Method and system for determining influence range of welding heat on heat resistance of low-temperature primer

Abstract

The invention provides a method and system for determining the influence range of welding heat on low-temperature primer heat resistance. The method comprises the steps that a simulated welding seam is built according to an actual welding structure; arranging n reference lines which are parallel to the simulated welding seam and are arranged at equal intervals on the surface of the plate; setting a temperature measuring point on each datum line; carrying out segmented welding on the welding seam according to a preset unit welding segment length, and recording the temperature value of the temperature measuring point; and determining a preselection result of the boundary line of the heat resistance influence range based on the temperature values of the temperature measurement points. According to the technical scheme, the datum lines and the temperature measuring points are arranged around the weld joint, the temperature is accurately measured, the influence range of the welding heat on the heat resistance of the low-temperature primer is determined, unnecessary grinding and repairing are reduced, resources are saved, and the construction efficiency is improved.

Description

Technical Field

[0001] The present application relates to the technical field of ship welding, and in particular to a method and system for determining the influence range of welding heat on the heat resistance of low-temperature primer. Background Art

[0002] During the construction of membrane-type LNG carriers, the integrity of the Mark_III containment system is one of the key technical indicators. In the later stages of cargo hold construction, process holes will be added to the inner hull plate on the side to improve the efficiency and convenience of construction, but at the same time it also brings corresponding difficulties. In the process of sealing the process holes, the welding heat generated will damage the low-temperature primer on the inner hull plate. Therefore, during the construction process, all primers on the edges of the process holes need to be removed, and the low-temperature primer must be reapplied after the process holes are sealed. Previously, there was no special method to determine the area where welding heat affects the heat resistance range of the low-temperature primer. It only relied on workers' experience and a spot temperature gun to test the area 300mm outside the edge of the process hole to ensure that the temperature in this area did not exceed 82°C.

[0003] Based on experience and point temperature guns, the protection of low-temperature primers during construction can indeed be met, but there are several shortcomings. First, the point temperature gun cannot continuously measure the temperature, and workers cannot ensure that the detection point always falls in one position during actual application. For steel plates, a deviation of several millimeters may produce a temperature difference of more than 10°C, and the accuracy of the measurement is difficult to guarantee. Secondly, the current guaranteed construction detection plan, that is, detection in the area 300mm outside the process hole, the point measurement temperature is basically below 60°C, which meets the requirements in terms of results, but this results in the area of ​​17.5㎡ for low-temperature primer grinding and then repairing, which not only wastes a lot of low-temperature primer and labor costs, but also makes it impossible to install the insulation box and corrugated plate in this area, affecting the integrity of the enclosure system and reducing construction efficiency. Finally, in the early construction process, the measurement area and measurement data were based on experience and handheld, and there were certain flaws in the accuracy and rationality of the data. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a method and system for determining the influence range of welding heat on the heat resistance of low-temperature primer. By setting multiple reference lines and temperature measuring points around the weld, the temperature is accurately measured to determine the influence range of welding heat on the heat resistance of low-temperature primer, thereby reducing unnecessary grinding and repairing, saving resources, and improving construction efficiency.

[0005] In a first aspect, a method for determining the influence range of welding heat on the heat resistance of a low-temperature primer is provided, comprising:

[0006] S0. According to the actual welding structure, use the same plate as the actual one to build the simulated weld;

[0007] S1. n reference lines with the same intervals and parallel to the simulated weld are set on the surface of the plate. The multiple reference lines are sequentially the first reference line, the second reference line, ... the nth reference line in the direction from close to the simulated weld to far away from the simulated weld;

[0008] S2. Set a temperature measurement point on each baseline; the temperature measurement point on the i-th baseline is Pi;

[0009] S3, welding the weld in sections according to the preset unit welding section length L, and recording the temperature value of the temperature measuring point; wherein the temperature value of the temperature measuring point Pi is recorded as Ti;

[0010] S4. Determine the preselected result of the boundary line of the heat resistance influence range based on the temperature value of the temperature measuring point; including:

[0011] Determine whether the temperature value Ti of the outermost temperature measurement point Pn is less than the preset heat resistance temperature value Tm;

[0012] If so, determine the temperature point T that is less than the preset heat resistance temperature value Tm and closest to the preset heat resistance temperature value Tm. x , temperature measuring point T x The xth reference line is used as the preselection result of the boundary line of the heat resistance influence range, where x = 1, 2, 3...n;

[0013] If not, reduce the value of the preset unit weld segment length L according to the preset interval difference, and repeat steps S3 to S4; if the preset unit weld segment length L is reduced to the lower limit value of the preset unit weld segment length, the temperature value Ti of the temperature measuring point Pn is still greater than or equal to the preset heat resistance temperature value Tm, increase the number of baselines, and repeat steps S2 to S4.

[0014] In an practicable solution, in step S4, after determining that the xth reference line where the temperature measurement point Tx is located is the pre-selected result of the boundary line of the heat resistance influence range, the method further includes:

[0015] S5. Verify and confirm the pre-selected results of the boundary line of the heat resistance influence range; including:

[0016] A plurality of calibration temperature measurement points with uniform spacing are set along the xth reference line; the calibration temperature measurement points are C1, C2...Cm;

[0017] During the segmented welding process, the temperature of the temperature measurement point is recorded; the temperature value of the temperature measurement point Ci is recorded as Ei;

[0018] Determine whether the temperatures of all the calibration temperature measurement points are less than the preset heat resistance temperature value Tm;

[0019] If yes, then determine the xth baseline as the final heat resistance impact range boundary line;

[0020] If not, the x+1th baseline is selected as the pre-selected result of the boundary line of the heat resistance influence range, and step S5 is repeated.

[0021] In an implementable solution, the number of the temperature measurement points to be checked is at least 3.

[0022] In an implementable solution, the number of the baselines is greater than or equal to three.

[0023] In an implementable solution, the interval between adjacent reference lines ranges from 20 to 70 mm.

[0024] In one feasible solution, the interval between adjacent reference lines is 50 mm.

[0025] In an implementable solution, the first reference line is 50 to 150 mm away from the simulated weld.

[0026] In an implementable solution, the preset unit welding section length L ranges from 300 to 500 mm.

[0027] In an implementable solution, in step S4 of "reducing the value of the preset unit welding segment length L according to the preset interval difference", the preset interval difference is 50 to 100 mm.

[0028] In a second aspect, a system for determining the influence range of welding heat on the heat resistance of low-temperature primer is also provided, comprising:

[0029] Simulate the plate and build a simulated weld that is identical to the actual weld;

[0030] A first thermocouple probe is provided on the surface of the simulated plate, and n reference lines with equal intervals are arranged parallel to the simulated welds, and a first thermocouple probe is installed on each simulated weld;

[0031] A first temperature display device, connected to the first thermocouple probes, for displaying the temperature measured by each first thermocouple probe;

[0032] The second thermocouple probe is configured to place at least three second thermocouple probes on the xth reference line in a uniformly spaced manner after determining that the xth reference line is a preselected result of a boundary line of a heat resistance influence range;

[0033] The second temperature display device is connected to the second thermocouple probes and is used to display the temperatures measured by each second thermocouple probe.

[0034] Compared with the prior art, the beneficial effects of this application are at least:

[0035] The method and system for determining the influence range of welding heat on the heat resistance of low-temperature primer of the present application, by setting multiple baselines near the weld and setting temperature measurement points on each baseline, by measuring the temperature of the temperature measurement points on the baseline, analyzing and determining the baseline of the influence range of welding heat on the heat resistance of low-temperature primer, and then determining the grinding and repairing area as the area within the determined baseline, effectively improves the accuracy of determining the influence range of welding heat on the heat resistance of low-temperature primer, reduces the grinding and repairing range of low-temperature primer, saves the consumption of low-temperature primer, is beneficial to environmental protection construction, reduces the construction volume, and improves construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present application, 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 application 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.

[0037] Figure 1 It is a flow chart of a method for determining the influence range of welding heat on the heat resistance of low-temperature primer according to an embodiment of the present application;

[0038] Figure 2 It is a schematic diagram of the composition of a system for determining the influence range of welding heat on the heat resistance of low-temperature primer according to an embodiment of the present application;

[0039] Figure 3 It is a structural schematic diagram of the transverse butt groove;

[0040] Figure 4 The schematic diagram of the weld layer arrangement of the horizontal butt groove is shown in FIG.

[0041] Figure 5 It is a structural schematic diagram of a vertical butt joint groove;

[0042] Figure 6 Schematic diagram of the weld layer layout of the vertical butt groove. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0045] like Figure 1 As shown, the embodiment of the present application first provides a method for determining the influence range of welding heat on the heat resistance of low-temperature primer, comprising:

[0046] S0, such as Figure 2 As shown, according to the actual welding structure, a simulated weld 101 is constructed using the same plate as the actual one;

[0047] S1, setting n reference lines 102 with the same intervals parallel to the simulated weld on the surface of the plate, and the multiple reference lines are sequentially the first reference line, the second reference line, ... the nth reference line in a direction from close to the simulated weld to far away from the simulated weld;

[0048] S2. Set a temperature measurement point on each reference line 102; wherein the temperature measurement point on the i-th reference line is P i ;

[0049] S3, perform segmented welding on the weld according to the preset unit welding section length L, and record the temperature value of the temperature measuring point; wherein the temperature measuring point P i The temperature value is recorded as T i ;

[0050] S4. Determine the preselected result of the boundary line of the heat resistance influence range based on the temperature value of the temperature measuring point; including:

[0051] Determine the outermost temperature measurement point P n Temperature value T i Is it less than the preset heat resistance temperature value T m size;

[0052] If so, it is determined that the temperature value is less than the preset heat resistance temperature value T m And it is closest to the preset heat resistance temperature value T m Temperature measurement point T x , temperature measuring point T x The xth reference line is used as the preselection result of the boundary line of the heat resistance influence range, where x = 1, 2, 3...n;

[0053] If not, the preset unit welding section length L is reduced according to the preset interval difference, and steps S3 to S4 are repeated; if the preset unit welding section length L is reduced to the lower limit of the preset unit welding section length, the temperature measuring point P n Temperature value T iStill greater than or equal to the preset heat resistance temperature value T m , then increase the number of baselines and repeat steps S2 to S4.

[0054] In this embodiment, if Figure 1 As shown, in step S4, the temperature measurement point T is determined x After the pre-selection result of the xth baseline being the boundary line of the heat resistance influence range, it also includes:

[0055] S5. Verify and confirm the pre-selected results of the boundary line of the heat resistance influence range; including:

[0056] Set multiple calibration temperature measurement points with uniform spacing along the xth reference line; the calibration temperature measurement point is C 1 , C 2 ……C m ;

[0057] During the segmented welding process, record the temperature of the temperature measurement point; among them, the temperature measurement point C i The temperature value is recorded as E i ;

[0058] Determine whether the temperature of all calibration temperature measurement points is less than the preset heat resistance temperature value T m size;

[0059] If yes, then determine the xth baseline as the final heat resistance impact range boundary line;

[0060] If not, the x+1th baseline is selected as the pre-selected result of the boundary line of the heat resistance influence range, and step S5 is repeated.

[0061] In this embodiment, the number of the verification temperature measurement points can be set to at least 3.

[0062] In this embodiment, the number of the reference lines may be greater than or equal to 3, for example, 3 or 4 may be initially set.

[0063] In this embodiment, the interval between adjacent reference lines ranges from 20 to 70 mm. In a preferred embodiment, the interval between adjacent reference lines is set to be less than or equal to 50 mm.

[0064] In this embodiment, the distance between the first reference line and the simulated weld may be 50-150 mm, for example, 50 mm, 80 mm, 100 mm, 120 mm, 150 mm, etc.

[0065] In this embodiment, the value range of the preset unit welding section length L may be 300-500 mm. In step S3, when performing the first segment welding, the value of the preset unit welding section length L may be 500 mm.

[0066] In this embodiment, in step S4 of "reducing the value of the preset unit weld segment length L according to the preset interval difference", the preset interval difference can be 50 to 100 mm, for example, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, etc.

[0067] like Figure 2 As shown, an embodiment of the present application provides a system for determining the influence range of welding heat on the heat resistance of low-temperature primer, comprising:

[0068] Simulating plate 1, building a simulated weld 101 that is the same as the actual weld;

[0069] A first thermocouple probe 2, wherein n reference lines 102 with the same intervals and parallel to the simulated welds 101 are arranged on the surface of the simulated plate 1, and one of the first thermocouple probes 2 is installed on each simulated weld 101;

[0070] a first temperature display device 3, connected to the first thermocouple probe 2, and used for displaying the temperature measured by each of the first thermocouple probes 2;

[0071] The second thermocouple probe 4, after determining that the xth reference line is a preselected result of the boundary line of the heat resistance influence range, at least three of the second thermocouple probes 4 are arranged on the xth reference line in a uniformly spaced manner;

[0072] The second temperature display device 5 is connected to the second thermocouple probes 4 and is used to display the temperatures measured by each of the second thermocouple probes 4 .

[0073] In order to explain the steps of the aforementioned technical solution and the effects that can be achieved in detail, the following actual experimental process and experimental data are provided.

[0074] First, in the welding of a certain grade of steel plate, the technical index of the heat resistance of the low-temperature primer is determined. According to the technical requirements of the primer (grade VP-186) used in the product, its continuous heating is ≯ (not greater than) 82°C, and intermittent heating is ≯ (not greater than) 93°C. That is, the preset heat resistance temperature value T in the aforementioned step S4 m The value range is not greater than 93℃.

[0075] like Figure 3 As shown in the figure, a simulated weld with a transverse butt groove is constructed using CO 2 Gas shielded single-sided horizontal butt welding, the groove angle is 25° at the upper mouth and 15° at the lower mouth, and the test plate assembly gap is 6mm. Figure 5 As shown in the figure, a simulated weld with a vertical butt weld groove is constructed using CO 2Gas shielded single-sided vertical butt welding, the groove angles on both sides are 20°, and the test plate assembly gap is 6mm. The welding material is a flux-cored wire with a diameter of 1.2mm. The welding process parameters are based on the actual ship construction parameters, and the specific data are shown in Table 1 below.

[0076] Table 1 Welding process parameters

[0077]

[0078] According to the steps S1 and S2 of this embodiment, refer to Figure 2 First, three reference lines are set at the weld. According to construction experience, the temperature rise caused by welding heat at 300mm from the weld edge is generally 50-60°C (the ambient temperature in the ship construction cabin is 23°C), so the distances of the three reference lines from the simulated weld are 100mm, 150mm, and 200mm from near to far. A temperature measurement point is set on each of the three reference lines. After setting, proceed to step S3 and step S4.

[0079] The welding process is strictly carried out according to the actual situation. The layout of the horizontal welding seam layers is as follows: Figure 4 As shown in the figure, the weld layer layout of vertical welding is as follows Figure 6 As shown, each weld is welded in sections with a length of 500 mm (preset unit welding section length L) during the first welding. Since the plate used in the experiment is made of low-carbon steel of ordinary strength, preheating and post-heat treatment are not required, and the inter-pass temperature of welding is controlled below 90°C.

[0080] During the welding process, monitor the data of the temperature detector. If the temperature of the detector on the 200mm baseline is greater than 82°C, stop welding. Reduce the length of the preset unit welding section L, and weld the next welding section as a separate welding section of 400mm. If the temperature still exceeds the standard, continue to reduce the welding section length to 300mm (the lower limit of the preset unit welding section length). If the temperature exceeds the standard during the welding process of the 300mm welding section, expand the temperature measurement baseline, increasing it by 50mm each time until the temperature meets the requirements.

[0081] In addition, during the welding process, it is determined that the temperature of the temperature measuring point on the 150mm reference line does not exceed the upper limit of heat resistance in horizontal welding and vertical welding, which is the reference line closest to the upper limit of heat resistance of the low-temperature primer. Therefore, three calibration temperature measuring points are arranged on the 150mm reference line. When recording the temperature of the calibration temperature measuring point, the maximum value of the three calibration temperature measuring points on the 150mm reference line or the average value of the three calibration temperature measuring points can be recorded.

[0082] During the horizontal and vertical welding process, record the maximum temperature data of each measurement reference line during each weld process. See Table 2 and Table 3 below. In the following table, the T1 column of each reference line represents the temperature measurement point P i The T2 column represents the temperature value obtained by verifying the temperature measurement point.

[0083] Table 2 Horizontal position butt welding temperature measurement record

[0084]

[0085] Table 3 Vertical position butt welding temperature measurement record

[0086]

[0087] From the above data, it can be confirmed that the 150mm baseline is the pre-selected result of the boundary line of the heat resistance influence range. After verification of the temperature measurement points, it is confirmed that the 150mm baseline is the final result of the boundary line of the heat resistance influence range.

[0088] Therefore, during the actual shipbuilding process, the area that needs to be polished and repaired after the cargo hold inner shell process door seal welding is within 150mm of the weld edge. The low-temperature primer polishing area is increased from 300mm of the original weld edge, which is equivalent to a total construction area of ​​17.5m 2 Reduced to 8.4m 2 This not only saves the consumption of low-temperature primer, which is beneficial to environmental protection construction, but also reduces the construction volume and improves construction efficiency. 2 Enclosure system construction can be carried out to further improve the paving integrity of the insulation layer and corrugated board.

[0089] In summary, the method and system for determining the influence range of welding heat on the heat resistance of low-temperature primer in this embodiment, by setting multiple baselines near the weld and setting temperature measurement points on each baseline, by measuring the temperature of the temperature measuring points on the baseline, analyzing and determining the baseline of the influence range of welding heat on the heat resistance of low-temperature primer, and then determining the grinding and repair area as the area within the determined baseline, effectively improves the accuracy of the identification of the influence range of welding heat on the heat resistance of low-temperature primer, reduces the grinding and repair range of low-temperature primer, saves the consumption of low-temperature primer, is beneficial to environmental protection construction, reduces the construction volume, and improves construction efficiency.

[0090] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for determining the influence range of welding heat on the heat resistance of low-temperature primer, characterized in that: include: S0. According to the actual welding structure, use the same plate as the actual one to build the simulated weld; S1. n reference lines with the same intervals and parallel to the simulated weld are set on the surface of the plate. The multiple reference lines are sequentially the first reference line, the second reference line, ... the nth reference line in the direction from close to the simulated weld to far away from the simulated weld; S2. Set a temperature measurement point on each baseline; the temperature measurement point on the i-th baseline is P i ; S3, welding the weld in sections according to the preset unit welding section length L, and recording the temperature value of the temperature measuring point; wherein the temperature measuring point P i The temperature value is recorded as T i ; S4. Determine the preselected result of the boundary line of the heat resistance influence range based on the temperature value of the temperature measuring point; including: Determine the outermost temperature measurement point P n Temperature value T i Is it less than the preset heat resistance temperature value T m size; If so, it is determined that the temperature value is less than the preset heat resistance temperature value T m And it is closest to the preset heat resistance temperature value T m Temperature measurement point T x , temperature measuring point T x The xth reference line is used as the preselection result of the boundary line of the heat resistance influence range, where x = 1, 2, 3...n; If not, the preset unit welding section length L is reduced according to the preset interval difference, and steps S3 to S4 are repeated; if the preset unit welding section length L is reduced to the lower limit of the preset unit welding section length, the temperature measuring point P n Temperature value T i Still greater than or equal to the preset heat resistance temperature value T m , then increase the number of baselines and repeat steps S2 to S4.

2. The method for determining the influence range of welding heat on the heat resistance of low-temperature primer according to claim 1, characterized in that: In step S4, the temperature measurement point T is determined. x After the pre-selection result of the xth baseline being the boundary line of the heat resistance influence range, it also includes: S5. Verify and confirm the pre-selected results of the boundary line of the heat resistance influence range; including: Set multiple calibration temperature measurement points with uniform spacing along the xth reference line; the calibration temperature measurement points are C1, C2...C m ; During the segmented welding process, record the temperature of the temperature measurement point; among them, the temperature measurement point C i The temperature value is recorded as E i ; Determine whether the temperature of all calibration temperature measurement points is less than the preset heat resistance temperature value T m size; If yes, then determine the xth baseline as the final heat resistance impact range boundary line; If not, the x+1th baseline is selected as the pre-selected result of the boundary line of the heat resistance influence range, and step S5 is repeated.

3. The method for determining the influence range of welding heat on the heat resistance of low-temperature primer according to claim 2, characterized in that: The number of the temperature measurement points to be checked is at least 3.

4. The method for determining the influence range of welding heat on the heat resistance of low-temperature primer according to claim 1 or 2, characterized in that: The number of the baselines is greater than or equal to 3.

5. The method for determining the influence range of welding heat on the heat resistance of low-temperature primer according to claim 4, characterized in that: The spacing between adjacent reference lines ranges from 20 to 70 mm.

6. The method for determining the influence range of welding heat on the heat resistance of low-temperature primer according to claim 4, characterized in that: The spacing between adjacent reference lines is 50 mm.

7. The method for determining the influence range of welding heat on the heat resistance of low-temperature primer according to claim 4, characterized in that: The distance between the first reference line and the simulated weld is 50 to 150 mm.

8. The method for determining the influence range of welding heat on the heat resistance of low-temperature primer according to claim 1 or 2, characterized in that: The preset unit welding section length L ranges from 300 to 500 mm.

9. The method for determining the influence range of welding heat on the heat resistance of low-temperature primer according to claim 8, characterized in that: In step S4, in "reducing the value of the preset unit welding segment length L according to the preset interval difference", the preset interval difference is 50 to 100 mm.

10. A system for determining the influence range of welding heat on the heat resistance of low-temperature primer, characterized in that: include: A simulated plate (1) is used to construct a simulated weld (101) that is identical to an actual weld; A first thermocouple probe (2) is provided on the surface of the simulated plate (1) with n reference lines (102) at equal intervals and parallel to the simulated welds (101), and one of the first thermocouple probes (2) is installed on each simulated weld (101); A first temperature display device (3), connected to the first thermocouple probe (2), and used for displaying the temperature measured by each of the first thermocouple probes (2); A second thermocouple probe (4), after determining that the xth reference line is a preselected result of the boundary line of the heat resistance influence range, at least three of the second thermocouple probes (4) are arranged on the xth reference line in a uniformly spaced manner; The second temperature display device (5) is connected to the second thermocouple probes (4) and is used to display the temperature measured by each of the second thermocouple probes (4).

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