Machining method for 72-pair-rod reduction furnace chassis

Abstract

The invention relates to a 72-pair-bar reduction furnace chassis machining method which comprises the steps that S1, materials are prepared, specifically, firstly, required materials such as an upper panel, a middle panel, a lower panel, 144 electrode holders, 80 air inlet forged pipes, an internal interlayer flow guide plate and a silicon powder slag discharging opening 8810 forged pipe are prepared; and S2, assembling and welding the chassis flange and the middle panel: assembling and welding the chassis internal flange and the middle panel, and under the condition that the machining allowance is reserved on the upper surface and the lower surface of the middle panel, machining each hole and the upper surface and the lower surface of the middle panel by taking the chassis flange as a reference. According to the invention, a whole set of processing method for controlling deformation and ensuring precision of the chassis is formed by improving the manufacturing method of the whole chassis, a foundation is laid for efficient silicon junction of equipment, the precision of the electrode holder affects the precision and purity of a silicon material, the method not only meets the precision requirement of 0.05 mm, and finally, the precision reaches 0.02 mm through measurement. And the purity and the yield of the bonded silicon in the reduction furnace are indirectly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of reduction furnaces, and in particular to a method for processing a chassis of a 72-pair-of-rod reduction furnace. Background Art

[0002] The most widely used reduction furnace in China at present is the 36-pair-rod reduction furnace. The energy consumption of the 36-pair-rod reduction furnace is about 60kwh / kg.Si, while the energy consumption of the 72-pair-rod reduction furnace is expected to be below 40kwh / kg.Si G, which can save 20kwh of electricity per kilogram. According to the calculation of a medium-sized polysilicon plant with an annual output of 10,000 tons, the use of a 72-pair-rod reduction furnace can save about 160 million yuan in energy each year.

[0003] As a key part of the 72-pair rod reduction furnace, the reduction furnace chassis is more complex than conventional equipment, and has higher requirements for straightness and assembly accuracy. The 72-pair rod reduction furnace base consists of a chassis flange, upper, middle and lower panels, and 144 electrode seats. After manufacturing, the verticality tolerance of the electrode seats must be 0.05mm. The three layers of panels are connected by welding. The existing welding technology and assembly accuracy cannot achieve this high tolerance. In addition, the upper, middle and lower panels are all spliced ​​with multiple steel plates, which will have a certain amount of deformation. The steel plates have processing allowances. The three panels must be welded to the chassis flange. How to ensure the final assembly accuracy is a problem that needs to be focused on.

[0004] Therefore, the inventor particularly needs to design a 72-pair rod reduction furnace chassis processing method to solve the above technical problems. Summary of the invention

[0005] The object of the present invention is to provide a method for processing a bottom plate of a 72-pair rod reduction furnace to solve the problems raised in the above-mentioned background technology.

[0006] In order to solve the above technical problems, the present invention provides a 72-pair rod reduction furnace chassis processing method, comprising: S1: material preparation: first, prepare the upper, middle and lower panels, 144 electrode holders, 80 air inlet forging tubes, internal interlayer guide plates and silicon powder slag discharge port 8810 forging tubes and other required materials;

[0007] S2: Assembly and welding of chassis flange and middle panel: Assemble and weld the internal flange of the chassis and the middle panel. With machining allowances left on the upper and lower sides of the middle panel, take the chassis flange as the reference to machine the holes and upper and lower surfaces of the middle panel.

[0008] S3: Install and weld the electrode holder and the air inlet forging pipe: Position and weld 144 electrode holders on the middle panel to ensure that the verticality tolerance of the electrode holder is within 0.05mm. Then position and weld 80 air inlet forging pipes on the middle panel to ensure that the position and angle of the air inlet meet the design requirements.

[0009] S4: Install and weld the internal barrier deflector: Position and weld the internal barrier deflector in the space between the middle panel and the chassis flange, ensuring that the position and angle of the deflector can guide the gas to be evenly distributed;

[0010] S5: Install and weld the upper and lower panels: Use support fixtures to fix the upper and lower panels to ensure that they are not deformed 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 holder and the air inlet forging pipe, ensure that the connection between the components is firm and the position is accurate, and reserve stress relief grooves and other measures to prevent welding deformation;

[0011] S6: Annealing treatment: The whole body is put into the furnace for stress relief annealing treatment, and the upper and lower panels are welded with 8810 forged pipes for silicon powder slag discharge ports. The upper and lower panels are welded and fixed to the chassis at this time.

[0012] Preferably, in the material preparation of S1, in the preparation of the upper, middle and lower panels, the middle panel and the chassis flange are welded and processed as a reference, the upper surface of the middle panel is processed first, and then the processed upper surface of the chassis is used to process various dimensions on the chassis, and all subsequent openings and grooves are processed and assembled based on the upper surface of the middle panel to process other dimensions on the chassis.

[0013] Preferably, during the welding process of S2 and S5, the steel plates of the upper, middle and lower panels of the reduction furnace chassis are designed to bear weight on both sides, and the front and back sides are welded alternately during the processing. After welding, they are immediately put into the furnace to eliminate stress, and are leveled with flame after being taken out of the furnace. The upper panel is of composite design, that is, it is composed of a composite layer of carbon steel and stainless steel heat-treated surface, and the bottom surface of the lower panel is subjected to surfacing treatment during annealing.

[0014] Preferably, in the S5 welding of the upper and lower panels, the specific steps of using supporting tooling to fix the upper and lower panels are: placing 7 cast iron tooling pieces on the heat treatment trolley → placing the upper panel on the tooling pieces, with the composite plate facing upwards → placing the lower panel on the tooling pieces, with the surfacing surface facing downwards → finally placing a tube sheet with a diameter of about 3.6m on the lower panel.

[0015] Preferably, the lower panel needs to be surfacing with a thickness of up to 20 mm, and automatic surfacing with a strip electrode is used. During welding, H-shaped steel is used to connect and fix the bottom side of the lower panel, and the H-shaped steel is removed after heat treatment in the furnace.

[0016] Preferably, if the lower panel is deformed after S6 annealing treatment, it is shaped by flame plus manual correction, and the furnace counterweight is used for shape correction at the same time, so as to finally meet the dimensional processing requirements. During the manufacturing of the lower panel, the upper plane of the panel is processed by vertical lathe, and the surfacing surface of the lower plane is processed with the upper plane as the reference, and finally the hole is processed to ensure the precision size of the hole.

[0017] Preferably, 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 an assembly anti-deformation tooling, and the welding of the upper and lower panels adopts submerged arc automatic welding with an upper positioner, leaving stress relief holes, and finally the stress relief holes are welded after the weld is qualified by flaw detection.

[0018] Preferably, the electrode holder and the air inlet forged tube are welded to the upper, middle and lower panels by low current argon arc welding, and the electrode holder and the forged tube opening are welded at multiple points, so that the overall deformation of the control panel is within 5 mm.

[0019] Preferably, the silicon powder slag discharge port 8810 forged pipe is made of 8810 nickel-based, and there are eleven pieces in total. The eleven silicon material port silicon powder slag discharge port 8810 forged pipes are assembled and welded after the entire chassis is heat treated.

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

[0021] The beneficial effects of the present invention are:

[0022] The present invention improves the manufacturing method of the entire chassis to form a complete set of chassis deformation control and precision processing methods, which lays a good foundation for the efficient siliconization of the equipment. The accuracy of the electrode seat affects the accuracy and purity of the silicon material. This method not only meets the 0.05mm accuracy requirement, but also reaches 0.02mm after measurement. Indirectly improve the purity and output of silicon in the reduction furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0024] Figure 1 It is a schematic diagram of the welding of chassis flange and middle panel of a chassis processing method of a 72-pair rod reduction furnace of the present invention;

[0025] Figure 2 It is a schematic diagram of positioning and welding electrode seats on the middle panel of a 72-pair rod reduction furnace chassis processing method of the present invention;

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

[0027] Figure 4 A schematic diagram of a correction tool for a method for processing a chassis of a 72-pair rod reduction furnace according to the present invention;

[0028] Figure 5 A schematic diagram of a tooling baffle for a 72-pair rod reduction furnace chassis processing method of the present invention Figure 1 ;

[0029] Figure 6 A schematic diagram of a tooling baffle for a 72-pair rod reduction furnace chassis processing method of the present invention Figure 2 ;

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

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

[0032] Fig. 9 The present invention is a processing flow chart of a method for processing a 72-pair rod reduction furnace chassis. DETAILED DESCRIPTION

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

[0034] like Figure 1-Figure 9 As shown, a method for processing a 72-pair rod reduction furnace chassis of the present invention comprises:

[0035] S1: Material preparation: First, prepare the upper, middle and lower panels, 144 electrode holders, 80 air inlet forging tubes, internal interlayer guide plates and 8810 forging tubes for silicon powder slag discharge ports;

[0036] S2: Chassis flange and middle panel welding: The internal flange of the chassis is welded to the middle panel. With machining allowances left on the upper and lower sides of the middle panel, the chassis flange is used as a reference to machine the holes and upper and lower surfaces of the middle panel. For details, see Figure 1 ;

[0037] S3: Install and weld the electrode holder and the air inlet forging pipe: Position and weld 144 electrode holders on the middle panel, ensuring that the verticality tolerance of the electrode holder is within 0.05mm. Then position and weld 80 air inlet forging pipes on the middle panel, ensuring that the position and angle of the air inlet meet the design requirements. For details, see Figure 2 ;

[0038] S4: Install and weld the internal barrier deflector: Position and weld the internal barrier deflector in the space between the middle panel and the chassis flange, ensuring that the position and angle of the deflector can guide the gas to be evenly distributed;

[0039] S5: Install and weld the upper and lower panels: Use support fixtures to fix the upper and lower panels to ensure that they are not deformed 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 holder and the air inlet forging pipe, ensure that the connection between the components is firm and the position is accurate, and reserve stress relief grooves and other measures to prevent welding deformation;

[0040] S6: Annealing treatment: The whole body is put into the furnace for stress relief annealing treatment. After annealing treatment, the upper and lower panels are welded with 8810 forged pipes for silicon powder slag discharge ports. The upper and lower panels are welded and fixed to the chassis at this time.

[0041] In the material preparation of S1, in the preparation of the upper, middle and lower panels, the middle panel and the chassis flange are welded and processed as the basis. The upper surface of the middle panel is processed first, and then the various dimensions on the chassis are processed based on the processed upper surface of the chassis. All subsequent openings, groove processing and assembly are based on the upper surface of the middle panel to process other dimensions on the chassis. Since the upper, middle and lower panels are all spliced ​​with multiple steel plates, there will be a certain amount of deformation, and the steel plates have processing allowances, and the three panels must be welded to the chassis flange. Therefore, the upper surface of the middle panel is used as the basis to improve the assembly accuracy. After the unified basis, all relative dimensions can be controlled within the accuracy range.

[0042] During the welding of the chassis flange and the middle panel of the S2, the welding of the middle panel and the chassis is assembled with anti-deformation tooling, and the upper and lower panels are welded using the upper positioner and submerged arc automatic welding to ensure the welding quality. At the same time, considering the excessive welding stress, stress relief holes are left, and finally the stress relief holes are welded after the weld is qualified through flaw detection.

[0043] During the welding process of S2 and S5, the steel plates of the upper, middle and lower panels of the reduction furnace chassis are designed with load-bearing on both sides, and the front and back sides are welded alternately during the processing. After welding, they are immediately put into the furnace to eliminate stress, and flame is used for leveling after coming out of the furnace. The upper panel is a composite design, that is, it is composed of a composite layer of carbon steel and stainless steel heat-treated surface, and the bottom surface of the lower panel is surfacing during annealing. Since the upper, middle and lower panels of the reduction furnace chassis are prone to bending and deformation during welding, and the steel plates are thick and have a large diameter, and the processing allowance is small, it is easy to cause bending and deformation during welding. Therefore, the load-bearing design on both sides can It can significantly improve the load-bearing capacity. Alternating welding on the front and back 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. Flame leveling after leaving the furnace 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, and optimizes the overall performance of the reduction furnace chassis. The surfacing layer usually has high hardness, wear resistance, heat resistance and corrosion resistance, and plays a good protective role.

[0044] Among them, the upper panel of the reduction furnace chassis is a composite plate, and the deformation shrinkage rate of carbon steel and stainless steel during heat treatment is different. When the joints are treated to eliminate stress, the two sides of the panel bend downward. The solution found is to use support tooling to fix the upper and lower panels during the S5 welding process before entering the furnace for heat treatment. The specific steps are: place 7 cast iron tooling pieces on the heat treatment trolley → place the upper panel on the tooling, with the composite plate facing up → place the lower panel on the tooling, with the surfacing surface facing down → finally place a tube sheet with a diameter of about 3.6m on the lower panel (see Figure 8 )

[0045] The lower panel of the reduction furnace needs to be surfacing, with a thickness of up to 20mm. Automatic surfacing with a strip electrode is used. To prevent deformation, H-shaped steel is used to connect and fix the bottom side of the lower panel. During the S6 annealing treatment, the panel is still deformed after the H-shaped steel is removed after entering the furnace for heat treatment. It does not meet the processing requirements, so it is corrected by flame plus manual correction. At the same time, the counterweight is put into the furnace for correction, and finally the size processing requirements are met. At the same time, the upper plane of the panel is processed by vertical lathe during the manufacture of the lower panel. Figure 7 The upper plane is used as the reference to process the surfacing surface of the lower plane, and finally the opening is processed to ensure the accuracy of the opening size.

[0046] During the annealing treatment of S6, in order to ensure the assembly gap between the upper and lower panels and the 144 electrode holders, 80 air inlet forging tubes and 11 silicon material port 8810 forging tubes after the return treatment, we took many control measures. First of all, in the assembly, we designed the anti-shaped plate tooling, such as Figure 3 To ensure the uniform spacing between the upper and lower panels, and to perform local correction on the areas with large deformation of the upper and lower panels, we designed a correction tool. Figure 4 As shown in the figure, the spacing between the panels is guaranteed, and the spacing between more than 200 forged tubes and the upper and lower panels is guaranteed. At the same time, we also made special requirements for welding. We used low-current argon arc welding for welding, and required multi-point welding of the electrode holder and the forged tube mouth. We also strictly controlled the welding process to reduce the impact of deformation. Finally, the overall deformation of the control panel was within 5mm, which met the panel processing requirements.

[0047] After the heat treatment, the 8810 forged pipe with silicon powder slag outlet is welded. The material is 8810 nickel-based. There are eleven pieces in total. Considering the influence of heat treatment on nickel-based materials, the eleven pieces of 8810 forged pipe with silicon material outlet and silicon powder slag outlet are welded after the entire chassis is heat treated. The iron filings from the upper plane processing are very easy to fall into the interlayer from the upper panel. The interlayer is a closed space and is extremely difficult to clean. We use the form of adding tooling baffles to prevent iron filings from falling into the panel interlayer in advance. Figure 5-Figure 6 As shown;

[0048] After the 8810 forged tube with silicon powder slag discharge port is welded, the electrode seat hole is processed. After the upper, middle and lower panels are welded to the chassis, all the electrode seat holes are also welded. Finally, the CNC boring and milling machine is used to process the holes. The precision of 144 electrode seat holes is extremely high, and the verticality meets the tolerance requirement of 0.05mm. In order to ensure this size requirement, we specially made electrode rods of the same size. The characteristics of this electrode rod are to ensure the same processing accuracy of all opening sizes, and its strength and hardness can meet the requirements of multiple uses without any deformation.

[0049] Working principle: The 72 pairs of rod reduction furnace bases in the present invention are composed of a chassis flange, upper, middle and lower panels, and 144 electrode seats. After manufacturing, the verticality tolerance of the electrode seats must be guaranteed to be 0.05mm. To ensure the manufacturing requirements, we use the middle panel as the reference. First, the middle panel is welded to the chassis flange. A processing allowance is left on the upper and lower sides of the middle panel. The holes and upper and lower surfaces of the middle panel are processed based on the chassis flange. 144 electrode seats and 80 air inlet forging pipes are welded. At the same time, the internal interlayer guide plate is welded. The upper and lower panels are welded in turn. The support tooling is used to fix them, and stress release grooves are reserved to prevent welding deformation. The upper and lower panels are welded to the electrode seats and the air inlet forging pipes. The tooling is used for size correction. The whole is put into the furnace for stress relief annealing treatment. The upper panel layer, the electrode seat and the inner hole of the air inlet are processed. Finally, the silicon powder slag discharge port 8810 forging pipe is welded to ensure all dimensional accuracy requirements of the entire chassis.

[0050] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A method for processing a chassis of a 72-pair rod reduction furnace, characterized in that: include: S1: Material preparation: First, prepare the upper, middle and lower panels, 144 electrode holders, 80 air inlet forging tubes, internal interlayer guide plates and 8810 forging tubes for silicon powder slag discharge ports; S2: Assembly and welding of chassis flange and middle panel: Assemble and weld the internal flange of the chassis and the middle panel. With machining allowances left on the upper and lower sides of the middle panel, take the chassis flange as the reference to machine the holes and upper and lower surfaces of the middle panel. S3: Install and weld the electrode holder and the air inlet forging pipe: Position and weld 144 electrode holders on the middle panel to ensure that the verticality tolerance of the electrode holder is within 0.05mm. Then position and weld 80 air inlet forging pipes on the middle panel to ensure that the position and angle of the air inlet meet the design requirements. S4: Install and weld the internal barrier deflector: Position and weld the internal barrier deflector in the space between the middle panel and the chassis flange, ensuring that the position and angle of the deflector can guide the gas to be evenly distributed; S5: Install and weld the upper and lower panels: Use support fixtures to fix the upper and lower panels to ensure that they are not deformed 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 holder and the air inlet forging pipe, ensure that the connection between the components is firm and the position is accurate, and reserve stress relief grooves and other measures to prevent welding deformation; S6: Annealing treatment: The whole body is put into the furnace for stress relief annealing treatment. After the treatment, the upper and lower panels are welded with 8810 forged pipes for silicon powder slag discharge ports. The upper and lower panels are welded and fixed to the chassis at this time.

2. A method for processing a 72-pair rod reduction furnace chassis as claimed in claim 1, characterized in that: In the material preparation of S1, in the preparation of the upper, middle and lower panels, the middle panel and the chassis flange are welded and processed as a reference, the upper surface of the middle panel is processed first, and then the various dimensions on the chassis are processed based on the processed upper surface of the chassis, and all subsequent openings, groove processing and assembly are based on the upper surface of the middle panel as a reference to process other dimensions on the chassis.

3. A method for processing a 72-pair rod reduction furnace chassis as claimed in claim 2, characterized in that: During the welding process of S2 and S5, the steel plates of the upper, middle and lower panels of the reduction furnace chassis are designed to bear weight on both sides, and the front and back sides are welded alternately during the processing. After welding, they are immediately put into the furnace to eliminate stress, and are leveled with flame after being taken out of the furnace. The upper panel is of composite design, that is, it is composed of a composite layer of carbon steel and stainless steel heat-treated surface, and the bottom surface of the lower panel is welded during annealing.

4. A method for processing a 72-pair rod reduction furnace chassis as claimed in claim 3, characterized in that: In the S5 welding of the upper and lower panels, the specific steps of using the supporting tooling to fix the upper and lower panels are as follows: 7 cast iron tooling pieces are placed on the heat treatment trolley → the upper panel is placed on the tooling pieces, with the composite plate facing upwards → the lower panel is placed on the tooling pieces, with the cladding surface facing downwards → finally, a tube sheet with a diameter of about 3.6m is placed on the lower panel.

5. A method for processing a 72-pair rod reduction furnace chassis as claimed in claim 4, characterized in that: The lower panel needs to be surfacing with a thickness of up to 20 mm, and automatic surfacing with a strip electrode is used. During welding, an H-shaped steel is used to connect and fix the bottom side of the lower panel. After completing the S6 furnace heat treatment, the H-shaped steel is removed.

6. A method for processing a 72-pair rod reduction furnace chassis as claimed in claim 5, characterized in that: If the lower panel is deformed after S6 annealing treatment, it is shaped by flame plus manual correction, and the counterweight is added to the furnace to shape it, so that the size processing requirements are finally met. During the manufacturing of the lower panel, the upper plane of the panel is processed by vertical lathe, and the surfacing surface of the lower plane is processed as the reference, and finally the hole is processed to ensure the accuracy of the hole size.

7. A method for processing a 72-pair rod reduction furnace chassis as claimed in claim 6, 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 an assembly anti-deformation tooling, and the welding of the upper and lower panels adopts an upper positioner and submerged arc automatic welding, leaving stress relief holes, and finally the stress relief holes are welded after the weld is qualified by flaw detection.

8. A method for processing a 72-pair rod reduction furnace chassis as claimed in claim 1, characterized in that: The electrode holder and the air inlet forged tube are welded to the upper, middle and lower panels by low current argon arc welding, and the electrode holder and the forged tube opening are welded at multiple points, so that the overall deformation of the control panel is within 5 mm.

9. A method for processing a 72-pair rod reduction furnace chassis as claimed in claim 7, characterized in that: The silicon powder slag discharge port 8810 forged pipe is made of 8810 nickel-based material, and there are eleven pieces in total. The eleven silicon material port silicon powder slag discharge port 8810 forged pipes are assembled and welded after the entire chassis is heat treated.

10. A method for processing a 72-pair rod reduction furnace chassis as claimed in claim 9, characterized in that: After the upper, middle and lower panels are welded to the chassis, all the electrode holder holes are also welded. Finally, a CNC boring and milling machine is used to process the holes. The verticality of 144 electrode holder holes meets the 0.05mm tolerance requirement.

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