44 results about "Flash welding" patented technology

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 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 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.

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 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 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 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 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.

This invention discloses a method for centering and flash welding rails, belonging to the field of rail welding technology, to solve at least one of the problems in existing technologies: poor centering accuracy of rail samples and residual misalignment after rail centering and welding. The centering method of this invention includes: placing multiple linear laser sensors on the side and top surfaces of the rail head of two rail samples respectively; measuring the deviation of the side surfaces of the rail head of two rail samples, determining if the deviation is below a threshold; measuring the deviation of the top surfaces of the rail head of two rail samples, determining if the deviation is below a threshold; if not, controlling the movement of electrodes on the welding rig to adjust the relative position of the two rail samples in the vertical direction, so that the deviation of the top surfaces of the rail head of the two rail samples is below the threshold. This invention can be used for rail centering and flash welding.

This invention discloses a method for reducing gray spot defects in flash welded joints of pearlitic steel rails. The method includes the following steps: molten steel is sequentially smelted in a converter, refined using an LF (sulfuric acid) furnace, refined using an RH (refined halogenated) furnace, and continuously cast to obtain pearlitic steel rails; wherein, metallic Ce is added during the RH vacuum refining stage; the pearlitic steel rails are then subjected to moving flash welding to obtain welded rails. This invention reduces gray spot defects in flash welded joints of pearlitic steel rails by adding rare earth elements in conjunction with a suitable welding process. The total area of ​​gray spot defects in the flash welded joints of rails treated using this method is reduced by more than 80%, and other microstructure properties of the joint meet TB / T 1632, while the overall performance is significantly improved, substantially reducing gray spot defects in flash welded joints of rails and improving overall performance.

The utility model relates to an automatic lifting positioning and clamping mechanism, which comprises two groups of clamping parts, the two groups of clamping parts are respectively arranged on the left side and the right side of a flash welding machine on a flash welding machine tool, each group of clamping parts comprises more than two mounting plates, one end of each mounting plate is provided with a motor, the output end of each motor is connected with a lead screw, and the lead screw is connected with a lead screw. A lead screw is arranged on the installation plate, a nut is in threaded connection with the lead screw, a sliding groove is formed in the position, corresponding to the lead screw, of the installation plate, the nut is arranged in the sliding groove in a sliding mode, a fixing shaft is arranged on the nut, a clamping roller is rotationally arranged outside the fixing shaft, and a long round hole with the width larger than the diameter of the clamping roller is formed in the position, corresponding to the sliding groove, of the flash welding machine tool. And the lifting device is fixedly connected with the mounting plate. According to the rail clamping device, a welded rail can be clamped, the clamping part can be prevented from influencing feeding and discharging of the rail by arranging the lifting mechanism and the oblong holes, and the clamping roller can freely move in the X-axis direction while being fixed in the y-axis direction of the rail.

The application discloses a method for improving the wear resistance of a rail head of a rail welded joint and a rail, and the method comprises the following steps: flash welding the rail, including: sequentially performing an electric heating stage and a press forging stage; wherein the voltage of the electric heating stage is 90%-100% of the total input voltage, the current is 40-80 kA, the number of short-circuit contacts is 6-14, the duration of each time is 4-6 s, and the interval is 0.5-2 s; and heat treating the rail after the flash welding, including: sequentially performing a first cooling stage, a heating stage, a holding stage, a second cooling stage and a third cooling stage; wherein the end temperature of the first cooling stage is 25-100 DEG C, the end temperature of the heating stage is 800-1100 DEG C, the temperature interval of the holding stage is 800-900 DEG C, the start temperature of the second cooling stage is greater than 900 DEG C and the end temperature is 600-700 DEG C, and the start temperature of the third cooling stage is 600-700 DEG C and the end temperature is 430-500 DEG C. The application can improve the wear resistance of the rail welded joint.

The application discloses a kind of switch rail flash welding construction methods, comprising the following operating steps: S1, construction preparation and switch investigation;S2, rail state inspection and pretreatment;S3, welding machine alignment and clamping;S4, dynamic compensation-based flash welding;S5, postweld normalizing treatment;S6, rough polishing;S7, welding head flaw detection;S8, fine polishing and profile finishing;S9, flatness and appearance inspection;S10, line locking.Effectively improve the consistency of welding quality, enhance the defect prevention capability, optimize the construction organization efficiency, reduce the operation threshold and realize the welding process traceability.

This invention relates to a welding method for the closure joint of seamless rail transit tracks. Current closure joint welding methods suffer from problems such as the inability to accurately match rail consumption values ​​to actual construction conditions and the inability to dynamically correct deviations in lap calculation. This invention includes: real-time parameter monitoring; lap calculation and closed-loop correction, calculating the lap amount of the rail closure joint; bending and alignment, sawing the rail and aligning the closure joint using a bending method; welding and pressure-holding heat treatment, performing flash welding on the aligned closure joint to form a welded joint, and performing post-weld heat treatment on the welded joint under pressure; displacement observation and calculation, combining displacement data from each displacement observation point with the calculated rail tensile amount; if the deviation exceeds a preset threshold, recalculating the lap amount and adjusting the welding parameters; locking the track; and joint grinding. The rail consumption values ​​of this invention can accurately match actual construction conditions and can dynamically correct deviations in lap calculation.

The utility model discloses a turnout flash welding machine with an upsetting oil cylinder and an overlap pushing oil cylinder on the same side. The turnout flash welding machine comprises an upsetting mechanism, a protrusion pushing mechanism, a movable frame assembly and a static frame assembly. The upsetting mechanism comprises an upsetting oil cylinder and an upsetting shaft, the upsetting oil cylinder comprises an upsetting cylinder body and an upsetting piston rod, the upsetting cylinder body is installed on the side, away from the movable frame assembly, of the static frame assembly, one end of the upsetting shaft is installed on the movable frame assembly, and the other end of the upsetting shaft is installed on the upsetting piston rod. The upsetting piston rod stretches out and draws back to drive the upsetting shaft and the movable frame assembly to reciprocate; the convex pushing mechanism comprises a convex pushing oil cylinder and a convex pushing cutter, the convex pushing oil cylinder comprises a convex pushing cylinder body and a convex pushing piston rod, the convex pushing cylinder body is installed on the static frame assembly, the convex pushing cutter is installed on the convex pushing piston rod, and the convex pushing cutter is located between the static frame assembly and the movable frame assembly. According to the turnout flash welding machine on the same side of the upsetting oil cylinder and the overlap pushing oil cylinder, it is guaranteed that the flash welding machine can also weld variable cross-section AT steel rails special for branch turnouts, and the applicability of the flash welding machine is improved.

The application discloses a steel rail flash welding seam rail bottom triangular area temperature control method and belongs to the technical field of steel material welding. The method is characterized in that the rail bottom triangular area and the rail bottom angle are greatly reduced in temperature difference by optimizing the normalizing cooling mode of the welding seam and controlling the rail bottom temperature difference, the temperature uniformity of the rail bottom welding seam is effectively controlled, the uniformity of the whole rail bottom surface organization and grain size is ensured, the grain size of the welding seam triangular area is improved by more than 1 grade, the triangular area flaw detection noise is obviously reduced, and the flaw detection qualified rate is obviously improved.

This invention proposes a method for switching single-source power supply modes in rail flash welding based on energy consumption optimization. It relates to the field of mode switching technology, determining the energy consumption paths of various single-source power supply modes, modeling and calculating energy conversion efficiency, and collecting relevant parameters and recording historical welding process curves in real time. The method integrates basic energy consumption data for each power supply mode to obtain comprehensive energy consumption information. By combining this basic energy consumption data with a short-term prediction model, it predicts key energy consumption indicators for future periods and calculates the comprehensive evaluation value of each power supply mode to obtain the target power supply mode with optimal energy consumption. Finally, it makes decisions and executes power supply mode switching based on the target power supply mode, preset thresholds, and welding interval requirements, obtaining target rail flash welding power supply energy consumption effect data. This invention achieves scientific switching, energy consumption optimization, and improved construction efficiency for single-source power supply modes in rail flash welding.

The steel rail flash welding machine head comprises a center shaft, two oil way integrated blocks, a control cable and a hydraulic oil pipe, the control cable and the hydraulic oil pipe are connected between the two oil way integrated blocks, a mounting inner hole is formed in the center shaft in the axial direction of the center shaft, and the control cable and the hydraulic oil pipe both penetrate through the mounting inner hole; compared with the prior art, the central shaft which is originally arranged in the connecting line direction of the two oil way integrated blocks is reasonably utilized, and the mounting inner hole is formed in the central shaft in the axial direction of the central shaft so that the section of control cable and the section of hydraulic oil pipe can be arranged in a hidden mode; therefore, splashing welding slag and sparks are prevented from being attached to the control cable and the hydraulic oil pipe in the welding process, the service life of the control cable and the hydraulic oil pipe is prolonged, and the safety of the steel rail flash welding machine head in the operation process is improved.

The invention discloses a flash welding device and process for dynamic distribution of heat input and grain refinement. The device comprises a heat input dynamic distribution system, a joint crystal grain active regulation and control system and a multi-field cooperative control unit. The system monitors the welding process in real time through an infrared thermal imager and a current and voltage acquisition module, carries out real-time calculation and decision making through a built-in three-dimensional transient thermal field coupling model, an ultrasonic vibration grain refinement model and a multiple-input-multiple-output mapping model, and dynamically adjusts output parameters of a pulse flash power source and process parameters of high-frequency ultrasonic vibration. And collaborative precise regulation and control of heat input and crystal grain evolution are realized. According to the method, overheating of a molten pool and grain coarsening can be effectively inhibited, the grain size of a weld joint is refined to be below 10 microns, the joint strength reaches 95% or above of base metal, the fatigue life is remarkably prolonged, and the method is particularly suitable for high-performance welding of high-strength steel, aluminum alloy, titanium alloy and other materials difficult to weld.