METHOD FOR CONTROLLING CONCENTRATION OF S-COMPOUND-CONTAINING SOLUTION FOR TREATING COLD ROLLED STEEL SHEET AND METHOD FOR PRODUCING COLD ROLLED STEEL SHEET

摘要

PROBLEM TO BE SOLVED: To provide a method for controlling concentration of an S-compound-containing solution for treating a cold rolled steel sheet, and a method for producing the cold rolled steel sheet, in which it is possible to reduce the amount of an S compound used for production of a high strength cold rolled steel sheet and to reduce a production cost, while stably producing the high strength cold rolled steel sheet.;SOLUTION: The method for controlling concentration of an S-compound-containing solution for treating a cold rolled steel sheet includes: measuring the concentration of an S-compound in the S-compound-containing solution using an analytical means having a minimum determination limit of 0.70 mg-S/L or less in terms of S, when annealing a cold rolled steel strip containing 0.8-3.0 mass% of Si, pickling the annealed strip, and then performing a treatment using the S-compound-containing solution; and controlling the concentration of the S-compound in the S-compound-containing solution to 3.5 mg-S/L or more in terms of S, based on the measured concentration of the S-compound. There is also disclosed a method for producing a cold rolled steel sheet using the method for controlling concentration.;COPYRIGHT: (C)2012,JPO&INPIT