Reasons for cold drawn fracture of YL82B steel used for prestressed steel strands

The YL82B steel used for prestressed steel strands produced by a certain steel plant had experienced multiple fractures during the cold drawing process. The causes of wire rod fracture were analyzed using methods such as macroscopic observation, chemical composition analysis and metallographic examination. The results show that the reasons for the occurrence of pen tip and horn shaped fractures were the slow cooling rate after hot rolling, increased pearlite phase transformation, resulting in a decrease in material strength, and central carbon segregation led to the formation of severe network carbides in material, ultimately led to the fracture of the wire rod. The reasons for the occurrence of flat and oblique fractures were collision on the surface of the material, unclean removal of oxide skin during cold drawing, improper lubrication, non-standard welding causing punctate burns on the material, and failure to normalize in a timely manner after welding.