Manufacturing process and application scope of prestressed steel wire
Cold-drawn prestressed steel wire is made of high-carbon steel wire rod after surface treatment and cold drawing. The carbon content of steel is selected in the range of 0.6-0.9. It must be pickled, phosphated or other forms of surface treatment before cold drawing. The cross-sectional area will generally be reduced by 50% to 80% after cold drawing, and the strength will be improved through the principle of cold working hardening. Prestressed Concrete Steel Wire
If the cold-drawn prestressed steel wire is stabilized, it will become a low-relaxation prestressed steel wire, obtain low-relaxation characteristics, and significantly improve yield strength, elongation and straightness. If it is galvanized, it will become a galvanized prestressed steel wire. The steel wire that is stabilized after galvanizing is called a low-relaxation galvanized prestressed steel wire.
Steel wire is generally delivered in coils. When used in sleepers, it can be cut into bundles according to the needs. The diameter of prestressed steel wire is generally in the range of four to twelve millimeters. At present, 5 mm and 7 mm specifications are commonly used in China. The high strength of this material is mainly manifested in the axial direction, and the radial direction is significantly lower. When heated to 400 degrees or higher, the relaxation and strength properties will be significantly damaged. When cold-drawn prestressed steel wire is used in pipelines, its stress corrosion resistance should be checked. When galvanized steel wire is used, its corrosion resistance should not be fully trusted, and the entire cable system should have other protective measures. Cold-drawn prestressed steel wire is generally used for pipelines, especially pipelines made by PCCP process.
Low-relaxation prestressed steel wire is widely used in railway sleepers and prestressed concrete poles, a small amount is used in building components, and prefabricated beams are basically not used. Low-relaxation galvanized prestressed steel wire is often used for cables of cable-stayed bridges, hangers of steel tube arch bridges, and prestressed cables for large-span buildings. Galvanized prestressed steel wire that has not been stabilized is generally used for cables of suspension bridges.