Prestressed steel strands are mainly used for railway bridges, highway bridges, highways and water conservancy facilities.
Its production material is generally SWRH82B line. In the production of prestressed steel strands, the phenomenon of wire breakage will occur, which not only affects the product quality of Chunpeng steel strands, but also seriously affects production efficiency and output. The specific reasons for the disconnection are:
1, wire surface defects
The fracture mainly occurs on the surface of the steel wire, with obvious wear marks and cracks. Under the microscope, the hard structural deformation zone of acicular martensite, troostite and the reasons are as follows: the temperature of the scraped area is too high due to rapid hardening and wear in the cold, but the martensite structure is generated because the scraped area is too high. It is small and cools too fast. Surface cracks appeared during the drawing process of Tianjin prestressed anchorage. As the deformation gradually increased, the steel wire broke.
2, central inclusions
Scanning electron microscope observed inclusions in the center of the crack source. The inclusions are mainly calcium aluminate type produced in the process of steelmaking and deoxidation. The existence of non-metallic inclusions in the metal wire destroys the continuity of the structure and the matrix, and the existence of the inclusions becomes microcracks. Once the force is applied, when the crack reaches the size of an unstable state, it will break immediately and form a broken wire.