A welding process for steel post marking lines

Abstract

This invention relates to the field of ship dredging equipment technology and discloses a welding process for steel pile marking lines, comprising: S1: machining grooves on a plate; S2: welding an isolation layer weld on the bottom and sides of the groove; S3: welding a cover layer weld on the isolation layer weld; S4: grinding the weld to form a marking line; S5: rolling, assembling, and welding the plate with the marking line facing outwards to form a steel pile, wherein the marking line is ring-shaped and encircles the outer perimeter of the steel pile. This invention, by machining grooves and welding marking lines before rolling and welding the plate to form the steel pile, reduces the labor intensity of the marking line welding operation, increases welding efficiency, reduces the number of weld joints, and ensures stable and reliable welding quality. Furthermore, the isolation layer weld reduces the migration of carbon elements from the steel pile plate to the cover layer weld of the steel pile marking line, lowers the carbon content of the cover layer weld, and improves the corrosion resistance of the cover layer weld.

Description

Technical Field

[0001] This invention relates to the field of ship dredging equipment technology, and in particular to a welding process for steel pile marking lines. Background Technology

[0002] Cutter suction dredgers are one of the main vessel types used for waterway dredging and port construction. A typical cutter suction dredger consists of two positioning steel piles: a main pile and an auxiliary pile. These piles are used for positioning and movement during dredging operations. When not dredging or underway, the steel pile trolley places the steel piles horizontally on the pile support. Before dredging, the trolley rotates the piles 90 degrees and inserts the pile tips into the riverbed or seabed to secure the dredger. The cutter head then moves in a fan-shaped trajectory to perform the dredging operation. When dredging is complete, the trolley lifts the piles inserted into the water and rotates them 90 degrees again, placing them horizontally on the pile support.

[0003] The lifting height of the steel piles needs to be accurate; otherwise, the piles cannot be placed into the pile holder, or the position of the pile holder clamping the pile is too far off from the pile's center of gravity, which could lead to a dangerous overturning process. Therefore, clear marking lines need to be made on the outer wall of the steel pile to help operators easily and accurately judge the lifting height, and then carry out precise lifting and overturning operations.

[0004] In existing technologies, some methods use painted tape sprayed onto the outer wall of the steel pile as the marking line. However, the paint tape is easily peeled off due to friction or corrosion, eventually resulting in damaged or blurred marking lines. Other methods involve machining annular grooves on the outer wall of the steel pile after welding, then filling the grooves with stainless steel welding wire to form the marking line. However, machining the annular grooves is difficult, and the welding process is complex and inefficient. Summary of the Invention

[0005] The purpose of this invention is to provide a welding process for steel post marking lines, thereby solving the problems of high difficulty and low efficiency in welding marking lines.

[0006] To achieve the above objectives, the present invention provides a welding process for steel post marking lines, comprising: S1: machining grooves on a plate;

[0007] S2: Weld the isolation layer welds at the bottom and sides of the trench;

[0008] S3: Weld the cover layer weld on the isolation layer weld;

[0009] S4: Grind the weld seam smooth to form a marking line;

[0010] S5: The sheet metal is rolled, assembled, and welded with the marking line facing outwards to form a steel pile, with the marking line in a ring shape and surrounding the outer wall of the steel pile.

[0011] Furthermore, the groove is trapezoidal in shape with its width gradually increasing from bottom to top, and the angle between the side edge and the bottom edge of the groove is 135±5°.

[0012] Furthermore, the depth of the trench is 6±1mm, and the top width of the trench is 80±10mm.

[0013] Further, the specific steps of S2 are as follows: first, weld the isolation layer weld at the bottom of the trench, and then weld the isolation layer welds on both sides of the trench.

[0014] Furthermore, the isolation layer weld is formed by welding along the bottom and sides of the trench using 309MoL stainless steel flux-cored welding wire, and the cover layer weld is formed by welding using 316L stainless steel flux-cored welding wire, with the cover layer weld superimposed on the isolation layer weld.

[0015] Furthermore, CO2 gas shielded welding is used, with CO2 gas purity of 99.5% and welding current of 180-210A.

[0016] Furthermore, both the isolation layer weld and the cover layer weld are composed of multiple welds, with each weld having a thickness of 3±1mm and a width of 10±1mm.

[0017] Furthermore, during welding, both the weld seam of the isolation layer and the weld seam of the cover layer are welded using a straight-line welding method.

[0018] Furthermore, before the groove is processed, welding bevels are processed on each edge of the plate; the groove is 50±10mm away from the welding bevels on the upper and lower sides.

[0019] Furthermore, after the isolation layer weld and the cover layer weld are completed, they are left to stand for 24 hours, and then dye penetrant testing is used to inspect the isolation layer weld and the cover layer weld.

[0020] Compared with existing technologies, the welding process for steel pile marking lines in this embodiment of the invention has the following advantages: Grooves are processed and marking lines are welded before the steel pile is formed by rolling and welding the sheet metal. This reduces the labor intensity of the marking line welding operation, makes processing convenient, increases welding efficiency, reduces the number of weld joints, and ensures stable and reliable welding quality. Furthermore, the isolation layer weld reduces the migration of carbon elements from the steel pile sheet to the steel pile marking line cover weld, lowers the carbon content of the steel pile marking line cover weld, and improves the corrosion resistance of the steel pile marking line cover weld. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the plate material according to an embodiment of the present invention;

[0022] Figure 2 yes Figure 1 Sectional view of AA;

[0023] Figure 3 yes Figure 1 BB section view;

[0024] Figure 4 This is a schematic diagram showing the location of the weld seam in the isolation layer according to an embodiment of the present invention;

[0025] Figure 5 This is a schematic diagram showing the location of the cover layer weld in an embodiment of the present invention;

[0026] In the diagram, 1 is the plate material; 11 is the welding bevel; 12 is the groove; 2 is the isolation layer weld; and 3 is the cover layer weld. Detailed Implementation

[0027] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0028] In the description of this invention, it should be understood that the terms "upper," "lower," "top," "bottom," etc., used in this invention to indicate the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this 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 this invention.

[0029] A preferred embodiment of the present invention provides a welding process for steel post marking lines, comprising:

[0030] S1: Groove 12 is machined on plate 1;

[0031] S2: Weld the isolation layer weld 2 at the bottom and both sides of the trench 12;

[0032] S3: Weld the cover layer weld 3 on the isolation layer weld 2;

[0033] S4: Grind the weld seam smooth to form a marking line;

[0034] S5: The plate 1 is rolled, assembled, and welded with the marking line facing outward to form a steel pile, and the marking line is in the shape of a ring and is arranged around the outer perimeter of the steel pile.

[0035] Based on this, in this embodiment of the invention, the groove 12 is processed and the marking line is welded before the steel pile is formed by rolling and welding the plate 1. This reduces the labor intensity of the marking line welding operation, makes processing convenient, increases welding efficiency, reduces the number of weld joints formed, and ensures stable and reliable welding quality. Furthermore, the state of the plate 1 allows for automated processing, further guaranteeing processing quality and efficiency. Preferably, to improve work efficiency and the surface quality of the marking line, the weld grinding process can be performed mechanically and automatically.

[0036] Furthermore, the marking line in this embodiment of the invention has two layers of welds. The isolation layer weld 2, which is in direct contact with the trench 12, plays an isolation role, which can reduce the migration of carbon elements in the steel pile plate to the steel pile marking line cover layer weld 3, reduce the carbon content of the steel pile marking line cover layer weld 3, and improve the corrosion resistance of the steel pile marking line cover layer weld 3.

[0037] Furthermore, such as Figures 1 to 5 As shown, the groove 12 is trapezoidal in shape, with the width gradually increasing from bottom to top, to facilitate welding, reduce filler metal, and facilitate welding of the welds on both sides of the groove 12. Specifically, to avoid affecting the performance of the weld and preventing non-fusion, the angle between the side and bottom edges of the groove 12 is 135±5°. Furthermore, the marking line of this invention includes two layers of welds, and the marking line needs to be ground smooth at the end, not protruding from the outer surface of the steel pile. To meet welding requirements, the depth of the groove 12 is 6±1mm. Furthermore, to ensure the marking line is of appropriate size—avoiding being too small to be inconspicuous and ineffective, and avoiding being too large to waste materials and time—the top width of the groove 12 is 80±10mm.

[0038] Furthermore, in order to allow the weld to shrink freely and avoid welding cracks at the weld joint, the specific steps of S2 are as follows: first weld the isolation layer weld 2 at the bottom of the trench 12, and then weld the isolation layer welds 2 on both sides of the trench 12.

[0039] Furthermore, the isolation layer weld 2 is formed by welding along the bottom and sides of the groove 12 using 309MoL stainless steel flux-cored welding wire, and the cover layer weld 3 is formed by welding using 316L stainless steel flux-cored welding wire. The cover layer weld 3 is superimposed on the isolation layer weld 2.

[0040] Based on this, the isolation layer weld 2 in this embodiment of the invention serves an isolation function, reducing the migration of carbon elements from the steel pile plate to the cover layer weld 3 of the steel pile marking line. Therefore, the carbon content of the isolation layer weld should be low to improve the isolation effect. Thus, 309MoL stainless steel flux-cored welding wire is used as the welding material for the isolation layer weld 2. Furthermore, 316L stainless steel flux-cored welding wire is used as the welding material for the cover layer weld 3, which ensures the acid and corrosion resistance, wear resistance, and lifespan of the steel pile marking line.

[0041] Furthermore, both the isolation layer weld 2 and the cover layer weld 3 are welded using CO2 gas shielded welding. This welding method is simple to operate, has high welding efficiency, low cost, and the 309MoL and 316L stainless steel flux-cored welding wires are almost unaffected by the CO2 shielding gas. Specifically, the diameter of both the 309MoL and 316L stainless steel flux-cored welding wires is 1.2 mm. Based on the diameter of each wire, the CO2 gas purity is selected as 99.5%, and the welding current is 180–210 A.

[0042] Furthermore, both the isolation layer weld 2 and the cover layer weld 3 are composed of multiple welds. The thickness of a single weld is 3±1mm and the width is 10±1mm. This ensures that the width and thickness of a single weld are appropriate, avoiding excessive stress and deformation caused by excessively large or thick welds, which would ultimately affect the surface quality of the weld. This also ensures that the welding speed and welding heat input are reasonable, thereby guaranteeing the mechanical properties of the weld.

[0043] Furthermore, during welding, both the isolation layer weld 2 and the cover layer weld 3 are welded using a straight-line motion method. During the welding process, the weld moves forward laterally without swaying along the length of the groove. Using the straight-line motion method results in fast welding speed and avoids producing welds that are too wide.

[0044] Furthermore, before processing the groove 12, welding bevels 11 are processed on each edge of the plate 1. After the welding bevels 11 on the edges of the plate 1 are processed, the position of the marking line is determined and marked, and this marking is used to assist in the processing of the groove 12. Specifically, the groove 12 is 50±10mm away from the welding bevels on the upper and lower sides, so as to prevent the end of the marking line from cracking due to tension when the plate 1 is rolled into a cylindrical steel pile.

[0045] Furthermore, after the isolation layer weld 2 and the cover layer weld 3 are welded, they are left to stand for 24 hours, and then dye penetrant testing is used to inspect the isolation layer weld 2 and the cover layer weld 3 to ensure that each weld is free of welding defects such as cracks and lack of fusion. Only welds that pass the inspection can proceed to the next step of grinding.

[0046] In summary, the embodiments of the present invention provide a welding process for steel pile marking lines. Before the steel pile is formed by rolling and welding the plate 1, the groove 12 is processed and the marking line is welded. This reduces the labor intensity of the marking line welding operation, makes the processing convenient, increases the welding efficiency, reduces the number of weld joints, and ensures stable and reliable welding quality. Furthermore, the plate condition can be easily automated, which can further guarantee the processing quality and efficiency.

[0047] Furthermore, the marking line has two layers of welds. The isolation layer weld 2, which is in direct contact with the trench 12, plays an isolation role, which can reduce the migration of carbon elements in the steel pile plate to the steel pile marking line cover layer weld 3, reduce the carbon content of the steel pile marking line cover layer weld 3, and improve the corrosion resistance of the steel pile marking line cover layer weld 3.

[0048] Meanwhile, the groove 12 is trapezoidal in shape with its width gradually increasing from bottom to top, which reduces the amount of filler metal required. Furthermore, the angle between the side and bottom edges of the groove 12 is 135±5°, thus preventing poor fusion and ensuring the surface quality of the weld. Both the isolation layer weld 2 and the cover layer weld 3 are welded using a straight-line welding method, moving laterally without swaying along the length of the groove 12 during welding. This results in fast welding speed and avoids excessively wide welds, further ensuring the mechanical properties of the weld and preventing excessive stress.

[0049] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A welding process for steel post marking lines, characterized in that, include: S1: Grooves are machined on the sheet material; S2: Weld the isolation layer welds at the bottom and sides of the trench; S3: Weld the cover layer weld on the isolation layer weld; S4: Grind the weld seam smooth to form a marking line; S5: The sheet metal is rolled, assembled, and welded with the marking line facing outwards to form a steel pile, with the marking line in a ring shape and encircling the outer wall of the steel pile. The isolation layer weld is formed by welding along the bottom and sides of the trench using 309MoL stainless steel flux-cored welding wire, and the cover layer weld is formed by welding using 316L stainless steel flux-cored welding wire. The cover layer weld is superimposed on the isolation layer weld.

2. The welding process for the steel pile marking line according to claim 1, characterized in that, The groove is trapezoidal in shape with its width gradually increasing from bottom to top, and the angle between the side and bottom edge of the groove is 135±5°.

3. The welding process for the steel pile marking line according to claim 2, characterized in that, The depth of the trench is 6±1mm, and the top width of the trench is 80±10mm.

4. The welding process for the steel pile marking line according to claim 1, characterized in that, The specific steps of S2 are as follows: first, weld the isolation layer weld at the bottom of the trench, and then weld the isolation layer welds on both sides of the trench.

5. The welding process for the steel pile marking line according to claim 1, characterized in that, CO2 gas shielded welding is used, with CO2 gas purity of 99.5% and welding current of 180~210A.

6. The welding process for the steel pile marking line according to claim 1, characterized in that, Both the isolation layer weld and the cover layer weld consist of multiple welds, with each weld having a thickness of 3±1mm and a width of 10±1mm.

7. The welding process for the steel pile marking line according to claim 6, characterized in that, During welding, both the isolation layer weld and the cover layer weld are welded using a straight-line welding method.

8. The welding process for the steel pile marking line according to claim 1, characterized in that, Before the groove is processed, welding bevels are processed on each edge of the plate; the groove is 50±10mm away from the welding bevels on the upper and lower sides.

9. The welding process for the steel pile marking line according to claim 1, characterized in that, After the isolation layer weld and the cover layer weld are completed, they are left to stand for 24 hours, and then the isolation layer weld and the cover layer weld are inspected by dye penetrant testing.

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