Abstract：In view of the defects of welding cracks in 1/4 thickness of Q345DZ25 steel plate produced by nanyang hanye special steel co., LTD., metallographic, electron microscope and energy spectrum analysis were conducted, and it was found that the cracks were mainly caused by oxide inclusion of aluminum and calcium. Through the study of calcium treatment process and the sampling of components and slag, it is concluded that the high content of aluminum-calcium oxide inclusion in molten steel is related to the inappropriate calcium treatment time in the production process. By adjusting the time of calcium treatment and controlling the amount of calcium line, [Ca]/[Als] =0.10-0.14 in the molten steel, the calcification treatment effect was improved and the purity of molten steel was improved.
2020, Vol. 27 