In recent years, as the country’s investment in infrastructure around the major municipal and construction works more and more use of the steel structure in the form, and large-sized thick-walled rectangular pipe due to the beautiful appearance, reasonable force, relatively simple processing nodesetc., and thus in the airport terminals, stadiums and convention center truss structural system, and curtain wall support system as the steel components are universally applied.

However, in practical applications, square and rectangular steel pipe also encountered some urgent problems. First, the domestic cold-formed steel available in the market are mostly ordinary precision small diameter, thin-walled cold-formed steel, the material is mostly Q235, while 300mm * 300mm * 12mm or more high-strength, thick-walled, large-sized rectangular steel pipe, room temperature online continuous molding difficult technology, investment, and there is a lot of risk, and thus many such components in the steel construction had to be imported from abroad, restricting the development of China’s construction steel. Second, rectangular steel pipe steel members also faced with the problem of high-temperature softening, no matter in what occasions are required to be fireproof treatment, this aspect has increased the workload and the project cost, but also a certain degree of influence of the party steel tube shape beautiful visual effects.

The large-sized high strength and high seismic localization of high fire-resistant the weather thick-walled cold-formed rectangular steel pipe to fill the gaps in the field of domestic building materials. So that a new type of cross-section, the steel components of the new material can be widely applied to the terminals, stadiums, convention centers and other spatial structure and truss structure system, also used in recent years, the rise of the steel structure residential system will effectively promotion of cold-formed steel structural adjustment, and promote the development of the steel building.