Hot-rolled sections are formed once in one shot, while cold-formed sections are formed twice or three times. The production cost is greater than hot-rolled sections. Although the strength is relatively high, it can save steel, but the price is more expensive. Therefore, cold-formed sections For the section steel, hot rolled section steel or wood with relatively poor safety performance is still widely used in China. At present, the price factor is one of the important reasons restricting the development of cold-formed steel in China.
The advantage of gauze cold-formed steel is that it can not produce thin specifications and hot-rolled special profiles with complex appearance. In some cases, cold-formed steel is used, such as cars, tractors, railway vehicles, etc., where the weight is light.
China's existing cold-formed steel units should be gradually transformed according to their existing problems, combined with the actual situation, absorb advanced technology and equipment at home and abroad, develop new products, new processes, and improve equipment levels. With little investment, Able to continuously expand product varieties and improve product quality. Old enterprises make full use of their rich production experience to produce small batches of products with multiple varieties and specifications, and make full use of the advantages of already having multiple sets of molds. At the same time improve the level of competitiveness in the market competition, under the premise of ensuring product quality, try to reduce costs as much as possible to achieve high quality and better prices, and better use the potential of the old factory.
At the same time, China should increase the following efforts in the development of cold-formed steel: 1. National standards for open-formed cold-formed steel have been formulated, but the shape of the cross-section needs to be modified and revised in the published design drawings; Standard, but it can not be used, it needs to be revised; 3. In the bearing beam and column material, hot-rolled H-section steel is suitable for beam, and rectangular tube is suitable for column. According to foreign survey data, the ratio of H-beam to rectangular tube is 1: 1, while hot-rolled H-beam has been used mainly in China, with an output of nearly 2 million tons. However, the manufacturing specifications of rectangular rectangular tubes are small, the manufacturing process of box beams is backward, and the number of rectangular rectangular tubes is far lower than that of hot-rolled H-beams, which is extremely unreasonable. The research on large square rectangular tubes should be concentrated to meet market demand. According to the conclusion of the national situation research: 350 × 350mm, t = 8-16mm square tube should be produced by one-shot straight seam welded tube, 350 × 350-800 × 800mm, t = 8-20mm square pipe should adopt the double-weld butt welding process, which can not only expand the product specifications but also weld the reinforcing ribs (inner partition), 800 × 800-1000 × 1000mm, t = 20-40mm should adopt the bending process. Is the best production method. The technology and equipment related to double-weld butt welding of large rectangular pipes have matured on the basis of studying abroad. The first production line will be completed in China. I am convinced that after one or two years of hard work, the columns used in steel structures will be fully satisfied.