阅读说明：本技术 一种ODS-FeCrAl合金包壳管燃料棒端塞电阻焊工艺 (Electric resistance welding process for end plugs of ODS-FeCrAl alloy cladding tube fuel rods ) 是由 李明伟 段家宝 何建军 夏胜全 张鹏程 潘际宇 李思功 杨国华 朱诚 李玉斌 刘 于 2021-05-27 设计创作，主要内容包括：本发明涉及一种利用ODS-FeCrAl合金包壳管燃料棒端塞电阻焊工艺：首先将包壳管端面内外及端塞清理干净；再将包壳管放置在电阻焊设备中送料机构上,端塞插入端塞电极杆上；再设置工艺参数；再将包壳管、带有端塞的端塞电极杆将送至焊接舱室指定焊接位置；再对焊接舱室进行充气密封操作,利用橡胶垫圈抱紧包壳管；再对焊接舱室依次进行抽真空、充氩气操作；再进行自动焊接；焊接结束后,进行复位操作,包壳管退出焊接舱室,端塞电极杆退出焊接舱室；再利用通规检测焊缝外径。上述焊接工艺能够实现ODS-FeCrAl合金包壳管与端塞焊接,可有效防止核泄漏的发生,故其有望于取代锆合金成为新型燃料棒包壳管材料。(The invention relates to a resistance welding process for an end plug of a fuel rod of an ODS-FeCrAl alloy cladding tube, which comprises the following steps: firstly, cleaning the inner and outer end surfaces and the end plugs of the end face of the cladding tube; then placing the cladding tube on a feeding mechanism in the resistance welding equipment, and inserting an end plug into an end plug electrode rod; setting technological parameters; then sending the cladding tube and the end plug electrode rod with the end plug to a specified welding position of the welding cabin; then, the welding cabin is inflated and sealed, and a rubber gasket is used for tightly holding the cladding tube; then, the welding cabin is sequentially vacuumized and filled with argon; then automatic welding is carried out; after welding, resetting operation is carried out, the cladding tube exits from the welding cabin, and the end plug electrode rod exits from the welding cabin; and detecting the outer diameter of the welding seam by using a go gauge. The welding process can realize the welding of the ODS-FeCrAl alloy cladding tube and the end plug, and can effectively prevent the occurrence of nuclear leakage, so that the ODS-FeCrAl alloy cladding tube is expected to replace zirconium alloy to become a novel fuel rod cladding tube material.)

1. An ODS-FeCrAl alloy cladding tube fuel rod end plug resistance welding process is characterized by comprising the following steps:

step 1: cleaning the inner and outer end faces and the end plugs of the cladding tube;

step 2: placing the cladding tube cleaned in the step 1 on a tube conveying mechanism of resistance welding equipment, and plugging the end plug cleaned in the step 1 into an end plug electrode rod;

and step 3: turning on power software of the resistance welding equipment, and setting welding process parameters;

and 4, step 4: opening operation software of the resistance welding equipment, conveying the cladding tube to a specified welding position of the welding cabin through the cladding tube positioning mechanism and the electrode block by using the tube conveying mechanism, and moving an end plug electrode rod inserted into the end plug to the specified position of the welding cabin by using a servo electric cylinder; then, inflating and sealing the welding chamber, and tightly holding the cladding tube by using an inflatable sealing ring;

and 5: then, carrying out vacuum pumping operation and argon filling operation on the welding cabin;

step 6: when the atmosphere in the cladding tube is argon atmosphere, setting operation software of resistance welding equipment to realize automatic electric welding;

and 7: after welding, resetting operation is carried out, the cladding tube exits from the welding cabin through the tube conveying mechanism, and the end plug electrode rod exits from the welding cabin;

and 8: and inspecting the surface of the welding seam of the welded cladding tube by using a 10-time magnifying lens, detecting the outer diameter of the welding seam by using a go gauge, and enabling the welded cladding tube to smoothly pass through the go gauge, namely indicating that the outer diameter of the welding seam is qualified.

2. The ODS-FeCrAl alloy cladding tube fuel rod end plug resistance welding process of claim 1, wherein the step 1 of cleaning the inner and outer end faces and the end plugs of the cladding tube comprises the following processes: firstly, flattening the end face of a cladding tube by using an automatic lathe, then cleaning oil stains on an end plug and the cladding tube by using ultrasonic waves twice, wherein mediums are respectively butyl (propyl) ketone and alcohol, the ultrasonic cleaning time is 10-40 min, and then drying by using a vacuum furnace, wherein the drying temperature is 80-120 ℃, and the vacuum degree is less than or equal to 1.0 multiplied by 10^-1Pa, and the drying time is 0.5-1.5 h.

3. An ODS-FeCrAl alloy cladding tube fuel rod end plug resistance welding process according to claim 1, characterized in that the process parameters in step 3 include: the pressure is 400-700 daN, the current is 6.00-10.0 kA, and the duration is 40-120 ms.

4. The ODS-FeCrAl alloy cladding tube fuel rod end plug resistance welding process according to claim 1, wherein in the step 4, when the cladding tube is sent to the designated welding position of the welding cabin by the tube feeding mechanism, the end face of the cladding tube is 0.35-0.75 mm away from the outer end face of the end plug electrode, the end plug is subjected to end plug adsorption operation, and the end plug electrode rod is moved to the designated position of the welding cabin by the servo electric cylinder and is in close contact with the cladding tube.

5. The ODS-FeCrAl alloy cladding tube fuel rod end plug resistance welding process of claim 1, wherein the ODS-FeCrAl alloy cladding tube wall thickness is 0.28 mm-0.45 mm.

6. The ODS-FeCrAl alloy cladding tube fuel rod end plug resistance welding process of claim 1, wherein the step 4 comprises centering the cladding tube and the end plug, and specifically comprises the following steps:

1) uniformly coating a coloring agent on the inner wall of the cladding tube;

2) respectively moving the end plug and the cladding tube to the specified position of the welding cabin, and keeping for 2s to enable the coloring agent on the inner wall of the cladding tube to be attached to the end plug;

3) then, resetting is carried out, the end plug and the cladding tube sequentially withdraw from the welding cabin, the adhesion condition of the coloring agent on the end plug is observed, and if the coloring agent is uniformly adhered to the circumference of the end plug, the centering performance of the end plug and the cladding tube is good;

4) if the obvious uneven condition of the coloring agent exists on the end plug, adjusting the electrode rods of the end plug from the upper direction, the lower direction, the left direction and the right direction according to the specific uneven condition of the coloring agent;

5) after the adjustment is finished, the end plug and the cladding tube are continuously moved to be in close contact for centering, the adhesion condition of a coloring agent of the end plug is observed, and if the coloring agent is uniformly adhered, the centering performance of the end plug and the cladding tube is good;

6) if the stain is still not uniformly attached, the steps (1), (2), (3), (4) and (5) are continued until the stain is uniformly attached on the end plug.

7. The ODS-FeCrAl alloy cladding tube fuel rod end plug resistance welding process according to claim 1, characterized in that in step 5, the welding chamber is vacuumized to a degree of vacuum below 50 pa; and after the vacuum degree is reached, automatically filling argon into the welding cabin, wherein the set value of the argon filling is within the range of 0.11 Mpa-2 Mpa, namely the cladding tube can be welded under the internal pressure of 0.11 Mpa-2 Mpa.

8. The ODS-FeCrAl alloy cladding tube fuel rod end plug resistance welding process according to claim 1, characterized in that in step 8, a 10 times magnifying glass is used for observing a welding seam, and when a defect occurs on the surface of the welding seam, an electrode block needs to be replaced; when utilizing leading to rule to detect the welding seam external diameter, need smoothly pass through, can not block, if the cladding pipe after the welding end can not pass through leading to the rule, then need the inspection copper electrode and weld the inside condition in cabin, later according to actual conditions, select to change copper electrode or other spare parts in welding cabin.

Technical Field

The invention belongs to the field of advanced cladding material welding processes of nuclear power plant fault-tolerant accident fuel (ATF), and particularly relates to an ODS-FeCrAl alloy cladding tube fuel rod end plug resistance welding process.

Background

Fuel rods for nuclear power plant potentially fault tolerant accident fuel (ATF) are an important process used in the manufacture of pressurized water reactor fuel assemblies. The fuel rod is internally provided with pellets, and the fuel rod cladding tube is connected with the end plug through welding. However, current results regarding welding of fuel rods indicate that welding defects, such as porosity, cracks, slag inclusions, etc., are likely to occur between the fuel rods and the end plugs. The quality of the welding seam between the fuel rod cladding tube and the end plug directly determines the service life and the operation safety of the pressurized water reactor fuel assembly. The ODS-FeCrAl alloy is an advanced cladding material designed around potential fault tolerant accident fuel (ATF) at present, is not reacted with water at high temperature, can effectively prevent nuclear leakage, and is expected to replace zirconium alloy to become a novel fuel rod cladding tube material. The end plug resistance pressure welding is a mature zirconium alloy fuel rod cladding tube-end plug welding technology applied internationally at present, and the end plug resistance pressure welding method has the following advantages for the welding form of the fuel rod cladding tube-end plug: high welding efficiency, good quality stability, easy realization of automation and the like. However, the ODS-FeCrAl alloy end plug resistance welding process is still blank internationally at present, so that the development of a mature ODS-FeCrAl alloy end plug resistance welding process is very important.

Disclosure of Invention

The invention aims to provide a resistance welding process for an ODS-FeCrAl alloy cladding tube fuel rod end plug. The ODS-FeCrAl alloy is used for designing an advanced cladding material of fault tolerant accident fuel (ATF), can effectively prevent nuclear leakage, and is expected to replace zirconium alloy to become a novel fuel rod cladding tube material.

An ODS-FeCrAl alloy cladding tube fuel rod end plug resistance welding process comprises the following steps:

step 1: cleaning the inner and outer end faces and the end plugs of the cladding tube;

step 2: placing the cladding tube cleaned in the step 1 on a tube conveying mechanism of resistance welding equipment, and plugging the end plug cleaned in the step 1 into an end plug electrode rod;

and step 3: turning on power software of the resistance welding equipment, and setting welding process parameters;

and 4, step 4: opening operation software of the resistance welding equipment, conveying the cladding tube to a specified welding position of the welding cabin through the cladding tube positioning mechanism and the electrode block by using the tube conveying mechanism, and moving an end plug electrode rod inserted into the end plug to the specified position of the welding cabin by using a servo electric cylinder; then, inflating and sealing the welding chamber, and tightly holding the cladding tube by using an inflatable sealing ring;

and 5: then, carrying out vacuum pumping operation and argon filling operation on the welding cabin;

step 6: when the atmosphere in the cladding tube is argon atmosphere, setting operation software of resistance welding equipment to realize automatic electric welding;

and 7: after welding, resetting operation is carried out, the cladding tube exits from the welding cabin through the tube conveying mechanism, and the end plug electrode rod exits from the welding cabin;

and 8: and inspecting the surface of the welding seam of the welded cladding tube by using a 10-time magnifying lens, detecting the outer diameter of the welding seam by using a go gauge, and enabling the welded cladding tube to smoothly pass through the go gauge, namely indicating that the outer diameter of the welding seam is qualified.

Preferably, the step 1 of cleaning the inner and outer end faces and the end plug of the cladding tube comprises the following processes: firstly, flattening the end face of a cladding tube by using an automatic lathe, then cleaning oil stains on an end plug and the cladding tube by using ultrasonic waves twice, wherein mediums are respectively butyl (propyl) ketone and alcohol, the ultrasonic cleaning time is 10-40 min, and then drying by using a vacuum furnace, wherein the drying temperature is 80-120 ℃, and the vacuum degree is less than or equal to 1.0 multiplied by 10^-1Pa, and the drying time is 0.5-1.5 h.

Preferably, the process parameters in step 3 include: the pressure is 400-700 daN, the current is 6.00-10.00 kA, and the duration is 40-120 ms.

Preferably, in the step 4, when the cladding tube is sent to the specified welding position of the welding cabin by using the tube conveying mechanism, the end face of the cladding tube is 0.35-0.75 mm away from the outer end face of the end plug electrode, the end plug is subjected to end plug adsorption operation, and the end plug electrode rod moves to the specified position of the welding cabin by using the servo electric cylinder and is in close contact with the cladding tube.

Preferably, the wall thickness of the ODS-FeCrAl alloy cladding tube is 0.28 mm-0.45 mm.

Preferably, step 4 is to perform a centering operation on the cladding tube and the end plug, and specifically includes the following processes:

1) uniformly coating a coloring agent on the inner wall of the cladding tube;

2) respectively moving the end plug and the cladding tube to the specified position of the welding cabin, and keeping for 2s to enable the coloring agent on the inner wall of the cladding tube to be attached to the end plug;

3) then, resetting is carried out, the end plug and the cladding tube sequentially withdraw from the welding cabin, the adhesion condition of the coloring agent on the end plug is observed, and if the coloring agent is uniformly adhered to the circumference of the end plug, the centering performance of the end plug and the cladding tube is good;

4) if the obvious uneven condition of the coloring agent exists on the end plug, adjusting the electrode rods of the end plug from the upper direction, the lower direction, the left direction and the right direction according to the specific uneven condition of the coloring agent;

5) after the adjustment is finished, the end plug and the cladding tube are continuously moved to be in close contact for centering, the adhesion condition of a coloring agent of the end plug is observed, and if the coloring agent is uniformly adhered, the centering performance of the end plug and the cladding tube is good;

6) if the stain is still not uniformly attached, the steps (1), (2), (3), (4) and (5) are continued until the stain is uniformly attached on the end plug.

Preferably, in the step 5, the welding chamber is vacuumized, and the vacuum degree is lower than 50 pa; and after the vacuum degree is reached, automatically filling argon into the welding cabin, wherein the set value of the argon filling is within the range of 0.11 Mpa-2 Mpa, namely the cladding tube can be welded under the internal pressure of 0.11 Mpa-2 Mpa.

Preferably, in the step 8, the welding seam is observed by using a magnifying lens of 10 times, and when the surface of the welding seam has defects, the electrode block needs to be replaced; when utilizing leading to rule to detect the welding seam external diameter, need smoothly pass through, can not block, if the cladding pipe after the welding end can not pass through leading to the rule, then need the inspection copper electrode and weld the inside condition in cabin, later according to actual conditions, select to change copper electrode or other spare parts in welding cabin.

Compared with the prior art, the invention has the beneficial effects that:

the invention discloses a resistance welding process for an end plug of a fuel rod of an ODS-FeCrAl alloy cladding tube, which comprises the following steps of: firstly, cleaning the inner and outer end faces and the end plugs of the end face of a cladding tube, wherein the end plugs comprise surface oil stains, burrs and the like; then placing the cladding tube on a feeding mechanism in the resistance welding equipment; then inserting an end plug into the end plug electrode rod; then turning on power software, and setting technological parameters including current magnitude, current time and the like; then opening the operation software, operating the pipe conveying mechanism, and conveying the cladding pipe to the specified welding position of the welding cabin; then, operating the end plug electrode rod to send the end plug to the specified welding position of the welding cabin by continuously utilizing the operating software; then, carrying out inflation sealing operation on the welding cabin, and tightly embracing the cladding tube by using a rubber gasket; then, carrying out vacuum pumping operation and argon filling operation on the welding cabin, and automatically carrying out argon filling operation after the vacuum degree reaches a certain requirement; then clicking a welding option on the operation software to weld; after welding, resetting operation is carried out, the cladding tube exits from the welding cabin through the tube conveying mechanism, and the end plug electrode rod exits from the welding cabin; and detecting the outer diameter of the welding seam by using a go gauge. The welding process can realize the welding of the ODS-FeCrAl alloy cladding tube and the end plug, and can effectively prevent the occurrence of nuclear leakage, so that the ODS-FeCrAl alloy cladding tube is expected to replace zirconium alloy to become a novel fuel rod cladding tube material.

Drawings

FIG. 1 is a schematic view of a fuel rod cladding tube-end plug of the present invention prior to resistance welding;

FIG. 2 is an external view of a fuel rod cladding tube-end plug weld seam of the present invention welded using an end plug resistance welding process;

FIG. 3 is a CT view of a fuel rod cladding tube-end plug weld joint welded using an end plug resistance welding process in accordance with the present invention;

FIG. 4 is a metallographic view of a fuel rod cladding tube-end plug weld of the present invention welded using an end plug resistance welding process.

Wherein, the names corresponding to the reference numbers are:

1-end plugging of an electrode rod; 2-end plugs; 3-end plugging electrode rod adjusting mechanism; 4-a cladding tube; 5-an electrode block; 6-inflating the sealing ring; 7-a welding chamber; 8-feeding pneumatic claw I; 9-feeding a second gas claw; 10-vacuum pumping port; 11-filling an argon port; 12-end plug adsorption air extraction port; 13-feeding and positioning air claw.

Detailed Description

The foregoing summary of the invention is described in further detail below with reference to specific embodiments. It should not be understood that the scope of the above-described subject matter of the present invention is limited to the following examples. Various substitutions and alterations can be made without departing from the technical idea of the invention as described above, according to the common technical knowledge and conventional means in the field, and the scope of the invention is covered.

The ODS-FeCrAl alloy is an advanced cladding material designed around potential fault-tolerant accident fuel (ATF) at present, does not react with water at high temperature, and can effectively prevent nuclear leakage, so the ODS-FeCrAl alloy is expected to replace zirconium alloy to become a novel fuel rod cladding tube material, however, the ODS-FeCrAl alloy is used as a novel nuclear fuel rod cladding tube material, because dispersion strengthening phase exists in the ODS-FeCrAl alloy, and the wall thickness is thin and is only about 0.30mm, the welding difficulty is high (the defects such as cracks are easily generated in the welding seam, and the like), therefore, the ODS-FeCrAl alloy is still blank internationally as an end plug resistance welding process at present, and therefore, the ODS-FeCrAl alloy cladding tube fuel rod end plug resistance welding process provided by the application specifically comprises the following steps, as shown in figure 1:

step 1: cleaning the inner end surface and the outer end surface of the cladding tube 4 and the end plug 2;

step 2: placing the cladding tube 4 cleaned in the step 1 on a tube conveying mechanism of resistance welding equipment, and plugging the end plug 2 cleaned in the step 1 into the end plug electrode rod 1;

and step 3: turning on power software of the resistance welding equipment, and setting welding process parameters;

and 4, step 4: opening operation software of the resistance welding equipment, conveying the cladding tube 4 to a specified welding position of a welding cabin 7 through an electrode block 5 by using a tube conveying mechanism, and moving an end plug electrode rod 1 inserted into an end plug 2 to the specified position of the welding cabin by using a servo electric cylinder; then, the welding cabin 7 is inflated and sealed, and the cladding tube 4 is tightly held by an inflatable sealing ring 6;

and 5: then, the welding cabin 7 is vacuumized through the vacuumizing port 10, and then is filled with argon through the argon injecting port 11;

step 6: when the internal atmosphere of the cladding tube 4 is argon atmosphere, setting operation software of resistance welding equipment to realize automatic electric welding;

and 7: after welding, resetting operation is carried out, the cladding tube 4 exits from the welding cabin 7 through the tube conveying mechanism, and the end plug electrode rod 1 exits from the welding cabin 7;

and 8: and (3) inspecting the surface of the welding seam of the welded cladding tube 4 by using a magnifying lens of 10 times, detecting the outer diameter of the welding seam by using a go gauge, and enabling the welded cladding tube 4 to smoothly pass through the go gauge, namely, indicating that the outer diameter of the welding seam is qualified.

Further, the step 1 of cleaning the inner end face and the outer end face of the cladding tube 4 and the end plug 2 comprises the following processes: firstly, the end face of the cladding tube is flattened by an automatic lathe, and then ultrasonic waves are utilizedCleaning oil stains on the end plug and the cladding tube twice, wherein the cleaning media are butyl (propyl) ketone and alcohol respectively, the ultrasonic cleaning time is 10-40 min, and then drying by using a vacuum furnace, the drying temperature is 80-120 ℃, and the vacuum degree is less than or equal to 1.0 multiplied by 10^-1Pa, and the drying time is 0.5-1.5 h. For the adoption of the ODS-FeCrAl cladding tube, the existence of burrs on the end face of the ODS-FeCrAl cladding tube can cause uneven wall thickness of a tube end, great influence is generated on welding of the ODS-FeCrAl cladding tube, meanwhile, if the tube end is not thoroughly dewatered, welding cracks can be easily generated, and particularly, the ODS-FeCrAl alloy containing a large amount of dispersed brittle-hard strengthening phases has larger influence on the ODS-FeCrAl alloy, so that burrs, oil stains and moisture of a part to be welded at the tube end of the cladding tube are thoroughly removed through mechanical processing, ultrasonic cleaning and vacuum furnace drying. In the prior art, zirconium alloy is generally adopted as a cladding tube, and the wall thickness has low requirements on residual burrs and water on the end face, so that butyl (propyl) ketone is frequently adopted for wiping, and the influence on welding is not great.

Further, in step 2, the cladding tube 4 needs to be placed on the first feeding gas claw 8, the second feeding gas claw 9 and the feeding positioning gas claw 13 at the same time, so as to ensure that the centering performance can be ensured when the cladding tube 4 can move to the specified welding position of the welding cabin 7, and the end plug 2 needs to be completely inserted when being inserted into the end plug electrode rod 1.

Further, the process parameters in step 3 include: the pressure is 400-700 daN, the current is 6.00-10.00 kA, and the duration is 40-120 ms. For the resistance welding process, for different materials and different wall thicknesses, the welding parameters of the materials have great influence on the success of welding, the sensitivity of pressure, current and welding time parameters to the welding stability is found to have difference through research, wherein the sensitivity of the pressure and the current to the welding stability is high, the sensitivity of the welding time to the welding stability is low, when thinner materials are adopted for resistance welding, the conventional operation of reducing resistance heat should be adopted, but the welding stability factor is considered in the application, the change amplitude of the pressure and the current is found to be increased through research to reduce the welding contact resistance greatly, and the stable welding is realized by increasing the welding time properly.

Further, in the step 4, when the cladding tube 4 is conveyed to the designated welding position of the welding cabin 7 by using the tube conveying mechanism, the distance between the end face of the cladding tube 4 and the outer end face of the electrode block 5 is 0.35-0.75 mm; the end plug electrode rod 1 adsorbs the end plug 2 through the end plug adsorption air exhaust port 12, and the end plug electrode rod 1 moves to the specified position of the welding cabin 7 by using the servo electric cylinder and is in close contact with the cladding pipe. According to the invention, researches show that the distance between the end face of the cladding tube 4 and the outer end face of the electrode block 5 also influences welding, but the welding is not influenced by the distance between the end face of the cladding tube and the outer end face of the electrode block 5 due to the wall thickness of the zirconium tube in the prior art, and the distance between the end face of the cladding tube and the outer end face of the electrode block 5 is smaller in the application, so that the distance between the position where a welding seam for welding the cladding tube 4 and the end plug 1 is located and the outer end face of the electrode block 5 is smaller, and the deformation of the welding seam in the welding process can not be completely limited by the shape of the inner contour of the electrode block 5, so that the welding seam cannot smoothly pass through a go-gauge; when the distance is large, meaning that the weld is located at a large distance from the outer end face of the electrode block 5, there is an amplification of the difference in centring between the end plug 2 and the cladding tube 4, making the welding difficult to succeed.

Further, the ODS-FeCrAl alloy cladding tube wall thickness described in this application is 0.28 mm-0.45 mm.

Further, the step 4 is to perform a centering operation on the cladding tube 4 and the end plug 2, and specifically includes the following processes:

1) uniformly coating a coloring agent on the inner wall of the cladding tube 4;

2) moving the end plug 2 and the cladding tube 4 to the specified positions of the welding chamber 7 respectively, and keeping for 2s to make the coloring agent on the inner wall of the cladding tube 4 adhere to the end plug;

3) then, resetting is carried out, the end plug 2 and the cladding tube 4 sequentially withdraw from the welding cabin 7, the adhesion condition of the coloring agent on the end plug 2 is observed, and if the coloring agent is uniformly adhered to the circumference of the end plug 2, the centering performance of the end plug 2 and the cladding tube 4 is good;

4) if the obvious uneven condition of the coloring agent exists on the end plugs 2, the end plug electrode rods 1 are adjusted from four directions, namely up, down, left and right, through the end plug electrode rod adjusting mechanisms 3 according to the specific uneven condition of the coloring agent;

5) after the adjustment is finished, the end plug 2 and the cladding tube 4 are continuously moved to be in close contact for centering, the adhesion condition of a coloring agent of the end plug 2 is observed, and if the coloring agent is uniformly adhered, the centering performance of the end plug 2 and the cladding tube 4 is good;

6) if the stain is still not uniformly attached, the steps (1), (2), (3), (4) and (5) are continued until the stain is uniformly attached on the end plug 2.

In the method, because the dispersion strengthening phase exists in the ODS-FeCrAl alloy cladding tube and the wall is thin, strict centering operation is required, the existing centering operation is mainly ensured by the self-coaxiality of equipment, a combined inspection tool is adopted for verification in the centering process and is divided into two parts, the two parts are in clearance conical surface fit, one end of the combined inspection tool is fixed on an end plug electrode rod, the other end of the combined inspection tool is fixed on an electrode block, then one part of the combined tool of a carrier of the end plug electrode rod is operated to move to the electrode, if the two parts can be matched, the centering performance is good, but the rigidity of the combined inspection tool is high, therefore, the end surface deformation of the ODS-FeCrAl alloy cladding tube can be caused if the centering process in the prior art is used for centering, therefore, the method designs that the centering operation utilizes a coloring agent to directly observe the centering performance, and simultaneously, the deformation of the end plug and the cladding tube under the actual welding condition is considered. If the centering performance is not good, the coloring agent on the circumference of the end plug is not uniformly attached, the characterization observation precision of the centering performance is higher, the centering performance can be better adjusted, and the centering is more accurate.

Further, in the step 5, the welding chamber 7 is vacuumized through the vacuumizing port 10, and the vacuum degree is lower than 50 pa; after the vacuum degree is reached, the argon filling operation is automatically carried out on the welding cabin 7 through the argon filling port 11, the argon filling set value is in the range of 0.11 Mpa-2 Mpa, and the cladding tube 4 can be welded with the internal pressure of 0.11 Mpa-2 Mpa.

Further, in the step 8, the welding seam is observed by using a magnifying lens with the magnification of 10 times, and when the surface of the welding seam has defects, the electrode block 5 needs to be replaced; when utilizing leading to rule to detect the welding seam external diameter, need smoothly pass through, can not block, if the cladding pipe after the welding end can not pass through leading to the rule, then need the inspection copper electrode and weld the inside condition in cabin, later according to actual conditions, select to change copper electrode or other spare parts in welding cabin.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. The invention extends to any novel feature or any novel combination of features disclosed in this specification and any novel method or process steps or any novel combination of features disclosed.