A helium-filled hole-plugging welding method for CLA16F / M alloy rod

Abstract

The embodiment of the present invention provides a helium-filled hole-plugging welding method for a CLA16F / M alloy rod, comprising: starting a welding machine and inserting the end of the CLA16F / M alloy rod to be plugged into a welding chamber; adjusting the distance between the tungsten electrode in the welding chamber and the end of the CLA16F / M alloy rod to be plugged; emptying the welding chamber, the emptying operation is performed more than twice, and the emptying operation includes a vacuuming operation, a low-pressure helium filling operation, and a helium release operation performed in sequence; filling the welding chamber that has completed the emptying operation with helium and welding the end of the CLA16F / M alloy rod to be plugged in the welding chamber. The embodiment of the present invention realizes helium-filled hole-plugging welding of CLA16F / M alloy rods, and the helium leakage rate of the weld is less than 1.01×10 ‑9 Pa·m 3 / s. This fully guarantees the reliability of the hole plugging welding of the CLA16F / M alloy rod.

Description

Technical Field

[0001] The invention relates to a helium filling hole plugging welding method for a CLA16F / M alloy rod. Background Art

[0002] The service life and safety and reliability of fuel elements are closely related to the performance of the cladding material. As a new type of stainless steel material, CLA16 F / M alloy has excellent comprehensive performance and can be used as a candidate material for the cladding of high-burnup and long-life core fuel elements. However, the quality of welding during the preparation of the elements will directly affect the safety of reactor operation, so the welding quality must be reliably guaranteed. Fuel assemblies work in reactors for a long time and are exposed to neutron irradiation, high temperature and high pressure, and corrosion for a long time. In order to reduce the internal and external pressure difference of the cladding tube during the operation of the reactor, prevent the creep collapse of the cladding tube and the reduction of the heat transfer performance of the fuel rod, an air filling hole is plugged at the upper end of the fuel rod to fill helium into the tube, and then seal the hole with spot welding. There is no mature welding method reported for helium-filled hole-plugging welding of CLA16 F / M alloy rods. Summary of the invention

[0003] The embodiment of the present invention provides a helium filling hole plugging welding method for a CLA16F / M alloy rod, so as to enhance the hole plugging welding reliability of the CLA16F / M alloy rod.

[0004] The embodiment of the present invention is achieved through the following technical solutions:

[0005] In a first aspect, an embodiment of the present invention provides a helium-filled hole-plugging welding method for a CLA16F / M alloy rod, comprising:

[0006] Start the welding machine and insert the end of the CLA16F / M alloy rod to be plugged into the welding chamber;

[0007] Adjust the distance between the tungsten electrode in the welding chamber and the end of the hole to be plugged of the CLA16F / M alloy rod;

[0008] The welding chamber is emptied for more than 2 times, and the emptied operation includes vacuuming, low-pressure helium filling and helium releasing in sequence;

[0009] The evacuated welding chamber is filled with helium and the end of the CLA16F / M alloy rod to be plugged in the welding chamber is welded.

[0010] Furthermore, the helium-filled hole-plugging welding method of the CLA16F / M alloy rod also includes:

[0011] Check the weld shape of the end of the CLA16F / M alloy rod to be plugged after the plugging welding is completed and clean the plugging surface.

[0012] Further, the welding chamber that has completed the evacuation operation is filled with helium and the end of the CLA16F / M alloy rod to be plugged in the welding chamber is welded; including:

[0013] Adjust the pressure of the pressure reducing valve of the helium cylinder to the specified pressure and inject helium into the welding chamber that has completed the evacuation operation. When the helium filling pressure reaches the set value, the welding chamber closes the helium injection valve;

[0014] Weld the end of the CLA16F / M alloy rod to be plugged in the welding chamber.

[0015] Further, the end of the CLA16F / M alloy rod to be plugged in the welding chamber is welded; including:

[0016] Open the compressed air valve and make the compressed air pressure ≥0.5MPa before starting the welding machine.

[0017] Furthermore, the welding process parameters are welding current 48-55A, duty cycle 50%, welding time 0.8s, and decay time 0.7s.

[0018] Furthermore, the set value is 0.085 MPa.

[0019] Further, the specified pressure is 0.08 MPa~0.09 MPa.

[0020] Further, the distance between the tungsten electrode in the welding chamber and the end of the hole to be plugged of the CLA16F / M alloy rod is adjusted; including:

[0021] Adjust the distance between the tungsten electrode in the welding chamber and the end of the hole to be plugged of the CLA16F / M alloy rod to 0.6mm~0.8mm.

[0022] Further, the weld shape of the end of the CLA16F / M alloy rod to be plugged after the plugging welding is completed is checked and the plugging surface is cleaned; including:

[0023] If the helium leak detection rate of the weld is less than 1.01×10 -9 Pa•m 3 / s, the welding is qualified.

[0024] Furthermore, the nominal composition values ​​of the CLA16F / M alloy rod are: C:0.15~0.25, Mn:0.45~0.65, Si:0.15~0.35, Cr:11.2~11.8, Ni:0.45~0.65, Mo:0.95~1.05; W:0.45~0.55, V:0.25~0.35, Y:0~0.05, Nb:0.10~0.30, S:<0.004,P:<0.008.

[0025] Compared with the prior art, the embodiments of the present invention have the following advantages and beneficial effects:

[0026] The invention discloses a helium-filled hole-plugging welding method for a CLA16F / M alloy rod, which comprises the following steps: inserting the end of the CLA16F / M alloy rod to be plugged into a welding chamber; adjusting the distance between the tungsten electrode in the welding chamber and the end of the CLA16F / M alloy rod to be plugged; emptying the welding chamber, wherein the emptying operation is performed more than twice, and the emptying operation includes a vacuuming operation, a low-pressure helium-filling operation, and a helium-releasing operation performed in sequence; filling the welding chamber after the emptying operation with helium and welding the end of the CLA16F / M alloy rod to be plugged in the welding chamber, thereby realizing helium-filled hole-plugging welding of the CLA16 F / M alloy rod, and the helium leak detection rate of the weld is less than 1.01×10 -9 Pa•m 3 / s. This fully guarantees the reliability of the hole plugging welding of the CLA16F / M alloy rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 The figure is a schematic flow chart of the helium filling hole plugging welding method for CLA16F / M alloy rods. DETAILED DESCRIPTION

[0029] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0030] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is apparent to one of ordinary skill in the art that these specific details are not necessarily employed to practice the present invention. In other embodiments, in order to avoid obscuring the present invention, well-known structures, circuits, materials, or methods are not specifically described.

[0031] Throughout the specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment," "an embodiment," "an example," or "an example" appearing in various places throughout the specification do not necessarily all refer to the same embodiment or example. In addition, particular features, structures, or characteristics may be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. In addition, it will be appreciated by those of ordinary skill in the art that the figures provided herein are for illustrative purposes and that the figures are not necessarily drawn to scale. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0032] In the description of the present invention, the directions or positional relationships indicated by terms such as “front”, “rear”, “left”, “right”, “up”, “down”, “vertical”, “horizontal”, “high”, “low”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the scope of protection of the present invention. Example

[0033] In order to enhance the reliability of the hole plugging welding of the CLA16F / M alloy rod, the embodiment of the present invention provides a helium-filled hole plugging welding method of the CLA16F / M alloy rod, referring to Figure 1 As shown, including:

[0034] S1. Start the welding machine and insert the end of the CLA16F / M alloy rod to be plugged into the welding chamber;

[0035] S2. Adjust the distance between the tungsten electrode in the welding chamber and the end of the hole to be plugged of the CLA16F / M alloy rod;

[0036] S3. The welding chamber is emptied for more than 2 times, and the evacuation operation includes a vacuum operation, a low-pressure helium filling operation and a helium release operation performed sequentially;

[0037] S4. Fill the evacuated welding chamber with helium and weld the end of the CLA16F / M alloy rod to be plugged in the welding chamber.

[0038] Therefore, the embodiment of the present invention implements helium-filled hole-plugging welding of CLA16 F / M alloy rod by inserting the hole-plugging end of CLA16F / M alloy rod into the welding chamber; adjusting the distance between the tungsten electrode in the welding chamber and the hole-plugging end of CLA16F / M alloy rod; performing an evacuation operation on the welding chamber, wherein the evacuation operation is performed more than twice, and the evacuation operation includes a vacuuming operation, a low-pressure helium filling operation, and a helium releasing operation performed in sequence; and filling the evacuated welding chamber with helium and welding the hole-plugging end of CLA16F / M alloy rod in the welding chamber. The helium leak detection rate of the weld is less than 1.01×10 - 9 Pa•m 3 / s. This fully guarantees the reliability of the hole plugging welding of the CLA16F / M alloy rod.

[0039] Furthermore, the helium-filled hole-plugging welding method of the CLA16F / M alloy rod also includes:

[0040] Check the weld shape of the end of the CLA16F / M alloy rod to be plugged after the plugging welding is completed and clean the plugging surface.

[0041] Further, the welding chamber that has completed the evacuation operation is filled with helium and the end of the CLA16F / M alloy rod to be plugged in the welding chamber is welded; including:

[0042] Adjust the pressure of the pressure reducing valve of the helium cylinder to the specified pressure and inject helium into the welding chamber that has completed the evacuation operation. When the helium filling pressure reaches the set value, the welding chamber closes the helium injection valve;

[0043] Weld the end of the CLA16F / M alloy rod to be plugged in the welding chamber.

[0044] Further, the end of the CLA16F / M alloy rod to be plugged in the welding chamber is welded; including:

[0045] Open the compressed air valve and make the compressed air pressure ≥0.5MPa before starting the welding machine.

[0046] Furthermore, the welding process parameters are welding current 48-55A, duty cycle 50%, welding time 0.8s, and decay time 0.7s.

[0047] Furthermore, the set value is 0.085 MPa.

[0048] Further, the specified pressure is 0.08 MPa~0.09 MPa.

[0049] Further, the distance between the tungsten electrode in the welding chamber and the end of the hole to be plugged of the CLA16F / M alloy rod is adjusted; including:

[0050] Adjust the distance between the tungsten electrode in the welding chamber and the end of the hole to be plugged of the CLA16F / M alloy rod to 0.6mm~0.8mm.

[0051] Further, the weld shape of the end of the CLA16F / M alloy rod to be plugged after the plugging welding is completed is checked and the plugging surface is cleaned; including:

[0052] If the helium leak detection rate of the weld is less than 1.01×10 -9 Pa•m 3 / s, the welding is qualified.

[0053] Furthermore, the nominal composition values ​​of the CLA16F / M alloy rod are: C:0.15~0.25, Mn:0.45~0.65, Si:0.15~0.35, Cr:11.2~11.8, Ni:0.45~0.65, Mo:0.95~1.05; W:0.45~0.55, V:0.25~0.35, Y:0~0.05, Nb:0.10~0.30, S:<0.004,P:<0.008.

[0054] Specifically, an embodiment of the present invention provides a helium-filled hole-plugging welding method for a CLA16F / M alloy rod, comprising:

[0055] Step 1: Open the compressed air valve, ensure that the compressed air pressure gauge value is ≥0.5MPa, and start the welding machine power supply.

[0056] Step 2: Open the welding application, and after the compressed air pressure is ≥0.5MPa, load the welding program and set the plugging welding process parameters.

[0057] Step 3: Open the chamber and put the workpiece in. Insert the end of the CLA16F / M alloy rod to be plugged into the welding chamber horizontally from the sealed inner hole on the left side of the helium-filled plugging welding device, so that it is close to the workpiece positioning device, and the chamber automatically clamps the workpiece and seals it.

[0058] Step 4: Adjust the distance from the tungsten electrode to the plugging end of the workpiece through the tungsten electrode adjustment mechanism, and use a crosshair ruler (minimum scale 0.01mm) to ensure that the distance between the tungsten electrode and the plugging end is between 0.6mm and 0.8mm.

[0059] Step 5: Start the program, repeat the vacuuming, low-pressure inflation and deflation of the welding room for no less than 2 times to ensure the purity of the helium in the welding room and the inflation pipeline. The vacuuming value is ≤6Pa.

[0060] Step 6: Set the helium pressure to 0.085MPa in the plugging welding program interface in advance, and adjust the pressure of the pressure reducing valve on the helium cylinder to 0.08MPa~0.09MPa, and slowly fill it with helium. When the helium pressure reaches (0.085±0.005)MPa, the welding chamber automatically closes the valve.

[0061] Step 7: Welding, real-time monitoring and recording of the welding process.

[0062] Step 8: Take out the workpiece, check whether the appearance of the solder joint is good, and clean the surface of the plugging hole with a stainless steel brush. Turn off the equipment.

[0063] The following are specific examples.

[0064] Example 1

[0065] The plugging hole is welded with CLA16 F / M alloy end plug. The specific steps are as follows:

[0066] Step 1: Open the compressed air valve, ensure that the compressed air pressure gauge value is ≥0.5MPa, and start the welding machine power supply.

[0067] Step 2: Open the welding application, wait until the compressed air pressure is ≥0.5MPa, load the welding program, and set the process parameters for each stage: welding current 50A, duty cycle 50%, welding time 0.8s, decay time 0.7s. Set the vacuum value ≤6Pa, and repeat the vacuuming for no less than 2 times. Set the helium pressure to 0.085MPa, and adjust the pressure of the pressure reducing valve on the helium cylinder to 0.08MPa~0.09MPa.

[0068] Step 3: Open the chamber and put the workpiece in. Insert the end of the CLA16F / M alloy rod to be plugged into the welding chamber horizontally from the sealed inner hole on the left side of the helium-filled plugging welding device, so that it is close to the workpiece positioning device, and the chamber automatically clamps the workpiece and seals it.

[0069] Step 4: Use the tungsten electrode adjustment mechanism to adjust the distance from the tungsten electrode to the plugging end of the workpiece to 0.62mm.

[0070] Step 5: Start the program and repeat vacuuming, low-pressure inflation and deflation in the welding chamber.

[0071] Step 6: Slowly fill with helium and close the valve when the helium pressure reaches 0.086MPa.

[0072] Step 7: Welding, real-time monitoring and recording of the welding process.

[0073] Step 8: Take out the workpiece, check whether the appearance of the solder joint is good, and clean the surface of the plugging hole with a stainless steel brush. Turn off the equipment.

[0074] The plugging weld surface has no cracks or defects, and the leakage rate is measured to be 2.2×10 -10 Pa•m 3 / s, meeting welding quality requirements.

[0075] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A helium-filled hole-plugging welding method for CLA16F / M alloy rods, characterized in that: include: Insert the end of the CLA16F / M alloy rod to be plugged into the welding chamber; Adjust the distance between the tungsten electrode in the welding chamber and the end of the hole to be plugged of the CLA16F / M alloy rod; The welding chamber is emptied for more than 2 times, and the emptied operation includes vacuuming, low-pressure helium filling and helium releasing in sequence; The evacuated welding chamber is filled with helium and the end of the CLA16F / M alloy rod to be plugged in the welding chamber is welded; The welding chamber after the evacuation operation is completed is filled with helium and the end of the CLA16F / M alloy rod to be plugged in the welding chamber is welded; including: Adjust the pressure of the pressure reducing valve of the helium cylinder to the specified pressure and inject helium into the welding chamber that has completed the evacuation operation. When the helium filling pressure reaches the set value, the welding chamber closes the helium injection valve; Weld the end of the CLA16F / M alloy rod to be plugged in the welding chamber; Welding the end of the CLA16F / M alloy rod to be plugged in the welding chamber; including: Open the compressed air valve to make the compressed air pressure ≥0.5MPa and then start the welding machine; The welding process parameters are welding current 48-55A, duty cycle 50%, welding time 0.8s, decay time 0.7s; The set value is 0.085MPa; The specified pressure is 0.08 MPa~0.09 MPa; Adjust the distance between the tungsten electrode in the welding chamber and the end of the hole to be plugged of the CLA16F / M alloy rod; including: Adjust the distance between the tungsten electrode in the welding chamber and the end of the CLA16F / M alloy rod to be plugged to 0.6mm~0.8mm; Check the weld shape of the end of the CLA16F / M alloy rod to be plugged after the plugging welding is completed and clean the plugging surface; including: If the helium leak detection rate of the weld is less than 1.01×10 -9Pa •m 3 / s, the welding is qualified; The nominal composition values ​​of CLA16F / M alloy rod are: C:0.15~0.25, Mn:0.45~0.65, Si:0.15~0.35, Cr:11.2~11.8, Ni:0.45~0.65, Mo:0.95~1.05; W:0.45~0.55, V:0.25~0.35, Y:0~0.05, Nb:0.10~0.30, S:<0.004,P:<0.

008.

2. The helium-filled hole-plugging welding method of the CLA16F / M alloy rod as claimed in claim 1, characterized in that: Also includes: Check the weld shape of the end of the CLA16F / M alloy rod to be plugged after the plugging welding is completed and clean the plugging surface.

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