66 results about "Flash welding" patented technology

The flash welding mechanism comprises a static frame clamp, a movable frame clamp, an upsetting cylinder, a first clamping cylinder, a second clamping cylinder and a center shaft, a rail top block is installed on the center shaft, a first clamping piece comprises an outer side electrode and an abutting piece, and firstly, a first side face abuts against the rail head side face of the variable-section steel rail; then, the abutting end abuts against the rail head lower jaw of the variable-section steel rail, the spring is installed on the installation end and the outer side electrode in a compressed mode, and the bolt is installed at the installation end in a threaded mode; and finally, the variable-cross-section steel rail is clamped through the first clamping piece, the normal steel rail is clamped through the second clamping piece, the upsetting cylinder drives the upsetting piston rod, and flash welding of the normal steel rail and the variable-cross-section steel rail is achieved. The flash welding mechanism for the variable-cross-section steel rail can clamp and weld the variable-cross-section steel rail.

The invention discloses a traveling wave magnetic field assisted flash welding method and equipment for rare earth alloyed wheel steel, and the method adopts a traveling wave magnetic field assisted flash welding process for the rare earth alloyed wheel steel meeting the automobile lightweight requirement, and enables a traveling wave magnetic field to continuously act on a welding area in the full stages of preheating, flashing and upsetting. Wherein the rare earth elements comprise cerium (Ce) and the like, and the components of the wheel steel are optimized through microalloying treatment; the temperature is accurately controlled to be 500-650 DEG C in the preheating stage, a traveling wave magnetic field of 10-30 mT and 50-100 Hz and specific welding parameters are adopted in the flash stage, the upsetting distance is controlled to be 2-5 mm and the upsetting pressure is controlled to be 6-8 MPa in the upsetting stage, heat transfer, metal flow and rare earth distribution are improved by means of the magnetic field, grains are refined, and defects are reduced. Meanwhile, the magnetic field and welding parameters are optimized through machine learning, and the purpose of minimizing the grain size is achieved. The method can remarkably improve the metallurgical bonding strength and the structure performance of the weld joint, and is suitable for efficient and high-quality welding of the rare earth alloying wheel steel.

The invention provides special equipment for group replacement of high-speed railway turnouts and a construction method, and belongs to the technical field of railway engineering. Comprising a heavy rail car, a container type rail welding car, a plurality of special turnout transportation flatcars, a container type rail welding car and a heavy rail car which form a whole-column special marshalling used for integrated operation of transportation, replacement, welding and recovery of grouped rail pieces. A rail welding vehicle folding arm crane, a flash welding machine, rail welding vehicle auxiliary supporting legs and the like are carried on the container type rail welding vehicle; at least two flatcar folding arm cranes, flatcar auxiliary supporting legs, a lifting handrail and a special loading tool are installed on the special turnout transportation flatcar. Special equipment and a construction method are used for achieving integrated operation of the high-speed railway turnout from bulk material pre-assembly to group transportation, replacement, welding and old turnout recycling, the problem that group replacement of an existing high-speed railway turnout is completed at a skylight point is solved, and the defects of a group replacement operation technology of the high-speed railway turnout are overcome.

The invention discloses a wheel flash welding optimization system and method based on digital twinning, and belongs to the crossing field of intelligent manufacturing, welding processes and artificial intelligence. The system comprises a material attribute database module, a multi-source data acquisition and preprocessing module, a digital twin module integrating heat-force-microstructure and other multi-physics field models, an AI prediction and multi-objective optimization module, an advanced visualization and interaction module and a closed-loop control module. The method comprises the following steps: initializing and matching material parameters; collecting data in real time to update the twinborn model; running simulation and AI to predict the welding temperature, the structure and the performance; if the prediction does not reach the standard, starting a multi-objective optimization algorithm to generate an optimal process parameter set; and executing optimization parameters through closed-loop control and performing real-time visual feedback. According to the method, full-chain real-time mapping, transparent monitoring and intelligent optimization of technology-structure-performance in the welding process are achieved, the performance stability of joints is remarkably improved, and the efficiency and the product quality are optimized.

The utility model relates to the technical field of track welding equipment, in particular to a seamless long track steel welding device, which is used for carrying out flash welding on a track by arranging a welding device I and a welding device II, can be used for well and thoroughly welding the central position of the track and improving the welding quality, and also can be used for carrying out flash welding on the track by arranging the welding device I and the welding device II. The rails are quickly and repeatedly contacted for multiple times before formal welding, so that the rails are preheated, and the welding quality is improved; comprising a body; the welding machine further comprises a moving device, a first welding device, a second welding device, an overlap pushing device and a grinding device, the moving device, the first welding device and the grinding device are all installed on the machine body, the second welding device is installed on the machine body and the first welding device, and the overlap pushing device is installed on the first welding device.

The invention provides a self-propelled flash welding rail heat treatment vehicle for urban rail transit, and belongs to the technical field of rail engineering machinery. Comprising a frame, a shed, a hook buffer device, hydraulic supporting legs, a bogie, a fuel tank, a wind source device, a tool box, an auxiliary generator set, a cab, an electrical room, a power room, a working room and a welding machine room. And a welding machine device and a movable shed capable of being electrically opened and closed are arranged in the welding machine chamber. The device has the advantages of integration of welding and heat treatment, high automation degree, environmental protection, energy conservation, flexible operation and the like, and is suitable for urban rail transit steel rail welding operation.

The application discloses a kind of 800 MPa level cold-rolled martensitic steel hot-rolled substrate laser welding method, belongs to the technical field of welding.The application adopts laser butt welding process, the tail of front coil strip steel and the head of rear coil strip steel is formed loop respectively by welding machine pinch roll before and after welding machine, positioning and centering after being carried out to strip head and tail, using double cutting shear is cut to head and tail to ensure the quality of welding machine end surface.The application moves laser from operating side to transmission side by protection gas purging, cooperates with the front and rear heat devices that advance with laser and carries out butt welding, avoids the shortcomings of traditional laser welding high energy consumption and flash welding, reduces production cost and process complexity, improves production speed and weld quality, reaches the purpose that 800 MPa level cold-rolled martensitic steel hot-rolled substrate is welded.

The utility model belongs to the technical field of railway engineering mechanical equipment manufacturing, and particularly relates to an overlap pushing knife structure for turnout welding. The device comprises an upper overlap pushing knife assembly and a rail bottom overlap pushing knife, a cutting edge is formed in the inner side of the upper beading removing cutter assembly; pull rod locking notches are formed in the two ends of the top of the upper overlap pushing knife assembly; a cutting edge opening is formed in the top of the rail bottom beading pushing knife; each of the two ends of the rail bottom beading pushing knife is rotationally connected with a beading pushing knife pull rod; after being rotated towards the direction close to the upper portion tumor pushing knife assembly, the tumor pushing knife pull rod is clamped into the pull rod locking notch of the upper portion tumor pushing knife assembly, and then the tumor pushing knife pull rod is fixed into the pull rod locking notch through a fixing piece; according to the invention, the overlap pushing knife can be used under the condition that the space gap between the steel rails is narrow, so that the field turnout flash welding operation is more convenient, and the efficiency is higher.

The application discloses a method for reducing the flash welding forming cracking rate of 590MPa grade wheel rim wheel steel, and the chemical components of the wheel steel are as follows in percentage by weight: C: 0.06-0.10%, Si: 0.05-0.30%, Mn: 1.40-1.60%, P: 0.020% or less, S: 0.010% or less, Alt: 0.020-0.040%, Nb: 0.035-0.055%, Ti: 0.010-0.025%, N: 0.0040-0.0060%, Ti / N: 2.0-4.0, and the balance is Fe and inevitable impurities; and the manufacturing process comprises the following steps: final rolling temperature: 840-880 DEG C, cooling speed after final rolling: 20-30 DEG C / s, and coiling temperature: 570-600 DEG C. The application aims to provide a method for reducing the flash welding forming cracking rate of 590MPa grade wheel rim wheel steel, improving the welding process adaptability of products, reducing the welding forming cracking rate, and reducing the waste product rate.

The utility model provides an endless direct rolling production device for bars and wires, which comprises a billet discharge roller way, a hot delivery roller way, a hot delivery roller way and a hot rolling roller way, wherein the billet discharge roller way is used for transporting billets produced by a continuous casting machine; the hot conveying roller way is used for conveying the steel billets to the induction heating device and conveying the steel billets subjected to heat compensation to the first pinch roller; the induction heating device is used for compensating heat of the steel billet to a preset temperature; the first pinch roll is used for adjusting the moving speed of the steel billet; the movable flash welding device is used for welding the front steel billet and the rear steel billet together; the swing roller way is used for supporting the welded steel billet; the second pinch roll is used for providing clamping thrust for the welded steel billet; and the deburring device is used for removing welding burrs on the welded steel billets and conveying the steel billets with the burrs removed to the roughing mill unit. The continuous-cast billets are directly conveyed to the rolling mill through the roller way to be rolled, the tails and the heads of the front billet and the rear billet are welded together in the conveying process, the front billet and the rear billet enter a roughing mill unit as one billet, and therefore endless direct rolling is achieved.

This invention belongs to the field of metal welding technology and relates to a heat treatment method for hypereutectoid rail steel after flash welding, comprising the following steps: post-weld cooling: the welded joint is allowed to cool naturally in air after flash welding; normalizing treatment: the welded joint is heated to a normalizing temperature above the austenitizing temperature and held at that temperature; controlled cooling: the temperature of the weld heat-affected zone of the welded joint is cooled from the normalizing temperature to the isothermal transformation temperature within the pearlite phase transformation temperature range at a first cooling rate, held at that temperature until the austenite undergoes pearlite transformation, and then the welded joint is cooled from the isothermal transformation temperature to below 200°C at a second cooling rate lower than the first cooling rate. The method of this invention can effectively eliminate the network cementite structure in the flash welding heat-affected zone, while avoiding the introduction of harmful structures such as martensite or bainite, ensuring that the microstructure of the weld heat-affected zone is pearlite with fine lamellar spacing.

This invention discloses a friction-assisted flash welding device and method for steel rails, comprising a stationary frame, a moving frame, a fixture, a drive device, an extrusion end electrode, a moving frame electrode, a friction extruder, a stationary frame electrode, an upsetting device, and a controller. The friction extruder is detachably mounted on the fixture and includes a first contact surface and a second contact surface. The first contact surface is used to contact a first welding surface, and the second contact surface is used to contact a second welding surface. The drive device drives the fixture and the friction extruder to reciprocate together along a length direction perpendicular to the first rail to be welded. The first rail to be welded includes a first welding end, and the moving frame electrode is attached to the first welding end. The second rail to be welded includes a second welding end, and the stationary frame electrode is attached to the second welding end. The extrusion end electrode is attached to the friction extruder. The friction-assisted flash welding device and method for steel rails provided by this invention improve the mechanical properties and welding quality of the welded joint.

A welding machine, preferably of the flash-butt type, designed to facilitate the maintenance of clamping devices (3, 4, 6, 7) of two longitudinal metal products to be welded, for example the maintenance of the clamps. Advantageously, a first structure (2) provided with first clamping devices (3, 4) and a second structure (5) provided with second clamping devices (6, 7) are supported in a first portion (10) of a carriage (1) delimited by a first beam (9) and a second beam (8) of the carriage (1) parallel to the feed direction X, while at least one transformer (36) is fixed to the carriage (1) and supported in a second portion (11) of the carriage (1) arranged laterally outside the first portion (10). Furthermore, two upsetting cylinders (23, 24) are arranged along a plane Y inclined at a non-zero acute angle with respect to the horizontal plane and passing through the passage area of the longitudinal metal products along the feed direction X.

This invention provides a control system and method for a rail flash welding machine based on a distributed fieldbus. The system includes a host module, a DC power supply module, a voltage regulator, and multiple fieldbus slave modules. The host module, the DC power supply module, and the voltage regulator are housed in a control system cabinet. The multiple fieldbus slave modules are distributed among the power supply unit, the chiller, the hydraulic station, the crane, the flash welding head, and the voltage regulator. Therefore, the host module and the multiple slave modules in this invention can select either a fieldbus or an Ethernet bus based on the characteristics of the transmitted signals to achieve collaborative communication between the host and slave modules, meeting the real-time requirements of the signals. Furthermore, the data transmission lines of this invention are simple, have strong anti-interference capabilities and stability, and improve the high-speed data acquisition requirements and the execution efficiency of the carrier.

This invention provides a pressure welding equipment and method for the combined flash welding of the end face and the induction welding of the inner wall of thick-walled cylindrical parts. The equipment includes a frame, a rotating device, a rotating electrode device, an upsetting device, an argon protection device, a cleaning device, and an inner wall induction heating device. The rotating electrode device and the inner wall induction heating device constitute a dual heat source system that can operate independently or in tandem. The outer wall electrode uses contact discharge to achieve flash heating, while the inner wall induction coil uses non-contact heating to address the temperature difference between the inside and outside of the thick-walled part. The upsetting device applies axial upsetting pressure to form the weld. After upsetting, the inner induction coil continuously induction heats the weld to achieve in-situ high-temperature normalizing, eliminating uneven microstructure. The vertical roller has both axial feeding and positioning functions and upsetting reverse locking functions. The inner wall device uses a web-type support mechanism to deploy the traveling wheels to fit the inner wall, achieving automated welding and cleaning of the inner wall. This invention achieves dual-process synergy, integrated post-weld normalizing, and high-quality welding of the end face of large, thick-walled cylindrical parts.

This invention belongs to the field of rail welding and discloses a method for controlling the softening zone of bainitic rail welded joints. The method includes: welding bainitic rails using flash welding, wherein the flash welding includes a preheating stage, a continuous melting stage, and an accelerated melting stage. During the preheating stage, the thickness of the molten layer of the welded joint is controlled to be 1.5~2.5 mm; during the continuous melting stage, the temperature of the molten pool is controlled to be 1480~1530℃; the welded high-temperature rail joint is then subjected to a three-stage gradient cooling process: first, cooling at a rate of 18~22℃ / s to near the bainitic transformation point; then, cooling at a rate of 0.08~0.12℃ / s for a predetermined time; and finally, cooling at a rate below 0.5℃ / s to room temperature. This invention significantly reduces the melting amount, avoids excessive melting of the rail base material, and reduces the expansion of the heat-affected zone, achieving a softening zone width ≤0.5 mm, which is 80% smaller than the softening zone width of the Bombardier BWR system.

The application discloses a steel rail with good flash welding performance, and chemical components include C 0.60-0.74%, Si 0.30-0.60%, Mn 0.25-0.50%, Nb 0.01-0.04%, Ti 0.02-0.06%, P≤0.025%, S≤0.025%, wherein the ratio of the content of Mn element to the content of S element should be controlled to be 30-40, and the rest is Fe and inevitable impurities. The application aims to solve the problem that the Mn element gathered at the rail waist and rail bottom during the flash welding process of the steel rail for railway is easy to form oxides, resulting in more ash spot defects at the weld. The application provides a steel rail with good flash welding performance and a production method thereof. The alloy element regulation and the smelting, rolling and heat treatment process are used to realize the good matching of the welding performance and the mechanical performance of the steel rail, thereby improving the comprehensive use performance and the service life of the steel rail, and meeting the railway development requirement.

The invention discloses a thermal simulation method capable of predicting the flash welding performance of a steel rail, and belongs to the technical field of steel rail welding. Comprising the following steps: (1) a thermal simulation method: step 1, extracting welding thermal cycle parameters, collecting a temperature-time curve T-t of field flash welding by adopting an infrared thermometer and a thermocouple, and extracting characteristic parameters; 2, performing a thermal-mechanical coupling simulation test; 3, performance testing and model establishment; 2) standardized sample design and geometric dimension: simulating flash welding scene design, and slotting at 1 / 2 position of a conventional compressed sample by linear cutting with the width delta L of 0.1 mm and the depth d of 2.5 mm; material matching: chemical components of the sample are consistent with those of the to-be-welded steel rail, and the sample is treated by the same rolling process. The microscopic structure of the steel rail flash welding joint is accurately predicted through laboratory tests, the mechanical property of the steel rail flash welding joint is determined, the field test frequency is reduced, and the production cost is reduced.

The application discloses a heat treatment method for improving the width uniformity of a heat affected zone of a rail welded joint, and the method comprises the following steps: moving a rail through flash welding to obtain a welded rail; naturally cooling the welded joint of the welded rail to room temperature; using an electric induction coil to perform full-section induction heating on the welded joint; controlling the width of the heating area of the rail welded joint by using a cooling device during the heating process; and immediately spraying air to cool after heating to a predetermined temperature. The heat treatment method mainly aims at the technical problems that the width of the heat affected zone of the rail flash welded joint after post-weld heat treatment is not uniform, the width of the heat affected zone is too large, and the use performance and driving safety of the rail are affected. After the method is used, a pearlitic rail flash welded joint with high comprehensive performance, high uniformity of the width of the heat affected zone and small width of the heat affected zone is finally obtained.

A method for increasing hardened layer thickness of a rail head of a flash welded joint of a steel rail and a steel rail is provided. The method includes carrying out a flash welding on the steel rail, which includes sequentially carrying out an energization heating stage and a pressurizing and upsetting stage; wherein the energization heating stage has a voltage of 300~385V, an average current of 500~800 A, and a duration time of 80~100 s; and carrying out a heat treatment on the flash welded steel rail, which includes carrying out an accelerated cooling on a top surface of the rail head, a side surface of the rail head and a lower jaw of the rail head in a near welding seam area of the steel rail joint, the accelerated cooling has an initial temperature greater than 700° C., a final temperature of 430° C.~500° C., and an average cooling speed of 5~35° C. / s.

The present application relates to the technical field of rail welding, and particularly relates to a method for eliminating martensite structure of hypereutectoid rail flash butt joint. The method comprises the following steps: S10, normalizing the hypereutectoid rail flash butt joint with martensite structure by using medium-frequency induction heating, wherein the peak heating temperature of the joint is 20-30 DEG C higher than the normal heating temperature during normalizing, and the peak heating temperature is kept for 10-15 s; S20, air cooling the top surface of the rail and the two sides of the rail head, so that the air cooling is stopped after the top surface of the rail is cooled to the set temperature, and the air cooling is continued until the room temperature is reached. The peak heating temperature is kept for 10-15 s, and then the top surface of the rail and the two sides of the rail head are air cooled by spraying, so that the martensite structure of the hypereutectoid rail joint is eliminated, the hardness, grain size, strength and toughness of the joint meet the standard requirements, and a large amount of manpower and material resources are saved, and valuable construction time is saved.

The utility model relates to the technical field of flash welding equipment, and discloses an auxiliary fixing mechanism of artificial intelligence flash welding equipment, which comprises a frame body, the inner wall of the top of the frame body is in sliding connection with a sliding frame, the sliding frame is connected with the frame body through an adjusting assembly, and connecting seats are welded at four corners of the outer wall of the bottom of the sliding frame. Due to the fact that the frame body and the rotating frame are arranged, the gravity center of the device is lowered, meanwhile, the gravity center of the device can coincide with a rail, and due to the fact that a supporting point of the flash welding equipment is located on the frame body, the supporting point of the flash welding equipment and the supporting point of the frame body are transferred to the frame body. And by arranging the extending assemblies, the two sliding rods move outwards at the same time, so that the supporting blocks are far away from the fixing pipes, the length of the fixing pipes is increased, the contact area between the fixing pipes and the ground or the sleeper is increased, and the stability of the device is further improved.

The application discloses a flash welding method of a wheel rim based on titanium and manganese alloy strengthening, and mainly solves the technical problems that the weld strength is reduced and the welding heat affected zone is cracked in subsequent processing in the welding process of a straight seam of a 500MPa-grade steel wheel rim based on titanium and manganese alloy strengthening. The technical scheme is as follows: a flash welding method of a wheel rim based on titanium and manganese alloy strengthening, comprising the following steps: 1) preparing a wheel rim blank, and obtaining the wheel rim blank by butt joint after rolling a hot-rolled and pickled steel plate with a thickness of 3.0-5.0 mm; the metallographic structure of the hot-rolled and pickled steel plate is fine-grained ferrite + a small amount of pearlite; 2) clamping and fixing the wheel rim blank; 3) welding and processing the wheel rim blank; and 4) processing the weld joint after butt joint of the wheel rim blank. The welding method has the advantages that the qualified rate of the air tightness of the weld joint is greater than or equal to 95%, the tensile strength of the weld joint is greater than or equal to 530 MPa, and the weld joint quality is good.

The utility model discloses a railway turnout, long steel rail flash welding and heat treatment integrated machine, including top forging mechanism, normalizing heat treatment mechanism, controller, movable frame and static frame, normalizing heat treatment mechanism sets up between movable frame and static frame, and can be up and down slip setting along the direction perpendicular to the welding joint, first clamping mechanism includes first tongs and second tongs, and second clamping mechanism includes third tongs and fourth tongs, and first tongs are installed with detachable first electrode, and second tongs are installed with detachable second electrode, and first rail waist clamping electrode is installed on third tongs, and second rail waist clamping electrode is installed on fourth tongs. The utility model provides a railway turnout, long steel rail flash welding and heat treatment integrated machine, have the integrated equipment of satisfying turnout, long steel rail field flash welding and postweld heat treatment simultaneously, have reduced equipment cost, avoided the welding operation mutual interference due to the too many field equipment.

The application discloses a steel rail welding method and a steel rail. The method comprises the following steps: welding a steel rail to form a welded joint; performing induction normalizing heat treatment on the welded joint; after the holding is completed, performing first-stage air cooling on the welded joint by using a first air blowing pressure; after the welded joint is cooled to a first preset temperature, performing second-stage air cooling on the welded joint by using a second air blowing pressure which is smaller than the first air blowing pressure; and stopping air blowing after the welded joint is cooled to below a second preset temperature. The scheme provided by the application finally eliminates the martensite abnormal structure in the flash butt welded joint of the steel rail through the multi-process control method of the welding process, the post-welding heat treatment holding and the air cooling, the martensite structure does not appear in the full cross section of the joint, the remaining organizational performance of the joint meets the requirements, and the service performance and the running safety of the flash butt welded joint are improved.

A flash welding device and method for a frog with an inclined end, relating to the field of rail welding technology, includes a welding machine fixed frame, a welding machine movable frame, and two positioning clamps. The welding machine fixed frame is connected to the welding machine movable frame, and the two positioning clamps respectively cooperate with the welding machine fixed frame and the welding machine movable frame. Each positioning clamp includes a movable clamping plate, a first fixed clamping plate, and a second fixed clamping plate. The movable clamping plate is mounted on the welding machine fixed frame or the welding machine movable frame. The first fixed clamping plate has a first positioning surface, and the second fixed clamping plate has a second positioning surface. The first and second fixed clamping plates are selectively mounted on the welding machine fixed frame or the welding machine movable frame, and the angles between the first and second positioning surfaces relative to the horizontal plane are different. The distance between the movable clamping plate and the first or second positioning surface is adjustable to clamp or release the workpiece. This method can improve the docking accuracy of the frog and the primary joint, and improve the quality of flash welding.

This invention discloses a rail limb thickness measuring ruler, comprising a main scale, a secondary scale, a measuring vernier caliper, and a positioning vernier caliper arranged perpendicularly to each other. A measuring arm is located below the measuring vernier caliper, with its horizontal bottom edge aligned with the 0 position of the measuring vernier caliper. Initially, the horizontal bottom edge is in close contact with the top of the positioning vernier caliper, and the end of the measuring arm, the 0 position of the positioning vernier caliper, and the 0 position of the secondary scale are aligned. The rail limb thickness is measured by using the secondary scale and the positioning vernier caliper in conjunction with the positioning transverse measuring position of the rail limb, and by using the measuring arm, the measuring vernier caliper, and the main scale in conjunction with the measuring position. This measuring ruler can be directly used for rail limb thickness detection at frog welds, effectively solving the detection deviations and human errors caused by qualitative detection of rail limb thickness. It addresses the pain points of low efficiency, strong reliance on experience, and non-quantitative expression of detection results in the detection process, achieving quantitative monitoring and measurement of rail limb thickness at international railway flash welding frog welds.

The present application belongs to the field of railway welding rail construction, and in particular, relates to a mechanized construction method for ensuring the quality of welded joints under the working condition of railway shoulder welding rail, comprising railway roadbed forming; 25m steel rail storage on the railway shoulder; erection of welding rail production station; self-walking alignment of public rail welding rail unit on the railway shoulder; rail end rust removal and polishing before steel rail welding; steel rail welding, including rail clamping alignment, flash welding, upsetting, and nodule pushing; post-welding normalizing; post-welding straightening and polishing; ultrasonic flaw detection of welded joints, data recording and analysis; steel rail welding joint inspection and qualification, and steel rail storage. The construction method of the present application is a field seamless line construction scattered paving construction method based on public rail welding rail and normalizing train equipment, and 25m steel rail is welded into 250m long steel rail on the shoulders on both sides of the roadbed before the completion of the roadbed construction and before ballast paving, and the quality of the welded joints of the welding rail on the railway shoulder is ensured.

The invention provides a multi-power highway-railway dual-purpose rail welding vehicle suitable for railway main track and turnout areas, which comprises a highway-railway dual-purpose crawler excavator, and the highway-railway dual-purpose crawler excavator comprises a steel rail walking device, an operation arm, a hydraulic support leg, a chassis and a crawler boundary beam. According to the multi-power highway-railway dual-purpose rail welding vehicle suitable for the railway main track and turnout area, the structures such as the highway-railway dual-purpose crawler excavator, the power system and the flash welding system are matched with one another, and when the multi-power highway-railway dual-purpose rail welding vehicle is used, the highway-railway dual-purpose crawler excavator serves as a basic carrier; compared with a traditional automobile chassis, the crawler belt structure has the advantages that the gradeability is obviously improved, and the crawler belt structure can flexibly realize up-and-down operation and is suitable for complex operation environments such as railway main lines and turnout areas; the power system adopts a multi-power mode of combining the storage battery and the internal combustion engine generator, the storage battery can provide clean power, exhaust emission is reduced, the environment-friendly requirement is met, and the problem that a traditional fuel power system is not environmentally friendly is solved.

The application provides a method for field flash welding of U71Mn steel rail under low-temperature environment, adopts a mobile flash welding machine, and comprises the following steps: preheating the steel rail to be welded before welding, performing mobile flash welding under set process parameters, and performing normalizing treatment on the welded joint after welding. The application also provides application of the method in field welding of U71Mn steel rail under low-temperature environment (environmental temperature is not lower than -10 DEG C). The U71Mn steel rail welded joint obtained by the method has excellent adaptability in each performance and base material. Therefore, the application solves the difficulty that the welding quality of U71Mn steel rail under low-temperature environment condition is reduced and the U71Mn steel rail cannot serve stably for a long time.