Seamless Line Welding Technology of Crane Rail

Seamless Line Welding Technology of Crane Rail
The seamless welding of the crane rail can significantly improve the smoothness of the crane rail, eliminate the harmful space generated by the crane rail joint and improve the service life of the crane rail. Welding of steel rails by arc welding began in the 1950s. With the method of using the end face of the rail end face, or the vertical welding method. It takes 3 to 5 hours to weld a joint, and some local areas cannot be effectively fused, so the welding quality is not ideal. The static bending strength is less than half of the other welding methods, and the service life is less than one year. In addition, the welding time is too long, and the labor intensity of the welder is large, so the actual use effect is poor. The narrow gap forced forming arc welding method is currently widely used in Japan and Europe, and is mainly used for wire welding of rails. Among them, Japan mainly applies to the Shinkansen’s orbital welding of trains. Due to the high reliability of this method, no derailment has occurred since 1993. In Sweden, Spain and other countries, 50% of the on-site welding, especially the joints on the two sides of the ballast, narrow gap forced forming arc welding is used. Japan’s rail forced forming arc welding method is more complicated and has a longer welding time. The research on rail forced forming arc welding in China began in the 1990s. Up to now, special rails, lifting rail welding materials, welding equipment and welding processes have been developed, and rails or lifting rails of various rail types can be welded.
A gap is left between the end faces of the two rails, surrounded by a mold matching the shape of the crane rail, and then welded. The welding of the rail waist and the rail top is completed by continuous welding, and no slag removal is performed in the middle of the process. In order to ensure continuous welding, the key to this technology are as following two aspects. One is to use special special welding rods, which can be continuously welded without removing slag, and the welding and sewing gold is matched with the material of the rail. The second is the structural design of the mold material and the mold matched with the shape of the rail. The welding quality of the forced gap forming of the narrow gap is stable. Compared with air pressure welding and aluminum heat welding, the requirements for the treatment of rail cross-section by gas pressure welding are too strict, and the surface of the section must be treated flat. It is not allowed to touch by hand, otherwise there will be spots. The aluminum heat welding seam is an as-cast metal structure, and the strength and toughness of the weld are relatively limited. The narrow gap forced forced arc welding has a small working area, which is beneficial to high-altitude field welding. The strength of the welded joint is high. Taking a 60KG/M rail welded joint as an example, the static bending value of a span of 1 m is generally 150t-160t. Another feature of the welding method is the low cost of the welding material, which reduces the cost of the seamless line. This welding method requires less staff, but has higher technical requirements for the welder. Welders must receive professional and rigorous training in welding rails and need to be certified.