A welding method for single-sided welding and double-sided forming of thick plate square butt weld
By setting a weld overlay layer at the bevel of the vertical plate and the panel of the thick plate, and combining the welding methods of the underlay and the filler layer, the problem of uneven weld quality in the single-sided welding and double-sided forming of thick plates was solved, and high-quality weld formation was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- WUCHANG SHIPBUILDING INDUSTRY GROUP CO LTD
- Filing Date
- 2023-07-17
- Publication Date
- 2026-05-29
AI Technical Summary
In the welding method of single-sided welding and double-sided forming of thick plates, the plate is thinner on one side and thicker on the other side, which leads to uneven heating of the weld and causes defects such as curling, slag inclusion, and incomplete penetration.
A weld overlay layer is set at the bevel between the upright plate and the panel. Welding parameters are controlled by welding the bottom layer and the filler layer. A sawtooth short arc and a small oscillation welding method are used. The distance between the upright plate and the bottom of the bevel is increased during welding to ensure uniform heat distribution.
It improves the weld quality of single-sided welding with double-sided forming on thick plates, reduces defects such as edge curling, slag inclusion, and incomplete penetration, and enhances the welding effect.
Smart Images
Figure CN116727913B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of welding technology, and in particular to a welding method for single-sided welding and double-sided forming of thick plate fillet welds. Background Technology
[0002] Conventional horizontal fillet welds are primarily constructed using double-sided welding. The bevel type is mainly a single-sided "V" bevel with a blunt edge, or a "K" bevel. Critical welds require non-destructive testing after welding, therefore, after the first side (flat weld) is completed, root cleaning is necessary on the subsequent side (overhead weld). Carbon arc gouging is the most common root cleaning method. In actual production, this method is mainly used in locations with ample space, facilitating welding, root cleaning, and grinding. However, in confined spaces, especially when the space on the subsequent side (overhead weld) is insufficient, it significantly impacts weld quality.
[0003] Currently, the single-sided welding with double-sided forming method is mainly used in the field of medium plates (thickness: 3mm-20mm). Before welding, the bevel shape and root gap are strictly controlled. During welding, the root of the bevel is welded using the arc-extinguishing method to achieve the purpose of single-sided welding with double-sided forming. However, in the field of thick plates (20mm-60mm), because the root of the plate is thinner on one side of the bevel and thicker on the other side, the difference in thickness between the two sides is huge. During the root pass welding, the root of the base material is heated unevenly. Defects such as curling, slag inclusion, and incomplete penetration are easily formed on the thicker side, which has a significant impact on the weld quality. Summary of the Invention
[0004] In view of the deficiencies in the existing technology, the technical problem solved by the present invention is: how to improve the weld quality of thick plates under the welding method of single-sided welding and double-sided forming.
[0005] To achieve the above objectives, the present invention provides a welding method for single-sided welding and double-sided forming of thick plate fillet welds, which includes the following steps:
[0006] Several welds are made in the welding area on the upright plate to form a weld overlay layer;
[0007] Welding rods are installed between the weld overlay and the bevel of the panel, and arc-extinguishing welding is performed to form the bottom layer. The vertical plate is the vertically placed thick plate among two welded thick plates, and the panel is the horizontally placed thick plate among two welded thick plates, and the thick plate has the bevel.
[0008] Welding is performed on the upper part of the base layer, and between the bevels of the upright plate and the panel, to form a filler layer.
[0009] Based on the above technology, before adding welding rods between the weld overlay and the panel, the following steps are also included: processing the bevel of the panel so that the angle β between the surface of the bevel and the vertical direction is between 25° and 40°.
[0010] Based on the above technology, several welds are made on the side of the upright plate that will be welded to the panel to form a weld overlay layer, specifically including the following steps:
[0011] Using the intersection line obtained by the lower surface of the panel and the vertical plate as the welding symmetry line, two welds are welded in the welding area on the vertical plate, and the two welds are made symmetrical about the welding symmetry line.
[0012] Welding is then performed on the two aforementioned weld seams to form a weld overlay.
[0013] Based on the above technology, two adjacent welds are made in the welding area of the upright plate.
[0014] Based on the above technology, after the weld overlay is formed, before the welding rod is installed between the weld overlay and the panel, the following steps are also included: cleaning and polishing the weld overlay.
[0015] Based on the above technology, the vertical length of the weld overlay is defined as A, and the horizontal width of the weld overlay is defined as B; the length from the point where the weld overlay has the greatest width to the vertical line where the bevel is located is defined as C, and the height difference between the horizontal line where the weld overlay has the greatest width and the bottom layer of the panel is defined as D, and the height of the bottom layer of the panel is higher than the horizontal line where the weld overlay has the greatest width; the range of A is 6-8mm, the range of B is 4-5mm, the range of C is 2-5mm, and the range of D is 1-2mm.
[0016] Based on the above technology, after forming the weld overlay layer, before adding welding rods between the weld overlay layer and the panel, the following steps are also included: performing tack welding between the upright plate and the panel, and the thickness of the tack weld layer needs to reach 6-8mm.
[0017] Based on the above technology, after the tack welding is performed between the upright plate and the panel, and before the welding rod is installed between the weld overlay and the panel, the following steps are also included: grinding the two ends of the tack weld into a wedge-shaped bevel.
[0018] Based on the above technology, the specific steps for performing arc-extinguished welding include: controlling the welding parameters, selecting a current of 130-170A, a voltage of 22-28V, and a welding speed of 160-220mm / min.
[0019] Based on the above technology, when welding is performed on the upper part of the base layer and between the vertical plate and the panel to form the filler layer, the welding method selected is a sawtooth short arc and small oscillation welding method.
[0020] Compared with the prior art, the advantages of the present invention are as follows:
[0021] This invention involves providing a weld overlay layer on the side of the upright plate to be welded to the panel, followed by the initial root pass welding, and finally the filler layer welding. Compared to existing single-sided welding with double-sided forming for thick plates, this welding method increases the distance between the upright plate and the bottom of the bevel due to the weld overlay layer at the bottom of the weld joint. This solves the problem of uneven heating of the base material root during the root pass welding due to the significant thickness difference between the two sides of the plate, where one side of the plate is thinner at the root and the other side is thicker. Therefore, it improves the weld quality of thick plates using the single-sided welding with double-sided forming method. Attached Figure Description
[0022] Figure 1 This is a schematic diagram of the first structure of single-sided welding and double-sided forming of thick plate fillet welding in an embodiment of the present invention;
[0023] Figure 2 This is a schematic diagram of the second structure of single-sided welding and double-sided forming of thick plate fillet welding in an embodiment of the present invention;
[0024] Figure 3 This is a schematic diagram of the positioning weld layer in an embodiment of the present invention;
[0025] In the diagram: 1-Upright plate, 2-Face panel, 3-Weld overlay, 4-Underlay, 5-Fill layer, 6-Tack weld layer. Detailed Implementation
[0026] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.
[0027] See Figure 1 , 2 As shown, the welding method for single-sided welding and double-sided forming of thick plate fillet welds in this embodiment of the invention includes the following steps:
[0028] S1: Weld several welds in the welding area on the vertical plate 1 to form a weld overlay layer 3;
[0029] S2: Welding rods are installed between the weld overlay layer 3 and the bevel of the panel 2, and arc-extinguishing welding is performed to form the bottom layer 4. The vertical plate 1 is a vertically placed thick plate among two welded thick plates, and the panel 2 is a horizontally placed thick plate among two welded thick plates, and the thick plate has the bevel.
[0030] S3: Welding is performed on the upper part of the base layer 4, and between the bevels of the vertical plate 1 and the panel 2, to form the filler layer 5.
[0031] Therefore, this invention provides a weld overlay layer 3 on the side of the upright plate 1 to be welded to the panel 2, followed by the welding of the root pass 4, and finally the welding of the filler layer 5. Compared with existing single-sided welding and double-sided forming of thick plates, this welding method increases the distance between the upright plate and the bottom of the bevel due to the weld overlay layer at the bottom of the weld joint. This solves the problem of uneven heating of the base material root during root pass welding due to the large difference in thickness between the two sides of the plate, which is thinner at the root of the plate on one side of the bevel and thicker on the other side. Therefore, it improves the weld quality of thick plates using the single-sided welding and double-sided forming welding method.
[0032] Preferred, see Figure 1 As shown, before installing welding rods between the weld overlay layer 3 and the panel 2, the following steps are also included: processing the bevel of the panel 2 so that the angle β between the surface of the bevel and the vertical direction is between 25° and 40°.
[0033] The advantage of this design is that before welding thick plates with bevels, there may be unevenness or angle problems at the bevel, which will lead to a decrease in welding quality. Therefore, the bevel is processed before welding so that the angle β between the surface of the bevel and the vertical direction is between 25° and 40°.
[0034] Preferably, several welds are welded on the side of the upright plate 1 that will be welded to the panel 2 to form a weld overlay layer 3. Specifically, the following steps are included: taking the intersection line obtained by the intersection of the lower surface of the panel 2 and the upright plate 1 as the weld overlay symmetry line, two welds are welded in the welding area on the upright plate 1, and the two welds are symmetrical about the weld overlay symmetry line; welds are then welded on the two welds to form the weld overlay layer 3.
[0035] The advantage of this design is that the weld overlay 3 is designed in a way that makes it easy to control its length and width and ensures quality. The design of the weld overlay 3 directly affects the welding quality between thick plates. Therefore, by controlling the size of the weld overlay 3 according to the welding requirements, the welding quality of the thick plates can be improved.
[0036] Preferably, the two welds welded in the welding area on the upright plate 1 are adjacent.
[0037] The advantage of this design is that the two welds that are welded first on the upright plate 1 and are symmetrical about the weld overlay symmetry line can be adjacent or have a certain gap. Adjacent welds result in better weld quality.
[0038] Preferably, after the weld overlay 3 is formed, before the welding rod is installed between the weld overlay 3 and the panel 2, the following steps are also included: cleaning and polishing the weld overlay 3.
[0039] The advantage of this design is that the weld overlay 3 is formed by the accumulation of welding rods, and there are certain errors and quality problems in the welding process. Therefore, before welding the weld overlay 3 to the panel 2, the weld overlay 3 should be cleaned and polished to improve the subsequent welding quality.
[0040] Preferred, see Figure 1 As shown, the vertical length of the weld overlay 3 is defined as A, and the horizontal width of the weld overlay 3 is defined as B; the length of the vertical line from the point where the weld overlay 3 has the greatest width to the bevel is defined as C; the height difference between the horizontal line where the weld overlay 3 has the greatest width and the bottom layer of the panel 2 is defined as D, and the height of the bottom layer of the panel 2 is higher than the horizontal line where the weld overlay 3 has the greatest width; the range of A is 6-8 mm, the range of B is 4-5 mm, the range of C is 2-5 mm, and the range of D is 1-2 mm.
[0041] The advantage of this design is that the vertical length of the weld overlay, the horizontal width of the weld overlay, the vertical length from the point where the weld overlay is widest to the bevel, and the height difference between the horizontal line where the weld overlay is widest and the bottom layer of the panel all have a direct relationship with the welding quality between thick plates. Therefore, by designing and controlling A, B, C, and D within a certain range based on welding requirements, the welding quality can be improved.
[0042] Preferred, see Figure 3 As shown, after the weld overlay layer 3 is formed, before the welding rod is installed between the weld overlay layer 3 and the panel 2, the following steps are also included: locating welding is performed between the upright plate 1 and the panel 2, and the thickness of the locating weld layer 6 needs to reach 6-8mm.
[0043] The advantage of this design is that, in order to keep the upright plate 1 and the panel 2 in the designed position, they are tack welded together. The design position of the tack weld is not required, as long as it can meet the positioning requirements between the upright plate 1 and the panel 2. In order to ensure the quality of positioning, the thickness of the tack weld layer 6 needs to reach 6 to 8 mm.
[0044] Preferred, see Figure 3 As shown, after the tack welding is performed between the upright plate 1 and the panel 2, and before the welding rod is installed between the weld overlay layer 3 and the panel 2, the following steps are also included: the two ends of the tack weld are ground into wedge-shaped bevels.
[0045] The advantage of this design is that, in order to make the welding process between thick plates smoother, the two ends of the tack weld are ground into a wedge-shaped bevel, thereby further improving the welding quality.
[0046] Preferably, when performing arc-extinguished welding, the specific steps include: controlling the welding parameters, selecting a current of 130-170A, a voltage of 22-28V, and a welding speed of 160-220mm / min.
[0047] The advantage of this design is that the welding of the bottom layer 4 needs to be carried out by the arc-extinguishing welding method. In order to ensure the welding quality, the current, voltage and welding speed are controlled during welding.
[0048] When welding is performed on the upper part of the base layer 4, and between the vertical plate 1 and the panel 2 to form the filler layer 5, the welding method selected is a sawtooth short arc and small oscillation welding method.
[0049] The advantage of this design is that there are multiple options for welding the filler layer 5. One option is the serrated short arc and small oscillation method, while crescent-shaped and triangular oscillation methods can also be used for welding.
[0050] Preferably, the welding rod can be a Ф3.2mm or Ф4mm welding rod.
[0051] The advantage of this design is that the selection of the electrode type is mainly based on the length defined by the vertical line from the point where the weld overlay 3 is widest to the vertical direction where the bevel is located. When C is designed to be 3-5mm, a Ф4mm electrode can be selected; when C is designed to be 2-4mm, a Ф3.2mm electrode can be selected.
[0052] Preferably, after the bottom layer 4 is welded and before the filler layer 5 is welded, the bottom layer 4 needs to be cleaned and polished.
[0053] The advantage of this design is that it can further improve the welding quality between thick plates.
[0054] This invention is not limited to the embodiments described above. Those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention. Contents not described in detail in this specification are prior art known to those skilled in the art.
Claims
1. A welding method for single-sided welding and double-sided forming of thick plate fillet welds, characterized in that, It includes the following steps: Several welds are welded in the welding area on the upright plate (1) to form a weld overlay layer (3); Welding rods are installed between the weld overlay (3) and the bevel of the panel (2), and arc extinguishing welding is performed to form the bottom layer (4). The vertical plate (1) is a vertically placed thick plate among two welded thick plates, and the panel (2) is a horizontally placed thick plate among two welded thick plates, and the thick plate has the bevel. Welding is performed on the top of the base layer (4) and between the bevels of the upright plate (1) and the panel (2) to form a filler layer (5). The vertical length of the weld overlay (3) is defined as A, and the horizontal width of the weld overlay (3) is defined as B. The vertical line from the point where the weld overlay (3) has the largest width to the bevel is defined as C. The height difference between the horizontal line where the weld overlay (3) has the largest width and the bottom layer of the panel (2) is defined as D, and the height of the bottom layer of the panel (2) is higher than the horizontal line where the weld overlay (3) has the largest width. The range of A is 6~8mm, the range of B is 4~5mm, the range of C is 2~5mm, and the range of D is 1~2mm. When C is designed to be 2~4mm, use Ф3.2mm welding rod; when C is designed to be 3~5mm, use Ф4mm welding rod. Before installing welding rods between the weld overlay (3) and the panel (2), the following steps are also included: processing the bevel of the panel (2) so that the angle β between the surface of the bevel and the vertical direction is between 25° and 40°; Several welds are made on the side of the upright plate (1) that will be welded to the panel (2) to form a weld overlay (3), specifically including the following steps: Using the intersection line obtained by the lower surface of panel (2) and vertical plate (1) as the welding symmetry line, two welds are welded in the welding area on vertical plate (1), and the two welds are symmetrical about the welding symmetry line. Weld again on the two weld seams to form a weld overlay (3).
2. The welding method for single-sided welding and double-sided forming of thick plate fillet welds as described in claim 1, characterized in that: Two adjacent welds are welded in the welding area on the upright plate (1).
3. The welding method for single-sided welding and double-sided forming of thick plate fillet welds as described in claim 1, characterized in that, After the weld overlay (3) is formed, before the welding rod is installed between the weld overlay (3) and the panel (2), the following steps are also included: cleaning and polishing the weld overlay (3).
4. The welding method for single-sided welding and double-sided forming of thick plate fillet welds as described in claim 1, characterized in that, After the weld overlay (3) is formed, before the welding rod is installed between the weld overlay (3) and the panel (2), the following steps are also included: locating welding is performed between the upright plate (1) and the panel (2), and the thickness of the locating welding layer (6) needs to reach 6~8mm.
5. The welding method for single-sided welding and double-sided forming of thick plate fillet welds as described in claim 4, characterized in that, After the tack weld is performed between the upright plate (1) and the panel (2), before the welding rod is installed between the weld overlay (3) and the panel (2), the following steps are also included: the two ends of the tack weld are ground into wedge-shaped bevels.
6. The welding method for single-sided welding and double-sided forming of thick plate fillet welds as described in claim 1, characterized in that, When performing arc-extinguished welding, the specific steps include: controlling the welding parameters, selecting a current of 130~170A, a voltage of 22~28V, and a welding speed of 160~220mm / min.
7. The welding method for single-sided welding and double-sided forming of thick plate fillet welds as described in claim 1, characterized in that: When welding is performed on the upper part of the base layer (4) and between the upright plate (1) and the panel (2) to form the filler layer (5), the welding method is a sawtooth short arc and small oscillation bar method.