High Strength + High Durability: Prestressed Steel Strands Become the "Core Backbone" of Super Projects
Core Features: An "Engineering Hard Currency" Combining Strength and Toughness
The core competitiveness of prestressed steel strands stems from their excellent comprehensive performance. In terms of strength, mainstream products generally have a tensile strength of over 1860MPa, with some high-end products exceeding the 2000MPa level. A single 1×7 type steel strand with a diameter of 15.2mm can have a breaking force of over 260kN, equivalent to bearing 186 kilograms of tension per square millimeter, effectively resisting the enormous loads of engineering structures. Low relaxation is another major highlight—after stabilization treatment, the product's relaxation rate can be controlled within 2.5%, and some enterprises' products even as low as 2.0%, ensuring stress stability in long-term load-bearing environments and avoiding structural deformation and failure.
In structural design, prestressed steel strands adopt a concentric stranded structure of "central wire + outer wires". The outer wires are evenly arranged and twisted around the central wire, which not only ensures uniform overall force bearing but also endows the product with good flexibility, facilitating bending and threading operations during construction. Meanwhile, through surface treatment processes such as galvanizing and epoxy coating, their corrosion resistance is significantly improved, enabling adaptation to harsh environments such as coastal salt spray, industrial humidity, and deep seas. The service life is 2-3 times longer than that of ordinary steel strands.
In addition, standardized production and strict quality control make it a "reliable material". Products must comply with domestic and international standards such as GB/T5224 and ASTM A416. From raw material procurement to finished product delivery, they undergo multiple inspections including composition analysis, mechanical property testing, and relaxation testing. The product qualification rate of leading enterprises has increased to 99.6%.
Application Scenarios: Wide Coverage from High-Speed Railway Bridges to New Energy Fields
The application scenarios of prestressed steel strands have extended from traditional infrastructure to emerging strategic industries, becoming a "safety cornerstone" in multiple fields. In the field of transportation infrastructure, it is a core material for bridge stay cables, railway sleepers, and subway segments—each stay cable of the Qujiang Grand Bridge on the Chengdu-Dazhou-Wanzhou High-Speed Railway is composed of 55 epoxy-coated steel strands, with a single length of 125.4 meters and a weight of 7.8 tons. Through precise tensioning, it provides key support for the bridge, connecting the cable tower and the main beam and bearing the main load. In major transportation projects such as the Hong Kong-Zhuhai-Macao Bridge and the Beijing-Shanghai High-Speed Railway, the application of prestressed steel strands not only reduces concrete usage by 30% but also extends the structural service life to over 100 years.
Demand for it in the hydropower and new energy sectors continues to rise. In large-scale hydropower projects such as the Yarlung Zangbo River Hydropower Station, prestressed steel strands are used to reinforce ultra-long tunnels and dam bodies, resisting 8.5-magnitude seismic pressure and extreme water pressure; in the wind power sector, wind turbine towers over 100 meters adopt prestressed concrete structures. The application of steel strands reduces tower costs by 30% and extends the design life to 25 years, adapting to complex terrains such as mountainous areas and tidal flats. In addition, high-end fields such as nuclear power containment structures, LNG projects, and super high-rise buildings have an increasing demand for special prestressed steel strands with radiation resistance and low-temperature resistance, and domestic products have fully replaced imports.
Under the trend of infrastructure upgrading, the application scenarios of prestressed steel strands are continuously expanding. In projects such as urban comprehensive pipe galleries, underground integrated transportation hubs, and landslide protection, their anchoring and reinforcement functions are fully utilized, providing safety guarantees for engineering construction under complex geological conditions.
Industry Trends: Accelerated Transformation towards High-Endization and Greenization
In recent years, China's prestressed steel strand industry has shown a high-quality development trend. From 2020 to 2024, the national output has steadily increased from 21 million tons to 25.5 million tons, with a capacity utilization rate of 91%. The proportion of high-strength products has risen from 58% to 68%, and the output of special products such as epoxy-coated and retarding-bonded strands has grown rapidly. Industry concentration continues to increase, with the top ten enterprises accounting for over 60% of the national capacity. Industrial clusters have formed in regions such as Hebei, Jiangsu, Shandong, and Sichuan, and the popularity of intelligent manufacturing and digital production lines has exceeded 50%.
Green transformation has become an industry consensus. By adopting environmental protection technologies such as tunnel-type continuous pickling, waste heat recovery systems, and variable-frequency motors, enterprises have reduced the comprehensive energy consumption per ton of steel by 9.5% compared with 2020, and over 70% of production enterprises have completed ultra-low emission transformations. Meanwhile, green processes such as scrap steel recycling and environmentally friendly anti-corrosion grease are gradually promoted, in line with the industrial development requirements under the "dual carbon" goal.
The export market has also performed brilliantly. In 2024, China's export volume of prestressed steel strands reached 1.42 million tons, a year-on-year increase of 9.2%. Among them, exports to countries along the "Belt and Road" accounted for 68% of the total, and the average export unit price of high-end products increased by 15.3%, significantly enhancing international competitiveness.