Method for processing a 72-pair rod reduction furnace chassis

Abstract

The present application relates to a kind of 72 pairs of stick reduction furnace chassis processing method, comprising: S1: material preparation: first, prepare upper middle lower panel, 144 electrode holder, 80 gas inlet forging tube, internal partition guide plate and silicon powder slagging-off port 8810 forging tube and other required materials;S2: chassis flange and intermediate panel welding: the inside flange of chassis and intermediate panel are welded, in the case that there is machining allowance on the upper and lower surface of intermediate panel, the holes and upper and lower surface of intermediate panel are processed with the chassis flange as reference.The present application forms a complete set of chassis processing method for controlling deformation and ensuring accuracy by improving the manufacturing method of the whole chassis, which lays a good foundation for the efficient silicon production of the equipment.The accuracy of electrode holder affects the accuracy and purity of silicon material.This method not only meets the 0.05mm accuracy requirement, but also achieves 0.02mm accuracy after final measurement, which indirectly improves the purity and yield of reduction furnace silicon production.

Description

Technical Field

[0001] This invention relates to the field of reduction furnace technology, and more specifically, to a method for processing the chassis of a 72-pair rod reduction furnace. Background Technology

[0002] The most commonly used reduction furnace in China is the 36-pair rod reduction furnace, which consumes about 60 kWh / kg Si. The energy consumption of the 72-pair rod reduction furnace is estimated to be below 40 kWh / kg Si G. This means that 20 kWh of electricity can be saved per kilogram. Based on a medium-sized polysilicon plant with an annual production of 10,000 tons, the use of the 72-pair rod reduction furnace can save about 160 million yuan in energy per year.

[0003] The reduction furnace chassis, a key component of the 72-pair rod reduction furnace, is more complex than conventional equipment, requiring higher straightness and assembly precision. The 72-pair rod reduction furnace chassis consists of a chassis flange, upper, middle, and lower panels, and 144 electrode holders. After manufacturing, the electrode holders must maintain a verticality tolerance of 0.05mm. The three panels are connected by welding, a high tolerance that current welding techniques and assembly precision cannot achieve. Furthermore, the upper, middle, and lower panels are all made of multiple steel plates, resulting in some deformation. Machining allowances are left on the steel plates, and all three panels must be welded to the chassis flange. Ensuring the final assembly precision is a crucial issue that needs to be addressed.

[0004] Therefore, the inventors specifically needed to design a method for processing the chassis of a 72-pair rod reduction furnace to solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide a method for processing the chassis of a 72-pair rod reduction furnace to solve the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the present invention provides a method for processing a 72-pair rod reduction furnace chassis, including: S1: Material preparation: First, prepare the required materials such as upper, middle and lower panels, 144 electrode seats, 80 inlet forged tubes, internal partition guide plates and silicon powder slag discharge port 8810 forged tubes.

[0007] S2: Welding the chassis flange to the intermediate panel: Weld the internal flange of the chassis to the intermediate panel. With machining allowance on the upper and lower surfaces of the intermediate panel, use the chassis flange as a reference to machine the holes and upper and lower surfaces of the intermediate panel.

[0008] S3: Welding electrode holders and inlet forged tubes: Position and weld 144 electrode holders on the middle panel, ensuring that the perpendicularity tolerance of the electrode holders is within 0.05mm. Then position and weld 80 inlet forged tubes on the middle panel, ensuring that the position and angle of the inlet meet the design requirements.

[0009] S4: Install and weld the internal partition guide plate: Position and weld the internal partition guide plate in the space between the middle panel and the chassis flange to ensure that the position and angle of the guide plate can guide the gas to be evenly distributed.

[0010] S5: Welding the upper and lower panels: Use support fixtures to fix the upper and lower panels to ensure that no deformation occurs during the welding process. Weld the upper and lower panels to the upper and lower ends of the chassis. Weld the upper and lower panels to the electrode seat and the air inlet forged pipe to ensure that the connection between each component is firm and the position is accurate. Measures such as reserving stress relief grooves are used to prevent welding deformation.

[0011] S6: Annealing treatment: The whole furnace is subjected to stress-relieving annealing treatment. 8810 forged pipes for silicon powder slag discharge ports are welded on the upper and lower plates. The upper and lower plates are then welded and fixed to the chassis.

[0012] Preferably, in the material preparation of S1, in the preparation of the upper, middle and lower panels, the upper surface of the middle panel is processed first, based on the processing after welding the middle panel to the chassis flange, and then the various dimensions on the chassis are processed based on the processed upper surface of the chassis. Furthermore, all subsequent opening and beveling processing and assembly are based on the upper surface of the middle panel for processing other dimensions on the chassis.

[0013] Preferably, during the welding processes of S2 and S5, the steel plates of the upper, middle and lower panels of the reduction furnace chassis are designed with load-bearing capacity on both sides, and the front and back sides are welded alternately during the processing. After welding, the plates are immediately put into the furnace to relieve stress, and after exiting the furnace, they are leveled by flame. The upper panel is a composite design, consisting of a composite layer of carbon steel and stainless steel heat-treated surfaces, and the bottom surface of the lower panel is overlaid during annealing.

[0014] Preferably, in the S5 assembly and welding of the upper and lower panels, the specific steps for fixing the upper and lower panels using support fixtures are as follows: place 7 cast iron fixtures on the heat treatment trolley → place the upper panel on the fixtures, requiring the composite plate to face upwards → place the lower panel on the fixtures, requiring the weld overlay surface to face downwards → finally place a tube sheet with a diameter of approximately 3.6m on the lower panel.

[0015] Preferably, the lower panel needs to be welded to a thickness of up to 20mm, and automatic welding with electrodes is used. During the welding process, H-beams are used to connect and fix the bottom side of the lower panel, and the H-beams are removed after heat treatment in the furnace.

[0016] Preferably, if the lower panel deforms after S6 annealing, it is corrected by flame and manual correction, and the panel is also corrected by counterweight in the furnace to finally meet the dimensional processing requirements. During manufacturing, the upper surface of the lower panel is machined by a vertical lathe, and the weld overlay surface of the lower panel is machined with the upper surface as a reference. Finally, the opening is machined to ensure the dimensional accuracy of the opening.

[0017] Preferably, in the assembly and welding of the chassis flange and the middle panel of S2, the welding of the middle panel and the chassis adopts the assembly anti-deformation tooling, the welding of the upper and lower panels adopts the submerged arc automatic welding of the upper positioner, stress relief holes are left, and the stress relief holes are welded after the final weld is qualified by flaw detection.

[0018] Preferably, when welding the electrode holder and the forged inlet tube to the upper, middle, and lower panels, a low-current argon arc welding method is used, and multiple points are required to weld the electrode holder and the forged tube opening, so that the overall deformation of the control panel is within 5mm.

[0019] Preferably, the silicon powder discharge port 8810 forged tube is made of 8810 nickel-based material, and there are eleven pieces in total. The eleven silicon material port silicon powder discharge port 8810 forged tubes are welded together after the entire chassis has been heat-treated.

[0020] Preferably, after the upper, middle and lower panels are welded to the chassis, all electrode seat holes are also welded. Finally, a CNC boring and milling machine is used to process the holes, and the perpendicularity of 144 electrode seat holes meets the tolerance requirement of 0.05mm.

[0021] The beneficial effects of this invention are:

[0022] This invention improves the manufacturing method of the entire chassis, forming a complete set of processing methods for controlling chassis deformation and ensuring precision. This lays the foundation for efficient silicon formation in the equipment. The precision of the electrode holder affects the precision and purity of the silicon material. This method not only meets the 0.05mm precision requirement, but also achieves a final precision of 0.02mm. This indirectly improves the purity and yield of silicon formed in the reduction furnace. Attached Figure Description

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] Figure 1 This is a schematic diagram of the welding of the chassis flange and the intermediate panel in a method for processing the chassis of a 72-pair rod reduction furnace according to the present invention.

[0025] Figure 2 This is a schematic diagram of positioning and welding electrode holders on the middle panel of a 72-pair rod reduction furnace chassis processing method according to the present invention.

[0026] Figure 3 This is a front view of the anti-forming plate tooling for a 72-pair rod reduction furnace chassis processing method according to the present invention;

[0027] Figure 4 This is a schematic diagram of the calibration tooling for a 72-pair rod reduction furnace chassis machining method according to the present invention;

[0028] Figure 5 This is a schematic diagram of the tooling baffle for a method of machining the chassis of a 72-pair rod reduction furnace according to the present invention. Figure 1 ;

[0029] Figure 6 This is a schematic diagram of the tooling baffle for a method of machining the chassis of a 72-pair rod reduction furnace according to the present invention. Figure 2 ;

[0030] Figure 7 This is a schematic diagram of the lower panel of a 72-pair rod reduction furnace chassis processing method according to the present invention;

[0031] Figure 8 This is a schematic diagram of the tube sheet for a method of processing the chassis of a 72-pair rod reduction furnace according to the present invention;

[0032] Figure 9 This is a flowchart illustrating the processing method for a 72-pair rod reduction furnace chassis according to the present invention. Detailed Implementation

[0033] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0034] like Figures 1-9 As shown, a method for processing a 72-pair rod reduction furnace chassis according to the present invention includes:

[0035] S1: Material preparation: First, prepare the required materials such as the upper, middle and lower panels, 144 electrode holders, 80 air inlet forged tubes, internal partition guide plates and silicon powder slag discharge port 8810 forged tubes.

[0036] S2: Welding the chassis flange to the intermediate panel: Weld the internal chassis flange to the intermediate panel. With machining allowances on the top and bottom surfaces of the intermediate panel, use the chassis flange as a reference to machine the holes and the upper and lower surfaces of the intermediate panel. See details. Figure 1 ;

[0037] S3: Electrode Mounting and Welding of Inlet Forged Tubes: Position and weld 144 electrode mounts on the middle panel, ensuring the perpendicularity tolerance of the electrode mounts is within 0.05mm. Then, position and weld 80 inlet forged tubes on the middle panel, ensuring the position and angle of the inlets meet design requirements. See details... Figure 2 ;

[0038] S4: Install and weld the internal partition guide plate: Position and weld the internal partition guide plate in the space between the middle panel and the chassis flange to ensure that the position and angle of the guide plate can guide the gas to be evenly distributed.

[0039] S5: Welding the upper and lower panels: Use support fixtures to fix the upper and lower panels to ensure that no deformation occurs during the welding process. Weld the upper and lower panels to the upper and lower ends of the chassis. Weld the upper and lower panels to the electrode seat and the air inlet forged pipe to ensure that the connection between each component is firm and the position is accurate. Measures such as reserving stress relief grooves are used to prevent welding deformation.

[0040] S6: Annealing treatment: The whole furnace is subjected to stress-relieving annealing treatment. After annealing, the silicon powder slag discharge port 8810 forged pipe is welded on the upper and lower plates. The upper and lower plates are then welded and fixed to the chassis.

[0041] In the material preparation of S1, the upper, middle and lower panels are manufactured with the middle panel after welding to the chassis flange as the reference. The upper surface of the middle panel is machined first, and then the various dimensions on the chassis are machined with the machined upper surface of the chassis. All subsequent openings, beveling and assembly are machined with the upper surface of the middle panel as the reference for other dimensions on the chassis. Since the upper, middle and lower panels are all made of multiple steel plates spliced ​​together, there will be a certain amount of deformation. The steel plates have a machining allowance, and all three panels need to be welded to the chassis flange. Therefore, using the upper surface of the middle panel as the reference improves the assembly accuracy. After unifying the reference, all relative dimensions can be controlled within the accuracy range.

[0042] In the assembly and welding of the chassis flange and the middle panel of the S2, the welding of the middle panel and the chassis is done with anti-deformation tooling. The welding of the upper and lower panels uses submerged arc automatic welding with the upper positioner to ensure welding quality. At the same time, considering the excessive welding stress, stress relief holes are left. Finally, the stress relief holes are welded after the weld is inspected and qualified.

[0043] During the welding of S2 and S5, the steel plates of the upper, middle, and lower panels of the reduction furnace chassis are reinforced with load-bearing structures on both sides. During processing, welding is performed alternately on both sides. After welding, the plates are immediately placed in the furnace to relieve stress, and after exiting the furnace, they are leveled using a flame. The upper panel is a composite design, consisting of a composite layer of carbon steel and heat-treated stainless steel. The bottom surface of the lower panel undergoes surfacing during annealing. Because the upper, middle, and lower panels of the reduction furnace chassis are prone to bending deformation during welding, and due to the thickness and large diameter of the steel plates, coupled with limited machining allowance, the addition of load-bearing structures on both sides is crucial. It can significantly improve the load-bearing capacity. Alternating welding on both sides can distribute the welding heat more evenly, reduce welding deformation caused by local overheating, and help maintain the flatness and dimensional accuracy of the steel plate. After exiting the furnace, flame leveling can restore the flatness of the steel plate more quickly. The upper panel is composed of a composite layer of carbon steel and stainless steel heat-treated surface. This design combines the strength of carbon steel and the corrosion resistance of stainless steel, optimizing the overall performance of the reduction furnace chassis. The weld overlay layer usually has high hardness, wear resistance, heat resistance and corrosion resistance, which plays a good protective role.

[0044] The upper panel of the reduction furnace chassis is made of composite plate. Since carbon steel and stainless steel have different heat treatment deformation and shrinkage rates, the panels bend downwards on both sides during the seam elimination process. The solution found is to use supporting fixtures to fix the upper and lower panels during the S5 welding process before heat treatment in the furnace. The specific steps are: place 7 cast iron fixtures on the heat treatment trolley → place the upper panel on the fixtures, ensuring the composite plate faces upwards → place the lower panel on the fixtures, ensuring the weld overlay faces downwards → finally place a tube sheet with a diameter of approximately 3.6m on top of the lower panel (see details). Figure 8 That's all.

[0045] The lower panel of the reduction furnace required surfacing, with a weld thickness of up to 20mm, using an automatic electrode welding method. To prevent deformation, H-beams were used for connection and fixation on the bottom side of the lower panel. During S6 annealing, after the furnace heat treatment, the H-beams were removed, but the panel was still deformed and did not meet the processing requirements. A combination of flame and manual straightening was used for reshaping. Simultaneously, counterweights were used for reshaping during furnace entry, ultimately meeting the dimensional processing requirements. The upper surface of the lower panel was machined using a vertical lathe during manufacturing. (See...) Figure 7 Using the upper plane as a reference, the weld overlay surface of the lower plane is machined, and finally the hole is machined to ensure the dimensional accuracy of the hole.

[0046] During the annealing process of S6, to ensure the assembly clearance between the upper and lower panels and the 144 electrode holders, 80 inlet forged tubes, and 11 silicon material inlet 8810 forged tubes after the annealing process, we adopted many control measures. Firstly, in assembly, we designed anti-formation plate tooling, such as... Figure 3 As shown, to ensure uniform spacing between the upper and lower panels, and to perform localized correction in areas of significant deformation on the upper and lower panels, we designed a correction fixture. Figure 4 As shown, the spacing between the panels was ensured, guaranteeing the spacing between the more than 200 forged tubes and the upper and lower panels. At the same time, we also made special requirements for welding, using low-current argon arc welding, and requiring multiple points to be stacked for welding to the electrode seat and forged tube opening. We also strictly controlled the welding process to reduce the impact of deformation. In the end, the overall deformation of the control panel was within 5mm, meeting the panel processing requirements.

[0047] After heat treatment, eleven 8810 forged pipes with silicon powder discharge ports were welded together. The material is 8810 nickel-based. Considering the impact of heat treatment on nickel-based materials, these eleven 8810 forged pipes with silicon powder discharge ports were welded together after the entire chassis had undergone heat treatment. Iron filings from machining the upper surface easily fall into the interlayer from the upper panel. The interlayer is a closed space and extremely difficult to clean. Therefore, we used tooling baffles to prevent iron filings from falling into the interlayer in advance. Figures 5-6 As shown;

[0048] After the 8810 forged pipe for the silicon powder slag discharge port was welded, the electrode seat holes were machined. After the upper, middle, and lower panels were welded to the chassis, all electrode seat holes were also welded. Finally, a CNC boring and milling machine was used to machine the holes. The 144 electrode seat holes required extremely high precision, with a perpendicularity tolerance of 0.05mm. To ensure this dimensional requirement, we specially manufactured electrode rods of the same size. These electrode rods are characterized by ensuring consistent machining precision for all openings, and their strength and hardness are sufficient to withstand multiple uses without deformation.

[0049] Working Principle: The 72-pair rod reduction furnace base of this invention consists of a base flange, upper, middle and lower panels, and 144 electrode holders. After manufacturing, the verticality tolerance of the electrode holders must be 0.05mm. To ensure manufacturing requirements, we adopted the method of using the middle panel as a reference. First, the middle panel is welded to the base flange, leaving machining allowance on the upper and lower surfaces of the middle panel. Using the base flange as a reference, the holes and upper and lower surfaces of the middle panel are machined. 144 electrode holders and 80 inlet forged tubes are then welded. At the same time, the internal partition guide plate is welded. The upper and lower panels are then welded in sequence, using support fixtures for fixation and reserving stress relief grooves to prevent welding deformation. The upper and lower panels are then welded to the electrode holders and inlet forged tubes. Dimensions are corrected using fixtures. The entire furnace is then subjected to stress-relieving annealing treatment. The upper panel is then machined with a cladding layer, and the inner holes of the electrode holders and inlets are machined. Finally, the 8810 forged tube for the silicon powder slag discharge port is welded, ensuring the dimensional accuracy requirements of the entire base.

[0050] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for machining the chassis of a 72-pair rod reduction furnace, characterized in that, include: S1: Material preparation: First, prepare the materials required for the upper, middle and lower panels, 144 electrode holders, 80 air inlet forged tubes, internal partition guide plates and silicon powder slag discharge port 8810 forged tubes. S2: Welding the chassis flange to the intermediate panel: Weld the internal flange of the chassis to the intermediate panel. With machining allowance on the upper and lower surfaces of the intermediate panel, use the chassis flange as a reference to machine the holes and upper and lower surfaces of the intermediate panel. S3: Welding electrode holders and inlet forged tubes: Position and weld 144 electrode holders on the middle panel, ensuring that the perpendicularity tolerance of the electrode holders is within 0.05mm. Then position and weld 80 inlet forged tubes on the middle panel, ensuring that the position and angle of the inlet meet the design requirements. S4: Install and weld the internal partition guide plate: Position and weld the internal partition guide plate in the space between the middle panel and the chassis flange to ensure that the position and angle of the guide plate can guide the gas to be evenly distributed. S5: Welding the upper and lower panels: Use support fixtures to fix the upper and lower panels to ensure that no deformation occurs during the welding process. Weld the upper and lower panels to the upper and lower ends of the chassis. Weld the upper and lower panels to the electrode seat and the air inlet forged pipe to ensure that the connection between each component is firm and the position is accurate. Reserve stress relief grooves to prevent welding deformation. S6: Annealing treatment: The whole furnace is subjected to stress-relieving annealing treatment. After the treatment, the silicon powder slag discharge port 8810 forged pipe is welded on the upper and lower plates. The upper and lower plates are then welded and fixed to the chassis. In the material preparation of S1, in the preparation of the upper, middle and lower panels, the processing of the middle panel after welding with the chassis flange is taken as the reference. First, the upper surface of the middle panel is processed, and then the various dimensions on the chassis are processed based on the processed upper surface of the chassis. All subsequent opening and beveling processing and assembly are based on the upper surface of the middle panel to process other dimensions on the chassis. After the upper, middle and lower panels are welded to the chassis, all electrode seat holes are also welded. Finally, a CNC boring and milling machine is used to process the holes, and the perpendicularity of 144 electrode seat holes meets the tolerance requirement of 0.05mm.

2. The method for processing a 72-pair rod reduction furnace chassis as described in claim 1, characterized in that, During the welding processes of S2 and S5, the steel plates of the upper, middle and lower panels of the reduction furnace chassis are designed to bear loads on both sides, and the front and back sides are welded alternately during the processing. After welding, the plates are immediately put into the furnace to relieve stress, and after exiting the furnace, they are leveled by flame. The upper panel is a composite design, consisting of a composite layer of carbon steel and stainless steel heat-treated surfaces. The bottom surface of the lower panel is overlaid during annealing.

3. The method for processing a 72-pair rod reduction furnace chassis as described in claim 2, characterized in that, The specific steps for fixing the upper and lower panels using support fixtures in the S5 assembly and welding process are as follows: seven cast iron fixtures are placed on the heat treatment trolley → the upper panel is placed on the fixtures with the composite plate facing upwards → the lower panel is then placed on the fixtures with the weld overlay facing downwards → finally, a tube sheet with a diameter of approximately 3.6m is placed on the lower panel.

4. The method for processing a 72-pair rod reduction furnace chassis as described in claim 3, characterized in that, The lower panel requires a weld thickness of up to 20mm and uses automatic electrode welding. During welding, H-beams are used to connect and fix the bottom side of the lower panel. After the S6 furnace heat treatment is completed, the H-beams are removed.

5. The method for processing a 72-pair rod reduction furnace chassis as described in claim 4, characterized in that, If the lower panel deforms after S6 annealing, it is corrected by flame and manual correction, and the panel is also corrected by counterweight in the furnace to finally meet the dimensional processing requirements. During manufacturing, the upper surface of the lower panel is machined by a vertical lathe, and the weld overlay surface of the lower panel is machined with the upper surface as the reference. Finally, the opening is machined to ensure the dimensional accuracy of the opening.

6. The method for processing a 72-pair rod reduction furnace chassis as described in claim 5, characterized in that, In the assembly and welding of the chassis flange and the middle panel of the S2, the welding of the middle panel and the chassis adopts the assembly anti-deformation tooling, and the welding of the upper and lower panels adopts the submerged arc automatic welding of the upper positioner, with stress relief holes left, and the stress relief holes are welded after the final weld is qualified by flaw detection.

7. A method for processing a 72-pair rod reduction furnace chassis as described in claim 1, characterized in that, When welding the electrode holder and the forged tube for the air inlet to the upper, middle and lower panels, a low-current argon arc welding method is used, and multiple points are required to weld the electrode holder and the forged tube opening. Finally, the overall deformation of the control panel is within 5mm.

8. A method for processing a 72-pair rod reduction furnace chassis as described in claim 7, characterized in that, The silicon powder slag discharge port 8810 forged tube is made of 8810 nickel-based material, and there are eleven pieces in total. The eleven silicon powder slag discharge port 8810 forged tubes are welded together after the entire chassis has been heat-treated.

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