Grinding and polishing method for inner cavity of bus shell of gas insulated transmission line

Abstract

The invention relates to a grinding and polishing method for an inner cavity of a bus shell of a gas insulated transmission line, and belongs to the technical field of metal material surface treatment. The grinding and polishing method for the inner cavity of the bus shell of the gas insulated transmission line comprises the following steps: firstly, removing the excess weld metal of an annular welding seam between an inner flange and a cylinder of the bus shell of the gas insulated transmission line, and then grinding the welding seam by adopting louver blades, and then grinding the welding seam and the heat affected areas on the two sides of the welding seam by adopting a multi-leaf wheel, then grinding the welding seam and the heat affected areas on the two sides of the welding seam by adopting abrasive paper, and finally polishing by adopting a scouring pad. According to the grinding and polishing method for the inner cavity of the bus shell of the gas insulated transmission line, operation is easy, the mass production operation effect is stable, the operation efficiency is high, the ground and polished inner cavity of the bus shell is smooth and flat, the grinding defects of protrusions, burrs, disordered patterns and the like do not exist, the product discharging risk can be reduced, and the product quality can be improved.

Description

Technical Field

[0001] The invention relates to a grinding and polishing method for the inner cavity of a busbar shell of a gas-insulated power transmission line, and belongs to the technical field of metal material surface treatment. Background Art

[0002] Gas-insulated transmission lines, also known as gas-insulated metal-enclosed transmission lines (GIL), have the advantages of large transmission capacity and good energy-saving effect, and are increasingly widely used. The busbar shell is generally welded by flanges at both ends and an aluminum alloy extruded shell between the two flanges. In order to ensure that the inner diameter of the annular weld between the flange and the shell and its heat-affected zone (the heat-affected zone on both sides of the weld, one side is located on the flange and the other side is located on the shell) is not less than the design requirement, the weld and its heat-affected zone need to be polished after welding. Affected by the polishing process and production environment, the surface treatment quality of the annular weld and the surrounding inner cavity area is unstable, prone to defects such as random lines and protrusions, and there will be burrs, metal particles and other foreign matter. Protrusions and burrs will affect the uniform distribution of the electric field and easily cause tip discharge. When metal particles enter the shell, they will gradually move to the high field strength area under the action of the AC electric field, and finally move to the weak field strength area, causing internal flashover and resulting in discharge in the shell space. The cost of rework or repair of products due to discharge increases production costs and affects product quality. Therefore, in order to solve the problem of unstable effect, easy grinding defects and foreign matter when grinding and polishing the inner cavity of the busbar shell of the gas-insulated transmission line, it is urgent to develop a grinding and polishing method for the inner cavity of the busbar shell of the gas-insulated transmission line to reduce the risk of discharge during product assembly and actual operation. Summary of the invention

[0003] The purpose of the present invention is to provide a method for grinding and polishing the inner cavity of a busbar shell of a gas-insulated transmission line, which can solve the problem that grinding defects and foreign matter are easily generated when grinding and polishing the inner cavity of a busbar shell of a gas-insulated transmission line.

[0004] In order to achieve the above-mentioned object, the technical solution adopted by the method for grinding and polishing the inner cavity of the busbar housing of the gas-insulated transmission line of the present invention is:

[0005] A method for grinding and polishing the inner cavity of a busbar shell of a gas-insulated transmission line comprises the following steps: firstly removing the excess height of an annular weld between a flange and a cylinder in the busbar shell of the gas-insulated transmission line, then grinding the weld with a shutter blade, then grinding the weld and foreign matters on a heat-affected zone on both sides of the weld with a flap wheel, then grinding the weld and foreign matters on the heat-affected zone on both sides of the weld with sandpaper having a particle size of not less than 240 meshes, then grinding the weld and the heat-affected zones on both sides of the weld with sandpaper having a particle size of not less than 600 meshes, and finally polishing the weld and the heat-affected zones on both sides of the weld with a scouring pad.

[0006] The method for grinding and polishing the inner cavity of the busbar shell of a gas-insulated transmission line of the present invention is simple to operate, has stable mass production operation effect, and has high operation efficiency. The inner cavity of the busbar shell after grinding and polishing is smooth and flat, without grinding defects such as protrusions, burrs, and random lines, which can reduce the risk of product discharge and improve product quality.

[0007] In order to avoid the weld being lower than the barrel wall parent material after subsequent grinding, preferably, after removing the excess height of the annular weld in the busbar housing of the gas-insulated transmission line, the weld excess height is 0.4 to 0.6 mm. Preferably, after the weld is ground with louvers, the weld excess height is not less than 0.2 mm and less than 0.4 mm. After the weld is ground with louvers, the ground weld is almost flush with the barrel wall parent material, but is not allowed to be lower than the barrel wall parent material.

[0008] In order to reduce costs, preferably, the model of the louver is 60#.

[0009] When using the shutter blades to grind the weld, a corresponding power device can be selected. Preferably, an angle grinder is used in combination with the shutter blades to grind the weld.

[0010] In order to better grind the weld and avoid the weld having a small residual height after grinding, preferably, the rotation speed of the louver blade is 6000-7000 r / min and the moving speed is 0.35-0.40 m / min. For example, the rotation speed of the louver blade is 6000 r / min and the moving speed is 0.35 m / min.

[0011] When the flap wheel is used to grind the weld and the heat-affected zones on both sides of the weld, the weld is first grinded, and then extended to the heat-affected zones on both sides of the weld to preliminarily remove the welding slag and foreign matter attached to both sides of the weld. However, in order to reserve a certain space for subsequent sandpaper grinding and subsequent polishing, preferably, after the flap wheel is used to grind the weld and the foreign matter on the heat-affected zones on both sides of the weld, the weld residual height is 0.1-0.2mm, and the maximum height of the foreign matter on the heat-affected zones on both sides of the weld is 0.1-0.2mm. When the flap wheel is used to grind the weld and the foreign matter on the heat-affected zones on both sides of the weld, the flap wheel is swept across the heat-affected zones on both sides of the weld to remove the foreign matter. If the height of the foreign matter is greater than the residual height of the weld, the foreign matter is ground during the sweeping process. If the height of the foreign matter is less than the residual height of the weld, the foreign matter is not ground during the sweeping process.

[0012] In order to ensure that the heights of the weld and the heat-affected zones on both sides of the weld are close, and thus make the surfaces of the weld and the heat-affected zones on both sides of the weld more uniform, preferably, the rotation speed of the flap wheel is 6000-7000 r / min, and the moving speed is 0.25-0.30 m / min. For example, the rotation speed of the flap wheel is 6000 r / min, and the moving speed is 0.25 m / min.

[0013] In order to reduce costs, preferably, the model of the flap wheel is 120#.

[0014] When the flap wheel is used for grinding, a power device used in combination with the flap wheel can be selected according to the use environment. Preferably, a grinding machine is used in combination with the flap wheel to grind the weld.

[0015] In order to ensure that the roughness of each position of the grinding area meets the requirements after grinding with sandpaper with a grit of not less than 240 mesh, and to obtain a higher processing speed, preferably, the grit of the sandpaper used for grinding with sandpaper with a grit of not less than 240 mesh is 240-300 mesh. Preferably, the grit of the sandpaper used for grinding with sandpaper with a grit of not less than 600 mesh is 600-800 mesh.

[0016] In order to make the thickness of the busbar housing meet the requirements after grinding, preferably, after grinding with sandpaper with a particle size of not less than 240 mesh, the weld excess height is 0.05-0.1mm, and the maximum height of foreign matter on the heat-affected zone on both sides of the weld is 0.1-0.2mm. When using sandpaper with a particle size of not less than 240 mesh to grind the weld and foreign matter on the heat-affected zone on both sides of the weld, sweep the sandpaper over the heat-affected zone on both sides of the weld to remove foreign matter. If the height of the foreign matter is greater than the weld excess height, grind the foreign matter during the sweeping process. If the height of the foreign matter is less than the weld excess height, do not grind the foreign matter during the sweeping process.

[0017] In order to make the thickness of the busbar shell meet the requirements after grinding, preferably, when grinding the weld and the heat-affected areas on both sides of the weld with sandpaper with a particle size of not less than 600 mesh, first grind the weld and the foreign matter on the heat-affected areas on both sides of the weld. After one grinding, the weld's excess height and the height of the welding slag and foreign matter on the heat-affected areas on both sides of the weld are all 0; then grind the weld and the heat-affected areas on both sides of the weld for a second time, and the depth of the second grinding is the thickness of the oxide layer on the heat-affected areas on both sides of the weld. After grinding with sandpaper with a particle size of not less than 600 mesh, it can be ensured that there are no random lines on the surface of the inner cavity of the busbar shell, no bright filamentary marks, and no scratching or pricking feeling when touched.

[0018] When using sandpaper with a grit size of not less than 240 mesh and sandpaper with a grit size of not less than 600 mesh to grind the weld and the heat-affected areas on both sides of the weld, it can be done manually or with an electric tool. In order to improve processing efficiency and ensure the uniformity of grinding, it is preferably used to grind the weld and the heat-affected areas on both sides of the weld with a polishing machine and sandpaper.

[0019] In order to ensure the uniformity of grinding and obtain a faster processing rate, preferably, the rotation speed of sandpaper with a particle size of not less than 240 mesh is 12000-13000 r / min, and the moving speed is 0.2-0.3 m / min. Preferably, the rotation speed of sandpaper with a particle size of not less than 600 mesh is 12000-13000 r / min, and the moving speed is 0.2-0.3 m / min.

[0020] Preferably, after the weld and the heat-affected areas on both sides of the weld are polished with a scouring pad, the roughness of each position in the weld and the heat-affected areas on both sides of the weld is no more than 6 μm. After the weld and the heat-affected areas on both sides of the weld are polished with a scouring pad, the weld and the heat-affected areas on both sides of the weld have a smooth and flat surface, almost glossy, with no obvious visible grinding lines.

[0021] When polishing with a scouring pad, it can be done manually or with the aid of an electric tool. Preferably, a polishing machine is used in combination with a scouring pad to polish the weld and the heat-affected areas on both sides of the weld.

[0022] When grinding and polishing the annular weld between the flange and the cylinder of the busbar shell of the gas-insulated transmission line, in order to prevent welding slag, debris and other foreign matter generated by grinding and polishing from splashing into the internal area of ​​the busbar shell, preferably, when grinding and polishing the inner cavity of the busbar shell of the gas-insulated transmission line, a shield is set at a position on one side of the heat-affected zone on the cylinder close to the internal area of ​​the shell to shield and protect the area inside the shell other than the grinding and polishing. For example, a baffle is set at a position on one side of the heat-affected zone on the cylinder close to the internal area of ​​the shell to shield and protect the area inside the shell other than the grinding and polishing.

[0023] It is understandable that, since the shell is generally circular, in order to effectively seal and protect the area outside the grinding and polishing area in the shell, the baffle is also circular to form an effective seal. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic flow chart of a method for grinding and polishing the inner cavity of a busbar housing of a gas-insulated transmission line according to Embodiment 1 of the present invention;

[0025] Figure 2 This is a schematic diagram of the state of the busbar housing used in Example 1 of the present invention during grinding and polishing; the figure numbers are as follows: 1-busbar cylinder; 2-connecting flange; 3-baffle. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0027] Example 1

[0028] The method for grinding and polishing the inner cavity of the busbar housing of the gas-insulated transmission line of this embodiment is as follows: Figure 1 As shown, the busbar housing used in the method for grinding and polishing the inner cavity of the busbar housing of the gas-insulated transmission line of this embodiment is as follows Figure 2 As shown, it includes a busbar barrel 1 and connecting flanges 2 arranged at both ends of the busbar barrel. The busbar barrel 1 and the two connecting flanges 2 are connected by welding, and an annular weld is formed in the connecting area. The annular weld and the heat-affected areas on both sides of the annular weld have protrusions, burrs, metal particles, etc., which need to be ground and polished. When the annular weld and the heat-affected areas on both sides of the annular weld are ground and polished, in order to prevent foreign matter such as welding slag and debris generated by grinding and polishing from splashing into the internal area of ​​the busbar shell, two circular baffles 3 are respectively arranged on one side of the shell away from the connecting flange 2 to seal and protect the area outside the grinding and polishing in the shell;

[0029] The method for grinding and polishing the inner cavity of the busbar housing of the gas-insulated transmission line of this embodiment specifically comprises the following steps:

[0030] (1) First, two circular baffles are respectively set on the side of the shell away from the flange to seal and protect the area outside the grinding and polishing inside the shell, and then a pneumatic milling cutter is used to remove the excess height of the annular weld between the flange and the cylinder inside the busbar shell. After removal, the excess height of the weld is 0.5 mm;

[0031] (2) Use an angle grinder to clamp a 60# shutter blade (the abrasive material of the shutter blade is brown corundum) to grind the milled weld. During grinding, the shutter blade rotates at 6000 r / min and the moving speed is 0.35 m / min. After grinding, the weld has a residual height of 0.3 mm. The weld after this grinding is almost flush with the base material of the cylinder wall (the weld is about 0.3 mm higher than the base material). This step is a rough grinding.

[0032] (3) Use a grinding machine to clamp a 120# flap wheel (the abrasive material of the flap wheel is brown corundum) to perform secondary grinding on the polished weld and extend it to both sides of the weld to preliminarily remove the welding slag and foreign matter attached to both sides of the weld. During grinding, the rotation speed of the flap wheel is 6000r / min, the moving speed is 0.25m / min, the grinding depth of the weld is 0.1mm, and while grinding the weld, the flap wheel is swept across the heat-affected zone on both sides of the weld to grind the welding slag and foreign matter on the heat-affected zone. After grinding, the residual height of the weld is 0.2mm, and the maximum height of the welding slag and foreign matter on the heat-affected zone on both sides of the weld is 0.2mm (if the initial height of the welding slag and foreign matter in this step is greater than 0.2mm, the height of the welding slag and foreign matter after grinding is 0.2mm, and if the initial height of the welding slag and foreign matter is less than 0.2mm, the height of the welding slag and foreign matter remains unchanged during the grinding process); this step is secondary rough grinding;

[0033] (4) Use a pneumatic polisher to clamp a white circular sandpaper with a particle size of 240 mesh, and polish the weld and both sides of the weld. During polishing, the sandpaper speed is 12000r / min, the moving speed is 0.2m / min, and the polishing depth of the weld is 0.1mm. While polishing the weld, sweep the white circular sandpaper across the heat-affected zone on both sides of the weld to polish the welding slag and foreign matter on the heat-affected zone. After polishing, the residual height of the weld is 0.1mm, and the maximum height of the welding slag and foreign matter on the heat-affected zone on both sides of the weld is 0.1mm (if the initial height of the welding slag and foreign matter in this step is greater than 0.1mm, the height of the welding slag and foreign matter after polishing is 0.1mm; if the initial height of the welding slag and foreign matter is less than 0.1mm, the height of the welding slag and foreign matter remains unchanged during the polishing process); this step is a one-time fine polishing;

[0034] (5) Use a pneumatic polisher to clamp a white round sandpaper with a particle size of 600 to polish the weld and both sides of the weld. During polishing, the sandpaper speed is 12000r / min and the moving speed is 0.2m / min. During polishing, first polish the weld once. During the first polishing, sweep the white round sandpaper across the heat-affected zone on both sides of the weld to polish the welding slag and foreign matter on the heat-affected zone. After the first polishing, the weld excess height and the height of the welding slag and foreign matter on the heat-affected zone on both sides of the weld (the maximum distance between the welding slag and foreign matter on the heat-affected zone and the oxide layer on the heat-affected zone) are all 0. Then, the weld and the heat-affected zone on both sides of the weld are polished for the second time. The depth of the second polishing is the thickness of the oxide layer on the heat-affected zone on both sides of the weld. After polishing, there are no random lines or bright filamentary marks on the surface of the polished area, and there is no scratching or pricking feeling when touched. This step is the second fine polishing.

[0035] (6) Use a pneumatic polisher to clamp a scouring pad (Umaida industrial scouring pad, model YMD159, size 5 inches) to dry polish the weld and the heat-affected area on both sides of the weld. When the roughness of each position in the polishing area is no more than 6 μm, the polishing is completed. At this time, the polished area has no obvious steps or scratches when touched, and is almost smooth, with no obvious visible polishing lines, completing the polishing of the inner cavity of the busbar shell of the gas-insulated transmission line.

[0036] Example 2

[0037] The method for grinding and polishing the inner cavity of the busbar housing of the gas-insulated transmission line of this embodiment specifically comprises the following steps:

[0038] (1) First, two circular baffles are respectively set on the side of the shell away from the flange to seal and protect the area outside the grinding and polishing inside the shell, and then a pneumatic milling cutter is used to remove the excess height of the annular weld between the flange and the cylinder inside the busbar shell. After removal, the excess height of the weld is 0.4 mm;

[0039] (2) Use an angle grinder to clamp a 60# shutter blade (the abrasive material of the shutter blade is brown corundum) to grind the milled weld. During grinding, the shutter blade rotates at 6000 r / min and the moving speed is 0.35 m / min. After grinding, the weld has a residual height of 0.2 mm. The weld after this grinding is almost flush with the base material of the cylinder wall.

[0040] (3) Use a grinding machine to clamp a 120# flap wheel (the abrasive material of the flap wheel is brown corundum) to perform secondary grinding on the polished weld and extend it to both sides of the weld to preliminarily remove the welding slag and foreign matter attached to both sides of the weld. During grinding, the rotation speed of the flap wheel is 6000r / min, the moving speed is 0.25m / min, the grinding depth of the weld is 0.1mm, and while grinding the weld, the flap wheel is swept across the heat-affected zone on both sides of the weld to grind the welding slag and foreign matter on the heat-affected zone. After grinding, the residual height of the weld is 0.1mm, and the maximum height of the welding slag and foreign matter on the heat-affected zone on both sides of the weld is 0.1mm (if the initial height of the welding slag and foreign matter in this step is greater than 0.1mm, the height of the welding slag and foreign matter after grinding is 0.1mm; if the initial height of the welding slag and foreign matter is less than 0.1mm, the height of the welding slag and foreign matter remains unchanged during the grinding process);

[0041] (4) Use a pneumatic polisher to clamp a white circular sandpaper with a particle size of 300 to polish the weld and both sides of the weld. During polishing, the sandpaper speed is 12000r / min, the moving speed is 0.2m / min, and the polishing depth of the weld slag and foreign matter on the heat-affected zone on both sides of the weld is 0.05mm. While polishing the weld, sweep the white circular sandpaper across the heat-affected zone on both sides of the weld to polish the weld slag and foreign matter on the heat-affected zone. After polishing, the weld residual height is 0.05mm, and the maximum height of the weld slag and foreign matter on the heat-affected zone on both sides of the weld is 0.05mm (if the initial height of the weld slag and foreign matter in this step is greater than 0.05mm, the height of the weld slag and foreign matter after polishing is 0.05mm; if the initial height of the weld slag and foreign matter is less than 0.05mm, the height of the weld slag and foreign matter remains unchanged during the polishing process);

[0042] (5) Use a pneumatic polisher to clamp a white round sandpaper with a particle size of 800 to polish the weld and both sides of the weld. During polishing, the sandpaper speed is 12000r / min and the moving speed is 0.2m / min. During polishing, first polish the weld once. During the first polishing, sweep the white round sandpaper across the heat-affected zone on both sides of the weld to polish the welding slag and foreign matter on the heat-affected zone. After the first polishing, the weld excess height and the height of the welding slag and foreign matter on the heat-affected zone on both sides of the weld (the maximum distance between the welding slag and foreign matter on the heat-affected zone and the oxide layer on the heat-affected zone) are all 0. Then, the weld and the heat-affected zone on both sides of the weld are polished for the second time. The depth of the second polishing is the thickness of the oxide layer on the heat-affected zone on both sides of the weld. After polishing, there are no random lines on the surface of the polished area, no bright filamentous marks, and no scratching or pricking feeling when touched.

[0043] (6) Use a pneumatic polisher to clamp a scouring pad (Umaida industrial scouring pad, model YMD159, size 5 inches) to dry polish the weld and the heat-affected area on both sides of the weld. When the roughness of each position in the polishing area is no more than 6 μm, the polishing is completed. At this time, the polished area has no obvious steps or scratches when touched, and is almost smooth, with no obvious visible polishing lines, completing the polishing of the inner cavity of the busbar shell of the gas-insulated transmission line.

[0044] Example 3

[0045] The method for grinding and polishing the inner cavity of the busbar housing of the gas-insulated transmission line of this embodiment is as follows: Figure 1 As shown, the specific steps include:

[0046] (1) First, two circular baffles are respectively set on the side of the shell away from the flange to seal and protect the area outside the grinding and polishing inside the shell, and then a pneumatic milling cutter is used to remove the excess height of the annular weld between the flange and the cylinder inside the busbar shell. After removal, the excess height of the weld is 0.6 mm;

[0047] (2) Use an angle grinder to clamp a 60# shutter blade (the abrasive material of the shutter blade is brown corundum) to grind the milled weld. During grinding, the shutter blade rotates at 6000 r / min and the moving speed is 0.35 m / min. After grinding, the weld has a residual height of 0.3 mm. The weld after this grinding is almost flush with the base material of the cylinder wall.

[0048] (3) Use a grinding machine to clamp a 120# flap wheel (the abrasive material of the flap wheel is brown corundum) to perform secondary grinding on the polished weld and extend it to both sides of the weld to preliminarily remove the welding slag and foreign matter attached to both sides of the weld. During grinding, the rotation speed of the flap wheel is 6000r / min, the moving speed is 0.25m / min, the grinding depth of the weld is 0.1mm, and while grinding the weld, the flap wheel is swept across the heat-affected zone on both sides of the weld to grind the welding slag and foreign matter on the heat-affected zone. After grinding, the residual height of the weld is 0.2mm, and the maximum height of the welding slag and foreign matter on the heat-affected zone on both sides of the weld is 0.2mm (if the initial height of the welding slag and foreign matter in this step is greater than 0.2mm, the height of the welding slag and foreign matter after grinding is 0.2mm; if the initial height of the welding slag and foreign matter is less than 0.2mm, the height of the welding slag and foreign matter remains unchanged during the grinding process);

[0049] (4) Use a pneumatic polisher to clamp a white circular sandpaper with a particle size of 250 to polish the weld and both sides of the weld. During polishing, the sandpaper speed is 12000r / min, the moving speed is 0.2m / min, and the polishing depth of the weld is 0.1mm. While polishing the weld, sweep the white circular sandpaper across the heat-affected zone on both sides of the weld to polish the welding slag and foreign matter on the heat-affected zone. After polishing, the residual height of the weld is 0.1mm, and the maximum height of the welding slag and foreign matter on the heat-affected zone on both sides of the weld is 0.1mm (if the initial height of the welding slag and foreign matter in this step is greater than 0.1mm, the height of the welding slag and foreign matter after polishing is 0.1mm; if the initial height of the welding slag and foreign matter is less than 0.1mm, the height of the welding slag and foreign matter remains unchanged during the polishing process);

[0050] (5) Use a pneumatic polisher to clamp a white circular sandpaper with a particle size of 700 to polish the weld and both sides of the weld. During polishing, the sandpaper speed is 12000r / min and the moving speed is 0.2m / min. During polishing, first polish the weld once. During the first polishing, sweep the white circular sandpaper across the heat-affected zone on both sides of the weld to polish the welding slag and foreign matter on the heat-affected zone. After the first polishing, the weld excess height and the height of the welding slag and foreign matter on the heat-affected zone on both sides of the weld (the maximum distance between the welding slag and foreign matter on the heat-affected zone and the oxide layer on the heat-affected zone) are all 0. Then, the weld and the heat-affected zone on both sides of the weld are polished for the second time. The depth of the second polishing is the thickness of the oxide layer on the heat-affected zone on both sides of the weld. After polishing, there are no random lines on the surface of the polished area, no bright filamentous marks, and no scratching or pricking feeling when touched.

[0051] (6) Use a pneumatic polisher to clamp a scouring pad (Umaida industrial scouring pad, model YMD159, size 5 inches) to dry polish the weld and the heat-affected area on both sides of the weld. When the roughness of each position in the polishing area is no more than 6 μm, the polishing is completed. At this time, the polished area has no obvious steps or scratches when touched, and is almost smooth, with no obvious visible polishing lines, completing the polishing of the inner cavity of the busbar shell of the gas-insulated transmission line.

[0052] Comparative Example 1

[0053] The difference between the method for grinding and polishing the inner cavity of the busbar shell of a gas-insulated transmission line in this comparative example and the method for grinding and polishing the inner cavity of the busbar shell of a gas-insulated transmission line in Example 1 is that, in the method for grinding and polishing the inner cavity of the busbar shell of a gas-insulated transmission line in this comparative example, step (1) is omitted, and the louver blades are directly used to grind the weld until the residual height of the weld after grinding is the same as the residual height of the weld in step (2) of Example 1, and at the same time, the method and time of polishing in step (6) are controlled to be the same as the method and time of polishing in step (6) of Example 1.

[0054] Comparative Example 2

[0055] The difference between the method for grinding and polishing the inner cavity of the busbar shell of a gas-insulated transmission line in this comparative example and the method for grinding and polishing the inner cavity of the busbar shell of a gas-insulated transmission line in Example 1 is that in the method for grinding and polishing the inner cavity of the busbar shell of a gas-insulated transmission line in this comparative example, step (2) is omitted, and the grinding depth of the weld slag and foreign matter on the heat-affected zone on both sides of the weld in step (3) is adjusted. After the adjustment, after the weld slag and foreign matter on the heat-affected zone on both sides of the weld are ground, the residual height of the weld is 0.2 mm, and the maximum height of the weld slag and foreign matter on the heat-affected zone on both sides of the weld is 0.2 mm; at the same time, the polishing method and time in step (6) are controlled to be the same as the polishing method and time in step (6) of Example 1.

[0056] Comparative Example 3

[0057] The difference between the method for grinding and polishing the inner cavity of the busbar shell of a gas-insulated transmission line in this comparative example and the method for grinding and polishing the inner cavity of the busbar shell of a gas-insulated transmission line in Example 1 is that in the method for grinding and polishing the inner cavity of the busbar shell of a gas-insulated transmission line in this comparative example, step (3) is omitted, and the grinding depth of the weld slag and foreign matter on the heat-affected zone on both sides of the weld in step (4) is adjusted. After the adjustment, after the weld slag and foreign matter on the heat-affected zone on both sides of the weld are ground, the residual height of the weld is 0.1 mm, and the maximum height of the weld slag and foreign matter on the heat-affected zone on both sides of the weld is 0.1 mm. At the same time, the polishing method and time in step (6) are controlled to be the same as the polishing method and time in step (6) of Example 1.

[0058] Comparative Example 4

[0059] The difference between the method for grinding and polishing the inner cavity of the busbar shell of a gas-insulated transmission line in this comparative example and the method for grinding and polishing the inner cavity of the busbar shell of a gas-insulated transmission line in Example 1 is that, in the method for grinding and polishing the inner cavity of the busbar shell of a gas-insulated transmission line in this comparative example, step (4) is omitted, and the polishing method and time in step (6) are controlled to be the same as the polishing method and time in step (6) in Example 1.

[0060] Experimental example

[0061] In order to evaluate the grinding and polishing effects of different grinding and polishing methods, and to investigate the stability of different grinding and polishing methods, the grinding and polishing methods of Examples 1-3 and Comparative Examples 1-4 were respectively used to grind and polish the busbar shells of the same gas-insulated transmission line. The number of busbar shells of the gas-insulated transmission line processed by each grinding and polishing method was 100, and then the grinding and polishing area in the busbar shell was checked for residual metal foreign matter, and the roughness at 5 different positions in the grinding and polishing area of ​​the busbar shell after grinding and polishing was tested. When there were residual metal foreign matter in the grinding and polishing area of ​​a certain sample or one or more of the roughness at 5 different positions of a certain sample was greater than 5.8 μm, the test result of the sample was unqualified, and then the qualified rates of the samples processed by different grinding and polishing methods were statistically calculated, and the maximum and minimum values ​​of the roughness tested in the 100 samples processed by different methods were recorded. The results are shown in Table 1.

[0062] Table 1 The qualified rate of samples treated by different grinding and polishing methods and the maximum and minimum values ​​of the roughness detected

[0063] Grinding and polishing methods Pass rate (%) Maximum roughness (μm) Minimum roughness (μm) Example 1 99 3.1 2.1 Example 2 96 3.2 3.0 Example 3 97 4.5 3.2 Comparative Example 1 0 25 20 Comparative Example 2 0 15 12 Comparative Example 3 0 12 10 Comparative Example 4 0 8 6.5

[0064] It can be seen from Table 1 that the qualified rate of samples obtained by the grinding and polishing method for the inner cavity of the busbar shell of the gas-insulated transmission line of Examples 1-3 is relatively high, and the detected roughness fluctuation is small, which means that the grinding and polishing method for the inner cavity of the busbar shell of the gas-insulated transmission line of the present invention has good processing stability and high operating efficiency, and can effectively reduce the residual fine metal foreign matter in the inner cavity of the shell, reduce the risk of product discharge, and ensure product quality.

[0065] In addition, when the inner cavity of the busbar housing of the gas-insulated transmission line is polished according to the method of Comparative Examples 1-4, when the polishing time of the last step using a scouring pad is extended by 3 times, the roughness of the polished area after polishing is still greater than 6μm. In addition, when the parameters in each step of Examples 1-3 are changed, when the excess height of the annular weld in the busbar housing of the gas-insulated transmission line is removed, the excess height of the weld is not 0.4-0.6mm, or when the weld is polished with a louver blade, the excess height of the weld is less than 0.2mm or greater than 0.4mm, the roughness of the polished area is greater than 6μm.

Claims

1. A method for grinding and polishing the inner cavity of a busbar housing of a gas-insulated transmission line, characterized in that: The following steps are involved: First, remove the excess height of the annular weld between the flange and the cylinder in the busbar shell of the gas-insulated transmission line, then use the shutter blades to grind the weld, and then use the flap wheel to grind the weld and foreign matter on the heat-affected area on both sides of the weld, and then use sandpaper with a particle size of not less than 240 mesh to grind the weld and foreign matter on the heat-affected area on both sides of the weld, and then use sandpaper with a particle size of not less than 600 mesh to grind the weld and the heat-affected area on both sides of the weld, and finally use a scouring pad to polish the weld and the heat-affected area on both sides of the weld.

2. The method for grinding and polishing the inner cavity of a busbar housing of a gas-insulated transmission line according to claim 1, characterized in that: After removing the excess height of the annular weld in the busbar shell of the gas-insulated transmission line, the excess height of the weld is 0.4-0.6 mm; after polishing the weld and the heat-affected zones on both sides of the weld with a scouring pad, the roughness of each position in the weld and the heat-affected zones on both sides of the weld is no more than 6 μm.

3. The method for grinding and polishing the inner cavity of a busbar housing of a gas-insulated transmission line according to claim 1, characterized in that: After the weld is polished with louver blades, the weld's excess height is not less than 0.2mm and less than 0.4mm.

4. The method for grinding and polishing the inner cavity of a busbar housing of a gas-insulated transmission line according to claim 1 or 3, characterized in that: The rotation speed of the louver blades is 6000-7000 r / min, and the moving speed is 0.35-0.40 m / min.

5. The method for grinding and polishing the inner cavity of a busbar housing of a gas-insulated transmission line according to claim 1, characterized in that: After grinding the weld and foreign matter on the heat-affected zones on both sides of the weld with a flap wheel, the weld residual height is 0.1 to 0.2 mm, and the maximum height of foreign matter on the heat-affected zones on both sides of the weld is 0.1 to 0.2 mm.

6. The method for grinding and polishing the inner cavity of a busbar housing of a gas-insulated transmission line according to claim 1 or 5, characterized in that: The rotation speed of the flap wheel is 6000-7000 r / min, and the moving speed is 0.25-0.30 m / min.

7. The method for grinding and polishing the inner cavity of a busbar housing of a gas-insulated transmission line according to claim 1, characterized in that: When sandpaper with a particle size of not less than 240 mesh is used for grinding, the particle size of the sandpaper used is 240-300 mesh; after grinding with sandpaper with a particle size of not less than 240 mesh, the residual height of the weld is 0.05-0.1mm, and the maximum height of foreign matter on the heat-affected zone on both sides of the weld is 0.1-0.2mm.

8. The method for grinding and polishing the inner cavity of a busbar housing of a gas-insulated power transmission line according to claim 1 or 7, characterized in that: The rotation speed of sandpaper with a particle size of not less than 240 mesh is 12000~13000r / min, and the moving speed is 0.2~0.3m / min.

9. The method for grinding and polishing the inner cavity of a busbar housing of a gas-insulated transmission line according to claim 1, characterized in that: When sandpaper with a grit of not less than 600 mesh is used for grinding, the grit of the sandpaper used is 600-800 mesh; when sandpaper with a grit of not less than 600 mesh is used to grind the weld and the heat-affected zone on both sides of the weld, first grind the weld and the foreign matter on the heat-affected zone on both sides of the weld once. After one grinding, the residual height of the weld and the height of the welding slag and foreign matter on the heat-affected zone on both sides of the weld are all 0; then the weld and the heat-affected zone on both sides of the weld are grinded for a second time, and the depth of the second grinding is the thickness of the oxide layer on the heat-affected zone on both sides of the weld.

10. The method for grinding and polishing the inner cavity of a busbar housing of a gas-insulated power transmission line according to claim 1 or 9, characterized in that: The rotation speed of sandpaper with a particle size of not less than 600 mesh is 12000-13000r / min, and the moving speed is 0.2-0.3m / min.

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