BAIC Ruiling New Energy Commercial Vehicle Project

　　Steel structures are structures composed of steel materials, and they are one of the main types of building structures. The structures are mainly composed of components such as steel beams, steel columns, and steel trusses made of steel sections and steel plates, and rust prevention processes such as silanization, pure manganese phosphating, water washing and drying, and galvanizing are used. The components or parts are usually connected by welds, bolts, or rivets. Because of their light weight and simple construction, they are widely used in large factories, venues, and super-high-rise buildings. Steel structures are prone to rust; generally, steel structures require derusting, galvanizing, or painting and require regular maintenance. 
　　1. High material strength, light weight 
　　Steel has high strength and high elastic modulus. Compared with concrete and wood, its ratio of density to yield strength is relatively low; therefore, under the same stress conditions, the cross-section of steel structure components is small, and the weight is light, which is convenient for transportation and installation and is suitable for structures with large spans, high heights, and heavy loads. 
　　2. Steel has good toughness, plasticity, uniform material, and high structural reliability 
　　Suitable for bearing impact and dynamic loads, it has good seismic performance. The internal structure of steel is uniform and close to an isotropic homogeneous body. The actual working performance of the steel structure is more consistent with the calculation theory. Therefore, steel structures have high reliability. 
　　3. Steel structures have a high degree of mechanization in manufacturing and installation 
　　Steel structure components are easy to manufacture in factories and assemble on site. Factory mechanized manufacturing of steel structure components has high precision, high production efficiency, fast on-site assembly speed, and short construction period. Steel structure is a type of structure with a high degree of industrialization. 
　　4. Steel structures have good sealing performance 
　　Because welded structures can be completely sealed, they can be made into high-pressure containers, large oil pools, and pressure pipelines with good airtightness and water tightness. 
　　5. Steel structures are heat-resistant but not fire-resistant 
　　When the temperature is below 150℃, the properties of steel change little. Therefore, steel structures are suitable for hot workshops, but when the surface of the structure is subjected to thermal radiation of around 150℃, heat insulation plates should be used for protection. When the temperature is between 300℃ and 400℃, the strength and elastic modulus of steel decrease significantly, and when the temperature is around 600℃, the strength of steel tends to zero. In buildings with special fire protection requirements, steel structures must be protected with fire-resistant materials to improve the fire rating. 
　　6. Steel structures have poor corrosion resistance 
　　Especially in humid and corrosive environments, it is prone to rust. Generally, steel structures require derusting, galvanizing, or painting and require regular maintenance. For marine platform structures in seawater, special measures such as "zinc block anode protection" should be used for corrosion prevention. 
　　7. Low-carbon, energy-saving, environmentally friendly, and reusable 
　　The demolition of steel structure buildings produces almost no construction waste, and the steel can be recycled and reused.