Un-diluted non-heat reflowed filler metal tensile property test fixture and method

Abstract

The application provides a non-dilution non-reheat deposited metal tensile property test clamp and test method, and belongs to the technical field of welding. The technical problems of the prior art that no special test method for non-dilution non-reheat deposited metal is formed, the test result is distorted, and the original performance of the non-dilution non-reheat deposited metal cannot be accurately characterized are solved. The application eliminates the influence of the base material dilution and the weld bead reheating on the deposited metal performance from the source through the technical path of "double-layer isolation surfacing + wire cutting separation + micro sample tensile". The method comprises the following steps: a single-layer surfacing is performed on a pure deposited metal test block as a base to prepare a pure deposited metal test piece without dilution and reheating; a micro tensile sample is obtained; and a special micro tensile clamp and a high-precision extensometer are used to obtain a real stress-strain curve and intrinsic performance indexes such as tensile strength, yield strength and elongation after fracture. The method is operable, controllable and capable of effectively avoiding the influence of weld dilution and weld bead reheating on the deposited metal performance.

Description

Technical Field

[0001] This invention belongs to the field of welding technology, and in particular relates to a fixture and test method for testing the tensile properties of undiluted non-reheat-deposited metal. Background Technology

[0002] Against the backdrop of rapid development in materials genome engineering, advanced structural materials such as ultra-high strength steel and Invar alloys have become core materials for major projects including hydropower, LNG carriers, aerospace, nuclear power, hydrogen energy equipment, high-end engineering machinery, and marine vessels. Welding is a key process in the manufacturing of components for these high-end equipment. The intrinsic tensile properties of the weld metal deposited by the welding wire directly determine the scientific nature of the welding material formulation design, the rationality of the welding process, and the safety of the equipment in service.

[0003] Welded components are generally formed using multi-layer, multi-pass welding. The weld is highly susceptible to the combined effects of base metal dilution and weld bead reheating, leading to heterogeneity of the deposited metal microstructure and deterioration of its mechanical properties. Conventional test data cannot reflect the true performance of the weld metal deposited by the welding wire. Undiluted, unreheated single-pass weld metal is the most direct and authentic carrier of the original performance of the welding wire. Its accurate tensile performance data is the core foundation for building a welding wire composition-process-microstructure-performance database, realizing digital design of welding wires, high-throughput R&D, and precise control of microstructure and performance. It is also a key support for the independent R&D of welding consumables for advanced structural materials.

[0004] There is a fundamental technological gap in the industry: there is no dedicated tensile testing device or standardized testing method for undiluted, non-reheating weld metal, and conventional testing techniques have key deficiencies. On the one hand, conventional methods all use samples affected by dilution and reheating, which cannot eliminate interfering factors. The tensile data obtained cannot characterize the intrinsic properties of the weld metal and are difficult to support the digital design and accurate performance prediction of welding wire. On the other hand, undiluted, non-reheating weld metal has a thin surface layer structure. Conventional devices cannot achieve stable formation, reliable clamping, and precise alignment of the thin surface weld layer. Sample clamping is prone to slippage and force eccentricity, resulting in distorted tensile data with large dispersion, which completely fails to meet the accuracy requirements of high-end welding material research and development and welding process qualification for major equipment.

[0005] Therefore, developing a testing device and method for the tensile properties of undiluted, non-regenerative heat-deposited metal fills the gap in industry-specific testing technologies, accurately obtains the intrinsic tensile properties of the deposited metal, supports the digital design, high-throughput preparation, and database construction of welding wire, and accelerates the independent R&D process of high-end welding materials; it can also cover applications in all scenarios such as nuclear power, petrochemicals, aerospace, shipbuilding, hydrogen energy equipment, and hydropower projects, providing core data support for welding material R&D verification, process qualification, and in-service testing; furthermore, it can promote the transformation of welding material R&D from experience-based trial and error to data-driven, reduce R&D energy consumption and carbon emissions, and help upgrade the localization of high-end manufacturing, which has irreplaceable engineering application value and significance. Summary of the Invention

[0006] The purpose of this invention is to overcome the technical problems in the prior art, such as the lack of a dedicated testing method for undiluted, non-reheat weld metal, distorted test results, and inability to accurately characterize its original properties. This invention provides a tensile property testing fixture and method for undiluted, non-reheat weld metal. This method is standardized, highly controllable, and can effectively avoid the influence of weld dilution and weld reheating on the properties of the weld metal. It accurately obtains the true tensile property data of undiluted, non-reheat weld metal, providing reliable test support for welding material development, welding process qualification, and the safe operation of high-end equipment.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a method for testing the tensile properties of undiluted, non-rebound heat-fused metals. Step S1: Substrate preparation: Select a substrate of the same material as the welding material to be tested for overlay welding, and obtain a pure weld metal substrate test block after removing the substrate; Step S2: Preparation of target weld layer: Only one weld layer is deposited on the pure weld metal substrate, and then the weld is separated from the substrate to obtain an undiluted, unreheated pure weld metal specimen; Step S3: Sample preparation: The pure weld metal specimen is processed into a miniature tensile specimen; Step S4: Tensile test: The specimen is clamped with a fixture adapted to the micro specimen and stretched at a set rate on an electronic tensile testing machine until it breaks. Load and strain data are collected to obtain tensile performance indicators.

[0008] Preferably, in step S1, the pure fused metal substrate test block has a size of 100 mm × 50 mm × 20 mm, and its surface flatness and roughness meet the requirements of precision surfacing.

[0009] Preferably, in step S2, the single-pass welding strictly adopts the welding process parameters consistent with the actual project, and no subsequent welding passes are applied to avoid the effects of reheating.

[0010] Preferably, in step S3, the dimensional tolerance of the parallel length segment of the micro tensile specimen does not exceed ±0.05 mm, and the surface roughness Ra ≤ 1.6 μm.

[0011] Preferably, in step S4, the stretching rate v is calculated according to the formula... v = e×L c × 60 calculations, of which e For strain rate, L c is the parallel length of the sample.

[0012] A fixture for a tensile property test method of undiluted, non-rebound heat-deposited metal includes a clamping end, a tensile positioning hole, a support platform, a fixing plate, and bolts; the clamping end is used to connect to an electronic tensile testing machine; the support platform is used to support the clamping part of the specimen; the fixing plate presses and fixes the specimen to the support platform by bolts; the tensile positioning hole is used to ensure that the specimen axis is coaxial with the direction of tensile force.

[0013] Preferably, the fixture is suitable for miniature tensile specimens with a total length of 10 to 50 mm.

[0014] Compared with the prior art, the beneficial effects of the tensile property testing fixture and method for undiluted, non-rebound heat-deposited metals described in this invention are: 1. This invention establishes a complete evaluation chain, from the preparation of undiluted, weightless heat-fused metal specimens and verification of specimen integrity to the standardized implementation of tensile testing, and finally to the precise analysis of tensile test data and extraction of performance indicators. The evaluation indicators cover multiple key dimensions such as the tensile strength, yield strength, and elongation after fracture of the fused metal. In particular, by conducting tensile tests on specially prepared specimens, the true values ​​of each performance indicator are accurately obtained, providing quantitative and accurate evaluation criteria for the tensile properties of undiluted, weightless heat-fused metals.

[0015] 2. Compared with the existing technology, which lacks an effective evaluation method for the tensile properties of undiluted non-gravity heat-fused metals and cannot accurately obtain their true tensile properties, the method described in this invention solves for the first time the technical problem of the difficulty in accurately obtaining the tensile properties of undiluted non-gravity heat-fused metals. It significantly improves the accuracy, reliability and engineering guidance value of the evaluation results, and provides solid technical support for the performance evaluation, process optimization and engineering application of related heat-fused metals. Attached Figure Description

[0016] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 A schematic diagram showing the sampling locations for undiluted, non-reheat-deposited metal specimens. Figure 2 for Figure 1 Top view; Figure 3 Drawings of miniature tensile specimens; Figure 4 This is a schematic diagram of the structure of a miniature tension clamp; Figure 5 for Figure 4 The right view; Figure 6 Stress-strain curve of undiluted, non-reheat-deposited metal of a certain nickel-based alloy welding material under tensile test. Figure 7 Stress-strain curve of undiluted, non-reheat-deposited metal of a certain nickel-based alloy welding material under tensile test. Figure 6 and Figure 7 The images are all tensile stress-strain curves of undiluted, non-reheated weld metals of a certain nickel-based alloy weld metal, the difference being their size specifications.

[0017] In the diagram: 1-clamping end, 2-tension positioning hole, 3-support platform, 4-bolt, 5-fixing pressure plate. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the drawings, and not all of them. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the invention.

[0019] Specific Implementation Example 1: See Figure 1-3 as well as Figure 6-7 This embodiment describes a method for testing the tensile properties of undiluted, non-rebound heat-deposited metals. Step 1: Select a base material and welding material that are completely identical to the material of the weld metal to be tested. Strictly follow the welding process parameters of the actual engineering scenario and carry out weld metal surfacing on the surface of the base material to complete the initial formation of the weld metal layer. After the surfacing operation is completed, the formed weld metal layer is processed through multiple processes. First, the base material is completely removed by precision cutting, leaving only the pure weld metal material. Then, the upper and lower surfaces of the test block are ground and trimmed by precision grinding. Finally, a rectangular pure weld metal substrate test block with the dimensions of 100mm (length) × 50mm (width) × 20mm (thickness) after removing the base material is formed. During the processing, it is necessary to ensure that the surface of the test block is flat and smooth, without obvious unevenness, pores, cracks and other defects. The surface flatness meets the test standard requirements, providing a flat, clean and impurity-free working surface for subsequent secondary surfacing operations, and ensuring the accuracy of subsequent tests.

[0020] Step 2: Preparation of the Target Welded Metal Layer: Using the welded metal substrate from Step 1, which has been precisely machined and free of substrate interference, as a reference, welding materials consistent with the welded metal to be tested are selected. The target welded metal layer is deposited only once, strictly following the preset welding process parameters (including current, voltage, shielding gas flow rate, etc.). This welding process uses a pure welded metal substrate as the new base material, with the core objective of eliminating weld dilution from its source. By depositing only one layer, the interference of weld dilution and weld reheating on the weld metal properties is completely avoided, ensuring that the target welded layer is a pure welded material without any additional heat effects, truly achieving the test requirements of no reheating and no dilution. After the weld overlay is completed, the surface of the weld bead is first precision machined to ensure it is level and flat, without any protrusions or depressions. Then, wire cutting is used to completely separate the weld overlay layer from the pure weld metal substrate (new substrate), resulting in a pure weld metal specimen. This specimen has a thickness of not less than 1 mm, a width of not less than 10 mm, and a length greater than 50 mm. It is also free from any dilution or reheating interference, and is a pure weld metal specimen without dilution or reheating (e.g., ...). Figure 1-2 As shown in the figure, this serves as the basis for the processing of samples for subsequent tests, ensuring that the samples used in subsequent tests are standard specimens that are undiluted and not reheated.

[0021] Step 3: Tensile Specimen Preparation: The pure welded metal specimen obtained in Step 2 is precision machined into miniature tensile specimens that meet the test standards (e.g., Figure 3 As shown in the figure, the specific processing flow is as follows: The processing method can be flexibly selected according to the actual processing conditions. Precision turning process can be used to remove burrs and wire cutting residue on the surface of the specimen, initially process the specimen outline and reserve 0.2~0.3mm for finishing; or precision grinding process can be used directly for finishing without turning steps; after processing, the size and surface quality of the specimen are inspected to ensure that the dimensional accuracy deviation of the parallel length section of the specimen does not exceed ±0.05mm and the surface roughness is controlled within Ra≤1.6μm to ensure that it meets the test standards.

[0022] Step 4: Matching fixture: Suitable for tensile testing of various micro specimens with a total length of 10~50mm, which can realize stable clamping and precise positioning of micro specimens.

[0023] Step 5: Test Procedure: After assembling the clamp holding the specimen into the electronic tensile testing machine, set the test parameters. Accurately calculate the tensile test rate based on the parallel length parameter of the miniature specimen, and establish the test rate calculation formula: v = e×L c×60, where v is the displacement rate of the beam. e The strain rate (the strain rate is selected in accordance with the requirements of GB / T 228.1). Lc represents the parallel length of the specimen. The tensile test is conducted at the calculated test rate until the specimen breaks. Simultaneously, an extensometer capable of meeting the testing requirements of micro tensile specimens (such as a video extensometer or a laser extensometer) is used to collect the specimen strain in real time. Combined with the load data fed back by the electronic tensile testing machine, the stress-strain curve is accurately obtained, and the true tensile performance indicators of the undiluted non-reheat-welded metal are obtained at the same time. This provides accurate and reliable test data support for subsequent performance evaluation of the welded metal, optimization of welding processes, and related technology research.

[0024] Example 1: According to step 1 of the invention, a nickel-based alloy welding wire and substrate of the same material as the weld metal to be tested are selected. According to step 1 of the invention, the weld metal layer is deposited by following the actual engineering welding process parameters. After precision cutting to remove the substrate and precision grinding and finishing, a pure weld metal substrate test block of 100mm×50mm×20mm is made to ensure that the surface is free of defects and that the flatness and roughness meet the standards.

[0025] According to step 2 of the invention, using a pure weld metal substrate as a reference, a target weld layer is deposited in a single pass using welding wire of the same material according to preset process parameters. After precision machining and finishing, wire cutting is used to separate undiluted, non-reheating pure weld metal specimens with a thickness ≥1mm, width ≥10mm, and length >50mm (e.g., ...). Figure 1-2 (As shown).

[0026] According to step 3 of the invention, the above-mentioned specimen is precisely machined into a micro tensile specimen that meets the standard (e.g., Figure 3 (As shown); the inspection ensures that the dimensional deviation of the parallel length segment is ≤ ±0.05 mm and the surface roughness Ra is ≤ 1.6 μm.

[0027] According to step 4 of the invention, the miniature tensile specimen is installed in the matching fixture: the specimen clamping end is placed on the support platform, the test part passes through the positioning hole, and after being fixed by the fixing plate and bolts, it is connected to the electronic tensile testing machine through the clamping end of the fixture.

[0028] Perform a tensile test according to step 5 of the invention: set parameters, based on the parallel length of the specimen, and using the formula v= e×L c×60 (e is the strain rate, selected according to GB / T 228.1), the calculated test rate is 0.375 mm / min; the specimen is stretched until fracture, and strain is collected using a video extensometer. The stress-strain curve and relevant tensile property parameters (such as...) are obtained by combining the load data. Figure 6-7 (As shown).

[0029] Specific Implementation Example 2: See Figure 4-5This embodiment describes a tensile test fixture for undiluted, weightless heat-fused metals. The matching tensile fixture includes a clamping end 1, a tensile positioning hole 2, a support platform 3, bolts 4, and a fixing plate 5. The tensile positioning hole 2, the support platform 3, and the clamping end 1 are an integral, non-removable structure. The fixing plate 4 and bolts 5 are used to fix the installation of the specimen. The clamping end 1 is used to connect to an electronic tensile testing machine.

[0030] The embodiments of the present invention disclosed above are merely illustrative of the invention. These embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Many modifications and variations can be made based on the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A method for testing the tensile properties of undiluted, non-repressed hot-melt metals, characterized in that: Step S1: Substrate preparation: Select a substrate of the same material as the welding material to be tested for overlay welding, and obtain a pure weld metal substrate test block after removing the substrate; Step S2: Preparation of target weld layer: Only one weld layer is deposited on the pure weld metal substrate, and then the weld is separated from the substrate to obtain an undiluted, unreheated pure weld metal specimen; Step S3: Sample preparation: The pure weld metal specimen is processed into a miniature tensile specimen; Step S4: Tensile test: The specimen is clamped with a fixture adapted to the micro specimen and stretched at a set rate on an electronic tensile testing machine until it breaks. Load and strain data are collected to obtain tensile performance indicators.

2. The method for testing the tensile properties of undiluted, non-rebound heat-fused metals according to claim 1, characterized in that: In step S1, the pure fused metal substrate test block has dimensions of 100 mm × 50 mm × 20 mm, and its surface flatness and roughness meet the requirements for precision surfacing.

3. The method for testing the tensile properties of undiluted, non-rebound heat-fused metals according to claim 1, characterized in that: In step S2, the single-pass welding strictly adopts the welding process parameters consistent with the actual project, and no subsequent welding passes are applied to avoid the effects of reheating.

4. The method for testing the tensile properties of undiluted, non-repressed hot-melt metals according to claim 1, characterized in that: In step S3, the dimensional tolerance of the parallel length segment of the micro tensile specimen does not exceed ±0.05 mm, and the surface roughness Ra ≤ 1.6 μm.

5. The method for testing the tensile properties of undiluted, non-repressed hot-melt metals according to claim 1, characterized in that: In step S4, the stretching rate v is calculated according to the formula v = e×Lc Calculated by ×60, where e For strain rate, Lc The parallel length of the sample.

6. A fixture used in the tensile property testing method for undiluted, non-repressed hot-melt metals as described in any one of claims 1-5, characterized in that: It includes a clamping end (1), a tensile positioning hole (2), a support platform (3), a fixing plate (5), and bolts (4); the clamping end (1) is used to connect to an electronic tensile testing machine; the support platform (3) is used to support the clamping part of the specimen; the fixing plate (5) uses bolts (4) to press and fix the specimen on the support platform (3); the tensile positioning hole (2) is used to ensure that the specimen axis is coaxial with the tensile force direction.

7. The fixture used in the tensile property test method for undiluted, non-repressed hot-melt metals according to claim 6, characterized in that: The fixture is suitable for miniature tensile specimens with a total length of 10 to 50 mm.

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