Hot bending forming process of fixing plate for beam falling prevention device

Abstract

The invention relates to the technical field of bridge structure safety device manufacturing, in particular to a hot bending forming process of a fixing plate for a beam falling prevention device, which comprises the following steps: blanking of the fixing plate for the beam falling prevention device: selecting Q355 hot rolled steel, cutting the Q355 hot rolled steel to a preset size by using a laser cutting machine, blanking, and reserving 3-5mm machining allowance on two sides; according to the hot bending forming process, laser cutting blanking and milling machine finish machining are combined, material waste is reduced while the precision is guaranteed, the high-frequency rapid heating and hot forging forming process is adopted, the machining efficiency and material plasticity are remarkably improved, meanwhile, oxidation burning loss is reduced, and the product quality is improved. Meanwhile, a special tool cavity, a water cooling system and a profiling detection and shape correction technology are matched, the forming precision and the size stability are ensured, in addition, the technology is achieved based on conventional equipment, the comprehensive advantages of procedure simplification, cost reduction, efficiency improvement, performance optimization, forming precision and the like are achieved, and the method is suitable for batch production and has good industrial popularization value.

Description

Technical Field

[0001] This invention relates to the field of bridge structural safety device manufacturing technology, specifically to a hot bending forming process for a fixing plate used in an anti-falling beam device. Background Technology

[0002] With the rapid development of railway engineering in my country, bridge anti-falling beam devices are playing an increasingly important role in bridge structural safety. In the new anti-falling beam device, the upper and lower bearing plates are connected to the bottom of the beam and the top of the pier pad, respectively. A rectangular damping ring provides damping force, and the lower bearing plate is anchored to the damping ring by a "U"-shaped fixing plate. Therefore, the strength and reliability of the fixing plate are directly related to the safety performance of the entire anti-falling beam device.

[0003] Currently, the manufacturing of fixing plates for anti-falling beam devices in existing technologies mostly adopts processes such as steel plate welding or machining of relatively thick steel plates. These methods have problems such as cumbersome procedures, high processing difficulty, low processing efficiency, serious waste of raw materials, and high manufacturing costs. Especially for fixing plates with complex geometric shapes, such as the "Z" shape, traditional machining methods not only have long processing cycles, but also require high thickness of raw materials, further increasing material costs and processing difficulty.

[0004] Therefore, there is an urgent need in this field for a fixed plate forming process that is simple, efficient, low-cost, and can guarantee product performance, in order to solve the above-mentioned problems in the prior art. Summary of the Invention

[0005] The purpose of this invention is to provide a hot bending forming process for a fixing plate for a beam-prevention device, so as to solve the problems of cumbersome procedures, low processing efficiency, high cost and difficulty in guaranteeing material properties in the existing fixing plate processing process for beam-prevention devices mentioned in the background art.

[0006] To achieve the above objectives, the present invention aims to provide a hot bending forming process for a fixing plate used in an anti-falling beam device, comprising the following steps: S1. Cutting of fixing plate for anti-fall beam device: Select Q355 hot-rolled steel, use laser cutting machine to cut to the preset size and cut the material, while leaving 3-5mm processing allowance on both sides; S2. Milling the end face of the fixing plate for the anti-fall beam device: Use a milling machine to finish the edge of the fixing plate, and control the dimensional accuracy to ±0.1mm; S3. Drilling holes in the fixing plate for the anti-falling beam device: Use a drilling machine to process the anchoring holes and anchoring hole grooves on the fixing plate. S4. High-frequency heating of the fixing plate for the anti-fall beam device: The fixing plate is heated to 900-1100℃ using a high-frequency heating furnace; S5. Anti-fall beam device fixing plate forming: The heated fixing plate is placed into the tooling cavity equipped with a water cooling system and hot forging is performed; S6. Correction of the fixing plate for the anti-fall beam device: Use a template to check the size of the fixing plate, and use a correction mold corresponding to the cavity structure to locally correct any unqualified parts on a double column press. S7. Surface treatment of the fixing plate for the anti-fall beam device: After sandblasting the fixing plate, use a spray painting machine to perform multi-layer spray painting.

[0007] As a further improvement to this technical solution, in step S3, the diameter of the anchoring hole is 32-41mm, and the center distance tolerance of the anchoring hole is ±0.1mm.

[0008] As a further improvement to this technical solution, in step S4, under the premise of avoiding billet cracking and excessive cross-sectional temperature difference, the heating time is 5-8 minutes, and after reaching the target temperature, it is maintained for 1-2 minutes to eliminate the core-surface temperature difference.

[0009] As a further improvement to this technical solution, in step S5, the inner wall of the tooling cavity is provided with an inclined angle to facilitate demolding, and the tooling cavity is equipped with a water cooling system to control the temperature.

[0010] As a further improvement to this technical solution, in step S7, the walking speed of the painting machine is no higher than 0.1 meters / minute, and the coating thickness meets the requirements of 80-100μm for primer, 100-120μm for intermediate paint, and 50-70μm for topcoat.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The present invention simplifies the process and reduces costs: by combining laser cutting blanking with milling precision machining, material waste can be reduced while ensuring accuracy, thereby reducing processing costs.

[0012] 2. The processing efficiency of the present invention is significantly improved: the fixed plate can be rapidly heated to 900-1100℃ by a high-frequency heating furnace, thereby greatly improving the plasticity of the material, and thus making the hot forging forming efficiency 100% higher than that of traditional cold working or medium-temperature working.

[0013] 3. The material properties of the present invention are superior: hot forging can be used to make thinner plates, thereby avoiding the loss of material properties caused by machining of thick plates. At the same time, high-frequency heating is used to control the temperature precisely, reducing oxidation and burn-off.

[0014] 4. The present invention has high molding precision: it adopts a special tooling cavity and water cooling system to ensure dimensional stability during the molding process. Subsequent mold inspection and correction processes ensure that the product dimensions meet the design requirements.

[0015] 5. The present invention has strong adaptability and good operability: the whole process is based on conventional processing equipment, which is easy to realize industrial production, suitable for mass manufacturing, and has good promotion value. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the hot bending forming process steps of the present invention.

[0017] Figure 2 This is a schematic diagram of the three-dimensional structure of the forging lower die of the present invention.

[0018] Figure 3 This is a schematic diagram of the three-dimensional structure of the forging upper die of the present invention.

[0019] Figure 4 This is a schematic diagram showing the state of the molded fixing plate of the present invention when it is placed inside the forging lower die.

[0020] Figure 5 This is a front view of the forging lower die of the present invention.

[0021] Figure 6 This is a top view of the forging die of the present invention.

[0022] Figure 7 This is a side view of the forging lower die of the present invention.

[0023] Figure 8 This is a front view of the forging upper die of the present invention.

[0024] Figure 9 This is a bottom view of the forging die of the present invention.

[0025] Figure 10 This is a side view of the forging die of the present invention.

[0026] Figure 11 This is a front view of the fixing plate for the anti-falling beam device of the present invention.

[0027] Figure 12 This is a top view of the fixing plate for the anti-falling beam device of the present invention.

[0028] Figure 13 This is a side view of the fixing plate for the anti-falling beam device of the present invention. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0030] In one specific embodiment, such as Figure 1 As shown, the present invention provides a hot bending forming process for a fixing plate for an anti-falling beam device, the specific steps of which are as follows: Step 1: Cutting the fixing plate for the anti-fall beam device: Select Q355 hot-rolled steel, use a laser cutting machine to cut it to the preset size and cut it, while leaving a 3-5mm processing allowance on both sides.

[0031] Step 2: Milling the end face of the fixing plate for the anti-fall beam device: Use a milling machine to finish the edge of the fixing plate, controlling the dimensional accuracy to ±0.1mm. In Step 1, a 3-5mm machining allowance was reserved during blanking. The edge of the steel plate blanked in Step 1 is finished using a milling machine with an accuracy requirement of ±0.1mm. The main purpose is to control the dimensional dimensions of the steel plate, providing dimensionally qualified material for subsequent thermoforming processes. Furthermore, using laser cutting for blanking combined with precise milling is more cost-effective than directly using a milling machine for one-time forming.

[0032] Step 3: Drilling holes for the anti-fall beam device fixing plate: Use a drilling machine to machine the anchor holes and countersunk grooves on the fixing plate. The diameter of the anchor holes is 32-41mm, and the center distance tolerance is ±0.1mm. The anchor holes machined in this step are for bolts to fix the anchor plate, while the countersunk grooves are added to prevent the fixing bolts from protruding too much, allowing part of the nut to sink into the countersunk hole. After the anchor plate is finally machined, it needs to be fixed to the anti-fall beam device with bolts. The threads of the bolts and the anti-fall beam device have precision requirements, so a milling machine is needed to precisely machine the position, size, and countersunk groove depth of the anchor holes. The anchor holes and countersunk grooves need to be machined using a milling machine. At the same time, the influence of subsequent hot bending deformation on the position and size deformation of the anchor holes must also be considered during the machining process.

[0033] Step 4: High-frequency heating of the fixing plate for the anti-fall beam device: The fixing plate is heated to 900-1100℃ using a high-frequency heating furnace. To avoid cracking of the billet and excessive temperature difference across the cross-section, the heating time is 5-8 minutes, and the temperature is maintained for 1-2 minutes after reaching the target temperature to eliminate the core-surface temperature difference.

[0034] There are two reasons for using high-frequency heating: first, high-frequency heating avoids the waste of energy caused by heating the entire furnace, thus saving production costs; second, high-frequency heating can more accurately control the temperature of the billet, ensuring product performance.

[0035] Step 5: Forming the anti-fall beam device using a fixing plate: The tooling cavity consists of a lower forging die and an upper forging die. The lower forging die is as follows... Figure 2 As shown, the forging die is as follows Figure 3As shown, the two are used together. The heated fixing plate is placed into the tooling cavity equipped with a water-cooling system for hot forging. After forming, the upper forging die is opened, and the formed fixing plate is located inside the lower forging die, as shown. Figure 4 As shown. The molded fixing plate is as follows. Figure 11 , Figure 12 and Figure 13 As shown.

[0036] The fixing plate is formed by hot forging, transforming the original flat raw material into a Z-shaped product. This can effectively improve processing efficiency, save raw materials, and avoid the waste of raw materials and processing time associated with machined parts. At the same time, the hot forging process can use thinner raw material plates, which better ensures the performance of the steel.

[0037] Meanwhile, during the hot forging process, the steel plate stretching issue caused by forging was considered for the fixing plate. The required plate size was calculated to be smaller than the actual finished product centerline length during the initial design of the raw material plate dimensions. Furthermore, the demolding of the fixed plate needed to be considered; therefore, the inner wall of the cavity in the lower forging die has a certain inclination angle. This satisfies the forming size requirements while avoiding demolding difficulties. The tooling cavity is equipped with a water cooling system to control the temperature. Specifically: Inside the lower and upper forging dies used in hot forging, a continuous network of cooling channels is pre-machined. These channels typically surround the working surface of the cavity and are connected to an external circulating cooling system. During the forging process, the high-temperature billet is inside the cavity, and circulating cooling water (or a dedicated coolant) continuously flows through the cooling channels inside the die, rapidly carrying away the heat accumulated on the cavity surface. By adjusting the flow rate and temperature of the cooling water, the working temperature of the die can be stably controlled within a reasonable range, effectively preventing die expansion, dimensional deformation, or decreased surface hardness caused by overheating of the cavity. This not only ensures dimensional stability and repeatability during the forging process but also significantly extends the die's service life and reduces production interruptions caused by cooling waiting time.

[0038] When using a high-frequency heating furnace, for Q355 hot-rolled steel billets, heating for 5-8 minutes is required. The specific time depends on the ambient temperature and heat preservation measures to bring it to the initial forging temperature of 1000-1100℃ required for forging. At the same time, reduce the power and maintain it for 1-2 minutes to eliminate the temperature difference between the core and surface of the billet. Next, place the heated billet in the lower forging die and use a press to close the upper and lower forging dies. After forging is completed, it is necessary to ensure that the billet temperature is not lower than 900 degrees before forging is completed, otherwise defects such as cracks may easily appear on the surface of the billet.

[0039] Because of the high-frequency furnace heating blocks, high temperature, and precise temperature control, the hardness of the billet steel plate is very low after being heated to 1100℃, which can effectively reduce the processing difficulty in the forming process and improve the processing efficiency. At the same time, due to the heating blocks, the billet is exposed to the air for a short time, avoiding excessive oxidation and burning of the billet caused by high temperature.

[0040] Step 6: Correction of the fixing plate for the anti-falling beam device: Use a template to check the dimensions of the fixing plate. For any unqualified parts, use a correction mold corresponding to the cavity structure to perform local correction on a double-column press. Through machining, precisely machine a template that matches the outer dimensions of the finished fixing plate. The gap between the template and the finished fixing plate is used to check the accuracy of the dimensions of the hot-forged fixing plate. During the inspection process, the template is attached to the surface of the finished fixing plate, and a vernier caliper or feeler gauge is used to check the gap between the finished fixing plate and the template to obtain the deviation between the finished fixing plate and the design value.

[0041] The double-column press is a hydraulic press, meaning it obtains greater mechanical pressure through hydraulic drive. After inspecting the finished product dimensions of the fixed plate using a template, a correction mold with the same structure as the forging cavity is designed for workpieces whose dimensions are outside the allowable error range. The forging cavity is for all dimensions of the fixed plate formed in one step, while the correction mold is designed for each detailed structure. Each mold corresponds to only one arc part of the fixed plate. The fixed plate with unqualified dimensions is placed in the correction mold, and pressure is applied by the press to shape the fixed plate into the shape of the correction mold, thereby achieving the purpose of correction. After correction, it is inspected again using a template. If it passes the inspection, the correction is complete. If the dimensions still exceed the allowable error range, a second correction is performed until it passes the inspection.

[0042] Step 7: Surface treatment of the fixing plate for the anti-fall beam device: Sandblast the fixing plate to remove oil and dust from its surface. Then, apply multiple layers of paint using a spray painting machine. Ensure the spray painting machine's travel speed does not exceed 0.1 meters per minute, and that the coating thickness meets the following requirements: primer 80-100μm, intermediate coat 100-120μm, and topcoat 50-70μm.

[0043] In summary, heating the fixing plate of the anti-fall beam device to 900-1100℃ increases processing efficiency by 100% compared to not heating or only heating to 300-500℃. The fixing plate of the anti-fall beam device uses high-frequency heating, improving productivity and reducing burn-off. The fixing plate of the anti-fall beam device uses a combination of a laser cutting machine and a CNC milling machine; the laser cutting machine is used for blanking first, followed by CNC milling, resulting in higher precision and efficiency. Therefore, this invention features a simple processing technology, easy implementation with conventional equipment, and a complete processing process that is simple, fast, highly operable, efficient, and precise.

[0044] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A hot bending forming process for a fixing plate used in an anti-falling beam device, characterized in that, Includes the following steps: S1. Cutting of fixing plate for anti-fall beam device: Select Q355 hot-rolled steel, use laser cutting machine to cut to the preset size and cut the material, while leaving 3-5mm processing allowance on both sides; S2. Milling the end face of the fixing plate for the anti-fall beam device: Use a milling machine to finish the edge of the fixing plate, and control the dimensional accuracy to ±0.1mm; S3. Drilling holes in the fixing plate for the anti-falling beam device: Use a drilling machine to process the anchoring holes and anchoring hole grooves on the fixing plate. S4. High-frequency heating of the fixing plate for the anti-fall beam device: The fixing plate is heated to 900-1100℃ using a high-frequency heating furnace; S5. Anti-fall beam device fixing plate forming: The heated fixing plate is placed into the tooling cavity equipped with a water cooling system and hot forged. S6. Correction of the fixing plate for the anti-fall beam device: Use a template to check the size of the fixing plate, and use a correction mold corresponding to the cavity structure to locally correct any unqualified parts on a double column press. S7. Surface treatment of the fixing plate for the anti-fall beam device: After sandblasting the fixing plate, use a spray painting machine to perform multi-layer spray painting treatment.

2. The hot bending forming process of the fixing plate for the anti-falling beam device according to claim 1, characterized in that, In step S3, the diameter of the anchor hole is 32-41mm, and the center distance tolerance of the anchor hole is ±0.1mm.

3. The hot bending forming process of the fixing plate for the anti-falling beam device according to claim 1, characterized in that, In step S4, under the premise of avoiding billet cracking and excessive cross-sectional temperature difference, the heating time is 5-8 minutes, and after reaching the target temperature, it is maintained for 1-2 minutes to eliminate the core-surface temperature difference.

4. The hot bending forming process of the fixing plate for the anti-falling beam device according to claim 1, characterized in that, In step S5, the inner wall of the tooling cavity is inclined to facilitate demolding, and the tooling cavity is equipped with a water cooling system to control the temperature.

5. The hot bending forming process of the fixing plate for the anti-falling beam device according to claim 1, characterized in that, In step S7, the traveling speed of the painting machine is no higher than 0.1 meters / minute, and the coating thickness meets the requirements of 80-100μm for primer, 100-120μm for intermediate paint, and 50-70μm for topcoat.

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