Formation Causes of Fracture of Black Center and White Spot for YL82B Wire Rod

The YL82B wire rods were subjected to tensile test after 20 d natural aging, the fracture of the samples showed the flush fracture of black center and white spot. The causes of the fracture were analyzed by means of chemical composition analysis, metallographic examination and macro and micro analysis of the fracture. The results show that the main reason for the formation of the flush fracture with black center and white spot of YL82B wire rods was the existence of reticular cementite and martensite, or some large granular inclusions in the center of the samples. These reticular cementite, martensite or large particle inclusions were the main reasons for the unqualified reduction of area.