High-strength construction steel purchase guide

I. Core performance indicators of high-strength construction steel
Mechanical properties
Yield strength and tensile strength: High-strength steel significantly improves yield strength and tensile strength through microalloying (such as adding vanadium, titanium and other elements) and thermomechanical rolling technology. For example, the yield strength of Q460 steel can reach 460MPa, far exceeding the 235MPa of ordinary Q235 steel, and is suitable for high-load scenarios such as large-span bridges and super-high-rise buildings.
Ductility and toughness: While the strength of high-strength steel is improved, it still maintains a high elongation and impact toughness. For example, the elongation of Q460 steel is usually above 20%, and the low-temperature impact toughness (such as -40℃) meets the requirements of the specification, ensuring the safety of the structure in extreme environments.
Yield strength ratio and stability: The yield strength ratio (yield strength/tensile strength) of high-strength steel is usually controlled between 0.85 and 0.95, which can not only ensure the structural strength, but also avoid the risk of brittle fracture. For example, the yield strength ratio of Q460 steel is about 0.9, which is suitable for earthquake-resistant design.
Earthquake-resistant performance
Fatigue performance: The fatigue life of high-strength steel is significantly better than that of ordinary steel. For example, the S-N curve of Q460 steel shows that under cyclic stress, its fatigue life is more than 30% higher than that of Q235 steel, which is suitable for dynamic load parts such as crane beams and bridge supports.
Energy dissipation capacity: High-strength steel shows higher hysteresis energy dissipation capacity under cyclic loading. For example, the cyclic hardening phenomenon of Q460 steel is significant, and the hysteresis curve is full, which is suitable for energy-absorbing components in earthquake-resistant structures.
Overall stability: The overall stability coefficient of high-strength steel compression columns is higher. For example, the stability coefficient of high-strength steel with a yield strength of 690MPa is 15%~20% higher than that of ordinary steel, which can reduce the cross-sectional size of components and reduce the amount of steel used.
II. Cost control strategy for earthquake-resistant steel
Material cost optimization
Reasonable material selection: Select steel grades and quality grades according to project requirements. For example, conventional building structures (such as office buildings) can use Q355-B steel, while industrial plants in low temperature environments (-25℃) need to use Q355-D steel to avoid blindly pursuing high strength and doubling costs.
Alternative materials: In coastal high-corrosion environments, weathering steel (such as Q355NH) can be used, which has its own corrosion resistance, reduces the cost of anti-corrosion coatings, and reduces long-term maintenance costs by about 40%.
Bulk procurement: Get real-time quotes through steel websites (such as building materials websites) and choose reputable suppliers to ensure material quality while reducing procurement costs.
Production process and surface treatment
Automated production: Use automated production lines such as C-shaped steel forming machines and hot rolled plate cold bending processing to improve production efficiency and reduce labor costs. For example, automated production lines can increase material utilization by 10%~15%.
Surface treatment process: Choose the appropriate surface treatment method according to the use environment. For example, hot-dip galvanizing is more corrosion-resistant than electroplating and is suitable for outdoor steel structures; epoxy spraying is suitable for indoor environments with high cleanliness requirements.
Installation and transportation costs
Modular design: Prefabricated components can reduce the amount of on-site welding, reduce installation difficulty and labor costs. For example, prefabricated trusses made of high-strength steel are used in large-span spatial structures, and the installation efficiency is increased by more than 30%.
Logistics optimization: Select the nearest steel supplier according to the project location to reduce transportation distance and costs. For example, projects far away from the manufacturer can consider transporting in batches to reduce inventory costs.
III. Practical suggestions for the selection of high-strength building steel
Super high-rise buildings
It is recommended to use high-performance building steel (such as Q345GJ), whose high strength and high ductility characteristics meet the requirements of earthquake resistance and construction. For example, the main structure of the Shanghai Tower uses Q460GJ steel, which reduces the amount of steel used by 15% and shortens the construction period by 20%.
Supporting measures: Strengthen the node connection design, use high-strength bolts or welding connections to ensure the integrity of the structure.
Large-span spatial structure
It is recommended to use Q390-C/Q420-C steel to reduce the cross-sectional size and reduce the deadweight. For example, the main truss of the steel structure of the National Stadium "Bird's Nest" uses Q460E steel, with a span of 330 meters, and the amount of steel used is 25% less than the traditional solution.
Supporting measures: Use finite element analysis to optimize the structural layout to avoid stress concentration.
Low temperature environment structure
It is recommended to use Q355-D/Q460-E steel to ensure low temperature impact toughness. For example, a factory building with crane beams (-25℃) in Northeast China uses Q355-D steel, and no low temperature brittle fracture accidents have occurred.
Supporting measures: Strengthen welding process control to avoid welding defects.
High corrosion environment structure
It is recommended to use weathering steel (such as Q355NH) to reduce the cost of anti-corrosion coating. For example, the steel structure of a coastal chemical plant uses Q355NH weathering steel, and the 10-year maintenance cost is 60% lower than that of ordinary steel.
Supporting measures: Regularly check the surface condition of the steel and repair local corrosion in time.
IV. Future trends of high-strength construction steel
High-performance steel (HPS)
Such as Q500qE bridge steel, which has high strength and toughness, is suitable for extra-large span bridges. For example, the Hong Kong-Zhuhai-Macao Bridge uses Q500qE steel with a span of 1,650 meters and a 18% reduction in steel consumption.
Technological breakthrough: Through nano-level precipitation strengthening technology, the strength and toughness of steel are further improved.
Refractory steel
The strength does not drop significantly at a high temperature of 600°C, which is suitable for venues with high fire protection requirements. For example, a large convention and exhibition center uses refractory steel, and the structural integrity remains good after the fire.
Application prospects: With the increase in high-rise buildings and large public facilities, the demand for refractory steel will continue to grow.
Green and environmentally friendly steel
Reduce carbon emissions by optimizing alloy composition and production processes. For example, a steel plant uses hydrogen-based reduction technology to produce high-strength steel, reducing carbon emissions by more than 50%.
Policy promotion: With the advancement of the "dual carbon" goal, green and environmentally friendly steel will become the mainstream of the market.
V. Conclusion
The selection of high-strength construction steel requires comprehensive consideration of performance, cost and application scenarios. By rationally selecting materials, optimizing production processes and strengthening quality control, project costs can be reduced while ensuring structural safety. In the future, with the development and application of high-performance steel, fire-resistant steel and green environmentally friendly steel, high-strength construction steel will provide more reliable and efficient support for modern buildings.