A CLA16F / M alloy tube girth weld electron beam welding method

Abstract

The embodiment of the present invention provides a method for electron beam welding of the girth weld of a CLA16F / M alloy tube, comprising: pressing a clean upper end plug or a lower end plug into both ends of a clean alloy tube to obtain a workpiece, wherein the joint between the end plug and the alloy tube is tight and the end plug is not damaged or deformed; placing the workpiece in a welding chamber of a vacuum electron beam welder for clamping and fixing; evacuating the electron gun chamber and the welding chamber of the vacuum electron beam welder; adjusting the focus of the vacuum electron beam welder and aligning the focus on the joint between the end plug and the alloy tube; welding the joint of the workpiece in a rotating state according to welding process parameters to obtain a workpiece with a girth weld. The embodiment of the present invention realizes electron beam welding of the girth weld of a CLA16F / M alloy tube, wherein the girth weld has no defects such as cracks, bulging, incomplete penetration, pores or inclusions, and the weld quality is good and the tensile strength is equivalent to that of the parent material.

Description

Technical Field

[0001] The invention relates to an electron beam welding method for a girth weld of a CLA16F / M alloy tube. Background Art

[0002] Vacuum electron beam welding has become the first choice for F / M alloy welding due to its advantages that are difficult to match with other welding methods, such as high energy density, narrow weld and heat-affected zone, small welding deformation, easy and precise control of process parameters and vacuum welding environment. 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, during the preparation of the elements, the quality of the welding will directly affect the safety of reactor operation, so the quality of the weld must be reliably guaranteed. There is no mature welding method reported for the CLA16 F / M alloy girth weld. Summary of the invention

[0003] The embodiment of the present invention provides a girth weld electron beam welding method for a CLA16F / M alloy tube, so as to realize the girth weld electron beam welding of the CLA16F / M alloy tube, wherein the girth weld has no defects such as cracks, bulging, incomplete penetration, pores or inclusions, and the weld quality is good and the tensile strength is equivalent to that of the parent material.

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

[0005] A CLA16F / M alloy tube girth weld electron beam welding method, comprising:

[0006] Pressing a clean upper end plug or a clean lower end plug into both ends of a clean alloy tube to obtain a workpiece, wherein the joint between the end plug and the alloy tube is tight and the end plug is not damaged or deformed;

[0007] The workpiece is placed in a welding chamber of a vacuum electron beam welding machine and clamped and fixed;

[0008] Evacuate the electron gun chamber and welding chamber of the vacuum electron beam welder;

[0009] Adjust the focus of the vacuum electron beam welder and align the focus on the joint between the end plug and the alloy tube;

[0010] The seam of the workpiece is welded in a rotating state according to welding process parameters to obtain a workpiece with a circumferential weld.

[0011] Furthermore, the interference between the end plug and the alloy tube is 0.01 mm to 0.03 mm.

[0012] Further, the weld is obtained by welding the joint of the workpiece in a rotating state according to the welding process parameters; including:

[0013] On the welding interface of the vacuum electron beam welder, high frequency power supply, grid bias, high voltage, filament and workpiece rotation are sequentially turned on;

[0014] The welding process parameters are set in seven stages and welding is performed while the workpiece is rotating. Among them, the welding process parameters are as follows: acceleration voltage 45 kV, filament current 20 A, upper and lower end plug focusing beam 6.0-7.0 mA, upper and lower end plug defocusing current 9 mA, focusing current 630 mA for focused welding, focusing current 600 mA for defocused welding, workpiece rotation speed 20 rpm, focusing current rise time 0.5 s, defocusing current decay time 5 s, focusing welding circle number 1.056 circles, and defocusing welding circle number 2 circles.

[0015] Further, the joint of the workpiece is welded in a rotating state according to the welding process parameters to obtain the weld; and further comprising:

[0016] After welding is completed, turn off the high voltage, filament, grid bias and workpiece rotation in sequence;

[0017] After waiting for the weld to cool, enter the vacuum interface of the vacuum electron beam welder to inflate the welding chamber and take out the workpiece.

[0018] Furthermore, the electron beam welding method for the girth weld of the CLA16F / M alloy tube further comprises:

[0019] Soak the ultrasonically cleaned upper end plug or lower end plug in acetone, scrub the alloy tube mouth with acetone, and dry them separately for assembly to obtain clean upper end plug, lower end plug and alloy tube respectively.

[0020] Furthermore, the vacuum degree of the electron gun chamber is 4×10 -3 Pa; the vacuum degree of the welding chamber is 8.4×10 -3 Pa.

[0021] Furthermore, the room temperature tensile strength of the weld of the workpiece with the girth weld is 753 MPa to 774 MPa; the stress-bearing fracture position of the workpiece with the girth weld is the base material.

[0022] Furthermore, the workpiece is placed in a welding chamber of a vacuum electron beam welding machine and clamped and fixed; comprising:

[0023] Place the workpiece into the upper end of the air extraction hole in the extension rod cavity and lock it;

[0024] After the welding chamber is filled with helium, the airbag is released to control the airbag in the welding chamber to hold the extension rod tightly to fix and seal the workpiece.

[0025] Further, adjusting the focus of the vacuum electron beam welder and aligning the focus to the joint between the end plug and the alloy tube; comprising:

[0026] Adjust the intersection of the cross focus lines of the vacuum electron beam welder to the center of the light spot so that the center of the light spot is on the seam to complete the seam alignment.

[0027] Furthermore, the diameter of the airbag is 18 mm, and the outer diameter of the extension rod is 17.95 mm.

[0028] Compared with the prior art, the embodiments of the present invention have the following advantages and beneficial effects:

[0029] The invention discloses an electron beam welding method for a girth weld of a CLA16F / M alloy tube. The method comprises the following steps: pressing a clean upper end plug or a lower end plug into two ends of a clean alloy tube to obtain a workpiece, placing the workpiece in a welding chamber of a vacuum electron beam welder for clamping and fixing; evacuating an electron gun chamber and a welding chamber of the vacuum electron beam welder; adjusting the focus of the vacuum electron beam welder and aligning the focus on the joint between the end plug and the alloy tube; and welding the joint of the workpiece in a rotating state according to welding process parameters to obtain a workpiece having a girth weld, thereby realizing electron beam welding of a girth weld of a CLA16 F / M alloy tube. The girth weld has no defects such as cracks, bulging, incomplete penetration, pores or inclusions, and the weld quality is good and the tensile strength is equivalent to that of the parent material. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] 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.

[0031] Figure 1 The figure is a schematic diagram of the flow of the electron beam welding method for the girth weld of CLA16F / M alloy tube. DETAILED DESCRIPTION

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] Example

[0037] To achieve the electron beam welding of the girth weld of CLA16 F / M alloy pipe, the girth weld has no defects such as cracks, bulging, incomplete penetration, pores or inclusions, and the weld quality is good and the tensile strength is equivalent to that of the parent material. The embodiment of the present invention provides a method for electron beam welding of the girth weld of CLA16F / M alloy pipe, with reference to Figure 1 As shown, including:

[0038] S1. Pressing a clean upper end plug or a clean lower end plug into both ends of a clean alloy tube to obtain a workpiece, wherein the joint between the end plug and the alloy tube is tight and the end plug is not damaged or deformed;

[0039] S2. The workpiece is clamped and fixed in a small welding chamber of a vacuum electron beam welder;

[0040] S3. Evacuate the electron gun chamber and welding chamber of the vacuum electron beam welder;

[0041] S4. Adjust the focus of the vacuum electron beam welder and focus on the joint between the end plug and the alloy tube;

[0042] S5. Welding the seam of the workpiece in a rotating state according to welding process parameters to obtain a workpiece with a circumferential weld.

[0043] Thus, in the embodiment of the present invention, a workpiece is obtained by pressing a clean upper end plug or a lower end plug into both ends of a clean alloy tube, and the workpiece is placed in a welding chamber of a vacuum electron beam welder for clamping and fixing; the electron gun chamber and the welding chamber of the vacuum electron beam welder are evacuated; the focus of the vacuum electron beam welder is adjusted and the focus is aligned with the joint between the end plug and the alloy tube; the joint of the workpiece is welded in a rotating state according to welding process parameters to obtain a workpiece with a girth weld, thereby realizing electron beam welding of the girth weld of the CLA16F / M alloy tube, the girth weld has no defects such as cracks, bulging, incomplete penetration, pores or inclusions, the weld quality is good, and the tensile strength is equivalent to that of the parent material.

[0044] Furthermore, the interference between the end plug and the alloy tube is 0.01 mm to 0.03 mm.

[0045] Further, the weld is obtained by welding the joint of the workpiece in a rotating state according to the welding process parameters; including:

[0046] On the welding interface of the vacuum electron beam welder, high frequency power supply, grid bias, high voltage, filament and workpiece rotation are sequentially turned on;

[0047] The welding process parameters are set in seven stages and welding is performed while the workpiece is rotating. Among them, the welding process parameters are as follows: acceleration voltage 45 kV, filament current 20 A, upper and lower end plug focusing beam 6.0-7.0 mA, upper and lower end plug defocusing current 9 mA, focusing current 630 mA for focused welding, focusing current 600 mA for defocused welding, workpiece rotation speed 20 rpm, focusing current rise time 0.5 s, defocusing current decay time 5 s, focusing welding circle number 1.056 circles, and defocusing welding circle number 2 circles.

[0048] Further, the joint of the workpiece is welded in a rotating state according to the welding process parameters to obtain the weld; and further comprising:

[0049] After welding is completed, turn off the high voltage, filament, grid bias and workpiece rotation in sequence;

[0050] After waiting for the weld to cool, enter the vacuum interface of the vacuum electron beam welder to inflate the welding chamber and take out the workpiece.

[0051] Furthermore, the electron beam welding method for the girth weld of the CLA16F / M alloy tube further comprises:

[0052] Soak the ultrasonically cleaned upper end plug or lower end plug in acetone, scrub the alloy tube mouth with acetone, and dry them separately for assembly to obtain clean upper end plug, lower end plug and alloy tube respectively.

[0053] Furthermore, the vacuum degree of the electron gun chamber is 4×10 -3 Pa; the vacuum degree of the welding chamber is 8.4×10 -3Pa.

[0054] Furthermore, the room temperature tensile strength of the weld of the workpiece with the girth weld is 753 MPa to 774 MPa; the stress-bearing fracture position of the workpiece with the girth weld is the base material.

[0055] Furthermore, the workpiece is placed in a welding chamber of a vacuum electron beam welding machine and clamped and fixed; comprising:

[0056] Place the workpiece into the upper end of the air extraction hole in the extension rod cavity and lock it;

[0057] After the welding chamber is filled with helium, the airbag is released to control the airbag in the welding chamber to hold the extension rod tightly to fix and seal the workpiece.

[0058] Further, adjusting the focus of the vacuum electron beam welder and aligning the focus to the joint between the end plug and the alloy tube; comprising:

[0059] Adjust the intersection of the cross focus lines of the vacuum electron beam welder to the center of the light spot so that the center of the light spot is on the seam to complete the seam alignment.

[0060] Furthermore, the diameter of the airbag is 18 mm, and the outer diameter of the extension rod is 17.95 mm.

[0061] Specifically, an embodiment of the present invention provides a method for electron beam welding of a girth weld of a CLA16F / M alloy tube, comprising the following steps:

[0062] Step 1: Clean and dry the alloy tube and end plug for assembly.

[0063] Step 2: Press the end plug into the alloy tube to make the joint tight without damage or deformation.

[0064] Step 3: Start the vacuum electron beam welding machine and wait for the equipment to be preheated.

[0065] Step 4: Place the alloy tube with the end plug pressed into the welding chamber and clamp it in place.

[0066] Step 5: Vacuum the electron gun chamber and welding chamber.

[0067] Step 6: Focus and align the seams.

[0068] Step 7: Set the welding process parameters in seven stages. Perform welding while the workpiece is rotating. After welding is completed, turn off the high voltage, filament, grid bias and workpiece rotation in sequence.

[0069] Step 8: Wait for the weld to cool for more than 3 minutes, enter the vacuum interface to inflate the chamber, and remove the workpiece.

[0070] Further, the electron beam welding method for the girth weld of the CLA16F / M alloy tube includes:

[0071] Step 1: Soak the upper and lower end plugs that have been ultrasonically cleaned in acetone, scrub the alloy tube mouth with silk cloth dipped in acetone, and dry them separately for assembly.

[0072] Step 2: Wearing fine yarn gloves, press the end plug on the special plugging equipment. When pressing the plug, first clamp the alloy tube, put the end plug (the interference with the alloy tube is 0.01mm~0.03mm) into the pressure head, and press the end plug into the alloy tube to make the joint tight without damage and deformation.

[0073] Step 3: Start the vacuum electron beam welding machine and wait for the equipment to be preheated.

[0074] Step 4: Place the alloy tube with the end plug pressed into the upper end of the air extraction hole of the extension rod cavity (when pressing the upper end plug, the alloy tube can be placed at the bottom of the extension rod cavity), and then tighten the locking nut so that the alloy tube will not shake in the extension rod. Ensure that the airbag of the welding chamber is Φ18mm (matching the outer diameter of the extension rod Φ17.95mm), inflate the welding chamber, release the airbag, and manually push the extension rod into the chamber to keep the weld and the cooling fixture at an appropriate distance. Control the airbag to hold the extension rod tightly to achieve fixation and sealing.

[0075] Step 5: Evacuate the electron gun chamber and welding chamber to a vacuum degree of 4×10 -3 Pa, the vacuum degree of the welding chamber reaches 8×10 -3 Pa or above.

[0076] Step 6: Adjust the intersection of the cross focus lines to the center of the light spot so that the center of the light spot is on the weld to complete the weld alignment.

[0077] Step 7: Turn on the high-frequency power supply, grid bias, high voltage, filament and workpiece rotation in sequence on the welding interface, check the rotation to ensure that there is no obvious radial runout. Set the welding process parameters and weld in seven sections, observe the seam alignment of the first section of the small beam, and stop the beam if there is any abnormality. Weld with the workpiece rotating, and turn off the high voltage, filament, grid bias and workpiece rotation in sequence after welding is completed.

[0078] Step 8: Wait for the weld to cool for more than 3 minutes, enter the vacuum interface to inflate the chamber, and remove the workpiece.

[0079] The following are specific embodiments.

[0080] In Example 1 of the present invention, the nominal composition values ​​of CLA16 F / M steel 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. The alloy tubes and bars are in the recrystallized tempered state.

[0081] Example 1

[0082] A CLA16F / M alloy tube girth electron beam welding method, the specific steps are:

[0083] Step 1: Soak the upper and lower end plugs that have been ultrasonically cleaned in acetone, scrub the alloy tube mouth with silk cloth dipped in acetone, and dry them separately for assembly.

[0084] Step 2: Wearing fine yarn gloves, press the end plug on the special plugging equipment. When pressing the plug, first clamp the alloy tube, put the end plug (the interference with the alloy tube is 0.01mm~0.03mm) into the pressure head, and press the end plug into the alloy tube to make the joint tight without damage and deformation.

[0085] Step 3: Start the vacuum electron beam welding machine and wait for the equipment to be preheated.

[0086] Step 4: Place the alloy tube with the end plug pressed into the welding chamber and control the airbag to achieve clamping, fixing and sealing.

[0087] Step 5: Evacuate the gun chamber and welding chamber, and the vacuum degree of the electron gun reaches 4×10 -3 Pa, the vacuum degree of the welding chamber reaches 8.4×10 -3 Pa.

[0088] Step 6: Adjust the intersection of the cross focus lines to the center of the light spot so that the center of the light spot is on the weld to complete the weld alignment.

[0089] Step 7: Turn on the high-frequency power supply, grid bias, high voltage, filament and workpiece rotation in sequence on the welding interface, check the rotation, and ensure that there is no obvious radial runout. Set the welding process parameters for seven stages of welding. The specific parameters are acceleration voltage 45kV, filament current 20A, upper and lower end plug focusing beam 6.0~7.0mA, upper and lower end plug defocusing current 9mA, focusing welding focusing current 630mA, defocusing welding focusing current 600mA, workpiece speed 20rpm, focusing current rise time 0.5s, defocusing current decay time 5s, focusing welding circle number 1.056 circles (380°), defocusing welding circle number 2 circles (720°). Welding is carried out when the workpiece is rotating. After welding is completed, turn off the high voltage, filament, grid bias and workpiece rotation in sequence.

[0090] The upper and lower end plug focused beam current range (6.0 mA to 7.0 mA) is determined by the electron beam welding process qualification test of the girth weld of the CLA16F / M alloy tube. Optionally, the upper and lower end plug focused beam current is 6.0 mA.

[0091] Step 8: Wait for the weld to cool for more than 3 minutes, enter the vacuum interface to inflate the chamber, and remove the workpiece.

[0092] No other defects such as inclusions and bulging were found. The room temperature tensile strength of the joint was 753MPa~774MPa, and the fracture position was the base material, proving that the joint quality was excellent and met the technical requirements.

[0093] The embodiment of the present invention utilizes solutions such as pre-welding cleaning, assembly tolerance control, optimization of clamping and holding technology, and segmented design of welding process to realize the electron beam welding of the girth weld of the CLA16 F / M alloy tube, and the weld has no defects such as cracks, bulging, incomplete penetration, pores or inclusions, and the weld quality is good and the tensile strength is equivalent to that of the parent material.

[0094] 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 CLA16F / M alloy tube girth weld electron beam welding method, characterized in that: include: Pressing a clean upper end plug or a clean lower end plug into both ends of a clean alloy tube to obtain a workpiece, wherein the joint between the end plug and the alloy tube is tight and the end plug is not damaged or deformed; The workpiece is placed in a welding chamber of a vacuum electron beam welder and clamped and fixed; the electron gun chamber and the welding chamber of the vacuum electron beam welder are evacuated; the focus of the vacuum electron beam welder is adjusted and the focus is aligned with the joint between the end plug and the alloy tube; the joint of the workpiece is welded in a rotating state according to welding process parameters to obtain a workpiece with a girth weld; The weld is obtained by welding the joint of the workpiece in a rotating state according to the welding process parameters; including: turning on the high-frequency power supply, grid bias, high voltage, filament and workpiece rotation in sequence on the welding interface of the vacuum electron beam welding machine; setting the welding process parameters in seven sections to perform welding when the workpiece is rotating, wherein the welding process parameters are an acceleration voltage of 45 kV, a filament current of 20 A, a focusing beam of 6.0 to 7.0 mA for the upper and lower end plugs, a defocusing current of 9 mA for the upper and lower end plugs, a focusing current of 630 mA for focused welding, a focusing current of 600 mA for defocused welding, a workpiece rotation speed of 20 rpm, a focusing current rise time of 0.5 s, a defocusing current decay time of 5 s, a focusing welding circle number of 1.056 circles, and a defocusing welding circle number of 2 circles.

2. The electron beam welding method for the girth weld of the CLA16F / M alloy tube according to claim 1, characterized in that: The interference between the end plug and the alloy tube is 0.01mm~0.03mm.

3. The electron beam welding method for the girth weld of the CLA16F / M alloy tube according to claim 1, characterized in that: The weld is obtained by welding the joint of the workpiece in a rotating state according to the welding process parameters; and the process also includes: after the welding is completed, the high voltage, the filament, the grid bias and the workpiece rotation are turned off in sequence; after waiting for the weld to cool, the vacuum interface of the vacuum electron beam welding machine is entered to inflate the welding chamber and the workpiece is taken out.

4. The electron beam welding method for the girth weld of the CLA16F / M alloy tube according to claim 1, characterized in that: Also includes: Soak the ultrasonically cleaned upper end plug or lower end plug in acetone, scrub the alloy tube mouth with acetone, and dry them separately for assembly to obtain clean upper end plug, lower end plug and alloy tube respectively.

5. The electron beam welding method for the girth weld of the CLA16F / M alloy tube according to claim 1, characterized in that: The vacuum degree of the electron gun chamber is 4×10-3Pa; the vacuum degree of the welding chamber is 8.4×10-3Pa.

6. The electron beam welding method for the girth weld of the CLA16F / M alloy tube according to claim 1, characterized in that: The room temperature tensile strength of the weld of the workpiece with the girth weld is 753MPa-774MPa; the stress-bearing fracture position of the workpiece with the girth weld is the parent material.

7. The electron beam welding method for the girth weld of the CLA16F / M alloy tube according to claim 1, characterized in that: The workpiece is placed in a welding chamber of a vacuum electron beam welding machine for clamping and fixing; including: placing the workpiece in the upper end of the exhaust hole of the extension rod cavity and locking it; releasing the airbag after the welding chamber is filled with helium to control the airbag in the welding chamber to hold the extension rod tightly to achieve fixation and sealing of the workpiece.

8. The electron beam welding method for the girth weld of the CLA16F / M alloy tube according to claim 1, characterized in that: The focus of the vacuum electron beam welder is adjusted and aligned with the joint between the end plug and the alloy tube; including: adjusting the intersection of the cross focus lines of the vacuum electron beam welder to the center of the light spot, so that the center of the light spot is on the joint to complete the joint alignment.

9. The electron beam welding method for the girth weld of the CLA16F / M alloy tube according to claim 7, characterized in that: The diameter of the airbag is 18mm and the outer diameter of the extension rod is 17.95mm.

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