A method for welding thick plate nickel-based materials

Abstract

The application discloses a welding method for thick plate nickel-based material, which comprises the following steps: bevel processing of a nickel-based alloy steel plate, and performing flaw detection to determine whether linear defects exist in the bevel; if the linear defects exist, polishing treatment is performed; if the linear defects do not exist, an arc guide plate is arranged in the bevel; a backing layer of a weld joint is welded by argon arc welding, and then multi-layer welding is performed on the bevel by electric arc welding until the surface of the weld joint is flush with the surface of the nickel-based alloy steel plate; the surface of the nickel-based alloy steel plate is polished, and after the polishing treatment, nondestructive testing is performed to determine whether welding defects exist in the welded joint; if the welding defects exist, the welding defects are polished for multiple times; if the welding defects do not exist, the welded nickel-based alloy steel plate is subjected to physical and chemical property testing; the U-shaped narrow gap and the V-shaped bevel type longitudinal joint consume less argon arc welding wire and electrode, and linear defect detection is performed before welding, and repeated polishing is performed during the welding process, so that the welding effect is improved.

Description

Technical Field

[0001] This invention relates to the field of welding, and more specifically, to a welding method for thick nickel-based plates. Background Technology

[0002] The cold hydrogenation fluidized bed reactor, a crucial piece of equipment in the new energy industry, is made of a 90mm thick nickel-based alloy, belonging to the Ni-Fe-Cr series. This alloy has a large coefficient of linear expansion and low thermal conductivity. During welding, impurities and low-melting-point substances in the weld seam tend to segregate and accumulate at grain boundaries, forming low-melting-point eutectics with nickel during solidification, leading to welding hot cracks. Simultaneously, due to the poor fluidity of the liquid nickel alloy weld metal and its rapid cooling rate, gases in the molten pool cannot escape quickly enough, resulting in porosity. Furthermore, gases such as oxygen, carbon dioxide, and hydrogen have high solubility in liquid nickel, which decreases significantly during cooling, further contributing to porosity. In existing technologies, we use an X-groove (…). Figure 1 Argon arc welding (ATW) is used for the root pass, followed by submerged arc welding (SAW) for the fill and cover passes. This method involves a large amount of filler material, resulting in high material costs. While repeated arc-stopping during welding helps control temperature and reduce hot cracking, it also increases the risk of crater cracks. Crack detection is time-consuming, leading to low welding efficiency and negatively impacting future market competitiveness and product quality. Summary of the Invention

[0003] To address at least one of the aforementioned technical problems, this invention proposes a welding method for thick nickel-based plates.

[0004] The first aspect of this invention provides a welding method for thick nickel-based plates, comprising the following steps:

[0005] S1. The nickel-based alloy steel plate is beveled and subjected to flaw detection to determine whether there are linear defects in the bevel. If linear defects are present, they are ground. If no linear defects are present, an arc-inducing plate is installed inside the bevel.

[0006] S2, the root pass of the weld is made by argon arc welding, and then the bevel is made by electric arc welding in multiple layers until the surface of the weld is flush with the surface of the nickel-based alloy steel plate.

[0007] S3. Grind the surface of the nickel-based alloy steel plate. After grinding, perform non-destructive testing to determine whether there are welding defects at the weld joint.

[0008] S4. If there are welding defects, the welding defects will be ground multiple times; if there are no welding defects, the welded nickel-based alloy steel plate will be subjected to physical and chemical property tests.

[0009] In a preferred embodiment of the present invention, before “performing the root pass welding of the weld by argon arc welding” in step S2, pre-welding cleaning is required. Pre-welding cleaning includes: cleaning the bevel and the 50mm range on both sides to remove oxides, oil, and chemical reagents.

[0010] In a preferred embodiment of the present invention, the cleaning process for removing oxides, oil stains, and chemical reagents specifically includes:

[0011] Surface oxides are removed by grinding with a stainless steel wire brush or stainless steel wire wheel, or an alumina or silica abrasive wheel.

[0012] Remove oil, chemicals, dust, and other harmful substances by cleaning and wiping with alcohol and silk cloth; welding must be carried out within 4 hours after all cleaning is completed, otherwise the pre-welding cleaning must be repeated.

[0013] In a preferred embodiment of the present invention, the bevel includes a U-shaped bevel and a V-shaped bevel, with the upper weld of the nickel-based alloy steel plate having a U-shaped bevel and the lower weld of the nickel-based alloy steel plate having a V-shaped bevel.

[0014] In a preferred embodiment of the present invention, step S2, "performing a root pass weld by argon arc welding, followed by multi-layer welding of the bevel by electric arc welding until the weld surface is flush with the surface of the nickel-based alloy steel plate," specifically includes:

[0015] The weld seam is welded by argon arc welding to form the root layer, and linear defects are detected by PT test reagent. After the test is completed, the defects are removed by wiping with alcohol or cleaning agent and cloth before the next layer of welding is carried out.

[0016] Welding electrodes are used to fill the V-groove and U-groove with multiple layers of welding to form multiple welding layers. The welding layers in the V-groove and U-groove are welded alternately. The arc-end point of each welding layer is ground to remove defects, oxide color and welding slag.

[0017] The power supply uses a constant voltage mode during the welding process.

[0018] In a preferred embodiment of the present invention, the welding defect includes one or a combination of two or more of the following: cracks, incomplete fusion defects, incomplete penetration defects, or undercut defects.

[0019] In a preferred embodiment of the present invention, step S4, "conducting physical and chemical property tests on the welded nickel-based alloy steel plate," specifically includes:

[0020] Stress tests were performed on the welded nickel-based alloy steel plates after welding to obtain stress information;

[0021] Determine whether the stress information meets the mechanical performance requirements. If not, the stress test results of the nickel-based alloy steel plate are deemed unqualified.

[0022] If the mechanical property requirements are satisfied, the stress test result of the nickel-based alloy steel plate is determined to be qualified.

[0023] In a preferred embodiment of the present invention, the step S4 of "performing physical and chemical property test on the welded nickel-based alloy steel plate" further comprises:

[0024] heating the welded nickel-based alloy steel plate after welding at a high temperature of 600 degrees Celsius, after heating for a predetermined time, performing a tensile test on the welded nickel-based alloy steel plate, and collecting image information of the weld joint in real time;

[0025] extracting image features of the weld joint, and analyzing elongation data of the nickel-based alloy steel plate at the weld joint according to the image features;

[0026] inputting the elongation data into a fracture test model, and outputting a fracture test result;

[0027] determining whether the fracture test result satisfies a preset test threshold;

[0028] if the requirement is satisfied, the welding is qualified; if the requirement is not satisfied, the welding is unqualified.

[0029] Compared with the prior art, the present invention achieves the following beneficial technical effects:

[0030] By arranging the U-shaped narrow gap and V-shaped groove, the consumption of argon arc welding wire and welding electrode for the longitudinal seam is reduced; linear defect detection is performed before welding, and repeated grinding is performed during the welding process, which improves the welding effect; meanwhile, physical and chemical property test is performed on the welded part after welding is completed, thereby ensuring that the welded nickel-based alloy steel plate meets the requirements of tensile and stress tests, and improving the use safety of the welded nickel-based alloy steel plate. Description of Drawings

[0031] Figure 1 shows a schematic view of a groove of the nickel-based alloy steel plate of the present invention;

[0032] Figure 2 shows a schematic view of the arrangement of a starting plate of the present invention;

[0033] Figure 3 shows a flow chart of the welding method for thick nickel-based plates of the present invention.

[0034] In the figures, 1 is a nickel-based alloy steel plate, 2 is a V-shaped groove, 3 is a U-shaped groove, 4 is a starting plate. Detailed Description of the Embodiments

[0035] In order to more clearly understand the above objects, features and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other.

[0036] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0037] like Figure 1-3 As shown, the first aspect of the present invention provides a welding method for thick nickel-based plates, comprising the following steps:

[0038] S1. The nickel-based alloy steel plate 1 is beveled and subjected to flaw detection to determine whether there are linear defects in the bevel. If there are linear defects, it is ground. If there are no linear defects, an arc-inducing plate 4 is installed in the bevel.

[0039] S2, the root pass of the weld is performed by argon arc welding, and then the bevel is welded in multiple layers by electric arc welding until the surface of the weld is flush with the surface of the nickel-based alloy steel plate 1.

[0040] S3, grind the surface of nickel-based alloy steel plate 1, and perform non-destructive testing after grinding to determine whether there are welding defects at the weld joint.

[0041] S4. If there are welding defects, the welding defects will be ground multiple times; if there are no welding defects, the welded nickel-based alloy steel plate 1 will be subjected to physical and chemical property tests.

[0042] It should be noted that the 90mm thick nickel-based alloy steel plate 1 was processed into a U-shaped narrow gap bevel and a V-shaped bevel 2. Argon arc welding was used for the root pass, and 100% PT inspection was performed, ensuring no linear defects (if defects were found, they were removed by grinding). Manual arc welding was used for the filler pass, followed by submerged arc welding for the filler and cover pass. Throughout the welding process, the arc termination points in the weld were ground, and PT inspection was added at any abnormal locations. To reduce the need for flipping the steel plate during longitudinal seam welding and welding the inner bevel before the outer bevel, and to prevent the first layer of submerged arc welding from penetrating the root pass and causing cracks, after argon arc welding for the root pass, three layers of manual arc welding were used to ensure the weld between argon arc welding and manual arc welding was ≥10mm; then submerged arc welding was used for the final pass. The interpass temperature during welding was ≤100℃. The nickel-based alloy steel plate 1 underwent a stabilization heat treatment (905±10℃×4.5h), and the tensile strength of the welded joint was tested through physical and chemical property testing.

[0043] According to an embodiment of the present invention, before “performing the root pass welding of the weld by argon arc welding” in step S2, pre-welding cleaning is required. Pre-welding cleaning includes: cleaning the bevel and the 50mm range on both sides to remove oxides, oil, and chemical reagents.

[0044] According to embodiments of the present invention, the cleaning process for removing oxides, oil stains, and chemical reagents specifically includes:

[0045] Surface oxides are removed by grinding with a stainless steel wire brush or stainless steel wire wheel, or an alumina or silica abrasive wheel.

[0046] Remove oil, chemicals, dust, and other harmful substances by cleaning and wiping with alcohol and silk cloth; welding must be carried out within 4 hours after all cleaning is completed, otherwise the pre-welding cleaning must be repeated.

[0047] According to an embodiment of the present invention, the bevel includes a U-shaped bevel 3 and a V-shaped bevel 2. The weld above the nickel-based alloy steel plate 1 is a U-shaped bevel 3, and the weld below the nickel-based alloy steel plate 1 is a V-shaped bevel 2.

[0048] According to an embodiment of the present invention, step S2, "performing a root pass weld by argon arc welding, and then performing multi-layer welding on the bevel by electric arc welding until the weld surface is flush with the surface of the nickel-based alloy steel plate 1," specifically includes:

[0049] The weld seam is welded by argon arc welding to form the root layer, and linear defects are detected by PT test reagent. After the test is completed, the defects are removed by wiping with alcohol or cleaning agent and cloth before the next layer of welding is carried out.

[0050] Welding electrodes are used to fill the V-groove 2 and U-groove 3 with multiple layers of welding to form multiple welding layers. The welding layers in the V-groove 2 and U-groove 3 are welded alternately. The arc-ending point of each welding layer is ground to remove defects, oxide color and welding slag.

[0051] The power supply uses a constant voltage mode during the welding process.

[0052] It should be noted that this application obtains the welding process parameters for nickel-based alloys with a wall thickness of 90mm by designing new bevels (V-shaped bevel 2 and U-shaped bevel 3), and through welding tests and mechanical property testing, thus realizing the product application.

[0053] Specifically, the size of the upper opening of the U-shaped bevel is 30-34mm, preferably 32mm; the diameter of the lower arc of the U-shaped bevel is 8-12mm, preferably 10mm; and the arc of the bottom opening of the V-shaped bevel is 50-60 degrees, preferably 55 degrees. The dimensions and arcs in this application do not constitute a limitation on the scope of protection of this invention. Those skilled in the art can make reasonable improvements to the dimensions and arcs based on the above.

[0054] Furthermore, stainless steel grounding clamps should be used to securely connect the cylinder to prevent arcing and contact between the copper wire and the cylinder; after the root pass of the weld, a 100% PT test should be performed, and any defects should be repaired immediately; the PT test reagent should be removed by wiping with alcohol or cleaning agent and a cloth before welding the next layer of weld; after the root pass of the weld, 2-3 layers of welding rods should be applied (weld thickness ≥10mm); this can effectively reduce burn-through caused by the high heat input and deep penetration of the first submerged arc weld, while also preventing cracking; when performing the first layer of submerged arc welding, it should be able to Perform welding in multiple passes; for shielded metal arc welding, the width of the weld pass should be ≤15mm; all weld termination points should be ground (using a grinding head); the diameter of the submerged arc welding wire should be 2.4mm, and the power supply characteristic should be constant voltage mode; strictly control the interpass temperature (≤100℃), and you can choose to spray water on the back of the weld to accelerate cooling; all welds should be welded layer by layer and pass by pass, and it is forbidden to continuously weld multiple layers in one section of the weld; the weld layers and passes should be cleaned (grinded or brushed) to remove defects, oxide color, weld slag, etc.

[0055] Furthermore, before welding, in order to ensure welding safety, anti-spatter measures are set up, specifically including covering the bevel edge with an aluminum plate or stainless steel strip (width ≥ 60mm); and applying a special anti-spatter agent to both sides of the weld.

[0056] According to embodiments of the present invention, welding defects include one or a combination of two or more of the following: cracks, incomplete fusion defects, incomplete penetration defects, or undercut defects.

[0057] According to an embodiment of the present invention, step S4, "conducting physical and chemical property tests on the welded nickel-based alloy steel plate 1," specifically includes:

[0058] Stress testing was performed on the welded nickel-based alloy steel plate 1 after welding to obtain stress information;

[0059] Determine whether the stress information meets the mechanical performance requirements. If it does not, the stress test result of nickel-based alloy steel plate 1 is deemed unqualified.

[0060] If the mechanical performance requirements are met, the stress test result of nickel-based alloy steel plate 1 is deemed qualified.

[0061] According to an embodiment of the present invention, step S4, "conducting physical and chemical property tests on the welded nickel-based alloy steel plate 1," further includes:

[0062] The welded nickel-based alloy steel plate 1 was heated at 600 degrees Celsius after welding. After heating for a predetermined time, a tensile test was performed on the welded nickel-based alloy steel plate 1, and image information of the weld was collected in real time.

[0063] Extract image features at the weld seam and analyze the elongation data of nickel-based alloy steel plate 1 at the weld seam based on the image features;

[0064] Outputting a fracture test result according to a fracture test model input with stretch data;

[0065] Determining whether the fracture test result meets a preset test threshold;

[0066] If the threshold is met, the welding is qualified; if not, the welding is unqualified.

[0067] It should be noted that through the stretch test and real-time determination of whether fracture or cracks occur at the weld seam, the welding firmness at the weld seam is analyzed, whether welding is qualified is tested, and it is ensured that the welded nickel-base alloy steel plate 1 meets the requirements for use safety.

[0068] In conclusion, by providing a U-shaped narrow gap and V-shaped groove 2 type longitudinal seam, the consumption of argon welding wires and welding electrodes is low, linear defect detection is performed before welding, repeated grinding is performed during welding, which improves the welding effect. Meanwhile, physical and chemical performance testing is performed on the welding position after welding is completed, thereby ensuring that the welded nickel-base alloy steel plate 1 meets the requirements of stretch and stress tests, and improving the use safety of the welded nickel-base alloy steel plate 1.

[0069] The device embodiments described above are merely illustrative. For example, the division of units is merely a logical function division, and there may be other divisions in actual implementation, for example: multiple units or components may be combined or integrated into another system, or some features may be omitted or not implemented. In addition, the coupling, or direct coupling, or communication connection between the displayed or discussed components may be indirect coupling or communication connection of devices or units through some interfaces, and may be electrical, mechanical or other forms.

[0070] The units described above as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units; they may be located in one place or distributed over multiple network units; some or all of the units may be selected according to actual needs to achieve the purpose of the solution of the present embodiment.

[0071] In addition, all functional units in various embodiments of the present invention may be integrated into one processing unit, or each unit may be separately taken as one unit, or two or more units may be integrated into one unit; the above integrated unit may be implemented in the form of hardware, or may be implemented in the form of hardware plus software functional units.

[0072] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A welding method for thick nickel-based plates, characterized in that, Comprises the following steps: S1, subjecting a nickel-based alloy steel plate to groove processing, performing flaw detection, determining whether linear defects exist in the groove, performing grinding treatment if linear defects exist; arranging an arc starting plate in the groove if no linear defect exists; S2, performing backing welding on a weld by argon tungsten arc welding, then performing multi-layer welding on the groove by arc welding until the weld surface is flush with the surface of the nickel-based alloy steel plate; S3, grinding the surface of the nickel-based alloy steel plate, performing non-destructive testing after grinding is completed, and determining whether there are welding defects at the welded position of the weld; S4, grinding welding defects for multiple times if welding defects exist; performing physical and chemical performance tests on the welded nickel-based alloy steel plate if no welding defect exists; Pre-welding cleaning is required before "performing backing welding on the weld by argon tungsten arc welding" in step S2, and the pre-welding cleaning comprises: removing oxides, oil stains and chemical agents within the range of 50mm on both sides of the groove; The cleaning for removing oxides, oil stains and chemical agents specifically comprises: removing surface oxides by grinding with a stainless steel wire brush or a stainless steel wire wheel, an alumina or silica grinding wheel; removing oil stains, chemical agents and floating dust by cleaning and wiping with alcohol and silk cloth; welding must be performed within 4 hours after all cleaning is completed, otherwise pre-welding cleaning shall be performed again; The step S2 "performing backing welding on the weld by argon tungsten arc welding, then performing multi-layer welding on the groove by arc welding until the weld surface is flush with the surface of the nickel-based alloy steel plate" specifically comprises: welding the weld by argon tungsten arc welding to form a backing layer, performing linear defect detection by using a PT detection reagent, and removing the detection reagent by wiping with alcohol or a cleaning agent and silk cloth after detection is completed before performing welding of the next layer; performing multi-layer welding filling on a V-shaped groove and a U-shaped groove respectively by using welding electrodes to form a plurality of welding layers, performing alternate welding on the welding layers in the V-shaped groove and the U-shaped groove, and grinding the arc closing position of each welding layer to remove defects, oxide color and welding slag; a power supply adopts a constant voltage mode in the welding process; "Performing physical and chemical performance tests on the welded nickel-based alloy steel plate" in step S4 specifically comprises: performing a stress test on the welded nickel-based alloy steel plate after welding is completed to obtain stress information; determining whether the stress information meets mechanical performance requirements, and determining that the stress test result of the nickel-based alloy steel plate is unqualified if the stress information does not meet the mechanical performance requirements; determining that the stress test result of the nickel-based alloy steel plate is qualified if the stress information meets the mechanical performance requirements; "Performing physical and chemical performance tests on the welded nickel-based alloy steel plate" in step S4 further comprises: placing the welded nickel-based alloy steel plate at a high temperature of 600 degrees Celsius for heating, after heating for a predetermined time, performing a tensile test on the welded nickel-based alloy steel plate, and collecting image information of the weld in real time; extracting image features of the weld, and analyzing elongation data of the nickel-based alloy steel plate at the weld according to the image features; inputting the elongation data into a fracture test model, and outputting a fracture test result; determining whether the fracture test result meets a preset test threshold; the welding is qualified if the fracture test result meets the preset test threshold; the welding is unqualified if the fracture test result does not meet the preset test threshold.

2. The welding method for thick nickel-based plates according to claim 1, characterized in that, The bevel includes U-shaped bevel and V-shaped bevel. The weld on the upper part of the nickel-based alloy steel plate is U-shaped bevel, and the weld on the lower part of the nickel-based alloy steel plate is V-shaped bevel.

3. The welding method for thick nickel-based plates according to claim 1, characterized in that, The welding defects include one or a combination of two or more of the following: cracks, lack of fusion, incomplete penetration, or undercut.

Images