A welding process for a concealed slide rail bracket

Abstract

This invention discloses a welding method for the support of a concealed slide rail, aiming to solve the problems of oil vaporization, porosity, embrittlement, and aging of seals caused by pre-assembly and oiling followed by welding. The method includes: S1, pre-scanning with an auxiliary heat source to vaporize and evaporate the lubricating oil before welding, and spreading high-temperature resistant ceramic powder to form a physical isolation layer to block capillary penetration; S2, during welding, using ultrasonic atomized inert gas to disperse oil fumes, while applying annular auxiliary heating to change the temperature gradient of the molten pool, driving the liquid metal to flow outward to expel bubbles and prevent ceramic powder from falling in; S3, after welding, spraying a small amount of catalytically active gas to use residual heat to oxidize and remove residual carbides in situ, and implementing gradient forced cooling to protect the seals. This invention eliminates welding defects caused by oil contamination, ensures the smoothness of slide rail pushing and pulling and the life of seals, and improves welding quality and production consistency.

Description

Technical Field

[0001] This invention belongs to the field of welding technology, specifically relating to a welding processing method for a concealed slide rail bracket. Background Technology

[0002] Concealed sliding rails are widely used in high-end custom furniture with heavy loads. Their structure typically includes a thin-walled metal rail body (such as a U-shaped or C-shaped cross-section), internal rolling or damping components, and external metal mounting brackets. To ensure the smooth sliding of the internal rolling components and the sealing performance of the damping components, a special lubricant must be applied before assembly. In current mainstream manufacturing processes, to balance the assembly precision of internal components and avoid welding heat deformation that could damage the pre-calibrated internal gaps, a process of first assembling and lubricating, followed by external welding, is usually adopted. That is, after the internal components are assembled and lubricated, the external metal mounting brackets are welded and fixed to the thin-walled rail body using processes such as laser welding or resistance welding.

[0003] However, this process of assembling and applying grease before external welding faces severe technical challenges in actual production. The grease pre-applied inside the concealed slide rail is usually in a semi-solid paste form. During welding, the large amount of localized high temperature can cause the semi-solid lubricant near the welding point to melt instantly into a liquid state. Driven by capillary action and thermal gradient, liquid lubricating oil rapidly diffuses and flows away from the welding point, directly causing localized lubrication failure within the slide rail and severely impacting the product's smoothness and damping performance. More seriously, the lost liquid lubricating oil continuously flows towards and converges at the high-temperature welding position, undergoing drastic physical and chemical changes upon contact with the weld pool: on one hand, the oil rapidly vaporizes and decomposes, generating a large amount of gas that cannot escape due to the extremely rapid solidification of the thin plate weld pool, forming dense pores and causing localized carbonization and embrittlement of the weld; on the other hand, the dense fumes generated by the vaporization of a large amount of oil flowing towards the weld disrupt the protective gas flow field, causing the weld to oxidize and blacken, and the spatter caused by the micro-explosion effect easily falls into the internal track, causing jamming. Furthermore, high-temperature heat conduction and oil carbonization accelerate the aging and failure of pre-installed rubber seals. Existing conventional wiping methods cannot prevent the dynamic melting and loss of lubricating oil caused by the high welding temperature, nor can they completely remove the trace amounts of oil continuously flowing towards the weld, resulting in a complex interplay of lubrication failure and welding defects.

[0004] Therefore, in order to effectively prevent the semi-solid lubricating oil from melting and leaking instantly due to high temperature during the welding process of the pre-assembled and oiled concealed slide rail, a welding process for the support of the concealed slide rail is proposed. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, this invention provides a welding process for a concealed slide rail bracket.

[0006] The objective of this invention can be achieved through the following technical solutions: A method for welding a bracket for a concealed slide rail, the concealed slide rail comprising a thin-walled metal rail body, a lubrication assembly with a seal pre-installed inside the thin-walled metal rail body, and a metal bracket to be welded, comprising the following steps: S1: Perform auxiliary heat source pre-scanning on the area to be welded and its two sides to allow the lubricating oil to vaporize and evaporate in advance and be blown away. At the same time, before arc initiation, spread high-temperature resistant ceramic powder on the joint surface to form a physical isolation layer to block the capillary penetration of residual lubricating oil. S2: During the existence of the weld pool, an inert gas with ultrasonic waves is used to protect the weld pool to disperse oil and smoke. At the same time, annular auxiliary heating is applied around the weld pool to make the molten metal on the surface of the weld pool flow from the center to the edge, thereby expelling the internal bubbles to the outside. The airflow also blocks the ceramic powder from step S1 outside the weld pool to prevent it from falling into the weld and forming impurities. S3: During the solidification and cooling stage of the molten pool, a small amount of catalytic active gas is injected and residual heat after welding is used to oxidize and remove residual carbides in situ. At the same time, gradient temperature control is implemented to protect the pre-installed seals.

[0007] As a further aspect of the present invention, step S1 includes: S11: Before arc initiation, an auxiliary heat source is used to symmetrically pre-scan and heat the weld joint between the metal rail body and the metal bracket and the preset heat-affected zones on both sides, so that the viscosity of the lubricating oil in this area is reduced and it vaporizes and evaporates in advance. S12: While pre-scanning and heating, a high-pressure inert gas flow is applied through a side nozzle to blow the volatile oil and gas away from the weld area; S13: Within a preset time window after the pre-scanning heating is completed and before the main welding heat source ignites, a layer of micron-sized high-temperature resistant ceramic powder is evenly spread on the surface of the joint to be welded using a micro distributor to form a physical isolation layer; the physical isolation layer is used to block the capillary penetration path of the residual lubricating oil below and to protect the edge of the molten pool during the main welding process.

[0008] As a further aspect of the present invention, the preheating temperature of the auxiliary heat source is controlled above the flash point of the lubricating oil and below the phase transformation temperature of the base material; the high-temperature resistant ceramic powder is alumina or zirconium oxide powder with a melting point higher than that of the base material, and its spreading thickness is set to a preset thickness that is sufficient to block capillary penetration and does not affect the melting depth of the main welding heat source.

[0009] As a further aspect of the present invention, step S2 includes: S21: Using a laser beam or electric arc as the main welding heat source, during the formation and existence of the molten pool, a high-purity inert protective gas flow of ultrasonic atomization is sprayed onto the surface of the molten pool through a coaxial nozzle wrapped around the main welding heat source to disperse the dense smoke formed above the molten pool due to the vaporization and ionization of residual lubricating oil. S22: A ring-shaped auxiliary beam is coaxially set around the main welding heat source to slightly heat the outer area of ​​the molten pool, so that the temperature at the edge of the molten pool is slightly higher than that at the center. S23: Utilizing the temperature difference between the high edge and the low center, the liquid metal on the surface of the molten pool is driven to flow from the center to the edge. This outward flow carries the bubbles inside the molten pool to the edge and discharges them. At the same time, in conjunction with the downward blowing force of the protective airflow, the ceramic powder laid in the first stage is stably blocked outside the edge of the molten pool.

[0010] As a further aspect of the present invention, the power of the annular auxiliary beam is controlled to be used only to change the temperature gradient on the surface of the molten pool to drive the liquid to flow outward, and the power density of the annular auxiliary beam has a gradient distribution with low power at the center and high power at the edges.

[0011] As a further aspect of the present invention, step S3 includes: S31. When the main welding heat source is removed, the molten pool begins to solidify, but the temperature of the weld area is still higher than the ignition point of lubricating oil carbides, a small amount of catalytic active gas is injected into the weld and heat-affected zone through a rear nozzle. S32. Under the catalytic action of the residual heat of the weld, the catalytically active gas reacts with the lubricating oil carbides and incompletely volatilized heavy oil droplets attached to the metal surface in an in-situ oxidation reaction, converting them into gaseous carbon dioxide and water vapor for volatilization and removal. S33. While injecting catalytic active gas, gradient forced cooling is applied to the area near the pre-installed lubrication component seal to control the heat transfer rate of the area.

[0012] As a further embodiment of the present invention, the catalytically active gas is an inert mixed gas containing trace amounts of ozone or reactive oxygen free radicals; the gradient forced cooling adopts a flexible thermally conductive bonding block combined with a semiconductor cooling chip, so that the temperature gradient in the area where the sealing component is located decreases gradually, ensuring that the surface temperature of the sealing component is always lower than the thermal aging critical temperature of its material.

[0013] As a further embodiment of the present invention, the method is integrated into a multi-station step-by-step welding production line, wherein steps S1, S2 and S3 correspond to the pretreatment station, main welding station and post-weld cleaning station on the production line, respectively; the auxiliary heat source, micro distributor, coaxial nozzle, annular auxiliary beam and rear nozzle are all integrated on the dedicated follow-up tooling of each station.

[0014] As a further aspect of the present invention, step S4 is included after step S3: S4: Post-weld ceramic powder removal and recovery. After the weld has solidified and the catalytic active gas has been purified, the high-temperature resistant ceramic powder spread in step S1 has fallen into the molten lubricating oil under the high temperature of welding, forming a powder-containing oil mixture. A negative pressure suction device is used to perform negative pressure suction on the area around the weld and both sides of the joint to remove and recover the ceramic powder along with the liquid lubricating oil attached to it.

[0015] As a further aspect of the present invention, in step S4, the negative pressure suction device includes a negative pressure source, a connecting pipeline, and a suction nozzle; the port of the suction nozzle is flat or arc-shaped, and its port width matches the weld width; the suction nozzle moves stepwise along the weld direction to perform suction; the suction temperature of the negative pressure suction device is controlled above the flow temperature of the lubricating oil, so that the ceramic powder is fully suspended in the liquid lubricating oil so that it can be completely suctioned.

[0016] The beneficial effects of this invention are as follows: It solves the comprehensive defects caused by grease loss through a three-stage synergistic mechanism of pre-weld isolation and blocking, dynamic venting during welding, and post-weld in-situ oxidation. S1 utilizes pre-scanning to vaporize the grease in advance, and uses ceramic powder to physically cut off the path of liquid oil to capillary penetration into the weld seam; S2 utilizes ultrasonic cavitation to break up ionized fumes, and changes the surface temperature field of the molten pool through annular heating, using surface tension gradients to drive the outward flow of liquid metal to expel bubbles, while simultaneously preventing powder from falling in; S3 utilizes the residual heat of the weld seam to catalytically oxidize residual carbides, and prevents heat conduction to internal seals through gradient temperature control; S4 uses auxiliary heat source pre-scanning to actively remove lubricating oil near the welding area before welding, and, combined with the ceramic powder physical isolation layer, blocks the capillary penetration path of residual oil, fundamentally avoiding a large amount of lubricating oil loss to the welding area. It eliminates the problems of weld porosity, carbon embrittlement, and oxidation blackening caused by lubricating oil vaporization, and significantly improves the load-bearing strength and density of the weld; it effectively prevents spatter from falling into the internal track and the aging and damage of the seals caused by oil condensation, ensuring the smoothness of the slide rail and its damping performance; through a combination of physical isolation and in-situ chemical cleaning, it achieves the treatment of trace amounts of oil in narrow gaps. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart of the steps of the present invention. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] While the existing process of assembling and applying oil before external welding ensures the assembly precision of internal components, the semi-solid grease liquefies instantly at high temperatures during welding and rapidly diffuses and flows away into the welding area under capillary action and thermal gradient. This dynamic lubricant loss leads to two consequences: firstly, lubricant loss from the track working surface directly causes local lubrication failure, affecting the smoothness and damping performance of the slide rail; secondly, lubricant lost to the welding area vaporizes and decomposes at high temperatures in the molten pool, producing welding defects such as porosity, carbon embrittlement, and spatter. Conventional pre-welding wiping methods can only remove surface-level free oil contaminants and are ineffective in preventing the dynamic melting and loss of lubricant caused by the high welding temperatures, and cannot completely remove trace amounts of oil contaminants that have seeped into narrow assembly gaps.

[0021] Please see Figure 1 The present invention discloses a welding method for a concealed slide rail bracket. The concealed slide rail includes a thin-walled metal rail body, a lubrication assembly with a seal pre-installed inside the thin-walled metal rail body, and a metal bracket to be welded. The method includes the following steps: S1: Perform auxiliary heat source pre-scanning on the area to be welded and its two sides to allow the lubricating oil to vaporize and evaporate in advance and be blown away. At the same time, before arc initiation, spread high-temperature resistant ceramic powder on the joint surface to form a physical isolation layer to block the capillary penetration of residual lubricating oil. S2: During the existence of the weld pool, an inert gas with ultrasonic waves is used to protect the weld pool to disperse oil and smoke. At the same time, annular auxiliary heating is applied around the weld pool to make the molten metal on the surface of the weld pool flow from the center to the edge, thereby expelling the internal bubbles to the outside. The airflow also blocks the ceramic powder from step S1 outside the weld pool to prevent it from falling into the weld and forming impurities. S3: During the solidification and cooling stage of the molten pool, a small amount of catalytic active gas is injected and residual heat after welding is used to oxidize and remove residual carbides in situ. At the same time, gradient temperature control is implemented to protect the pre-installed seals.

[0022] S4: Post-weld ceramic powder removal and recovery. After the weld has solidified and the catalytic active gas has been purified, the high-temperature resistant ceramic powder spread in step S1 has fallen into the molten lubricating oil under the high temperature of welding, forming a powder-containing oil mixture. A negative pressure suction device is used to perform negative pressure suction on the area around the weld and both sides of the joint to remove and recover the ceramic powder along with the liquid lubricating oil attached to it.

[0023] In step S4, the negative pressure suction device includes a negative pressure source, connecting pipes, and a suction nozzle. The nozzle has a flat or arc-shaped port, and its port width matches the weld width. The nozzle moves stepwise along the weld direction to perform suction. The suction temperature of the negative pressure suction device is controlled above the flow temperature of the lubricating oil, ensuring that the ceramic powder is fully suspended in the liquid lubricating oil for complete removal. Utilizing the still-fluid state of the lubricating oil after welding, before it cools and solidifies, the negative pressure suction device generates a strong suction force. Because the ceramic powder is fully suspended in the liquid lubricating oil, the negative pressure suction can simultaneously remove the oil-powder mixture as a whole. This not only thoroughly removes the hard powder mixed in the oil but also avoids the problem of powder being difficult to separate after the oil solidifies, achieving simultaneous removal of oil and powder.

[0024] The comprehensive defects caused by grease loss are solved through a three-stage synergistic mechanism: pre-weld isolation and blocking, dynamic venting during welding, and post-weld in-situ oxidation. S1 utilizes pre-scanning to vaporize the grease in advance and uses ceramic powder to physically cut off the path of liquid oil to capillary penetration into the weld seam. S2 uses ultrasonic cavitation to break up ionized fumes and changes the surface temperature field of the molten pool through annular heating, using surface tension gradients to drive the outward flow of liquid metal to expel bubbles while preventing powder from falling in. S3 uses residual heat from the weld seam to catalytically oxidize residual carbides and uses gradient temperature control to prevent heat conduction to internal seals. S4 uses an auxiliary heat source for pre-scanning to actively remove lubricating oil near the welding area before welding, and the ceramic powder physical isolation layer blocks the capillary penetration path of residual oil, fundamentally preventing a large amount of lubricating oil loss into the welding area. It eliminates the problems of weld porosity, carbon embrittlement, and oxidation blackening caused by lubricating oil vaporization, and significantly improves the load-bearing strength and density of the weld; it effectively prevents spatter from falling into the internal track and the aging and damage of the seals caused by oil condensation, ensuring the smoothness of the slide rail and its damping performance; through a combination of physical isolation and in-situ chemical cleaning, it achieves the treatment of trace amounts of oil in narrow gaps.

[0025] For high-temperature resistant ceramic powders, due to their melting point being much higher than that of the base material, their solid state throughout the welding process, and their being blocked from the edge of the molten pool by the protective gas flow and outward flow of the weld pool during the main welding stage, most of the ceramic powder ultimately deposits on the surface of the heat-affected zone on both sides of the weld. However, this portion of ceramic powder easily comes into contact with and mixes with the liquid lubricating oil that diffuses from the inside under the high-temperature welding environment, forming a powder-oil mixture. If this mixture is not cleaned in time, on the one hand, the ceramic powder, as a hard abrasive, will significantly aggravate friction and wear if it falls into the sliding track or rolling components during subsequent use of the slide rail, leading to push-pull jamming or even functional failure; on the other hand, the oil mixture solidifies further after cooling, increasing the difficulty of subsequent cleaning.

[0026] Therefore, after welding, the high-temperature resistant ceramic powder spread on the weld joint surface in step S1, after experiencing the high-temperature environment of the main welding stage and post-weld cleaning stage, ultimately deposits in the peripheral areas on both sides of the weld because the ceramic powder itself does not participate in the welding reaction and does not enter the molten pool. Under the high temperature of welding, a small amount of lubricating oil that flows from the inside to the outside exists in liquid form around the weld joint and mixes with the ceramic powder, forming a powder-oil mixture—the ceramic powder is encapsulated or suspended in the molten lubricating oil. Based on this, a negative pressure suction device is used, applying negative pressure suction force to the peripheral area of ​​the weld joint through the suction nozzle. Because the mixture formed by the ceramic powder and liquid lubricating oil has high fluidity, it can be sucked into the suction nozzle as a whole under negative pressure, thereby achieving the removal and recovery of the ceramic powder along with the liquid lubricating oil attached to it. The diameter and suction force of the suction nozzle are configured so that its suction range is limited to the softened area around the weld joint, without touching the solidified weld metal, thus ensuring that the weld itself is not disturbed. In another embodiment, graphite powder can also be used, which does not affect the transmission even if it falls into the sliding component.

[0027] Conventional preheating and cleaning methods often result in uneven heating, which can easily lead to thermal stress deformation in thin-walled base materials. Furthermore, lateral air blowing cannot accurately cover the joint root. In addition, if the isolation layer is not applied evenly or at the wrong time, the isolation layer thickness will be inconsistent, failing to effectively block capillary penetration, and may even be blown away by the airflow during welding. Therefore, as a further aspect of the present invention, step S1 includes: S11: Before arc initiation, the weld seam between the metal rail body and the metal bracket and the preset heat-affected zone on both sides are symmetrically pre-scanned and heated using auxiliary heat sources such as lasers, so that the viscosity of the lubricating oil in this area is reduced and it vaporizes and evaporates in advance. S12: While pre-scanning and heating, a high-pressure inert gas flow is applied through a side nozzle to blow the volatile oil and gas away from the weld area; S13: Within a preset time window after the pre-scanning heating is completed and before the main welding heat source ignites, a layer of micron-sized high-temperature resistant ceramic powder is evenly spread on the surface of the joint to be welded using a micro distributor to form a physical isolation layer; the physical isolation layer is used to block the capillary penetration path of the residual lubricating oil below and to protect the edge of the molten pool during the main welding process.

[0028] S11 employs symmetrical pre-scanning heating to ensure uniform heating on both sides of the thin-walled rail body, avoiding thermal deformation caused by unilateral heating, while rapidly reducing the viscosity of the lubricating oil and causing it to vaporize; S12 uses high-pressure inert airflow synchronized with pre-scanning to form a dynamic purging field, quickly carrying the vaporized oil and gas away from the heat-affected zone; S13 uses a micro distributor to spread powder within a precise time window, at which time the surface temperature of the base material is suitable, and the powder can adhere evenly to the joint surface by electrostatic adsorption or weak thermal adhesion, forming a continuous and dense physical isolation layer.

[0029] If the preheating temperature is too high, it may cause a phase change in the base material or damage the internal seals; if the temperature is too low, the lubricating oil cannot be fully vaporized. Simultaneously, if the melting point of the isolation layer powder is insufficient, it will melt during welding and mix into the weld, forming slag inclusions; if the thickness is too large, it will hinder the penetration depth of the main welding heat source, resulting in incomplete penetration. As a further aspect of the invention, the preheating temperature of the auxiliary heat source is controlled above the flash point of the lubricating oil and below the phase change temperature of the base material; the high-temperature resistant ceramic powder is alumina or zirconium oxide powder with a melting point higher than that of the base material, and its spreading thickness is set to a preset thickness sufficient to block capillary penetration without affecting the penetration depth of the main welding heat source.

[0030] By strictly limiting the preheating temperature to a narrow range "above the flash point of the lubricating oil and below the phase transformation temperature of the base material," thermal energy is used to precisely trigger the phase transformation of the lubricating oil (liquid to gas), while ensuring that the metallographic structure of the base material remains unchanged and that the heat is insufficient to transfer to the interior and damage the seal. Alumina or zirconium oxide powder is selected, utilizing its extremely high melting point (far exceeding the temperature of the base material and the weld pool) to ensure that it maintains a solid particle morphology during welding. By precisely controlling the spread thickness, it can both overcome microscopic gaps to block capillary forces and be easily blown away or melted in a very shallow layer under the high energy density of the main laser or electric arc, without affecting the core penetration depth.

[0031] During welding, the dense fumes formed by the vaporization and ionization of lubricating oil severely absorb and scatter laser / arc energy and disrupt the flow field of the protective gas flow. Simultaneously, air bubbles entrained within the molten pool are difficult to rise and escape naturally due to surface tension. Furthermore, ceramic powder at the edge of the molten pool is easily affected by convection or airflow and falls into the molten pool, forming inclusions. As a further aspect of the invention, step S2 includes: S21: Using a laser beam or electric arc as the main welding heat source, during the formation and existence of the molten pool, a high-purity inert protective gas flow of ultrasonic atomization is sprayed onto the surface of the molten pool through a coaxial nozzle wrapped around the main welding heat source to disperse the dense smoke formed above the molten pool due to the vaporization and ionization of residual lubricating oil. S22: A ring-shaped auxiliary beam is coaxially set around the main welding heat source to slightly heat the outer area of ​​the molten pool, so that the temperature at the edge of the molten pool is slightly higher than that at the center. S23: Utilizing the temperature difference between the high edge and the low center, the liquid metal on the surface of the molten pool is driven to flow from the center to the edge. This outward flow carries the bubbles inside the molten pool to the edge and discharges them. At the same time, in conjunction with the downward blowing force of the protective airflow, the ceramic powder laid in the first stage is stably blocked outside the edge of the molten pool.

[0032] In S21, the ultrasonically atomized inert gas generates high-frequency ultrasound upon ejection, producing strong microjets and shock waves that disperse dense smoke particles and ensure uniform diffusion, restoring the laminar flow state of the protective airflow. In S22 and S23, the annular auxiliary beam creates a temperature field with high edge temperature and low center temperature around the molten pool. As the surface tension of the liquid metal decreases with increasing temperature, the surface liquid metal flows from the center (high surface tension) to the edge (low surface tension) driven by the surface tension gradient. This outward convection not only carries internal bubbles to the edge for escape but also forms an outward liquid barrier, which, together with the downward protective airflow, firmly blocks the ceramic powder outside the molten pool.

[0033] If the power control is improper when applying auxiliary heating around the molten pool, it can lead to excessive heat input, causing the thin-walled base material to burn through or the molten pool to collapse excessively. If the power density distribution is unreasonable, a stable temperature gradient cannot be formed, resulting in turbulent flow of the liquid metal and instead drawing bubbles into the depths of the molten pool. As a further aspect of the present invention, the power of the annular auxiliary beam is controlled to be used only to change the temperature gradient on the surface of the molten pool to drive the outward flow of the liquid, and the power density of the annular auxiliary beam has a gradient distribution that is low in the center and high at the edges.

[0034] By strictly limiting the power of the annular auxiliary beam to a low threshold that only alters the surface temperature gradient, the superposition of additional heat on the overall heat input of the base material is avoided, preventing burn-through of thin-walled parts. The power density exhibits a gradient distribution, low at the center and high at the edges, precisely shaping a smooth, increasing temperature curve from the center to the edge of the molten pool surface, thereby generating a stable and continuous surface tension gradient. This stable gradient ensures smooth outward laminar flow of the liquid metal, avoiding turbulence caused by localized overheating, and ensuring the orderly discharge and blocking of bubbles and impurities.

[0035] After welding, trace amounts of lubricating oil carbides and incompletely volatilized heavy oil droplets remain on the surface of the weld and heat-affected zone. These substances can attract dust during later use, causing the slide rail to jam or inducing stress corrosion. Simultaneously, if the residual heat after welding cools naturally, it will bake the adjacent rubber seals for an extended period, leading to thermal aging and failure. As a further aspect of the present invention, step S3 includes: S31. When the main welding heat source is removed, the molten pool begins to solidify, but the temperature of the weld area is still higher than the ignition point of lubricating oil carbides, a small amount of catalytic active gas is injected into the weld and heat-affected zone through a rear nozzle. S32. Under the catalytic action of the residual heat of the weld, the catalytically active gas reacts with the lubricating oil carbides and incompletely volatilized heavy oil droplets attached to the metal surface in an in-situ oxidation reaction, converting them into gaseous carbon dioxide and water vapor for volatilization and removal. S33. While injecting catalytic active gas, gradient forced cooling is applied to the area near the pre-installed lubrication component seal to control the heat transfer rate of the area.

[0036] S31 and S32 utilize the principle of in-situ self-cleaning. After the molten pool solidifies, the weld area still retains significant residual heat. At this time, the injected trace amounts of catalytically active gas, under the dual catalysis of the metal surface and residual heat, exhibits extremely strong oxidizing activity. It can rapidly react with solid carbides and heavy oil droplets, converting them into CO2 and H2O gases that evaporate, achieving contactless chemical cleaning. In S33, gradient forced cooling is implemented simultaneously with the chemical reaction. By controlling the heat conduction rate, the path for residual heat to transfer to the internal seals is cut off, ensuring that the seals remain within a safe temperature range.

[0037] Conventional oxidizing gases exhibit low reactivity at low temperatures, making it difficult to quickly remove carbides after welding and easily introducing impurities such as nitrogen. Conventional forced cooling methods result in uneven cooling, easily generating significant thermal stress within thin-walled parts and causing sudden drops in localized temperatures of the seal, leading to microcracks or accelerated aging. As a further aspect of this invention, the catalytically active gas is an inert mixture containing trace amounts of ozone or reactive oxygen free radicals; the gradient forced cooling employs a flexible thermally conductive bonding block combined with a semiconductor cooling chip, ensuring a gradual decrease in temperature gradient in the area where the seal is located, guaranteeing that the surface temperature of the seal remains below the critical temperature for thermal aging of its material.

[0038] An inert gas mixture containing trace amounts of ozone or reactive oxygen free radicals maintains high oxidation removal efficiency even at gradually decreasing temperatures after welding due to the extremely high chemical reactivity of ozone and free radicals. Furthermore, the inert base gas prevents excessive oxidation of the base material. The flexible thermally conductive bonding block perfectly conforms to the complex, irregularly shaped surface of the concealed slide rail, ensuring uniform heat distribution. The semiconductor cooling chip uses temperature sensor data combined with a PID temperature control algorithm to achieve precise temperature regulation, causing the temperature in the sealing area to decrease along a preset, gradual curve, thus avoiding thermal shock.

[0039] Existing slide rail welding methods mostly employ single-station or semi-automatic processing, with pretreatment, welding, and post-weld treatment completed at the same station or under manual intervention. This results in long production cycles and low efficiency. Furthermore, the fixed processing fixtures cannot adapt to the long stroke or complex trajectory of the slide rail, leading to poor processing consistency and making it difficult to meet the large-scale mass production needs of high-end customized furniture and precision equipment. As a further solution of the present invention, the method is integrated into a multi-station step-by-step welding production line. Steps S1, S2, and S3 correspond to the pretreatment station, main welding station, and post-weld cleaning station on the production line, respectively. The auxiliary heat source, micro distributor, coaxial nozzle, annular auxiliary beam, and rear nozzle are all integrated into the dedicated follow-up fixtures at each station.

[0040] By decoupling the process into three independent stations—pretreatment, main welding, and post-weld cleaning—a stepper conveyor system is used to achieve parallel processing and synchronized cycle time, significantly reducing the processing time per piece. Each station is equipped with a dedicated follow-up fixture, which uses servo drive or contour-following mechanical structure to track the weld seam trajectory or slide rail contour in real time, ensuring that the auxiliary heat source, distributor, nozzle, and other actuators always maintain a constant optimal working distance and angle with the area to be treated.

[0041] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A method for welding a bracket for a concealed slide rail, the concealed slide rail comprising a thin-walled metal rail body, a lubrication assembly with a seal pre-installed inside the thin-walled metal rail body, and a metal bracket to be welded, characterized in that: Includes the following steps: S1: Perform auxiliary heat source pre-scanning on the area to be welded and its two sides to allow the lubricating oil to vaporize and evaporate in advance and be blown away. At the same time, before arc initiation, spread high-temperature resistant ceramic powder on the joint surface to form a physical isolation layer to block the capillary penetration of residual lubricating oil. S2: During the existence of the weld pool, an inert gas with ultrasonic waves is used to protect the weld pool to disperse oil and smoke. At the same time, annular auxiliary heating is applied around the weld pool to make the molten metal on the surface of the weld pool flow from the center to the edge, thereby expelling the internal bubbles to the outside. The airflow also blocks the ceramic powder from step S1 outside the weld pool to prevent it from falling into the weld and forming impurities. S3: During the solidification and cooling stage of the molten pool, a small amount of catalytic active gas is injected and residual heat after welding is used to oxidize and remove residual carbides in situ. At the same time, gradient temperature control is implemented to protect the pre-installed seals.

2. The method of claim 1, wherein: Step S1 includes: S11: Before arc initiation, an auxiliary heat source is used to symmetrically pre-scan and heat the weld seam between the metal rail body and the metal bracket and the preset heat-affected zones on both sides, so that the viscosity of the lubricating oil in this area is reduced and it vaporizes and evaporates in advance. S12: While pre-scanning and heating, a high-pressure inert gas flow is applied through a side nozzle to blow away the volatilized oil and gas from the weld area; S13: Within a preset time window after the pre-scanning heating is completed and before the main welding heat source ignites, a layer of micron-sized high-temperature resistant ceramic powder is evenly spread on the surface of the joint to be welded using a micro distributor to form a physical isolation layer; the physical isolation layer is used to block the capillary penetration path of the residual lubricating oil below and to protect the edge of the molten pool during the main welding process.

3. The method of claim 2, wherein: The preheating temperature of the auxiliary heat source is controlled above the flash point of the lubricating oil and below the phase transformation temperature of the base material; the high-temperature resistant ceramic powder is alumina or zirconium oxide powder with a melting point higher than that of the base material, and its spreading thickness is set to a preset thickness that is sufficient to block capillary penetration and does not affect the melting depth of the main welding heat source.

4. The method of claim 1, wherein: Step S2 includes: S21: Using a laser beam or electric arc as the main welding heat source, during the formation and existence of the molten pool, a high-purity inert protective gas flow of ultrasonic atomization is sprayed onto the surface of the molten pool through a coaxial nozzle wrapped around the main welding heat source to disperse the dense smoke formed above the molten pool due to the vaporization and ionization of residual lubricating oil. S22: A ring-shaped auxiliary beam is coaxially set around the main welding heat source to slightly heat the outer area of ​​the molten pool, so that the temperature at the edge of the molten pool is slightly higher than that at the center. S23: Utilizing the temperature difference between the high edge and the low center, the liquid metal on the surface of the molten pool is driven to flow from the center to the edge. This outward flow carries the bubbles inside the molten pool to the edge and discharges them. At the same time, in conjunction with the downward blowing force of the protective airflow, the ceramic powder laid in the first stage is stably blocked outside the edge of the molten pool.

5. The method of claim 4, wherein: The power of the annular auxiliary beam is controlled to be used only to change the temperature gradient on the surface of the molten pool to drive the liquid to flow outward, and the power density of the annular auxiliary beam has a gradient distribution with low power at the center and high power at the edges.

6. The method of claim 1, wherein: Step S3 includes: S31. When the main welding heat source is removed, the molten pool begins to solidify, but the temperature of the weld area is still higher than the ignition point of lubricating oil carbides, a small amount of catalytic active gas is injected into the weld and heat-affected zone through a rear nozzle. S32. Under the catalytic action of the residual heat of the weld, the catalytically active gas reacts with the lubricating oil carbides and incompletely volatilized heavy oil droplets attached to the metal surface in an in-situ oxidation reaction, converting them into gaseous carbon dioxide and water vapor for volatilization and removal. S33. While injecting catalytic active gas, gradient forced cooling is applied to the area near the pre-installed lubrication component seal to control the heat transfer rate of the area.

7. The method of claim 6, wherein: The catalytically active gas is an inert mixed gas containing trace amounts of ozone or reactive oxygen free radicals; the gradient forced cooling uses a flexible thermally conductive bonding block combined with a semiconductor cooling chip to make the temperature gradient in the area where the seal is located decrease gradually, ensuring that the surface temperature of the seal is always below the thermal aging critical temperature of its material.

8. The method of claim 1, wherein: The method is integrated into a multi-station step welding production line. Steps S1, S2 and S3 correspond to the pretreatment station, main welding station and post-weld cleaning station on the production line, respectively. The auxiliary heat source, micro distributor, coaxial nozzle, annular auxiliary beam and rear nozzle are all integrated into the dedicated follow-up tooling of each station.

9. The method of claim 1, wherein: Step S3 is followed by step S4: S4: Post-weld ceramic powder removal and recovery. After the weld has solidified and the catalytic active gas has been purified, the high-temperature resistant ceramic powder spread in step S1 has fallen into the molten lubricating oil under the high temperature of welding, forming a powder-containing oil mixture. A negative pressure suction device is used to perform negative pressure suction on the area around the weld and both sides of the joint to remove and recover the ceramic powder along with the liquid lubricating oil attached to it.

10. The method of claim 9, wherein: In step S4, the negative pressure suction device includes a negative pressure source, a connecting pipeline, and a suction nozzle; the port of the suction nozzle is flat or arc-shaped, and its port width matches the weld width. The suction nozzle moves stepwise along the weld direction to perform suction; the suction temperature of the negative pressure suction device is controlled above the flow temperature of the lubricating oil, so that the ceramic powder is fully suspended in the liquid lubricating oil so that it can be completely suctioned.

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