Classification and application of prestressed steel wire

Prestressed steel wireis a kind of Steel Wire made of carbon steel wire and used in prestressed concrete structure or prestressed steel structure.

Classification
Prestressed steel wire can be classified according to diameter, strength level, surface coating or cross-sectional shape:

1. According to diameter, it can be classified into: 4mm, 4.8mm, 5.0mm, 5.1mm, 6.0mm, 6.25mm, 7.0mm, 7.8mm, 8.0mm, 9.0mm, 9.5mm, 10.0mm, 11mm, 12mm, etc.

2. According to strength level, it can be classified into: medium-strength prestressed steel wire 800~1200MPa; high-strength prestressed steel wire 1470MPa, 1570MPa, 1670MPa, 1770MPa and 1860MPa, etc. 3. According to the surface coating, it can be classified into: uncoated prestressed steel wire, epoxy resin coated prestressed steel wire and galvanized prestressed steel wire. 4. According to the surface morphology, it can be classified into: smooth round prestressed steel wire, spiral ribbed or helix grooved prestressed steel wire (left-handed or right-handed), crimped prestressed steel wire or indented prestressed steel wire (two-sided indentation, three-sided indentation, four-sided indentation), etc. 5. According to the processing technology, it can be classified into: cold-drawn prestressed steel wire (no relaxation performance requirements) and low relaxation prestressed steel wire. Manufacturing method (process)

Cold drawn prestressed steel wire is made of high-quality high carbon steel wire rod after surface treatment. The carbon content of the 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 50-85% after cold drawing, and the strength will be improved through the principle of cold working hardening. If the cold drawn prestressed steel wire is further stabilized, it will become a low relaxation prestressed steel wire, which has low relaxation characteristics and significantly improves 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 low relaxation galvanized prestressed steel wire. The steel wire is generally delivered in coils. When used in railway sleepers, it can be cut into bundles according to the needs. The diameter of the prestressed steel wire is generally in the range of 4-12 mm. 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 performance and strength performance will be significantly damaged. When cold-drawn prestressed steel wire is used in pipelines, attention should be paid to checking its stress corrosion resistance. When using galvanized steel wire, its corrosion resistance should not be fully trusted, and the entire cable system should have other protective measures.

Application
Cold-drawn prestressing 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 cable stayed bridges, tie rods of steel tube arch bridges, and prestressed cables for large-span buildings. Galvanized steel wire that has not been stabilized is generally used for suspension bridges.