Although the application of cold-formed steel on Chinese railway wagons has a history of more than ten years, compared with Russia, the United States and other countries, there are many differences in the variety and quantity, and there are exist in the manufacturing process and product loading of cold-formed steel. The following problems: First, there is a large internal stress in the cold-formed steel as a finished product. In the early stage of cold-formed steel processing, the unwinding, rolling, rewinding, rewinding, and flat bending are performed, which increases the internal stress. In the process of cold bending, the processing method belongs to mechanical forced deformation, and there is a great internal stress after forming.
Although there is a correction process after cold bending, it is only accurate for the outer dimensions of the steel, and the effect of eliminating internal stress is not large. After the finished product is stored for a period of time, the aging deformation is obvious, which indicates that the cold-formed steel does have a large internal stress. Second, the treatment before loading makes the cold-formed steel produce large deformation. Since the cold-formed steel is not pre-primed in the delivery state, it is required to perform shot blasting treatment before loading. While derusting and passivating the surface of the cold-formed steel, the internal stress is also released, causing bending and torsional deformation.
For those openings with an asymmetrical structure, the deformation is particularly noticeable. Third, although the weathering steel developed in China has good mechanical properties, corrosion resistance and weldability, its stamping performance is not as good as ordinary carbon steel. The parts have a large rebound after bending, so reasonable process parameters should be studied during cold bending to ensure product quality. Fourth, the technical conditions of the new cold-formed steel should be improved as soon as possible. When applying cold-formed steel, railway wagons should formulate corresponding technical standards for the processing, manufacturing, working conditions and deformation characteristics of various cold-formed steels to suit production, use and inspection. There is currently no specification for cold-formed steel in the current inspection standards for railway wagons. This has hindered the process of application and development of cold-formed steel on railway wagons to some extent.
The application of cold-formed steel in Chinese railway wagons has just started. From the perspective of the development of foreign trucks developed by the railway industry, the application of cold-formed steel in Chinese trucks will be more and more. Although there are indeed many problems at present, such as the urgent need to improve the production process, how to finalize the application on the truck and how to set the corresponding industry standards. Relevant experts have suggested that as a cold-formed steel manufacturing plant and a truck production plant should be in close contact, strengthen communication and communicate with each other, so as to better promote the wide application of cold-formed steel in trucks, and also optimize the railway truck structure more rationally. , to make the overall performance of truck products to a new level.
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