A test method for optimizing the extrusion performance of a lead sheath for a submarine cable and a production method

Abstract

The application discloses a test method and a production method for optimizing the extrusion performance of a submarine cable lead sheath, and relates to the technical field of cable manufacturing test methods, and comprises the following steps: S1: in the production process of the lead sheath, setting a production speed V=V0; S2: formulating a process parameter table for producing the lead sheath; S3: selecting a column of process parameters in the process parameter table, adjusting an extrusion lead device, obtaining a current characteristic curve diagram of the extrusion lead device, and obtaining and recording an actual current difference AI according to the current characteristic curve diagram; S4: repeating step S3 until all records are completed; S5: comparing the actual current difference AI, obtaining a minimum AImin, and recording the process parameters corresponding to the production speed V and the AImin; S6: adjusting the production speed: V=V+AV; if VV', returning to step S2; if V>=V', entering the next step; and S7: counting the data recorded in step S5. The application solves the technical problem that the debugging mode of the existing lead sheath production process cannot meet the submarine cable production capacity demand.

Description

Technical Field

[0001] This invention relates to the field of cable manufacturing testing methods, and in particular to a testing method and production method for optimizing the extrusion performance of lead sheaths in submarine cables. Background Technology

[0002] Lead alloys, due to their high density and flexibility, are used as radial water-blocking layers in submarine cable structures, playing a crucial role in preventing water seepage. Currently, most submarine cable manufacturers use continuous extrusion processes to produce lead sheaths around the insulated cores. The sheaths should be continuous, smooth, crack-free, and have a uniform distribution of internal elements. Furthermore, the more stable the current during the extrusion process, the better the mechanical properties of the lead sheath. In traditional lead extrusion processes, the temperature settings for the extrusion equipment are relatively simple, not exceeding the range specified in the equipment manual. However, in reality, even for the same extrusion equipment, due to differences in the raw material suppliers and the varying elemental composition and grain properties of the lead ingots, occasional instability in extrusion pressure can occur when using the temperature parameters provided by the equipment manufacturer. This can lead to a drop in equipment current, causing fluctuations in lead sheath quality and even "lead stripping." Because lead sheath production must be continuous and uninterrupted, once "lead stripping" occurs, even if the stripped area is subsequently repaired, the quality of that area will never be as good as that of a intact lead sheath. In order to ensure the quality of the lead sheath, some submarine cable manufacturers have had to peel off the lead sheath that has already covered the core and start production again, which will greatly affect production costs and schedules, and also greatly limit the submarine cable manufacturers' ability to debug the lead sheath production process.

[0003] When debugging lead extrusion process parameters, existing submarine cable manufacturers often rely on past production experience. They first calculate the core advance speed based on the core specifications and lead output, and then adjust the temperature at individual locations within the parameter range provided by the equipment manufacturer, taking into account the appearance, outer diameter, and wall thickness of the lead sheath. This process debugging method involves simple parameter control and relatively simplistic evaluation standards for the lead sheath quality: whether the lead sheath's outer diameter, thinnest point thickness, and eccentricity value meet process requirements. This approach limits subsequent production speed because, in traditional debugging methods, production speed and lead output are fixed values ​​calculated based on the lead sheath's outer diameter, thickness, and other specifications, which significantly restricts submarine cable production capacity. Summary of the Invention

[0004] The purpose of this invention is to provide a test method and production method for optimizing the continuous extrusion performance of lead sheaths for submarine cables, which solves the technical problem that the debugging method of the lead sheath production process in the prior art cannot meet the production capacity requirements of submarine cables.

[0005] This application discloses a test method and a production method for optimizing the continuous extrusion performance of lead sheaths for submarine cables, including the following steps:

[0006] S1: In the production process of lead sheaths, the production speed is set to V = V0;

[0007] S2: Develop a process parameter table for producing lead sheaths;

[0008] S3: Select a column of process parameters from the process parameter table, adjust the temperature value of the lead extrusion device to the process parameter, obtain the current characteristic curve of the lead extrusion device, and obtain and record the actual current difference ΔI based on the current characteristic curve.

[0009] S4: Repeat step S3 until all actual current differences ΔI have been recorded;

[0010] S5: Compare the actual current difference ΔI to obtain the minimum actual current difference ΔImin, and record the process parameters corresponding to the production speed V and ΔImin;

[0011] S6: Adjust the production speed: V = V + ΔV; if V < V', return to step S2; if V ≥ V', proceed to the next step, where V' is the production speed limit.

[0012] S7: Compile the data recorded in step S5 into a statistical table.

[0013] This application embodiment can obtain suitable process parameters by detecting the current stability of the lead extrusion device, so as to provide a reference for subsequent lead sheath production.

[0014] Based on the above technical solution, the embodiments of this application can be further improved as follows:

[0015] Further, V0 is the initial speed, V0 = 1.8~2.0 m / min; ΔV is the adjustment range of the production speed, and ΔV = 0.2 m / min; V' is the production speed limit value, V' = 2.2 m / min~2.4 m / min.

[0016] Furthermore, the headers of the process parameter table in step S2 are, in order, number, starting temperature T1 of the feed pipe area, starting temperature T2 of the screw area, and starting temperature T3 of the die head area;

[0017] The temperature difference at the beginning of the feed pipe area between two adjacent rows of cells is ΔT1; the temperature difference at the beginning of the screw area between two adjacent rows of cells is ΔT2; the temperature difference at the beginning of the die head area between two adjacent rows of cells is ΔT3.

[0018] |ΔT1| is 0℃, 5℃, or 10℃; |ΔT2| is 0℃, 5℃, or 10℃; |ΔT3| is 0℃, 5℃, or 10℃.

[0019] Furthermore, 370℃≤T1≤380℃, 260℃≤T2≤270℃, 290℃≤T3≤300℃.

[0020] Furthermore, the specific steps in step S3 for obtaining the current characteristic curve of the lead extrusion device are as follows:

[0021] S301: Detect and record the current value of the lead extrusion device at the rated frequency;

[0022] S302: The current characteristic curve is formed by using the detection frequency in step 301 as the horizontal axis and the current value in step S301 as the vertical axis.

[0023] Furthermore, in step S301, the rated frequency is 60Hz; the detection time is 3-4 minutes; and the detection interval is 2-3 minutes.

[0024] Furthermore, in step S3, the actual current difference ΔI = Imax - Imin; where Imax is the maximum current value in the current characteristic curve diagram, and Imin is the minimum current value in the current characteristic curve diagram.

[0025] Furthermore, the process parameters include the starting temperature of the feed tube area, the starting temperature of the screw area, and the starting temperature of the die head area.

[0026] This application also discloses a production method for optimizing the extrusion performance of lead sheaths for submarine cables, comprising the following steps:

[0027] S1: The test was conducted using the aforementioned test method for optimizing the extrusion performance of the lead sheath of submarine cables;

[0028] S2: Calculate the production speed V based on production requirements, then compare it with the statistical table in step S1 to obtain the process parameters under the production speed V, adjust the temperature value of the lead extrusion device to the process parameters, and complete the production.

[0029] The one or more technical solutions provided in this application have at least the following technical effects or advantages:

[0030] 1. This application can determine the temperature range that has the greatest impact on the performance of lead sheaths, as well as the optimal matching temperature for different production speeds, providing a theoretical basis for the production and debugging of lead sheaths.

[0031] 2. After the data of this application is recorded, the corresponding equipment parameters can be quickly determined according to the statistical process parameter table, which can get rid of the limitations of traditional debugging methods on production capacity, while ensuring the quality of lead sheath. Attached Figure Description

[0032] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0033] Figure 1 This is a schematic flowchart of a test method for optimizing the continuous extrusion performance of lead sheaths for submarine cables, as described in a specific embodiment of the present invention.

[0034] Figure 2 Here are some current characteristic curves for a specific example;

[0035] Figure 3 The images shown are electron microscope images of two products in a specific example. Detailed Implementation

[0036] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0037] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0038] In the description of this application, it should be understood that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0039] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction 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.

[0040] To better understand the above technical solutions, the following will provide a detailed description of the technical solutions in conjunction with the accompanying drawings and specific embodiments.

[0041] Example 1:

[0042] This application discloses a test method and production method for optimizing the extrusion performance of lead sheaths for submarine cables. The method is used to detect and obtain the optimal process parameters during lead sheath production, and to use these process parameters in subsequent production processes to reduce lead stripping and eliminate the capacity limitations of existing debugging methods. The lead extrusion device in this application can be an existing lead extrusion device.

[0043] The specific steps are as follows:

[0044] S1: In the production process of lead sheaths, the production speed is set to V = V0;

[0045] V0 is the initial speed, V0 = 1.8~2.0 m / min; ΔV is the adjustment range of the production speed, and ΔV = 0.2 m / min; V' is the production speed limit value, V' = 2.2 m / min~2.4 m / min; where the value of V' can also be 2.4 m / min~3.0 m / min;

[0046] S2: Develop a process parameter table for producing lead sheaths;

[0047] In step S2, the header of the process parameter table is, in order, number, starting temperature T1 of the feed pipe area, starting temperature T2 of the screw area, and starting temperature T3 of the die head area.

[0048] The temperature difference at the beginning of the feed pipe area between two adjacent rows of cells is ΔT1; the temperature difference at the beginning of the screw area between two adjacent rows of cells is ΔT2; the temperature difference at the beginning of the die head area between two adjacent rows of cells is ΔT3.

[0049] |ΔT1| is 0℃, 5℃, or 10℃; |ΔT2| is 0℃, 5℃, or 10℃; |ΔT3| is 0℃, 5℃, or 10℃. This process parameter table is for easy subsequent machine adjustment. The adjustment range can be multiples of 0 or 5℃ to obtain more stable values.

[0050] Among them, 370℃≤T1≤380℃, 260℃≤T2≤270℃, and 290℃≤T3≤300℃, that is, T1, T2, and T3 are all set with limit values ​​to avoid wasting experimental resources;

[0051] S3: Select a column of process parameters from the process parameter table, adjust the temperature value of the lead extrusion unit to the specified process parameter, obtain the current characteristic curve of the lead extrusion unit, and obtain and record the actual current difference ΔI based on the current characteristic curve; specifically as follows:

[0052] S301: Detect and record the current value of the lead extrusion device at the rated frequency; the rated frequency in step S301 is 60Hz (i.e., 60 times in 1 second); the detection time is 3-4 minutes, and the detection interval is 2-3 minutes; the device used to detect the current value is the control host, the detection device and the display screen, which are existing detection equipment and will not be described in detail here, for the current value of the lead extrusion device.

[0053] S302: The current characteristic curve is formed with the detection frequency in step 301 as the horizontal axis and the current value in step S301 as the vertical axis.

[0054] In step S3, the actual current difference ΔI = Imax - Imin; where Imax is the maximum current value in the current characteristic curve diagram and Imin is the minimum current value in the current characteristic curve diagram.

[0055] S4: Repeat step S3 until all actual current differences ΔI have been recorded;

[0056] S5: Compare the actual current difference ΔI to obtain the minimum actual current difference ΔImin, and record the process parameters corresponding to the production speed V and ΔImin;

[0057] S6: Adjust the production speed: V = V + ΔV; if V < V', return to step S2; if V ≥ V', proceed to the next step, where V' is the production speed limit.

[0058] S7: Compile the data recorded in step S5 into a statistical table.

[0059] The process parameters described in this application include the starting temperature of the feed tube area, the starting temperature of the screw area, and the starting temperature of the die head area.

[0060] In the production process of lead sheaths, considering the fluidity of the metal (the fluidity of the metal is closely related to the temperature gradient, and temperature is the main driving force for changes in the metal's properties), the starting and ending temperatures of the feed tube area, the screw area, and the die head area are set and adjusted to obtain lead sheaths of better quality. Since the quality of the lead sheaths is related to the stability of the current, the quality of the lead sheaths produced under these process parameters can be obtained by detecting and comparing the stability of the current.

[0061] The starting and ending temperatures of the feed tube area are affected by the starting temperature T1 of the feed tube area, the starting and ending temperatures of the screw area are affected by the starting temperature T2 of the screw area, and the starting and ending temperatures of the die head area are affected by the starting temperature T3 of the die head area. Therefore, it is only necessary to perform detection and comparison under different T1, T2 and T3 conditions.

[0062] Then adjust the production speed again, repeat the above steps, until all production speed adjustments are completed and the corresponding process parameters are obtained, recorded, and tabulated to provide a basis for adjustments during subsequent actual production.

[0063] Example 2:

[0064] A method for producing a lead sheath for a cable includes the following steps:

[0065] S1: The experiment was conducted using Example 1;

[0066] S2: Calculate the production speed V based on production requirements, then compare it with the statistical table in step S1 to obtain the process parameters under the production speed V, adjust the temperature value of the lead extrusion device to the process parameters, and complete the production.

[0067] Specific examples:

[0068] With 220kV 3×630mm 2 Taking submarine cables as an example, according to GB / T 32346-2015, the nominal thickness of the lead sheath is 3.6mm, and the nominal outer diameter before lead extrusion is 91.3mm.

[0069] Production was carried out at a speed of 1.8 m / min, and the following table was obtained:

[0070] 1 370 260 290 1.437 2 370 260 295 1.893 3 370 260 300 1.710 4 370 265 290 1.581 5 370 265 295 1.340 6 370 265 300 1.329 7 370 270 290 1.652 8 370 270 295 1.415 9 370 270 300 1.124 10 375 260 290 2.190 11 375 260 295 1.681 12 375 260 300 1.907 13 375 265 290 2.080 14 375 265 295 2.069 15 375 265 300 1.601 16 375 270 290 1.245 17 375 270 295 1.192 18 375 270 300 1.664 19 380 260 290 1.592 20 380 260 295 1.394 21 380 260 300 2.538 22 380 265 290 1.088 23 380 265 295 1.322 24 380 265 300 1.593 25 380 270 290 1.037 26 380 270 295 0.991 27 380 270 300 1.170

[0071] Below is an example of four columns of data in a table:

[0072] Number 5: The starting temperature of the feed tube area is 370℃, the starting temperature of the screw area is 265℃, and the starting temperature of the die head area is 295℃; This yields... Figure 2 The current characteristic curve of .1;

[0073] Number 11: The starting temperature of the feed tube area is 375℃, the starting temperature of the screw area is 260℃, and the starting temperature of the die head area is 295℃; This yields... Figure 2 The current characteristic curve of .2;

[0074] Number 21: The starting temperature of the feed tube area is 380℃, the starting temperature of the screw area is 260℃, and the starting temperature of the die head area is 300℃; This yields... Figure 2 The current characteristic curve of .3;

[0075] Number 26: The starting temperature of the feed tube area is 380℃, the starting temperature of the screw area is 270℃, and the starting temperature of the die head area is 295℃; This yields... Figure 2 The current characteristic curve of .4;

[0076] about Figure 2The current characteristic curve of .1 shows fluctuations of decreasing and then rising, and the fluctuation of the current value is too large, with an actual current difference ΔI = 1.340A;

[0077] about Figure 2 The current characteristic curve of .2 shows that the overall current value is too large and there is a sudden increase. At the same time, the actual current difference ΔI = 1.681A.

[0078] about Figure 2 The current characteristic curve of .3 shows that the current rises rapidly and then drops instantly, with a large fluctuation range. The actual current difference ΔI = 2.538A.

[0079] about Figure 2 The current characteristic curve of .4 shows that the overall trend of change is stable over a long period of time, without any upward or downward slope. The actual current difference ΔI = 0.991A is the minimum value and relatively stable.

[0080] Further scanning electron microscopy was used to observe the elemental distribution and presence of cracks inside the lead sheaths of the above-mentioned test groups. Figure 2 .3 and Figure 2 .4 Scanning electron microscope images as shown Figure 3 As shown in the figure. Figure 2 The elemental distribution of the product sample is as follows: .4 Figure 3 As shown in Figure 2, it is uniform and without cracks; while Figure 2 The elemental distribution of the product sample is as follows: .3 Figure 3 As shown in Figure 1, internal cracks were observed, and alloying elements were mostly distributed near the cracks. The results indicate that changes in the current curve can reflect the quality of the lead sheath; a more stable current curve indicates better quality, and vice versa.

[0081] Numerous specific details are set forth in this specification. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A test method for optimizing the extrusion performance of lead sheaths in submarine cables, characterized in that, Includes the following steps: S1: In the production process of lead sheaths, the production speed is set to V=V0; S2: Develop a process parameter table for producing lead sheaths; the table headers are numbered sequentially as follows: starting temperature T1 for the feed tube area, starting temperature T2 for the screw area, and starting temperature T3 for the die head area; the difference in starting temperature between two adjacent rows of cells is ΔT1 for the feed tube area; the difference in starting temperature between two adjacent rows of cells is ΔT2 for the screw area; and the difference in starting temperature between two adjacent rows of cells is ΔT3 for the die head area. S3: Select a column of process parameters from the process parameter table, adjust the temperature value of the lead extrusion unit to the specified process parameter, obtain the current characteristic curve of the lead extrusion unit, and obtain and record the actual current difference ΔI based on the current characteristic curve. The specific steps for obtaining the current characteristic curve of the lead extrusion unit are as follows: S301: Detect and record the current value of the lead extrusion device at the rated frequency; S302: The current characteristic curve is formed with the detection frequency in step 301 as the horizontal axis and the current value in step S301 as the vertical axis; the actual current difference ΔI = Imax - Imin; where Imax is the maximum current value in the current characteristic curve and Imin is the minimum current value in the current characteristic curve. S4: Repeat step S3 until all actual current differences ΔI have been recorded; S5: Compare the actual current difference ΔI to obtain the minimum actual current difference ΔImin, and record the process parameters corresponding to the production speed V and ΔImin; S6: Adjust the production speed: V = V + ΔV; if V < V', return to step S2; if V ≥ V', proceed to the next step, where V' is the production speed limit. S7: Compile the data recorded in step S5 into a statistical table.

2. The test method according to claim 1, characterized in that, V0 is the initial speed, V0 = 1.8~2.0 m / min; ΔV is the adjustment range of the production speed, and ΔV = 0.2 m / min; V' is the production speed limit value, V' = 2.2 m / min~2.4 m / min.

3. The test method according to claim 2, characterized in that, In step S2, |ΔT1| is 0℃, 5℃, or 10℃; |ΔT2| is 0℃, 5℃, or 10℃; and |ΔT3| is 0℃, 5℃, or 10℃.

4. The test method according to claim 3, characterized in that, 370℃≤T1≤380℃, 260℃≤T2≤270℃, 290℃≤T3≤300℃.

5. The test method according to claim 4, characterized in that, The rated frequency in step S301 is 60Hz; the detection time is 3-4 minutes; and the detection interval is 2-3 minutes.

6. The test method according to claim 1, characterized in that, The process parameters include the starting temperature of the feed tube area, the starting temperature of the screw area, and the starting temperature of the die head area.

7. A production method for optimizing the extrusion performance of lead sheaths for submarine cables, characterized in that, Includes the following steps: S1: The test is conducted using the test method for optimizing the extrusion performance of the lead sheath of submarine cables as described in any one of claims 1-6; S2: Calculate the production speed V based on production requirements, then compare it with the statistical table in step S1 to obtain the process parameters under the production speed V, adjust the temperature value of the lead extrusion device to the process parameters, and complete the production.

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