0.0005 to 0.01%. In the range of from a depth from a surface of the steel sheet which corresponds to 5/8 the sheet thickness to a depth therefrom which corresponds to 3/8 the sheet thickness, the average pole density for {100}011 to {223}110 orientations which are represented by the crystal orientations {100}011, {116}110, {114}110, {113}110, {112}110, {335}110, and {223}110 is 6.5 or less and the pole density for the crystal orientation {332}113 is 5.0 or less. The steel sheet has a metallographic structure that contains pearlite in an amount exceeding 5% in terms of areal proportion and has a total content of bainite and martensite limited to below 5% in terms of areal proportion, with the remainder comprising ferrite.