Method for improving accuracy of test panel welding test performance result

Abstract

The invention discloses a method for improving test panel welding test performance result accuracy. The method comprises the following steps that temperature measuring points C are sequentially arranged outwards perpendicular to a workpiece welding seam, and temperature measuring devices are installed at the temperature measuring points C; welding the workpiece, and recording a temperature curve of the workpiece until the temperature of the temperature measuring point C is cooled to 50 DEG C; temperature measuring points C'are sequentially arranged outwards in a manner of being perpendicular to the weld joint of the test plate, and temperature measuring devices are mounted at the temperature measuring points C '; the temperature measuring point C'of the test plate corresponds to the temperature measuring point C of the workpiece, and the distances between the correspondingly arranged temperature measuring points and the center of the welding seam are equal; the test plate is welded, the test plate is rapidly cooled through an accelerated heat conduction device, and the welding temperature is recorded till the temperature of a temperature measuring point C'is cooled to 50 DEG C; the peak temperature of the temperature measuring point and the time for cooling the peak temperature of the temperature measuring point to 50 DEG C are the same or similar; and carrying out physical and chemical property test on the welded test plate. The method has the beneficial effects that the impact toughness of the test plate is similar to that of a workpiece, and the method is used for guiding field production line welding process design and optimization.

Description

Technical Field

[0001] This invention relates to a test plate welding method, and more particularly to a method for improving the accuracy of test plate welding performance results, belonging to the field of welding technology. Background Technology

[0002] Multi-wire submerged arc welding is a highly efficient welding process. Its main characteristic is the simultaneous welding of two or more welding wires within the bevel or gap of the steel plate. Through the melting of the welding wires and the base metal, the steel plates are metallurgically bonded, resulting in welds with significant depth and width. The weld is protected by flux during the welding process, resulting in welds with excellent appearance and internal quality. Multi-wire submerged arc welding is characterized by high cladding efficiency and stable quality, and is widely used in the manufacturing of steel structures, bridges, ships, pressure vessels, and large-diameter steel pipes, as well as other applications involving the welding of thick-walled steel plates.

[0003] Multi-wire submerged arc welding technology typically employs high welding current and voltage, along with slow welding speeds. This results in a significant heat input during the welding process, meaning the steel plate experiences substantial heat per unit distance. Consequently, a large temperature gradient exists between the molten weld metal and the unmelted areas near the weld, leading to severe metal growth during solidification and significantly impacting the weld's strength and toughness. Simultaneously, the heat-affected zone (HAZ) metal adjacent to the molten area is also subjected to thermal effects during welding, causing abnormal growth and phase transformation in the base metal structure, resulting in a severe reduction in weld impact toughness.

[0004] Welding tests are a crucial means of innovating and optimizing welding processes. Welding tests on actual products conducted on the production line most closely resemble those in mass production, yielding accurate data and the best results. However, they occupy production line equipment and personnel, significantly impacting production line rhythm and resulting in high overall testing costs. Especially during new product trials and welding process qualification, waiting for experimental results can lead to production stoppages and substantial losses. Laboratories offer convenient access to welding tests. Ideally, laboratories can conduct welding tests on small-scale test plates to determine optimal welding materials and guide production line process optimization.

[0005] Due to limitations such as space constraints and economic considerations, laboratory welding tests often use small steel plates cut from actual products for fixed-position welding tests. The main process is as follows:

[0006] 1. Assemble and weld the beveled test plates according to the requirements;

[0007] 2. Place the assembled and welded steel plates on the welding platform and perform welding on one side first;

[0008] 3. If the process requires, for steel plates that have been welded on one side, flip the test plate over and weld the other side.

[0009] 4. For the welded steel plates, perform sample processing and conduct physical and chemical property tests such as tensile strength and impact toughness.

[0010] Currently, due to the significant differences in heat dissipation conditions between laboratory welding of small-sized test plates and on-site large-sized workpieces, and the substantial differences in impact toughness test results between small-sized test plate welding and actual on-site large-sized welded products, laboratory welding tests of small-sized test plates are not very helpful for optimizing the welding process of production line products. Summary of the Invention

[0011] To overcome the shortcomings of existing small-sized welding test plates, which have large deviations from the impact toughness test results of actual large-sized workpieces on the production line due to different heat dissipation conditions, and the poor accuracy of test plates in guiding the optimization of welding processes for production line products, this invention provides a method to improve the accuracy of welding test performance results of test plates.

[0012] The technical solution adopted by the present invention to solve its technical problem is: a method for improving the accuracy of welding test performance results of test plates, including a workpiece and a test plate, wherein the workpiece and the test plate are made of the same material, have the same steel plate thickness, and use the same welding process, welding wire and flux;

[0013] The steps for the test plate welding performance method are as follows:

[0014] S1. The weld seam of the workpiece to be welded is parallel to the length direction. Two or more temperature measuring points C are set in the direction perpendicular to the weld seam and outward from the weld seam. Each temperature measuring point C is equipped with a temperature measuring device.

[0015] S2. Welding workpiece, the temperature measuring device records the workpiece temperature curve in real time until the temperature of the workpiece measuring point C cools down to 50℃, then stops collecting temperature data.

[0016] S3. The weld seam of the test plate to be welded is parallel to the length direction. Two or more temperature measuring points C' are set in the direction perpendicular to the weld seam and outward from the weld seam. Each temperature measuring point C' is equipped with a temperature measuring device.

[0017] The temperature measuring point C' of the test plate is set to correspond to the temperature measuring point C of the workpiece, and the corresponding temperature measuring points are equidistant from the center of the weld.

[0018] S4. Welding test plate: The test plate is rapidly cooled by the accelerated heat conduction device. The temperature measuring device at the temperature measuring point records the welding temperature in real time until the temperature of the temperature measuring point C' of the test plate cools down to 50°C, at which point the temperature data acquisition stops. Ensure that the peak temperature of the temperature measuring point of comparison parameter I and the peak temperature of the temperature measuring point of comparison parameter II cool down to 50°C in the same or similar time.

[0019] S5. Conduct physical and chemical property tests on the welded test plates.

[0020] When the workpiece is subjected to double-sided welding, steps S1-S4 are repeated after step S4 to weld the other side of the test plate.

[0021] Furthermore, the comparison parameter I is the peak temperature T of the workpiece temperature measuring point C and the peak temperature T' of the corresponding test plate temperature measuring point C'; the comparison parameter II is the time t for the workpiece temperature measuring point C to cool from the peak temperature T to 50°C and the time t' for the test plate temperature measuring point C' to cool from the peak temperature T' to 50°C.

[0022] The difference between the peak temperature T of the workpiece temperature measuring point C and the peak temperature T' of the corresponding test plate temperature measuring point C' is ≤ ±35%.

[0023] The difference between the time t taken for the workpiece temperature measuring point C to cool from its peak temperature to 50°C and the time t taken for the test plate temperature measuring point C' to cool from its peak temperature to 50°C is ≤ ±20%.

[0024] The length a of the workpiece is greater than the length a' of the test plate.

[0025] The width / perimeter b of the workpiece is greater than the width / perimeter b' of the test plate.

[0026] The temperature measuring point C of the workpiece is set at 1 / 2a.

[0027] The temperature measurement point C' of the test plate is set at 1 / 2a'.

[0028] Both the workpiece and the test plate were welded using a multi-wire submerged arc welding process.

[0029] Furthermore, the temperature measuring device in steps S1 and S3 is a thermocouple.

[0030] The accelerated heat conduction device includes a metal heat conduction support and a flexible heat conduction material disposed above it. The flexible heat conduction material is disposed between the test plate and the test device. By adjusting the size of the flexible heat conduction material, the heat dissipation conditions during the welding process of the test plate are improved.

[0031] Furthermore, the flexible thermally conductive material is high thermal conductivity silicone rubber.

[0032] The beneficial effects of this invention are that by changing the heat dissipation conditions during the welding process of the welding test plate, the temperature measurement system monitors the heat dissipation effect in real time, ensuring that the cooling rate of the weld is similar under two different heat dissipation conditions for the workpiece and the test plate, and that the impact toughness of the welding test plate and the workpiece is similar. The test results of the test plate are used to guide the design and optimization of welding processes on the production line, thereby improving the accuracy of guiding the welding process of products on the production line. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the temperature measurement position for welding large-sized workpieces according to the present invention.

[0034] Figure 2 This is a schematic diagram of the temperature measurement position in the welding test of the test plate of the present invention.

[0035] Figure 3 This is a temperature curve of the inner welding temperature measurement point of the workpiece L360 steel pipe of the present invention.

[0036] Figure 4 This is a temperature curve of the inner welding (accelerated heat dissipation) temperature measurement point of the L360 welding test plate of the present invention.

[0037] Figure 5 This is a temperature curve of the external welding temperature measurement point of the L360 steel pipe workpiece of the present invention.

[0038] Figure 6 This is a temperature curve of the external welding (accelerated heat dissipation) temperature measurement point of the L360 welding test plate of the present invention.

[0039] Figure 7 This is a temperature curve of the inner welding (normal heat dissipation) temperature measurement point of the L360 welding test plate of the present invention.

[0040] Figure 8 This is a temperature curve of the external welding (normal heat dissipation) temperature measurement point of the L360 welding test plate of the present invention.

[0041] In the figure: 1. Thermocouple I, 2. Thermocouple II, 3. Thermocouple III, 4. Thermocouple IV, 5. Workpiece, 6. Workpiece weld, 11. Thermocouple I', 12. Thermocouple II', 13. Thermocouple III', 14. Thermocouple IV', 15. Test plate, 16. Test plate weld. Detailed Implementation

[0042] The present invention will be further described below with reference to the accompanying drawings and embodiments. However, those skilled in the art should understand that the present invention is not limited to the specific embodiments listed, and any embodiment that conforms to the spirit of the present invention should be included within the scope of protection of the present invention.

[0043] In the description of this invention, it should be noted that the terms "vertical", "up", "down", "left", "right", "horizontal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing or simplifying the description of this invention, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0044] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, a connection can be a fixed connection or a detachable connection; it can be a direct connection or an indirect connection, or an integral connection; it can be a mechanical connection or an indirect connection through an intermediate medium; it can also refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0045] See appendix Figure 1 , 2 This invention discloses a method for improving the accuracy of welding test results of test plates, comprising a workpiece 5 and a test plate 15, wherein the workpiece 5 and the test plate 15 are made of the same material, have the same steel plate thickness, and use the same welding process, welding wire, and flux. The workpiece 5 is a steel plate, or it can be a steel pipe to be welded formed by pressing or rolling a single steel plate.

[0046] The length of the workpiece 5 is a, the length of the test plate 15 is a', and a > a'; the width / perimeter of the workpiece 5 is b, the width / perimeter of the test plate 15 is b', and b > b'.

[0047] The steps for the test plate welding performance method are as follows:

[0048] S1. The weld seam 6 of the workpiece 5 to be welded is parallel to the length direction. Two or more temperature measuring points C are set in the direction perpendicular to the weld seam 6 and outward from the weld seam. Each temperature measuring point C is equipped with a temperature measuring device.

[0049] S2. Weld workpiece 5. The temperature measuring device records the workpiece temperature curve in real time until the temperature of the measuring point C of workpiece 5 cools down to 50℃, and then stops collecting temperature data.

[0050] S3. The weld 16 of the test plate 15 to be welded is parallel to the length direction. Two or more temperature measuring points C' are set in the direction perpendicular to the weld 16 of the test plate and outward from the weld. Each temperature measuring point C' is equipped with a temperature measuring device.

[0051] The temperature measuring point C' of the test plate 15 is set to correspond to the temperature measuring point C of the workpiece 5, and the corresponding temperature measuring points are equidistant from the center of the weld.

[0052] S4. Welding test plate 15: The test plate 15 is rapidly cooled by the accelerated heat conduction device. The temperature measuring device at the temperature measuring point C' records the welding temperature in real time until the temperature at the temperature measuring point C' of the test plate 15 cools down to 50°C, at which point the temperature data acquisition stops. Ensure that the peak temperature at the temperature measuring point of comparison parameter I and the peak temperature at the temperature measuring point of comparison parameter II cool down to 50°C in the same or similar time.

[0053] S5. Conduct physical and chemical property tests on the completed welding test plate 15.

[0054] When the workpiece 5 is double-sided welded, after step S4, steps S1-S4 are repeated to weld the other side of the test plate 15.

[0055] Furthermore, the comparison parameter I is the peak temperature T of the workpiece 5 temperature measuring point C and the peak temperature T' of the corresponding test plate 15 temperature measuring point C'; the comparison parameter II is the time t for the peak temperature of the workpiece 5 temperature measuring point C to cool down to 50°C and the time t' for the peak temperature of the test plate 15 temperature measuring point C' to cool down to 50°C.

[0056] Furthermore, the difference between the peak temperature T of the workpiece 5 temperature measuring point C and the peak temperature T' of the corresponding test plate 15 temperature measuring point C' is ≤ ±35%.

[0057] The difference between the time t taken for the peak temperature at temperature measurement point C of workpiece 5 to cool down to 50°C and the time t' taken for the peak temperature at temperature measurement point C' of test plate 15 to cool down to 50°C is ≤ ±20%.

[0058] Furthermore, the temperature measuring point C of the workpiece 5 is set at 1 / 2a; the temperature measuring point C' of the test plate 15 is set at 1 / 2a'.

[0059] Preferably, both the workpiece 5 and the test plate 15 are produced by multi-wire submerged arc welding, and bevels are provided at the weld seams of both the workpiece 5 and the test plate 15.

[0060] Furthermore, the temperature measuring device in steps S1 and S3 is a thermocouple.

[0061] In step S1, thermocouples I1, II2, III3, and IV4 are installed sequentially from the workpiece weld 6 outwards. The distances of thermocouples I1, II2, III3, and IV4 from the center of the workpiece weld 6 are CⅠ, CⅡ, CⅢ, and CⅣ, respectively (e.g., CⅠ, CⅡ, CⅢ, CⅣ). Figure 1 (As shown).

[0062] In step S3, thermocouples I'11, II'12, III'13, and IV'14 are installed sequentially outward from the test plate weld 16. The distances between thermocouples I'11, II'12, III'13, and IV'14 and the center of the test plate weld 16 are C1', C2', C3', and CIV', respectively (e.g., ...). Figure 2 As shown). Wherein:

[0063] The temperature measuring point C' of the test plate 15 is set to correspond to the temperature measuring point C of the workpiece 5, that is: CⅠ' = CⅠ, CⅡ' = CⅡ, CⅢ' = CⅢ, CⅣ' = CⅣ.

[0064] Furthermore, the accelerated heat conduction device includes a metal heat conduction support and a flexible heat conduction material disposed above it (the applicant has filed a separate patent application for the accelerated heat conduction device, which will not be described in detail here). The flexible heat conduction material is disposed between the test plate 15 and the test device. By adjusting the size of the flexible heat conduction material, the heat dissipation conditions of the test plate 15 during the welding process are improved, ensuring that the peak temperature of the temperature measurement point of comparison parameter I and the peak temperature of the temperature measurement point of comparison parameter II cool down to 50°C in the same or similar time.

[0065] The flexible thermally conductive material is high thermal conductivity silicone rubber.

[0066] Example:

[0067] by Taking L360 steel pipe as an example, the diameter of the steel pipe to be welded... The wall thickness is 14.3 mm. The welding process parameters are shown in Table 1. The same welding wire and flux are used.

[0068] Table 1 Welding process parameters for steel pipes and test plates

[0069]

[0070] The workpiece 5 is a steel pipe to be welded, which is formed by pressing and rolling a steel plate.

[0071] The length of the workpiece 5 is a = 1000 mm and b = 1595 mm.

[0072] The length of the test plate 15 is a' = 600mm and b' = 260mm.

[0073] Both workpiece 5 and test plate 15 have bevels at their weld seams, and the bevel dimensions are the same.

[0074] The steps for the test plate welding performance method are as follows:

[0075] S1. The workpiece 5 to be welded has a weld seam 6 that is parallel to the length direction. Four temperature measuring points C are set in a direction perpendicular to the workpiece weld seam 6 and outward from the weld seam. The four temperature measuring points C are respectively equipped with temperature measuring thermocouples by welding. The temperature measuring points C are set at 1 / 2a.

[0076] Four temperature measuring points C are set out sequentially from the weld seam 6 of the workpiece. The four temperature measuring points C are respectively equipped with thermocouples I1, II2, III3, and IV4. The distances of thermocouples I1, II2, III3, and IV4 from the center of the weld seam 6 are CⅠ, CⅡ, CⅢ, and CⅣ, respectively (e.g., ...). Figure 1 (As shown).

[0077] Specifically, CⅠ = 30mm, CⅡ = 60mm, CⅢ = 90mm, and CⅣ = 120mm.

[0078] S2. Weld workpiece 5 using multi-wire submerged arc welding. Temperature measuring thermocouples I1, II2, III3, and IV4 record the temperature curves of the workpiece 5 at each measuring point in real time during the welding process until the temperature at measuring point C of workpiece 5 cools to 50℃, at which point temperature data acquisition stops. Record the peak temperature T at each measuring point C and the time t it takes for the peak temperature at measuring point C of workpiece 5 to cool to 50℃ (e.g., ...). Figures 3-8 (As shown).

[0079] S3. The weld 16 of the test plate 15 to be welded is parallel to the length direction. Four temperature measuring points C' are set in a direction perpendicular to the weld 16 and outward from the weld. The four temperature measuring points C' are respectively installed with temperature measuring thermocouples by welding. The temperature measuring points C' are set at 1 / 2a'.

[0080] Four temperature measuring points C' are set out sequentially from the weld seam 16 of the test plate. The four temperature measuring points C' are respectively equipped with thermocouples I'11, II'12, III'13, and IV'14. The distances between thermocouples I'11, II'12, III'13, and IV'14 and the center of the weld seam 16 of the test plate are C1', C2', C3', and CIV', respectively (e.g., ...). Figure 2 (As shown).

[0081] The temperature measuring point C' of the test plate 15 is set to correspond to the temperature measuring point C of the workpiece 5. The corresponding temperature measuring points are equidistant from the center of the weld, that is: CⅠ' = CⅠ = 30mm, CⅡ' = CⅡ = 60mm, CⅢ' = CⅢ = 90mm, CⅣ' = CⅣ = 120mm.

[0082] S4. The test plate 15 is welded using a multi-wire submerged arc welding process, and the test plate 15 is rapidly cooled by an accelerated heat conduction device. The temperature measuring thermocouples I'11, II'12, III'13, and IV'14 record the welding temperature at the temperature measuring point C' in real time until the temperature at the temperature measuring point C' of the test plate 15 cools down to 50°C, at which point the temperature data acquisition stops.

[0083] During the test plate welding process, the difference between the peak temperature T of workpiece 5 temperature measuring point C and the corresponding peak temperature T' of test plate 15 temperature measuring point C' is ≤ ±35% by using an accelerated heat conduction device; the difference between the time t for the peak temperature 5 temperature measuring point C of comparison parameter II to cool to 50℃ and the time t' for the peak temperature 15 temperature measuring point C' to cool to 50℃ is ≤ ±20% (e.g., Figure 3 , 5 (As shown).

[0084] The workpiece 5 is welded on both sides. Steps S1-S4 are repeated to complete the welding of the other side of the workpiece 5 and the test plate 15.

[0085] S5. Impact toughness tests were conducted on workpiece 5 and test plate 15 respectively. The test results are shown in Tables 2 and 3.

[0086] The accelerated heat conduction device includes a metal heat-conducting support and a flexible heat-conducting material disposed above it. The flexible heat-conducting material is silicone rubber with high thermal conductivity. The flexible heat-conducting material is placed between the test plate 15 and the test device. By adjusting the size of the flexible heat-conducting material, the heat dissipation conditions during the welding process of the test plate 15 are improved, ensuring that the peak temperature at the temperature measurement point of comparison parameter I and the peak temperature at the temperature measurement point of comparison parameter II cool down to 50°C in the same or similar time.

[0087] To further illustrate the features of this invention, a test plate welding experiment was conducted under natural cooling conditions (without using flexible thermally conductive materials to accelerate cooling). The peak temperature at the corresponding temperature measurement point C″ was T″, and the time for the peak temperature at temperature measurement point C″ to cool down to 50°C was t″ (e.g., Figure 7 , 8 As shown in the figure, the corresponding data are listed in Tables 2 and 3. Through data comparison, it can be shown that the test results of the test plate using the method of the present invention can provide accurate guidance for the production line processing of large-size welded pipes.

[0088] Table 2 shows the peak temperature and cooling time to 50°C at the temperature measurement points of the steel pipe and test plate.

[0089]

[0090] Table 3 Results of Low-Temperature Impact Toughness Tests on Workpieces and Test Plates

[0091]

[0092] The data in Table 3 show that the low-temperature impact toughness results of the test plates welded by accelerated cooling are similar to those of the normally processed workpieces, with an error of less than 10%; while the test plates welded by natural cooling have an error of about one time compared with the low-temperature impact toughness test results of the production-processed workpieces.

[0093] Multiple test results show that when the difference between the peak temperature T of workpiece 5 temperature measuring point C and the peak temperature T' of the corresponding test plate 15 temperature measuring point C' is ≤±35%; and the difference between the time t of workpiece 5 temperature measuring point C' cooling to 50℃ and the time t' of test plate 15 temperature measuring point C' cooling to 50℃ is ≤±20%, the difference in impact toughness test results between the test plate and the workpiece is ≤10%. The test results of the test plate have accurate guiding significance for the welding process design and optimization of the product processing production line.

[0094] This invention provides a method to improve the accuracy of welding test results for test plates. It uses the peak temperature T at the corresponding temperature measurement point of a large workpiece and the welding test plate, and the time t for the peak temperature to cool to 50°C, as comparative parameters. By changing the heat dissipation conditions during the welding process, the cooling rates of the weld seam of the test plate and the workpiece are made similar under two different conditions. Through performance testing of the welding test plate, the obtained test plate exhibits impact toughness similar to that of the actual welded workpiece. This can be used to guide the design and optimization of welding processes on the production line, improving the accuracy of test plate data in guiding production.

[0095] It should be noted that the above embodiments are examples and not limitations of the present invention, and those skilled in the art will be able to design many alternative embodiments without departing from the scope of the claims of this patent.

Claims

1. A method for improving the accuracy of welding test results of test plates, comprising a workpiece and a test plate, characterized in that: The workpieces and test plates are made of the same material, have the same steel plate thickness, and use the same welding process, welding wire, and flux. The steps for the test plate welding performance method are as follows: S1. The weld seam of the workpiece to be welded is parallel to the length direction. Two or more temperature measuring points C are set in the direction perpendicular to the weld seam and outward from the weld seam. Each temperature measuring point C is equipped with a temperature measuring device. S2. Welding workpiece, the temperature measuring device records the workpiece temperature curve in real time until the temperature of the workpiece measuring point C cools down to 50℃, then stops collecting temperature data. S3. The weld seam of the test plate to be welded is parallel to the length direction. Two or more temperature measuring points C' are set in the direction perpendicular to the weld seam and outward from the weld seam. Each temperature measuring point C' is equipped with a temperature measuring device. The temperature measuring point C' of the test plate is set to correspond to the temperature measuring point C of the workpiece, and the corresponding temperature measuring points are equidistant from the center of the weld. S4. Welding test plate: The test plate is rapidly cooled by the accelerated heat conduction device. The temperature measuring device at the temperature measuring point records the welding temperature in real time until the temperature of the temperature measuring point C' of the test plate cools down to 50°C, at which point the temperature data acquisition stops. Ensure that the peak temperature of the temperature measuring point of comparison parameter I and the peak temperature of the temperature measuring point of comparison parameter II cool down to 50°C in the same or similar time. S5. Conduct physical and chemical property tests on the welded test plates.

2. The method for improving the accuracy of welding test results of test plates according to claim 1, characterized in that: When the workpiece is subjected to double-sided welding, steps S1-S4 are repeated after step S4 to weld the other side of the test plate.

3. The method for improving the accuracy of welding test results of test plates according to any one of claims 1-2, characterized in that: The comparison parameter I is the peak temperature T of the workpiece temperature measuring point C and the peak temperature T' of the corresponding test plate temperature measuring point C'. The comparison parameter II is the time t for the workpiece temperature measuring point C to cool from the peak temperature T to 50°C and the time t' for the test plate temperature measuring point C' to cool from the peak temperature T' to 50°C.

4. The method for improving the accuracy of welding test results of test plates according to claim 3, characterized in that: The difference between the peak temperature T of the workpiece temperature measuring point C and the peak temperature T' of the corresponding test plate temperature measuring point C' is ≤ ±35%. The difference between the time t taken for the workpiece temperature measuring point C to cool from its peak temperature to 50°C and the time t taken for the test plate temperature measuring point C' to cool from its peak temperature to 50°C is ≤ ±20%.

5. The method for improving the accuracy of welding test results of test plates according to claim 1, characterized in that: The length a of the workpiece is greater than the length a' of the test plate; The width / perimeter b of the workpiece is greater than the width / perimeter b' of the test plate.

6. The method for improving the accuracy of welding test results of test plates according to claim 5, characterized in that: The temperature measuring point C of the workpiece is set at 1 / 2a; The temperature measurement point C' of the test plate is set at 1 / 2a'.

7. The method for improving the accuracy of welding test results of test plates according to claim 6, characterized in that: Both the workpiece and the test plate were welded using a multi-wire submerged arc welding process.

8. The method for improving the accuracy of welding test results of test plates according to claim 1, characterized in that: The temperature measuring device in steps S1 and S3 is a thermocouple.

9. The method for improving the accuracy of welding test results of test plates according to claim 1, characterized in that: The accelerated heat conduction device includes a metal heat conduction support and a flexible heat conduction material disposed above it. The flexible heat conduction material is disposed between the test plate and the test device. By adjusting the size of the flexible heat conduction material, the heat dissipation conditions during the welding process of the test plate are improved.

10. The method for improving the accuracy of welding test results of test plates according to claim 9, characterized in that: The flexible thermally conductive material is high thermal conductivity silicone rubber.

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