COLD-ROLLED STEEL SHEET AND HOT-DIPPED GALVANIZED STEEL SHEET EXCELLENT IN UNIFORM WORKABILITY, AND PROCESS FOR PRODUCING THE SHEETS

摘要

The workability of steel sheets is remarkably improved by using an extra-low-carbon steel containing Nb and/or Ti as the raw material and depositing carbide sulfides efficiently in the gamma -temperature zone during hot rolling under the conditions of the ratio of the sulfur content (%, in terms of MnS) to the total sulfur content of 0.2 or less and the ratio of the carbon content (%, in terms of carbide sulfide) to the total carbon content of 0.7 or less, thus reducing the dissolved carbon content and assuring the material uniformity along the entire coil length.