Analysis and Countermeasures of Defects in Protective Slag Inclusions in Cold Rolling Products
JIA Chongxue
DING Zizheng
MA Qiang
LI Ning
Abstract：Analysis indicates that the high content of Al2O3 inclusions in steel,leading to nozzle clogging and subsequently causing slag entrapment in the mold,is the primary cause of peeling and gray streak-like defects in cold-rolled products.By increasing the hot metal ratio and implementing a heat compensation system,the endpoint hit rate of the converter improved from 78.3%to 90.6%.The application of ferrosilicon and carbon powder pre-deoxidation processes reduced the residual oxygen content in RH to 72×10-6.Dynamically adjusting the addition of modifiers and lime based on endpoint oxygen levels resulted in a decrease in the TFe content of RH top slag from 6.73%to 4.47%,with the Ca/Al ratio in the slag stabilizing within standard limits.After process optimization,the occurrence rate of peeling and gray streak-like defects in cold-rolled products decreased from 0.65%to 0.31%.
Keywords：cold-rolled thin platedelamination defectinclusionstundish slag
Publication Date：2025-06-20
Online Publishing Date：2026-05-22(First online date of this platform, not the publication date of the document)
Pages：3( 14-16 )