Manufacturing method of long straight beam

Abstract

The invention discloses a manufacturing method of a long straight beam. The manufacturing method comprises the technological processes of assembly welding, correction, primary heat treatment, rough machining, secondary heat treatment, finish machining and surface grinding. The assembling and welding process comprises the steps that the middle beam, the nine datum plates, the seven base plates and the guide rail base are assembled and welded; the correction process comprises the following steps: correcting the flatness of the upper surface, the lower surface and the left side reference surface of the long straight beam formed after assembly welding; the rough machining process comprises the steps that the upper surface, the lower surface and the left datum plane of the middle beam, the bottom face of the guide rail base and the two-side positioning faces of the guide rail base are roughly machined; the finish machining process comprises the following steps: respectively finish-machining A, B, C, D, E and F surfaces; in the surface grinding process, A, B, C, D, E and F surfaces are ground through a grinding machine grinding method. According to the method, reasonable and effective technological process, allowance distribution technology of each procedure and machining technology planning are formulated, the precision requirement is finally met, and the technical blank is filled for manufacturing of the parts of the type.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical processing and relates to a manufacturing process method of a long straight beam. Background Art

[0002] The long straight beam is a welded structure. The middle beam is a rectangular steel tube (specification 250mm×100mm×6mm, length 5300mm). A total of 9 reference plates are welded on the upper A and lower B of the beam in the 100mm width direction. Seven pads are welded on one side of the beam in the 250mm dimension direction, and two 4040 guide rail seats are welded on the other side. Figure 1 ;Definition: C surface: the reference surface on the left side of the long straight beam; D surface: the bottom surface of the guide rail seat; E and F surfaces: the positioning surfaces on both sides of the guide rail seat; Figure 2 The size of the workpiece from A to B is 270js8±0.0405, and the size of the workpiece from E to B is 246H8( +0.072 0) Dimension from F to B: 55( 0 -0.046 ), the dimension from D surface to C surface is 118±0.027; B surface is the reference surface, the parallelism of E and F surfaces relative to B reference surface is 0.1mm, the parallelism of A surface and B reference surface is 0.08mm, and the straightness of A surface and B surface is 0.2mm.

[0003] In the prior art, long straight beams are manufactured by directly machining them with machine tools after welding. Problems in the manufacturing process are that the welding process, heat treatment process, and machining process cause large deformations, which are difficult to control, resulting in dimensional tolerances and form and position tolerances that cannot meet the requirements. Therefore, it is necessary to formulate reasonable and feasible manufacturing methods and manufacturing processes. Summary of the invention

[0004] (I) Purpose of the invention

[0005] The purpose of the present invention is to provide a method for manufacturing a long straight beam, design a reasonable and feasible process manufacturing route, an effective process plan, meet the design requirements of the product, solve the problems of high dimensional accuracy, high form and position tolerances and failure to meet the requirements in the manufacturing process, and improve production efficiency.

[0006] (II) Technical solution

[0007] In order to solve the above technical problems, the present invention provides a method for manufacturing a long straight beam, and its process is: welding-correction-primary heat treatment-rough machining-secondary heat treatment-finishing-grinding; the welding process is: welding the middle beam, 9 reference plates, 7 pads, and the guide rail seat; the correction process is: correcting the flatness of the upper surface, lower surface, and left reference surface of the long straight beam formed after welding; the rough machining process is: rough machining A, B, C, D, E, and F surfaces respectively, and each surface is defined as: A surface: upper surface; B surface: lower surface; C surface: left reference surface; D surface: bottom surface of the guide rail seat; E and F surfaces: positioning surfaces on both sides of the guide rail seat; the fine machining process is: fine machining A, B, C, D, E, and F surfaces respectively; the grinding process is: grinding A, B, C, D, E, and F surfaces respectively using a grinder grinding method.

[0008] Among them, during assembly welding, on the middle beam, first weld 9 reference plates, then weld 7 pads, and finally weld the guide rail seat.

[0009] Among them, when welding the reference plate, a 5mm processing allowance is left on the outer surface of the reference plate. The welding process is: position the reference plate on the upper and lower surfaces of the middle beam, and then place the middle beam as a whole on a platform with a T-slot, install a T-bolt in the T-slot, connect the top of the T-bolt to the pressure block, use a nut to position the pressure block, and use the pressure block to press the upper surface of the middle beam, and then weld the reference plate and the upper surface of the middle beam; after the upper surface reference plate is welded, weld the lower surface reference plate in the same way; after the reference plate is welded, the overall plane height difference between the upper and lower surfaces of the middle beam shall not exceed 5mm.

[0010] Among them, when welding the pad, the pad is positioned and arranged on the reference surface on the left side of the middle beam, and then the middle beam is placed as a whole on a platform with a T-slot, a T-bolt is installed in the T-slot, a pressure block is connected to the top of the T-bolt, a nut is used to position the pressure block, and the pressure block is pressed against the reference surface on the left side of the middle beam, and then the pad and the reference surface on the left side of the middle beam are welded; when welding the guide rail seat, the guide rail seat is positioned and arranged on the reference surface on the right side of the middle beam, and then the middle beam is placed as a whole on the platform with a T-slot, a T-bolt is installed in the T-slot, a pressure block is connected to the top of the T-bolt, a nut is used to position the pressure block, and the pressure block is pressed against the reference surface on the right side of the middle beam, and then the guide rail seat and the reference surface on the right side of the middle beam are welded.

[0011] Among them, during correction, the long straight beam after assembly and welding is corrected with a 3000-ton hydraulic press, and the surface to be corrected is arranged on the workbench of the hydraulic press. Before correction, a feeler gauge is used to check the gap between the surface to be corrected of the long straight beam and the workbench. When there is a gap in the middle, two equal-height blocks are placed on both sides of the long straight beam, and the middle of the beam is pressed with the hydraulic press head; when there is a gap on both sides, a pad is placed in the middle of the long straight beam, and two pads are placed on both sides above the long straight beam, and the two pads on the upper part of the long straight beam are pressed with the hydraulic press head to cause the long straight beam to produce local reverse bending deformation. After correction, the flatness of the long straight beam reaches 3mm.

[0012] Among them, during the first heat treatment, the long straight beam with a correction flatness of 3mm is pressed and fixed on a platform of 5m long and 500mm wide. The gap between the long straight beam and the platform is not more than 1mm. The platform and the long straight beam are cold-loaded into the heat treatment furnace at the same time. The heat treatment furnace is heated to 550±10℃ and kept warm. The heating time is: 4h00-4h30, and the insulation time is: 2h30-3h00. The furnace is cooled to below 250℃ and then air-cooled.

[0013] Among them, during rough machining, the long straight beam is pressed on the machine tool worktable, and the dial indicator is used to press it to the upper surface A of the long straight beam. During the pressing process, the swing error of the dial indicator is not greater than 0.1mm. When rough machining each surface of A, B, C, D, E, and F, the machining depth of each cut is not greater than 0.5mm. When rough machining each end surface, leave a 2mm margin. The overall flatness of the long straight beam after machining is not greater than 1.5mm.

[0014] Among them, during the secondary heat treatment, the long straight beam with a rough processing flatness of 1.5mm is pressed and fixed on a platform with a length of 5m and a width of 500mm. The gap between the long straight beam and the platform is not more than 0.5mm. The platform and the long straight beam are cold-loaded into the heat treatment furnace at the same time, and the heat treatment furnace is heated to 550±10℃ for insulation. The heating time is: 4h00-4h30, and the insulation time is: 2h30-3h00. The furnace is cooled to below 250℃ and then air-cooled.

[0015] Among them, during fine processing, the long straight beam that has undergone secondary heat treatment is pressed again on the workbench. When pressing, the pointer of the meter is pressed to the upper surface of the long straight beam. During the pressing process, the swing error of the meter is not greater than 0.02mm. The processing depth of each surface A, B, C, D, E, and F is not greater than 0.05mm each time. After processing, 0.5mm of grinding amount is left on each surface, and the overall flatness after processing is not greater than 0.4mm.

[0016] Among them, when grinding, the finely machined long straight beam is placed on the upper surface of the ground contour block. The accuracy of the contour block after grinding reaches 0.01mm. The long straight beam is clamped by the dial method, and the swing error of the dial is no more than 0.05mm. The A, B, C, D, E, and F surfaces are ground by a grinder respectively. After grinding, each end face meets the requirements of parallelism of 0.08mm and dimensional tolerance of ±0.0405.

[0017] (III) Beneficial effects

[0018] The method for manufacturing a long straight beam provided by the above technical solution has the following advantages compared with the prior art:

[0019] (1) Satisfied Figure 4 The size from A surface to B surface is 270js8±0.0405, and the size from E surface to B surface is 246H8( +0.072 0) Dimension from F to B: 55( -0.046 ), D-surface to C-surface dimension accuracy 118±0.027;

[0020] (2) Satisfied Figure 4 The parallelism of the E and F surfaces relative to the B reference surface is 0.1mm, the parallelism of the A surface flatness with the B reference surface is 0.08mm, and the straightness of the A and B surfaces is 0.2mm;

[0021] (3) Formulate a reasonable and effective process flow, plan the margin allocation technology and processing technology for each process, and ultimately meet the accuracy requirements, thus filling the technical gap in the manufacturing of such parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of a long straight beam structure in the prior art; I and III are schematic diagrams of two different welding states, FIG. II is a top view of FIG. I, and FIG. IV is a top view of FIG. III.

[0023] Figure 2 for Figure 1 Side view of.

[0024] Figure 3 It is a front view of the long straight beam according to an embodiment of the present invention.

[0025] Figure 4 for Figure 3 Top view of the .

[0026] Figure 5 for Figure 3 Side view DETAILED DESCRIPTION

[0027] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below in conjunction with the drawings and examples.

[0028] The manufacturing method of the long straight beam of the present embodiment has the following process: assembly welding - correction - heat treatment - rough machining - heat treatment - fine machining - grinding.

[0029] The specific process of each step is described as follows:

[0030] (1) Assembly welding: The middle beam, 9 reference plates, 7 pads and guide rail seat are assembled and welded;

[0031] according to Figures 3 to 5 Carry out assembly welding. On the middle beam, first weld 9 reference plates, then weld 7 pads, and finally weld the guide rail seat.

[0032] When welding the reference plate, a 5mm machining allowance is left on the outer surface of the reference plate. The welding process is as follows: the reference plate is positioned and arranged on the upper and lower surfaces of the middle beam, and then the middle beam is placed as a whole on a platform with a T-slot. A T-bolt is installed in the T-slot, and a pressure block is connected to the top of the T-bolt. The pressure block is positioned with a nut, and the pressure block is pressed against the upper surface of the middle beam. Next, the reference plate and the upper surface of the middle beam are welded; after the upper surface reference plate is welded, the lower surface reference plate is welded in the same way. After the reference plate is welded, the overall plane height difference between the upper and lower surfaces of the middle beam shall not exceed 5mm.

[0033] When welding the pad, position it on the reference surface on the left side of the middle beam, then place the entire middle beam on a platform with a T-slot, install a T-bolt in the T-slot, connect a pressure block to the top of the T-bolt, use a nut to position the pressure block, and use the pressure block to press the reference surface on the left side of the middle beam, then weld the pad and the reference surface on the left side of the middle beam.

[0034] When welding the guide rail seat, position the guide rail seat on the reference surface on the right side of the middle beam, then place the middle beam as a whole on the platform with T-slots, install T-bolts in the T-slots, connect the pressure blocks to the tops of the T-bolts, use nuts to position the pressure blocks, and use the pressure blocks to press the reference surface on the right side of the middle beam. Next, weld the guide rail seat and the reference surface on the right side of the middle beam.

[0035] (2) Correction: Correct the flatness of the upper surface A, lower surface B, and left reference surface C of the long straight beam formed after assembly welding.

[0036] The long straight beam after assembly and welding is calibrated with a 3000-ton hydraulic press. The surface to be calibrated is arranged on the workbench of the hydraulic press. Before calibration, the gap between the surface to be calibrated of the long straight beam and the workbench is checked with a feeler gauge. When there is a gap in the middle, two equal-height blocks are placed on both sides of the long straight beam, and the middle of the beam is pressed with the hydraulic press head; when there is a gap on both sides, a pad is placed in the middle of the long straight beam, and two pads are placed on both sides above the long straight beam, and the two pads on the upper part of the long straight beam are pressed with the hydraulic press head to cause the long straight beam to produce local reverse bending deformation, thereby achieving the purpose of straightening. After calibration, the flatness of the long straight beam reaches 3mm.

[0037] (3) Heat treatment: The straight beam with a flatness correction of 3 mm is pressed and fixed on a platform of 5 m in length and 500 mm in width, so that the straight beam fits tightly against the platform and the gap between the straight beam and the platform is no more than 1 mm. The platform and the straight beam are simultaneously cold-loaded into the heat treatment furnace, which is heated to 550 ± 10 °C and kept warm for 4 h 00-4 h 30 and 2 h 30-3 h 00. The beam is cooled to below 250 °C and then air-cooled.

[0038] (4) Rough machining: Press the long straight beam onto the machine tool workbench. Use a dial indicator to press it onto the upper surface A of the long straight beam. During the pressing process, the swing error of the dial indicator should not exceed 0.1 mm. When the clamping meets the above requirements, press Figure 4 , respectively process A, B, C, D, E, and F surfaces, and each surface is defined as: A surface: upper surface; B surface: lower surface; C surface: reference surface on the left side of the middle beam; D surface: bottom surface of the guide rail seat; E and F surfaces: positioning surfaces on both sides of the guide rail seat. Figure 4 When rough machining each surface A, B, C, D, E, and F, the machining depth of each cut shall not exceed 0.5 mm, and a 2 mm margin shall be left for each end surface during rough machining. The overall flatness of the completed long straight beam shall not exceed 1.5 mm.

[0039] (5) Heat treatment: The long straight beam with a rough processing flatness of 1.5 mm is pressed and fixed on a platform of 5 m in length and 500 mm in width, so that the long straight beam fits tightly against the platform, and the gap between the long straight beam and the platform is no more than 0.5 mm. The platform and the long straight beam are cold-loaded into the heat treatment furnace at the same time, and the heat treatment furnace is heated to 550±10℃ and kept warm. The heating time is: 4h00-4h30, and the holding time is: 2h30-3h00. The furnace is cooled to below 250℃ and then air-cooled.

[0040] (6) Finishing: Press the long straight beam after secondary heat treatment on the workbench again. When pressing, use the dial method to press the pointer of the meter to the upper surface of the long straight beam. During the pressing process, the swing error of the meter should not exceed 0.02mm. When the requirement is met, press Figure 4 , respectively finish the A, B, C, D, E, F surfaces, Figure 4The processing depth of each surface A, B, C, D, E, and F is not more than 0.05mm each time. After processing, 0.5mm of grinding amount is left on each surface, and the overall flatness after processing is not more than 0.4mm.

[0041] (7) Surface grinding: Place the finished straight beam on the upper surface of the ground equal height block. The accuracy of the ground equal height block reaches 0.01mm. Clamp the straight beam using a meter. The table swing error is no more than 0.05mm. Figure 4 The A, B, C, D, E, and F surfaces are ground by a grinder, and after grinding, each end surface meets the requirements of parallelism of 0.08mm and dimensional tolerance of ±0.0405.

[0042] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for manufacturing a long straight beam, characterized in that: The technological process is: welding - correction - primary heat treatment - rough machining - secondary heat treatment - finishing machining - grinding; the welding process is: welding the middle beam, 9 reference plates, 7 pads and the guide rail seat; the correction process is: correcting the flatness of the upper surface, lower surface and left reference surface of the long straight beam formed after welding; the rough machining process is: rough machining A, B, C, D, E, and F surfaces respectively, and each surface is defined as: A surface: upper surface; B surface: lower surface; C surface: left reference surface; D surface: bottom surface of the guide rail seat; E and F surfaces: positioning surfaces on both sides of the guide rail seat; the finishing process is: finishing machining A, B, C, D, E, and F surfaces respectively; the grinding process is: grinding A, B, C, D, E, and F surfaces respectively using a grinder.

2. The method for manufacturing a long straight beam according to claim 1, characterized in that: During assembly welding, first weld 9 reference plates on the middle beam, then weld 7 pads, and finally weld the guide rail seat.

3. The method for manufacturing a long straight beam according to claim 2, characterized in that: When welding the reference plate, leave a 5mm machining allowance on the outer surface of the reference plate. The welding process is as follows: position the reference plate on the upper and lower surfaces of the middle beam, then place the middle beam as a whole on a platform with a T-slot, install a T-bolt in the T-slot, connect a pressure block to the top of the T-bolt, use a nut to position the pressure block, and use the pressure block to press the upper surface of the middle beam. Next, weld the reference plate and the upper surface of the middle beam. After the upper surface reference plate is welded, weld the lower surface reference plate in the same way. After the reference plate is welded, the overall plane height difference between the upper and lower surfaces of the middle beam shall not exceed 5mm.

4. The method for manufacturing a long straight beam according to claim 3, characterized in that: When welding the pad, position the pad on the reference surface on the left side of the middle beam, and then place the middle beam as a whole on the platform with a T-slot, install a T-bolt in the T-slot, connect a pressure block to the top of the T-bolt, use a nut to position the pressure block, and use the pressure block to press the reference surface on the left side of the middle beam, and then weld the pad and the reference surface on the left side of the middle beam; when welding the guide rail seat, position the guide rail seat on the reference surface on the right side of the middle beam, and then place the middle beam as a whole on the platform with a T-slot, install a T-bolt in the T-slot, connect a pressure block to the top of the T-bolt, use a nut to position the pressure block, and use the pressure block to press the reference surface on the right side of the middle beam, and then weld the guide rail seat and the reference surface on the right side of the middle beam.

5. The method for manufacturing a long straight beam according to claim 4, characterized in that: During correction, the long straight beam after assembly and welding is corrected using a 3000-ton hydraulic press, and the surface to be corrected is arranged on the workbench of the hydraulic press. Before correction, a feeler gauge is used to check the gap between the surface to be corrected of the long straight beam and the workbench. When there is a gap in the middle, two equal-height blocks are placed on both sides of the long straight beam, and the hydraulic press head is used to apply pressure to the middle of the beam; when there is a gap on both sides, a pad is placed in the middle of the long straight beam, and two pads are placed on both sides above the long straight beam, and the hydraulic press head is used to apply pressure to the two pads on the upper part of the long straight beam, so that the long straight beam has a local reverse bending deformation. After correction, the flatness of the long straight beam reaches 3mm.

6. The method for manufacturing a long straight beam according to claim 5, characterized in that: During the primary heat treatment, the long straight beam with a flatness correction of 3mm is pressed and fixed on a platform of 5m long and 500mm wide. The gap between the long straight beam and the platform is not more than 1mm. The platform and the long straight beam are cold-loaded into the heat treatment furnace at the same time. The heat treatment furnace is heated to 550±10℃ and kept warm. The heating time is: 4h00-4h30, and the holding time is: 2h30-3h00. The beam is cooled to below 250℃ and then air-cooled.

7. The method for manufacturing a long straight beam according to claim 6, characterized in that: During rough machining, the long straight beam is pressed against the machine tool worktable and pressed to the upper surface A of the long straight beam using a dial indicator. During the pressing process, the swing error of the dial indicator is not greater than 0.1mm. During rough machining of surfaces A, B, C, D, E, and F, the machining depth of each cut is not greater than 0.5mm. During rough machining of each end surface, a 2mm allowance is left. After the machining, the overall flatness of the long straight beam is not greater than 1.5mm.

8. The method for manufacturing a long straight beam according to claim 7, characterized in that: During the secondary heat treatment, the long straight beam with a rough processing flatness of 1.5mm is pressed and fixed on a platform with a length of 5m and a width of 500mm. The gap between the long straight beam and the platform is not more than 0.5mm. The platform and the long straight beam are cold-loaded into the heat treatment furnace at the same time. The heat treatment furnace is heated to 550±10℃ and kept warm. The heating time is: 4h00-4h30, and the holding time is: 2h30-3h00. The furnace is cooled to below 250℃ and then air-cooled.

9. The method for manufacturing a long straight beam according to claim 8, characterized in that: During finishing, the long straight beam that has undergone secondary heat treatment is pressed again on the workbench. When pressing, the pointer of the dial is pressed to the upper surface of the long straight beam. During the pressing process, the swing error of the dial is not greater than 0.02mm. The processing depth of each surface A, B, C, D, E, and F is not greater than 0.05mm each time. After processing, 0.5mm of grinding amount is left on each surface, and the overall flatness after processing is not greater than 0.4mm.

10. The method for manufacturing a long straight beam according to claim 9, characterized in that: When grinding, place the finely machined long straight beam on the upper surface of the ground contour block. The accuracy of the contour block reaches 0.01mm after grinding. Use the dial method to clamp the long straight beam. The swing error of the dial is no more than 0.05mm. Use the grinder grinding method to grind the A, B, C, D, E, and F surfaces respectively. After grinding, each end face meets the requirements of parallelism 0.08mm and dimensional tolerance ±0.0405.

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