Low-deformation diffusion welding method for multi-layer complex runner aluminum alloy gas homogenizing structure

Abstract

The invention provides a low-deformation diffusion welding method for a multi-layer complex flow channel aluminum alloy gas homogenizing structure, which is suitable for manufacturing and detecting the multi-layer complex flow channel aluminum alloy gas homogenizing structure. The technical problem of high-quality diffusion welding of the aluminum alloy multi-layer structure is solved, the problem of position deviation before and after air hole welding is solved, and the problem of welding seam sealing performance detection of the multi-layer complex flow channel aluminum alloy gas homogenizing structure is solved.

Description

Technical Field

[0001] The invention relates to a low deformation diffusion welding method for a multi-layer complex flow channel aluminum alloy gas distribution structure, belonging to the technical field of aluminum alloy processing and welding. Background Art

[0002] At present, there are many welding methods for aluminum alloys, mainly including TIG welding, stir friction welding, electron beam welding, etc., which can also achieve good results. However, for plate-type aluminum alloy multi-layer welding structures, the welding surface is a plane with a large area, and welding between multi-layer planes is to be achieved. The above welding methods are difficult to achieve welding of such planar structures, while brazing and diffusion welding can well achieve welding of such plate-type multi-layer plane structures.

[0003] For aluminum alloy gas-distributing structures with complex flow channels, surface treatment is generally required after fine machining to meet the use requirements. During brazing, metallurgical reactions occur between the brazing material and the base material, resulting in changes in the chemical composition of the base material near the brazing seam, which may lead to local poor surface treatment or inconsistent surface treatment effects between the area near the brazing seam and other areas. In addition, when the brazing process is not properly controlled, weld nodules and corrosion may occur in the internal flow channel of the gas-distributing structure, resulting in uneven gas flow in the gas-distributing structure, affecting the use of the gas-distributing structure. Therefore, diffusion welding is generally used for aluminum alloy gas-distributing structures with complex flow channels. Summary of the invention

[0004] The technical problem to be solved by the present invention is: the present invention provides a low deformation diffusion welding method for a multi-layer complex flow channel aluminum alloy gas distribution structure, which is suitable for the manufacture and detection of a multi-layer complex flow channel aluminum alloy gas distribution structure, solves the technical problems of high-quality diffusion welding of aluminum alloy multi-layer structures, solves the problem of position offset of pores before and after welding, and solves the problem of weld sealing detection of a multi-layer complex flow channel aluminum alloy gas distribution structure.

[0005] The technical solution adopted by the present invention is:

[0006] A low deformation diffusion welding method for a multi-layer complex flow channel aluminum alloy gas homogenization structure, comprising:

[0007] (1) The upper plate, middle plate and lower plate are processed as blanks before welding according to the product structure. The vent holes of the lower plate are blind holes, and the allowance is not processed;

[0008] (2) Pickle the upper, middle and lower plates before welding to ensure that the welding surface is clean and free of oil stains;

[0009] (3) Select a batch welding scheme or a single welding scheme according to the ratio of the welding area between the upper plate and the middle plate, and between the middle plate and the lower plate, and perform welding according to the selected welding scheme;

[0010] (4) Ultrasonic testing is performed on the two-layer welds of the gas-homing structure. There shall be no penetration defects between the three gas passages and between the three gas passages and the outer side of the product.

[0011] (5) Perform helium inspection on the blank after welding of the uniform gas structure, evacuate the three gas channels respectively, and pass helium in other gas channels and around the product;

[0012] (6) Remove the excess of the lower plate to expose the vent, and during the processing, introduce clean compressed air from the side of the vent; then determine the processing benchmark based on the shape of the blank after the uniform gas structure is welded, use a projector to detect the vent position data, compare it with the theoretical position data on the drawing, and adjust the processing benchmark after the uniform gas structure is welded again;

[0013] (7) The post-welding blank of the gas-distributing structure is fine-processed according to the adjusted processing datum, and finally a multi-layer complex flow channel aluminum alloy gas-distributing structure product is obtained.

[0014] Furthermore, the multi-layer complex flow channel aluminum alloy gas distribution structure includes an upper plate, a middle plate, and a lower plate, and the upper plate, the middle plate, and the lower plate are connected by diffusion welding:

[0015] The upper plate has a number of air inlet holes, through which the process gas enters the structure;

[0016] There are radial and annular flow channels on the front and back of the middle plate respectively. There are several through holes in the flow channels to connect the front and back of the middle plate. The process gas is divided into three gas channels through the flow channel on the front of the middle plate, and then enters the back of the middle plate through the through holes in the flow channel, and is further evenly dispersed through the annular flow channel on the back of the middle plate.

[0017] The lower plate is distributed with a number of tiny air outlet holes, through which the process gas is evenly sprayed onto the parts below the gas distribution structure.

[0018] Furthermore, the process gas is divided into three gas channels through the front flow channel of the middle layer plate, and after entering the back side of the middle layer plate, three areas of outer circle, middle circle and inner circle are formed, which are used to independently control the gas flow in each area.

[0019] Furthermore, when processing the upper plate, middle plate and lower plate blanks before welding, ensure that the parallelism and flatness of the welding surface are no more than 0.05mm, and the roughness is better than 0.8um.

[0020] Furthermore, the ratio of the welding areas refers to the larger value divided by the smaller value.

[0021] Furthermore, when the ratio of the welding area is greater than 1.3, a step-by-step welding scheme is selected, where the two layers of plates with a larger welding area are firstly diffusion welded, and then the two layers of plates after welding are gas quenched. After the gas quenching, the two layers of plates are subjected to secondary processing to ensure that the parallelism and flatness of the welding surface are not greater than 0.05 mm, and the roughness is better than 0.8 um, and then the two layers of plates after gas quenching are diffusion welded with another layer of plates;

[0022] The parameters of both weldings are 560℃ insulation for 90min, welding pressure of 4MPa, and the actual welding area. Stainless steel limit blocks are set during welding and evenly placed along the circumference of the gas equalizing structure with an interval of 100-120mm. The thickness of the stainless steel limit blocks is 0.2mm lower than the thickness of the welded part, and the diameter is 1 / 10 of the diameter of the gas equalizing structure.

[0023] Furthermore, when the ratio of the welding area is less than or equal to 1.3, a single welding scheme is selected, and the upper plate, the middle plate, and the lower plate are diffusion welded at the same time. The diffusion welding parameters are 560°C insulation for 90 minutes, the welding pressure is 4 MPa, and the welding area is based on the larger welding area between the upper plate and the middle plate, and between the middle plate and the lower plate. The thickness of the stainless steel limit block is 0.3 mm lower than the thickness of the weld, and the diameter is 1 / 10 of the diameter of the gas distribution structure. It is evenly placed along the circumference of the gas distribution structure, with an interval of 100 to 120 mm.

[0024] Furthermore, ultrasonic testing is performed on the two-layer welds of the gas homogenizing structure, and the brazing rate is not less than 90%.

[0025] Furthermore, when the helium test is performed on the blank after the uniform gas structure is welded, the test weld leakage rate should be better than 1.0×10 - 10 Pa.m 3 / s.

[0026] Furthermore, the uniform gas structure welded blank is subjected to helium inspection, and three gas passages are evacuated respectively, and helium is passed through other gas passages and around the product. Specifically, when one of the gas passages is evacuated, helium is passed through the other two gas passages; the helium inspection is performed in this rotation.

[0027] Furthermore, the post-weld processing benchmark of the gas equalizing structure is adjusted so that the deviation between the actual position of all gas outlet holes and the theoretical position in the drawing is less than 0.2mm.

[0028] The advantages of the present invention compared with the prior art are:

[0029] (1) For multi-layer diffusion welding structures, when the difference between the areas of the two welds is large, the multi-layer structure is directly diffused. The weld with a smaller welding area will have a larger pressure per unit area, which will cause excessive welding deformation. The weld with a larger welding area will have a smaller pressure per unit area, which will cause a decrease in welding quality.

[0030] Therefore, the present invention adopts a multi-step welding scheme for diffusion welding structures with large differences in weld area, and performs gas quenching on the welded parts after the first welding to improve the strength of the parts, thereby reducing welding deformation during the second welding, thereby ensuring the welding quality of the multi-layer diffusion welding structure and reducing welding deformation;

[0031] For diffusion welding structures with small differences in weld area, a single welding scheme is adopted to reduce the number of welding times and use limit blocks to limit the deformation of welded parts, which not only ensures the welding quality of multi-layer diffusion welding structures but also reduces welding deformation.

[0032] (2) The diameter of the vent holes on the lower surface of the multi-layer complex flow channel aluminum alloy gas distribution structure is generally 0.5 to 2.5 mm, and the number is 300 to 1000.

[0033] If the vent holes are properly processed before welding, it will be very difficult to seal such a large number of small holes when the weld is subjected to helium inspection. If individual small holes are not sealed tightly, it will affect the helium inspection results.

[0034] If the vent holes are opened after welding, it will be inevitable that the machining debris will enter the interior of the gas equalization structure, and once the machining debris enters the internal flow channel, it will be difficult to remove it due to the complex flow channel structure.

[0035] Therefore, the present invention adopts a processing method for the air outlet hole that leaves a margin before welding and does not process it through, and the air outlet hole is a blind hole after welding, so as to ensure the sealing of the air outlet hole during helium inspection; after the helium inspection is completed, the margin of the air outlet hole is removed to expose the air outlet, and during the processing, 0.6-0.9MPa clean compressed air is introduced from one side of the air inlet hole, so that there is an outward airflow from the air outlet to prevent the entry of processing debris, which not only ensures the smooth completion of the helium inspection, but also avoids the entry of processing debris into the flow channel.

[0036] (3) Since diffusion welding is carried out under high temperature and high pressure, the overall gas distribution structure undergoes welding deformation after welding. On the one hand, the pre-welding processing datum is offset. If the gas distribution structure is subjected to post-welding finishing according to the general processing method and the pre-welding processing datum is still used, the position of the gas outlet holes on the lower surface of the gas distribution structure will have a large deviation, resulting in uneven gas outlet from the gas distribution structure. On the other hand, due to welding deformation, the position of the gas outlet holes will also be offset to a certain extent.

[0037] Therefore, the present invention adopts a method of secondary adjustment of the post-welding processing benchmark. First, the processing benchmark is determined based on the shape of the blank after welding of the uniform gas structure. Then a projector is used to detect the post-welding position data of the air holes, which is compared with the theoretical position data on the drawing. The post-welding processing benchmark of the uniform gas structure is adjusted secondary. At the same time, the method in technical advantage 1 is adopted to reduce the welding deformation of the uniform gas structure, and finally the deviation between the actual position of all air holes and the theoretical position on the drawing is made less than 0.2 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Schematic diagram of the upper plate;

[0039] Figure 2 This is a schematic diagram of the front of the middle layer board;

[0040] Figure 3 This is a schematic diagram of the reverse side of the middle layer board;

[0041] Figure 4 Schematic diagram of the lower plate;

[0042] Figure 5 Schematic diagram of vent hole processing. DETAILED DESCRIPTION

[0043] The present invention will be further described in detail below with reference to specific embodiments.

[0044] The present invention relates to a low deformation diffusion welding method for a multi-layer complex flow channel aluminum alloy gas distribution structure, wherein the multi-layer complex flow channel aluminum alloy gas distribution structure comprises an upper plate, a middle plate, and a lower plate, and the upper plate, the middle plate, and the lower plate are connected by diffusion welding:

[0045] like Figure 1 As shown, the upper plate has a number of air inlet holes, and the process gas enters the structure through the air inlet holes of the upper plate;

[0046] like Figure 2 and Figure 3 As shown, radial and annular flow channels are distributed on the front and back sides of the middle plate, respectively. There are several through holes in the flow channel to connect the front and back sides of the middle plate. The process gas is divided into three gas channels through the flow channel on the front side of the middle plate, and then enters the back side of the middle plate through the through holes in the flow channel, and is further evenly dispersed through the annular flow channel on the back side of the middle plate.

[0047] like Figure 4 As shown, the lower plate is distributed with a number of tiny air outlet holes, and the process gas is evenly sprayed onto the parts below the gas uniformity structure through the tiny air outlet holes.

[0048] The process gas is divided into three gas channels through the front flow channel of the middle plate. After entering the back side of the middle plate, three areas are formed: outer circle, middle circle, and inner circle, which are used to independently control the gas flow in each area.

[0049] by Figure 1 , Figure 2 and Figure 3 For example, the upper plate is provided with 5 through holes in the central area, wherein the central through hole corresponds to the shorter straight airway in the center of the middle plate, and vents are provided at both ends of the straight airway, connecting to the innermost annular airway on the back of the middle plate. The left and right through holes of the central through hole of the upper plate correspond to the left and right parts of the radial flow channels on the middle plate, respectively, and enter the annular flow channel in the middle circle area on the back of the middle plate through the left and right parts of the radial flow channels, such as the 2nd to 4th circles. The upper and lower through holes of the central through hole of the upper plate correspond to the upper and lower parts of the radial flow channels on the middle plate, respectively, and enter the annular flow channel in the outer circle area on the back of the middle plate, such as the 5th to 7th circles.

[0050] The diffusion welding method comprises the following steps:

[0051] (1) According to the product structure, the upper plate, middle plate and lower plate are processed before welding to ensure that the parallelism and flatness of the welding surface are not greater than 0.05mm, and the roughness is better than 0.8um. ​​The air outlet holes of the lower plate are blind holes, and the margin is not processed. Figure 5 shown.

[0052] (2) Pickle the upper, middle and lower plates before welding to ensure that the welding surface is clean and free of oil stains.

[0053] (3) According to the ratio of the welding area between the upper plate and the middle plate, and between the middle plate and the lower plate (the larger value is compared with the smaller value), select a batch welding scheme or a single welding scheme, and implement welding.

[0054] For diffusion welding structures with large differences in weld area, a multi-step welding scheme is adopted, and after the first welding, the welded parts are gas quenched to improve the strength of the parts, thereby reducing the welding deformation during the second welding, which not only ensures the welding quality of the multi-layer diffusion welding structure, but also reduces the welding deformation; for diffusion welding structures with small differences in weld area, a single welding scheme is adopted, by reducing the number of welding times and using limit blocks to limit the deformation of the welded parts, which not only ensures the welding quality of the multi-layer diffusion welding structure, but also reduces the welding deformation

[0055] The welding scheme selection is as follows:

[0056] When the ratio of the welding area is greater than 1.3, select the step-by-step welding scheme. First, the two layers of plates with a larger welding area are diffusion welded, and then the two layers of plates after welding are gas quenched. After gas quenching, the two layers of plates are processed again to ensure that the parallelism and flatness of the welding surface are not greater than 0.05mm, and the roughness is better than 0.8um. ​​Then the two layers of plates after gas quenching are diffusion welded with another layer of plate. The parameters of both weldings are 560℃ insulation for 90min, welding pressure of 4MPa, and the welding area is subject to the actual situation. The thickness of the stainless steel limit block is 0.2mm lower than the thickness of the welded part, and the diameter is 1 / 10 of the diameter of the gas-distributing structure. It is evenly placed along the circumference of the gas-distributing structure with an interval of 100-120mm.

[0057] When the ratio of welding area is less than or equal to 1.3, a single welding scheme is selected, and the upper plate, middle plate and lower plate are diffusion welded at the same time. The diffusion welding parameters are 560℃ insulation for 90min, welding pressure 4MPa, and the welding area is the larger welding area between the upper plate and the middle plate, and between the middle plate and the lower plate. The thickness of the stainless steel limit block is 0.3mm lower than the thickness of the welded part, and the diameter is 1 / 10 of the diameter of the gas distribution structure. It is evenly placed along the circumference of the gas distribution structure with an interval of 100-120mm.

[0058] (4) Ultrasonic testing should be carried out on the two layers of welds of the uniform gas structure respectively. The brazing rate should be no less than 90%. There should be no penetrating defects between the three gas channels and between the three gas channels and the outer side of the product.

[0059] (5) Perform helium inspection on the blank after welding of the uniform gas structure. Vacuum the three gas circuits respectively, and pass helium gas in other gas circuits and around the product. The weld leakage rate should be better than 1.0×10 -10 Pa.m 3 / s.

[0060] When one of the airways is evacuated, helium is passed through the other two airways, and helium inspection is performed alternately.

[0061] (6) Remove the excess of the lower plate to expose the vents. During the processing, introduce clean compressed air from one side of the vent. Then determine the processing datum based on the shape of the blank after welding. Use a projector to detect the vent position data and compare it with the theoretical position data on the drawing. Adjust the processing datum after welding of the vent structure again so that the deviation between the actual position of all vents and the theoretical position of the drawing is less than 0.2 mm.

[0062] (7) The post-welding blank of the gas-distributing structure is fine-processed according to the adjusted processing datum, and finally a multi-layer complex flow channel aluminum alloy gas-distributing structure product is obtained.

[0063] In the present invention, a processing method is adopted for the air outlet hole that a margin is left during processing before welding and the air outlet hole is a blind hole after welding, so as to ensure the sealing of the air outlet hole during helium inspection; after the helium inspection is completed, the margin of the air outlet hole is removed to expose the air outlet, and during the processing, 0.6-0.9MPa clean compressed air is introduced from one side of the air inlet hole so that there is an outward airflow from the air outlet hole to prevent the entry of processing debris, which not only ensures the smooth completion of the helium inspection, but also avoids the entry of processing debris into the flow channel.

[0064] At the same time, the present invention adopts a method for secondary adjustment of the post-welding processing benchmark, first determining the processing benchmark based on the shape of the blank after welding of the gas-distributing structure, then using a projector to detect the post-welding position data of the gas outlet holes, and comparing it with the theoretical position data on the drawing, and performing secondary adjustment on the post-welding processing benchmark of the gas-distributing structure; at the same time, the method in claim 2 is adopted to reduce the welding deformation of the gas-distributing structure, and ultimately making the deviation between the actual position of all gas outlet holes and the theoretical position data on the drawing less than 0.2 mm.

[0065] Embodiment 1:

[0066] According to the product structure, the upper plate, middle plate and lower plate are processed before welding, ensuring that the parallelism and flatness of the welding surface are not greater than 0.05mm, and the roughness is better than 0.8um. ​​The air outlet holes of the lower plate are blind holes, and the margin is not processed. The upper plate, middle plate and lower plate are pickled before welding to ensure that the welding surface is clean and free of oil.

[0067] Since the ratio of the welding area is greater than 1.3, the two layers of plates with a larger welding area are firstly diffusion welded, and then the two layers of plates after welding are gas quenched. After gas quenching, the two layers of plates are processed again to ensure that the parallelism and flatness of the welding surface are not greater than 0.05mm, and the roughness is better than 0.8um. ​​Then the two layers of plates after gas quenching are diffusion welded with another layer of plates. The parameters of the two weldings are 560℃ insulation for 90min, welding pressure 4MPa, welding area is subject to actual conditions, the thickness of the stainless steel limit block is 0.2mm lower than the thickness of the welded part, the diameter is 1 / 10 of the diameter of the gas-distributing structure, and it is evenly placed along the circumference of the gas-distributing structure with an interval of 100-120mm.

[0068] Ultrasonic testing is performed on the two-layer welds of the uniform gas structure. The brazing rate should not be less than 90%. There should be no penetration defects between the three gas channels and between the three gas channels and the outside of the product. Helium testing is performed on the blank after welding of the uniform gas structure. The three gas channels are vacuumed respectively, and helium is passed through other gas channels and around the product. The leakage rate of the tested weld should be better than 1.0×10 -10 Pa.m 3 / s.

[0069] The excess of the lower plate is removed to expose the vents. During the processing, clean compressed air is introduced from one side of the vent. Then the processing datum is determined based on the shape of the blank after welding of the uniform air structure. The position data of the vents is detected by a projector and compared with the theoretical position data on the drawing. The processing datum of the uniform air structure after welding is adjusted again to make the deviation between the actual position of all vents and the theoretical position data on the drawing less than 0.2mm.

[0070] The post-welding blank of the gas-distributing structure is fine-processed according to the adjusted processing benchmark, and finally a multi-layer complex flow channel aluminum alloy gas-distributing structure product is obtained.

[0071] Embodiment 2:

[0072] According to the product structure, the upper plate, middle plate and lower plate are processed before welding, ensuring that the parallelism and flatness of the welding surface are not greater than 0.05mm, and the roughness is better than 0.8um. ​​The air outlet holes of the lower plate are blind holes, and the margin is not processed. The upper plate, middle plate and lower plate are pickled before welding to ensure that the welding surface is clean and free of oil.

[0073] Since the ratio of welding area is less than or equal to 1.3, the upper plate, middle plate and lower plate are diffusion welded at the same time. The diffusion welding parameters are 560℃ insulation for 90min, welding pressure 4MPa, and the welding area is based on the larger welding area between the upper plate and the middle plate, and between the middle plate and the lower plate. The thickness of the stainless steel limit block is 0.3mm lower than the thickness of the weldment, and the diameter is 1 / 10 of the diameter of the gas distribution structure. It is evenly placed along the circumference of the gas distribution structure with an interval of 100-120mm.

[0074] Ultrasonic testing is performed on the two-layer welds of the uniform gas structure. The brazing rate should not be less than 90%. There should be no penetration defects between the three gas channels and between the three gas channels and the outside of the product. Helium testing is performed on the blank after welding of the uniform gas structure. The three gas channels are vacuumed respectively, and helium is passed through other gas channels and around the product. The leakage rate of the tested weld should be better than 1.0×10 -10 Pa.m 3 / s.

[0075] Remove the excess of the lower plate to expose the vent hole. Figure 5 As shown, during the processing, clean compressed air is introduced from one side of the air inlet, and then the processing datum is determined by the shape of the blank after the uniform air structure is welded. The position data of the air outlet is detected by a projector and compared with the theoretical position data on the drawing. The processing datum of the uniform air structure after welding is adjusted again to make the deviation between the actual position of all air outlets and the theoretical position data on the drawing less than 0.2mm.

[0076] The post-welding blank of the gas-distributing structure is fine-processed according to the adjusted processing benchmark, and finally a multi-layer complex flow channel aluminum alloy gas-distributing structure product is obtained.

[0077] Parts of the present invention that are not described in detail belong to the well-known technology for those skilled in the art.

Claims

1. A low deformation diffusion welding method for a multi-layer complex flow channel aluminum alloy gas homogenization structure, characterized in that include: (1) The upper plate, middle plate and lower plate are processed as blanks before welding according to the product structure. The vent holes of the lower plate are blind holes, and the allowance is not processed; (2) Pickle the upper, middle and lower plates before welding to ensure that the welding surface is clean and free of oil stains; (3) Select a batch welding scheme or a single welding scheme according to the ratio of the welding area between the upper plate and the middle plate, and between the middle plate and the lower plate, and perform welding according to the selected welding scheme; (4) Ultrasonic testing is performed on the two-layer welds of the gas-homing structure. There shall be no penetration defects between the three gas passages and between the three gas passages and the outer side of the product. (5) Perform helium inspection on the blank after welding of the uniform gas structure, evacuate the three gas channels respectively, and pass helium in other gas channels and around the product; (6) Remove the excess of the lower plate to expose the vent, and during the processing, introduce clean compressed air from the side of the vent; then determine the processing benchmark based on the shape of the blank after the uniform gas structure is welded, use a projector to detect the vent position data, compare it with the theoretical position data on the drawing, and adjust the processing benchmark after the uniform gas structure is welded again; (7) The post-welding blank of the gas-distributing structure is fine-processed according to the adjusted processing datum, and finally a multi-layer complex flow channel aluminum alloy gas-distributing structure product is obtained.

2. The low deformation diffusion welding method of a multi-layer complex flow channel aluminum alloy gas homogenizing structure according to claim 1, characterized in that: The multi-layer complex flow channel aluminum alloy gas distribution structure includes an upper plate, a middle plate, and a lower plate, and the upper plate, the middle plate, and the lower plate are connected by diffusion welding: The upper plate has a number of air inlet holes, through which the process gas enters the structure; There are radial and annular flow channels on the front and back of the middle plate respectively. There are several through holes in the flow channels to connect the front and back of the middle plate. The process gas is divided into three gas channels through the flow channel on the front of the middle plate, and then enters the back of the middle plate through the through holes in the flow channel, and is further evenly dispersed through the annular flow channel on the back of the middle plate. The lower plate is distributed with a number of tiny air outlet holes, through which the process gas is evenly sprayed onto the parts below the gas distribution structure.

3. The low deformation diffusion welding method of a multi-layer complex flow channel aluminum alloy gas homogenizing structure according to claim 2, characterized in that: The process gas is divided into three gas channels through the front flow channel of the middle plate. After entering the back side of the middle plate, three areas are formed: outer circle, middle circle, and inner circle, which are used to independently control the gas flow in each area.

4. The low deformation diffusion welding method of a multi-layer complex flow channel aluminum alloy gas homogenizing structure according to claim 2, characterized in that: When processing the upper plate, middle plate and lower plate blanks before welding, ensure that the parallelism and flatness of the welding surface are no more than 0.05mm and the roughness is better than 0.8um.

5. The low deformation diffusion welding method of a multi-layer complex flow channel aluminum alloy gas homogenizing structure according to claim 1, characterized in that: The ratio of the weld areas refers to the larger value divided by the smaller value.

6. The low deformation diffusion welding method of a multi-layer complex flow channel aluminum alloy gas homogenizing structure according to claim 1, characterized in that: When the welding area ratio is greater than 1.3, select the multi-step welding scheme. First, the two layers of plates with a larger welding area are diffusion welded, and then the two layers of plates after welding are gas quenched. After gas quenching, the two layers of plates are processed again to ensure that the parallelism and flatness of the welding surface are not greater than 0.05mm, and the roughness is better than 0.8um. ​​Then, the two layers of plates after gas quenching are diffusion welded with another layer of plates. The parameters of both weldings are 560℃ insulation for 90min, welding pressure of 4MPa, and the actual welding area. Stainless steel limit blocks are set during welding and evenly placed along the circumference of the gas equalizing structure with an interval of 100-120mm. The thickness of the stainless steel limit blocks is 0.2mm lower than the thickness of the welded part, and the diameter is 1 / 10 of the diameter of the gas equalizing structure.

7. The low deformation diffusion welding method of a multi-layer complex flow channel aluminum alloy gas homogenizing structure according to claim 1, characterized in that: When the ratio of welding area is less than or equal to 1.3, a single welding scheme is selected, and the upper plate, middle plate and lower plate are diffusion welded at the same time. The diffusion welding parameters are 560℃ insulation for 90min, welding pressure 4MPa, and the welding area is based on the larger welding area between the upper plate and the middle plate, and between the middle plate and the lower plate. The thickness of the stainless steel limit block is 0.3mm lower than the thickness of the weld, and the diameter is 1 / 10 of the diameter of the gas distribution structure. It is evenly placed along the circumference of the gas distribution structure with an interval of 100-120mm.

8. The low deformation diffusion welding method of a multi-layer complex flow channel aluminum alloy gas homogenizing structure according to claim 1, characterized in that: Ultrasonic testing is performed on the two layers of welds of the gas homogenizing structure respectively, and the brazing rate is not less than 90%.

9. The low deformation diffusion welding method of a multi-layer complex flow channel aluminum alloy gas homogenizing structure according to claim 1, characterized in that: When helium testing is performed on the blank after welding of the uniform gas structure, the test weld leakage rate should be better than 1.0×10 -10 Pa.m 3 / s.

10. The low deformation diffusion welding method of a multi-layer complex flow channel aluminum alloy gas homogenizing structure according to claim 1, characterized in that: Helium inspection is carried out on the blanks after welding of the uniform gas structure. The three gas channels are vacuumed respectively, and helium is passed through the other gas channels and around the product. Specifically, when one of the gas channels is vacuumed, helium is passed through the other two gas channels; the helium inspection is carried out in rotation.

11. The low deformation diffusion welding method of a multi-layer complex flow channel aluminum alloy gas homogenizing structure according to claim 1, characterized in that: Adjust the post-weld processing benchmark of the gas equalizing structure so that the deviation between the actual position of all gas outlet holes and the theoretical position in the drawing is less than 0.2mm.

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