Main welding method of rail
At present, the main methods used for rail welding in the world are flash welding, gas pressure welding, aluminum heat welding and arc welding. details as follows: 1, flash welding The rail is formed as a butt joint, energized and its end face gradually moved closer to local contact, and these contact points are heated by resistance heat (to produce a flash), so that the end faces are all melted until the end reaches a predetermined temperature within a certain depth range. Quickly apply the top forging force to complete the welding . Advantages: Flash welding has high automation degree, stable process and excellent welding quality. The welded joint is compact forged structure, the joint has good toughness, the mechanical properties are close to the steel base metal, and the production efficiency is high. It is mainly used for factory welding or base welding, and partly for unit. Rail joint welding . Disadvantages: the welding machine is expensive, the one-time investment is large, the equipment is complicated, and it needs to be equipped with high-power power supply and diesel generator set. The welding process parameters are more and the adjustment is cumbersome. At the same time, the rail burns seriously during the flash welding process, and the rails are consumed by each joint. 25.1-50mm. 2, pressure welding The heat generated by the gaseous fuel is used to heat the end of the rail to a molten state or a plastic state, and then a certain upsetting pressure is applied to complete the rail welding . Advantages: Low-pressure investment in air pressure welding, short welding time, good welding quality, welded joints are also compact forged structures, mainly used for on-site joint welding . The rail burns less, and the rail is shortened by about 30 mm after welding . Disadvantages: The welding requirements of the joint section are very strict during welding . The welding process is affected by many human factors, and the joint quality fluctuates greatly and is difficult to control. 3, aluminum heat welding It is a welding method in which aluminum and iron oxide (including additives) are used for redox reaction at a certain temperature to form a high-temperature liquid metal into a special mold, and the ends of the two welded steel rails are melted to realize connection. Advantages: simple equipment, convenient operation, low production cost, no upsetting process, good appearance of joints, short lock-up time, especially suitable for broken track repair, cross-section seamless line ball joint welding and transportation tasks On-line welding. Disadvantages: low strength, unsatisfactory quality, high breakage rate, poor overall performance, is the weakest link in seamless lines. 4, arc welding The welding rod or the welding wire and the arc generated by the end face of the rail are used to melt the rail and fill the joint gap, and the copper stopper is used for forced forming, and the welded joint is formed after cooling, which belongs to the fusion welding method. Advantages: With suitable welding rod and wire composition, the arc welding head can obtain bainite structure with excellent performance. The comprehensive performance can reach the level of the base metal, and the tensile strength and wear resistance sometimes exceed the steel base material. Disadvantages: At present, there is less promotion, and the welding process and technical level are strict. In several ways, flash welding is mainly used for factory welding or base welding; moving flash welding and moving gas pressure welding are used for unit rail joint welding; aluminum heat welding and arc welding are often used for field lock welding, overhaul rail change and ballast welding . [Safety and Ultra Lightweight]-- NO overheating after using for hours. 45 degree tilting head reduces neck fatigue. Adjustable Strap makes your head get the best comfortable condition. Led Head Lamp,Cob Led Headlamp,Led Head Light,Led Headlight Flashlight Ningbo Wason Lighting Technology Co.,Ltd , https://www.wasonlight.com
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