With the increasing speed of railway, more and more rails are connected by rail welding technology. Rail welding technology can be applied to ordinary rails, and can also be applied to high-speed seamless rails, special rails such as crane rails are also very suitable. Traditional railway tracks use fish plate to connect sections of rails. There will be joints of different sizes between rails, so that rails cannot be connected into a continuous whole. When the train passes through the joint of the rails, it will produce a large vibration, which will easily cause the loosening of the fixing fish bolts. Because there is no gap between the two sections of rails connected together by rail welding technology, they have become a whole, so there will be no loosening between the rails. In the daily work of railway connection, there are four ways of rail welding, they are flash butt rail welding, gas pressure welding rail, thermite rail welding and electric arc welding railroad.
When flash butt rail welding method is used to weld a rail, the first step is to place the two rail heads opposite each other. Connect the power supply to make the cross sections of the rails close to each other and reach local contact. And these contact points are heated by resistance heat (to produce a flash), so that the end faces are all melted. When a predetermined temperature is reached within a certain depth range, then quickly apply the forging force to complete the rail welding.
Advantages of flash butt rail welding
Flash butt rail welding has the characteristics of high automation, stable process and excellent welding quality. The welded joint of the rail is compact forged structure, the joint toughness is good, the mechanical properties are close to the steel base metal, and the production efficiency is high. It is mainly used for factory rail welding or base rail welding, and partly for unit steel rail welding.
Disadvantages of flash butt rail welding
The flash butt rail 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 bad seriously during the flash welding process, and single rail is consumed 25.1-50mm by each joint part.
Gas Pressure Welding Rail Method
Gas pressure welding rail is to use the heat energy generated by the gaseous fuel to heat the end of the rail to be in a molten state or a plastic state, and then apply a certain upsetting pressure to complete the rail welding.
Advantages of gas pressure welding rail
The one-time investment is lower for gas pressure welding rail, the welding time is shorter, the welding quality is better, and the welded joints are also compact forged structures. It mainly used for on-site joint welding. The steel rail burning loss is less, about 30mm shorter on average.
Disadvantages of gas pressure welding rail
The gas pressure 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.
Thermite Rail Welding for Rail Connection
Thermite rail welding is to use aluminum and iron oxide (including additives) to arise redox reaction at a certain temperature. The high-temperature liquid metal forms and is sent into a special mold, the two welded rail ends will get melted to achieve the connection.
Advantages of the thermite welding railroad
The thermite welding railroad has the characteristics of simple equipment, convenient operation, low production cost, no upsetting process, good appearance of joints and short lock-up time. The thermite welding railroad method is especially suitable for broken steel rail repair, on-site joint welding on railway frog section of seamless railway line ball and heavy transportation tasks.
Disadvantages of the thermite welding railroad
The thermite welding railroad has low strength, low quality, high breakage rate, poor overall performance. The welding part of the thermite welding railroad is the weakest link in seamless lines.
Electric Arc Welding Railroad
Electric arc welding railroad is to use welding rod or welding wire to melt steel rail by the arc heat generated on end faces and fill the joint gap and forced their ends to get the needed form with copper stopper. After cooling, it will form to be a welded joint. It is a melting welding method.
Advantages of electric arc welding railroad
With suitable welding rod and wire composition, the electric arc welding railroad joint part can obtain bainite structure with excellent performance. The comprehensive performance of welded rail joint part can reach the level of base metal, and the tensile strength and wear resistance sometimes exceed steel base material.
Disadvantages of electric arc welding railroad
At present, the electric arc welding railroad method has been less widely used, and the welding process and technical level are strict.
AGICO Railway can provide you with reasonable rail welding solutions, rail welding technical support and a variety of rail welding equipment. In addition to rail welding machine, we also produce various standard types of steel rails and rail fasteners. Welcome to send enquiry to us for details.