New trends in the prestressed steel strand industry -- developments in standards and technology

At a time when competition in various industries around the world is fierce, the PC steel strand industry is also at a critical juncture of change and faces many challenges. Innovation has become the core element driving the industry forward. Major companies have made efforts to achieve a double leap in product performance and market competitiveness through technological innovation, process breakthroughs, combined with standard upgrades and strength improvements. After an in-depth analysis of the current development trend, our company puts forward the following suggestions.

1. The new national standard reshapes the industry pattern

The new standard "Steel Strand for Prestressed Concrete" (GB/T 5224-2023), which was officially implemented in March 2024, is undoubtedly a key turning point in the industry's transformation. The standard upgrade this time is unprecedented, expanding the strength grade to 2160MPa, 2230MPa and 2360MPa, while gradually eliminating low-strength products of 1470-1670MPa. This move is of great significance, prompting the optimization and upgrading of the engineering design field. Engineers need to reconsider the structural design to adapt to higher-strength steel strands; it promotes raw material companies to increase R&D investment and improve product quality to meet the requirements of the new national standard; it also drives the technological innovation of the supporting anchor industry, from production technology to product performance, to achieve breakthroughs in order to perfectly match high-strength steel strands. The new national standard has comprehensively reshaped the industry's development pattern and pointed out the development direction for enterprises. Enterprises must keep up with the pace of standards to gain a firm foothold in market competition.

2. R&D needs to meet high-end needs

In order to comply with the requirements of the new national standard and the special needs of high-end application scenarios, various companies have actively engaged in the wave of research and development. At present, many companies have successfully achieved mass production of steel strands of 2160MPa and above, and have achieved phased victory in the field of high-strength steel strands. Some companies continue to innovate in material formulations and preparation processes, and cleverly adjust the internal organizational structure of materials by adding alloy elements such as chromium and silicon, significantly optimizing material performance; or use duplex stainless steel materials to make full use of their unique microstructural advantages, greatly enhancing the corrosion resistance and mechanical properties of products, and effectively meeting the stringent requirements of high-end scenarios such as nuclear power and bridge cables for durability and high strength. These research and development results have laid a solid material foundation for major projects, allowing projects to operate safely and stably in complex environments. For example, the construction of containment shells of nuclear power plants and the construction of large cross-sea bridges are inseparable from the support of high-performance steel strands.

3. Intelligent production lines improve quality and efficiency

Major companies are actively adapting to the trend of intelligence and vigorously promoting the intelligent transformation of deep processing production lines for wire products. Many companies have introduced fully automatic pickling, wire drawing and stabilization treatment units. These advanced equipment can accurately and efficiently complete various production tasks. At the same time, the integration of big data and 5G+ technology can monitor and analyze production parameters in real time. Once abnormal parameters are found, early warnings will be issued in time to ensure stable product quality; 5G+ technology is like a high-speed information channel, realizing high-speed communication of equipment, making the coordinated operation of various links of the production line smoother and more efficient, greatly improving production efficiency. For example, the Φ15.2mm low-relaxation 1×7 structural steel strand that has just been put off the production line is an outstanding achievement of the intelligent production line. It is a powerful witness to the company's move towards large-scale, intelligent and high-end steel strand production, marking a major breakthrough in the company's high-strength product field.

4. New technology of liquid nitrogen cryogenic treatment

The exploration of optimizing material performance has never stopped, and a new preparation method combining phosphating and liquid nitrogen cryogenic treatment has emerged. This method effectively improves the fatigue life of steel strands. Experiments show that the fatigue life reaches its peak after 176 minutes of liquid nitrogen treatment, but the treatment time must be strictly controlled within 30-210 minutes, otherwise the fatigue strength will decrease. This precise process parameter research provides a scientific basis for optimizing the performance of steel strands, fully meets the application scenarios with high requirements for material fatigue performance, and greatly improves the reliability and safety of the structure.