A groove structure for plasma welding a pipe box corner joint

Abstract

The utility model belongs to the welding bevel technical field of plasma welding pipe box corner joint, the utility model discloses a kind of bevel structure of plasma welding pipe box corner joint, horizontal plate is arranged in up-down position in parallel, vertical plate is arranged in the left and right sides of horizontal plate arranged in up-down parallel;The left and right end surface of two horizontal plates and the inner side surface of two vertical plates are matched as rectangular shape by plasma welding;Step is opened in the inner side surface upper and lower end of vertical plate;Arc-shaped notch is opened in the upper portion or lower portion position of horizontal plate left and right end, and arc-shaped notch or in the upper portion lower portion symmetry of horizontal plate left and right end is arranged.This utility model has beneficial effects: through the bevel structure design of plasma welding pipe box corner joint, using plasma arc welding gun welding pipe box butt joint internal and external weld even, slightly convex smooth, weld root forming even, there is no welding not and welding nodule case, can satisfy RT nondestructive testing requirement, realized the welding process of pipe box single-sided plasma arc welding double-sided forming.

Description

Technical Field

[0001] This utility model belongs to the technical field of welding beveling for plasma-welded corner joints of pipe boxes, specifically relating to a beveling structure for plasma-welded corner joints of pipe boxes. Background Technology

[0002] Corner joints are a common type of welding used in air cooler plug tube boxes. Currently, two welding processes are commonly used: one is double-sided submerged arc welding, which requires cleaning the tube sheet root before welding the outer side, resulting in slow production efficiency, high welding material consumption, and high production costs; the other is internal submerged arc welding with external vacuum electron beam welding, which reduces welding material consumption but requires vacuuming, leading to higher energy consumption. Using plasma welding can avoid cleaning the tube sheet root, reduce welding material consumption, and eliminate the need for vacuuming, effectively reducing energy consumption and further improving welding efficiency.

[0003] Plasma welding uses a relatively high welding current to completely melt the workpiece, creating a small through-hole under the influence of the plasma gas flow. Molten metal is forced around the through-hole, and the plasma arc exits from the back through the through-hole. The molten metal remains in equilibrium due to the interaction of the arc force, the gravity of the liquid metal, and surface tension. As the welding torch moves forward, the through-hole also moves forward. Due to surface tension, the molten metal adheres to the solid metal wall surrounding the plasma arc and, under the influence of the arc, continuously flows backward along the through-hole, eventually filling it and solidifying into a uniform weld. This effect is called the keyhole welding effect. A stable keyhole welding effect requires both a suitable welding current and a suitable plasma gas flow rate. Excessive plasma flow rate will blow away the molten metal, causing metal cutting; insufficient flow rate will prevent the formation of a welding through-hole in the workpiece. Using through-hole welding technology, a single-sided welding process with double-sided weld formation can be achieved. However, the maximum thickness that can be welded using perforated welding technology is limited. Currently, plasma perforated welding can stably weld tube sheets with a thickness of 3mm to 8mm, rarely exceeding 13mm. The main technical problem with existing plasma welding of air cooler plug boxes is that for tube sheets thicker than 8mm, when using corner joint welding, the commonly used methods for tube sheet assembly welding include no beveling, external Y-shaped beveling, and internal V-shaped beveling; for example... Figure 1 As shown, after the horizontal tube sheet 1 and the vertical tube sheet 2 are assembled, the lack of beveling plasma welding results in poor weld root formation and localized incomplete penetration, failing to meet the requirements of RT non-destructive testing; for example... Figure 2 As shown, after the horizontal tube sheet 1 and the vertical tube sheet 2 are assembled, the outer Y-shaped groove 3 is plasma welded. The weld root formation is poor, and there is local incomplete penetration, which does not meet the requirements of RT non-destructive testing. Figure 3As shown, after the horizontal tube sheet 1 and the vertical tube sheet 2 are assembled, plasma welding of the inner V-groove 4 results in improved weld root formation, good penetration, but a large weld bead, which does not meet the requirements of RT non-destructive testing. Based on the technical problems existing in the current technology of commonly used tube sheet welding corner joint bevels during plasma welding, the inventors have developed a bevel structure for plasma welding tube box corner joints, which can solve the technical problems existing in the current technology. Utility Model Content

[0004] To solve the above-mentioned technical problems, this utility model provides a bevel structure for plasma welding of corner joints in pipe boxes. The structure of this utility model is simple, scientific and reasonable, and can solve the problems of poor weld root formation quality, incomplete weld penetration and weld beads in corner joints of pipe boxes using plasma arc welding, which cannot meet the requirements of RT non-destructive testing.

[0005] The technical solution adopted in this utility model is: a bevel structure for a plasma-welded corner joint of a pipe box, including a horizontal plate and a vertical plate. The horizontal plate is arranged parallel to each other in the upper and lower positions, and the vertical plate is arranged on the left and right sides of the horizontal plate, and is arranged in a parallel manner. The left and right end faces of the two horizontal plates and the inner sides of the two vertical plates are plasma-welded into a rectangular shape. The upper or lower surface of the horizontal plate is flush with the upper or lower end face of the vertical plate. The assembly steps are opened at the upper and lower ends of the inner side of the vertical plate, and the depth of the assembly steps at the upper and lower ends of the inner side of the vertical plate is equal. The arc-shaped notches are opened at the upper or lower positions of the left and right ends of the horizontal plate, and the arc-shaped notches are symmetrically arranged at the upper and lower parts of the left and right ends of the horizontal plate. A molten pool is formed at the assembly point of the left or right end of the horizontal plate and the upper or lower end of the inner side of the vertical plate.

[0006] The length of the steps in the assembly is greater than the thickness of the horizontal plate; the gap between the left or right end of the horizontal plate and the inner side of the vertical plate is less than or equal to 0.5 mm.

[0007] The horizontal plate has symmetrical arc-shaped notches at its left and right ends, with a radius of 8 mm, which penetrate the longitudinal body of the horizontal plate.

[0008] The upper and lower ends of the upright plate have arc-shaped notches at their inner corners, and the arc-shaped notches penetrate the longitudinal body of the upright plate.

[0009] The depth of the steps is 0.5 mm, and the steps are L-shaped.

[0010] The arc-shaped notches at the upper and lower ends of the inner side of the vertical plate align with the upper arc-shaped notches at the left and right ends of the horizontal plate to form a U-shaped molten pool (e.g., Figure 4 (As shown).

[0011] The bends of the paired steps at the top and bottom of the vertical plate meet the arc-shaped recesses at the bottom left and right ends of the horizontal plate to form an irregularly shaped molten pool (e.g., Figure 4 (As shown).

[0012] The horizontal plate has arc-shaped notches at its lower or upper left and right ends. These notches, when joined with the upper and lower steps of the vertical plate, form an irregularly shaped molten pool (e.g., ...). Figure 5 (As shown).

[0013] The arc-shaped notches at the lower left and right ends of the horizontal plate align with the inner surface of the vertical plate to form an arc-shaped molten pool (e.g., Figure 6 (As shown).

[0014] The welding process for the bevel structure of this plasma welding pipe box corner joint is as follows: First, the vertical plate is placed vertically on the welding platform. Then, the left end of the horizontal plate is aligned with the inner side of the upper inner side of the vertical plate, making the upper surface of the horizontal plate flush with the upper end face of the vertical plate. The plasma welding torch is aimed at the reserved weld seam, melting the metal of the horizontal and vertical plates. At this time, the molten metal fills the U-shaped molten pool. A portion of the molten metal flows through the weld seam into the irregularly shaped molten pool at the bottom. As the plasma welding torch moves continuously, molten metal is continuously formed and melts in the upper U-shaped molten pool of the horizontal plate and the left vertical plate. A uniform, slightly convex, and smooth weld is formed, and a similar uniform, slightly convex, and smooth weld is also formed on the lower part (back) of the horizontal plate. Then, the two vertical plates are placed on the right side of the upper horizontal plate, so that the right end face of the horizontal plate is aligned with the assembly step on the upper inner side of the vertical plate. The same plasma arc welding action is repeated to achieve plasma arc welding of the corner joint at the joint between the upper horizontal plate and the left and right vertical plates. When it is necessary to weld the lower horizontal plate, the upper horizontal plate is flipped over so that it is placed flat on the welding platform. The plasma arc welding work of the upper horizontal plate and the left and right vertical plates is repeated to complete the assembly plasma arc welding of the pipe box, forming a rectangular pipe box.

[0015] The beneficial effects of this utility model are as follows: through the bevel structure design of the corner joint of the plasma welding pipe box, the inner and outer welds of the pipe box are uniform, slightly convex and smooth when welded by plasma arc welding gun, and the root of the weld is uniformly formed. There are no cases of incomplete welding and weld beads, which can meet the requirements of RT non-destructive testing and realize the welding process of single-sided plasma arc welding and double-sided forming of pipe box. Attached Figure Description

[0016] Figure 1 This is a front view of plasma welding without beveling after tube sheet assembly in the existing technology.

[0017] Figure 2 This is a front view of plasma welding of the outer Y-shaped groove after tube sheet assembly in the existing technology;

[0018] Figure 3 This is a front view of plasma welding of the inner V-groove after tube sheet assembly in the existing technology;

[0019] Figure 4 This is a front view of Embodiment 3 of the present invention;

[0020] Figure 5 This is a front view of Embodiment 2 of the present invention;

[0021] Figure 6 This is a front view of Embodiment 1 of the present utility model;

[0022] Figure 7 Macroscopic metallographic image of a pipe box welded by plasma arc welding;

[0023] Figure 1-3 The markings are: 1. Horizontal tube sheet, 2. Vertical tube sheet, 3. Y-shaped bevel, 4. V-shaped bevel.

[0024] Figure 4-6 The markings are: 1. Horizontal plate, 2. Vertical plate, 3. Alignment steps, 4. Arc-shaped notch, 5. Molten pool. Detailed Implementation

[0025] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings.

[0026] This utility model provides a bevel structure for plasma welding of corner joints in pipe boxes:

[0027] like Figure 4 As shown in Figure 5 or 6, the horizontal plate 1 is arranged in parallel at the top and bottom positions, and the vertical plate 2 is arranged on the left and right sides of the horizontal plate 1, which is arranged in parallel from left to right. The left and right end faces of the two horizontal plates 1 and the inner side faces of the two vertical plates 2 are plasma welded into a rectangular shape, and the upper or lower surface of the horizontal plate 1 is flush with the upper or lower end face of the vertical plate 2.

[0028] The main purpose of the above arrangement is to use the upper and lower horizontal plates 1 and the left and right vertical plates 2 to form a rectangular pipe box by assembling and welding with a plasma arc welding gun.

[0029] like Figure 4 and 5 As shown, the steps 3 are formed at the upper and lower ends of the inner side of the vertical plate 2, and the depth of the steps 3 at the upper and lower ends of the inner side of the vertical plate 2 is equal; the length of the steps 3 is greater than the thickness of the horizontal plate 1; the gap between the left or right end of the horizontal plate 1 and the inner side of the vertical plate 2 is less than or equal to 0.5 mm; the depth of the steps 3 is 0.5 mm, and the steps 3 are L-shaped.

[0030] The main purpose of the above arrangement is that when the two horizontal plates 1 and the two vertical plates 2 are joined together to form a rectangular tube box, the vertical plates 2 are used to form a space for the molten metal to melt by using the steps 3 and the arc-shaped recesses 4 at the upper or lower parts of the left and right ends of the horizontal plates 1. On the one hand, this increases the residence time of the molten metal in the molten pool 5 so as to form a plasma arc welding weld with good melting and shaping; on the other hand, it restricts the melting and shaping shape of the molten metal so as to form a weld with a smooth and regular surface.

[0031] like Figure 4 , 5 As shown, the arc-shaped notch 4 is opened at the upper or lower part of the left and right ends of the horizontal plate 1, or the arc-shaped notch 4 is symmetrically arranged at the upper and lower parts of the left and right ends of the horizontal plate 1; the arc-shaped notches 4 are symmetrically opened at the upper and lower ends of the left and right ends of the horizontal plate 1, the radius of the arc-shaped notch 4 is 8 mm, and the arc-shaped notch 4 penetrates through the longitudinal body of the horizontal plate 1; the arc-shaped notches 4 are opened at the inner corners of the upper and lower ends of the vertical plate 2, and the arc-shaped notches 4 penetrate through the longitudinal body of the vertical plate 2.

[0032] The main purpose of the above arrangement is to utilize the arc-shaped notch 4 on the horizontal plate 1, and the arc-shaped notch 4 at the inner corners of the upper and lower ends of the vertical plate 2, to form a molten pool 5 for the plasma arc welding molten metal to melt and form.

[0033] like Figure 4 As shown, the arc-shaped notches 4 at the upper and lower ends of the inner side of the vertical plate 2 are joined with the upper arc-shaped notches 4 at the left and right ends of the horizontal plate 1 to form a U-shaped molten pool 5. The main purpose of this design is that when the plasma arc melts the metal plate, the molten metal can be formed into a slightly convex arc shape in the U-shaped molten pool 5, which improves the forming quality of the plasma arc weld.

[0034] like Figure 4 As shown, the bends of the upper and lower assembly steps 3 of the vertical plate 2 connect with the lower arc-shaped recesses 4 at the left and right ends of the horizontal plate 1 to form an irregularly shaped molten pool 5. The main purpose of this design is that when the molten metal flows from the joint between the horizontal plate 1 and the inner side of the vertical plate 2 to the irregularly shaped molten pool 5, on the one hand, the combined effect of the bends of the assembly steps 3 and the lower arc-shaped recesses 4 at the left and right ends of the horizontal plate 1 can increase the residence time of the molten metal at the four corners inside the rectangular tube box, forming uniform and flat welds at the four corners inside the rectangular tube box (forming plasma arc welding on the outside of the tube box, forming welds at the four corners inside the tube box). On the other hand, it can limit the molten metal, preventing irregular flow and forming a smooth and linear weld.

[0035] like Figure 5As shown, the lower or upper part of the left and right ends of the horizontal plate 1 is provided with arc-shaped notches 4. After the arc-shaped notches 4 at the lower or upper parts of the left and right ends of the horizontal plate 1 are joined with the upper and lower assembly steps 3 of the vertical plate 2, an irregular molten pool 5 is formed. The main purpose of this setting is that when the molten metal flows from the joint gap between the horizontal plate 1 and the vertical plate 2 to the position of the irregular molten pool 5, on the one hand, the combined effect of the bending structure of the assembly steps 3 and the arc-shaped notches 4 at the lower parts of the left and right ends of the horizontal plate 1 can increase the residence time of the molten metal at the four corners inside the rectangular tube box, forming a uniform and flat weld at the four corners inside the rectangular tube box (forming plasma arc welding on the outside of the tube box, forming a weld at the four corners inside the tube box). On the other hand, it can limit the molten metal, prevent the irregular flow of the molten metal, and form a linear weld with a regular and smooth surface.

[0036] Example 1, such as Figure 6 As shown, horizontal plates 1 are arranged parallel to each other in the vertical position, and vertical plates 2 are arranged on the left and right sides of the horizontal plates 1, which are arranged in a parallel manner. The left and right end faces of the two horizontal plates 1 and the inner sides of the two vertical plates 2 are assembled and plasma-welded into a rectangular shape. The upper or lower surface of the horizontal plate 1 is flush with the upper or lower end face of the vertical plate 2. The radius of the arc-shaped notch 4 is 8 mm, and the arc-shaped notch 4 penetrates the longitudinal body of the horizontal plate 1. The arc-shaped notches 4 opened at the lower left and right ends of the horizontal plate 1 are joined with the inner sides of the vertical plates 2 to form an arc-shaped molten pool 5. The bevel structure of the plasma-welded corner joint of the pipe box in Example 1 is suitable for plasma arc welding of horizontal plates 1 or vertical plates 2 with a thickness of 10 mm, and finally welded into a rectangular pipe box.

[0037] Example 2, as follows Figure 5 As shown, horizontal plates 1 are arranged parallel to each other at the top and bottom, and vertical plates 2 are arranged on the left and right sides of the horizontal plates 1, which are arranged in a parallel manner. The left and right end faces of the two horizontal plates 1 and the inner sides of the two vertical plates 2 are assembled and plasma-welded into a rectangular shape. The upper or lower surface of the horizontal plate 1 is flush with the upper or lower end face of the vertical plate 2. The inner sides of the upper and lower ends of the vertical plate 2 are provided with assembly steps 3, the depth of which is 0.5 mm. The assembly steps 3 are symmetrically arranged on the inner sides of the vertical plate 2. The lower or upper parts of the left and right ends of the horizontal plate 1 are provided with arc-shaped notches 4, the radius of which is 8 mm. After the arc-shaped notches 4 at the lower or upper parts of the left and right ends of the horizontal plate 1 are joined with the upper and lower assembly steps 3 of the vertical plate 2, an irregular molten pool 5 is formed. Example 2: The bevel structure of the plasma welding corner joint of the pipe box is suitable for plasma arc welding of 12mm thick horizontal plate 1 or vertical plate 2, and finally welded into a rectangular pipe box.

[0038] Example 3, such as Figure 4As shown, horizontal plates 1 are arranged parallel to each other in the vertical position, and vertical plates 2 are arranged on the left and right sides of the horizontal plates 1, which are arranged in a parallel manner. The left and right end faces of the two horizontal plates 1 and the inner sides of the two vertical plates 2 are assembled and plasma-welded into a rectangular shape. The upper or lower surface of the horizontal plate 1 is flush with the upper or lower end face of the vertical plate 2. The assembly steps 3 are opened at the upper and lower ends of the inner side of the vertical plate 2, and the depth of the assembly steps 3 at the upper and lower ends of the inner side of the vertical plate 2 is equal. The arc-shaped notches 4 are opened at the upper or lower positions of the left and right ends of the horizontal plates 1, and the arc-shaped notches 4 are symmetrically arranged at the upper and lower parts of the left and right ends of the horizontal plates 1. The arc-shaped notches 4 at the upper and lower ends of the inner side of the vertical plate 2 are joined with the upper arc-shaped notches 4 at the left and right ends of the horizontal plates 1 to form a U-shaped molten pool 5. The bends of the assembly steps 3 at the upper and lower parts of the vertical plate 2 are joined with the lower arc-shaped notches 4 at the left and right ends of the horizontal plates 1 to form an irregular molten pool 5. Example 3: The bevel structure of the plasma welding corner joint of the pipe box is suitable for plasma arc welding of horizontal plate 1 or vertical plate 2 with a thickness of 14 mm or 16 mm, and finally welded into a rectangular pipe box.

[0039] like Figure 4-6 As shown, the welding process of the bevel structure of the corner joint of the pipe box using plasma welding is as follows: First, the vertical plate 2 is placed vertically on the welding platform. Then, the left end of the horizontal plate 1 is joined with the inner side of the upper inner side of the assembly step 3 of the vertical plate 2, and the upper surface of the horizontal plate 1 is flush with the upper end face of the vertical plate 2. The plasma welding gun is aimed at the reserved weld seam, and the metal of the horizontal plate 1 and the vertical plate 2 is melted. At this time, the molten metal fills the U-shaped molten pool 5. A portion of the molten metal flows through the weld seam into the irregularly shaped molten pool 5 at the bottom. As the plasma welding gun moves continuously, molten metal is continuously formed, and in the upper U-shaped molten pool 5 of the horizontal plate 1 and the left vertical plate 2... The molten metal forms a uniform, slightly raised, and smooth weld, and a similar uniform, slightly raised, and smooth weld is also formed on the lower part (back) of the horizontal plate 1. Then, the two vertical plates 2 are placed on the right side of the upper horizontal plate 1, so that the right end face of the horizontal plate 1 is aligned with the assembly step 3 on the upper inner side of the vertical plate 2. The same plasma arc welding action is repeated to achieve plasma arc welding of the corner joints at the joints of the upper horizontal plate 1 and the left and right vertical plates. When it is necessary to weld the lower horizontal plate 1, the upper horizontal plate 1 is flipped over so that it is placed flat on the welding platform. The plasma arc welding work of the upper horizontal plate 1 and the left and right vertical plates 2 is repeated to complete the assembly plasma arc welding of the pipe box, forming a rectangular pipe box.

[0040] like Figure 7As shown in the figure, this utility model adopts the plasma welding process for corner joints of pipe boxes. The macroscopic metallographic image of the welded pipe box shows that, through the bevel structure design of the corner joint of the plasma welding pipe box, the inner and outer welds of the pipe box are uniform, slightly convex and smooth, and the root of the weld is uniformly formed. There are no cases of incomplete welding or weld beads, which can meet the requirements of RT non-destructive testing and realize the welding process of single-sided plasma arc welding and double-sided forming of pipe boxes.

[0041] Various modifications to the above embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A bevel structure for a plasma-welded corner joint of a pipe box, comprising a horizontal plate and a vertical plate, the horizontal plate being arranged parallel to each other vertically, and the vertical plate being arranged on the left and right sides of the horizontal plate, and in a left-right parallel arrangement; the left and right end faces of the two horizontal plates and the inner sides of the two vertical plates are plasma-welded into a rectangular shape, and the upper or lower surface of the horizontal plate is flush with the upper or lower end face of the vertical plate; characterized in that: The steps are set at the upper and lower ends of the inner side of the vertical plate, and the depth of the steps at the upper and lower ends of the inner side of the vertical plate is equal; the arc-shaped notches are set at the upper or lower part of the left and right ends of the horizontal plate, and the arc-shaped notches are symmetrically set at the upper and lower parts of the left and right ends of the horizontal plate; a molten pool is formed at the assembly point of the left or right end of the horizontal plate and the upper or lower end of the inner side of the vertical plate.

2. The bevel structure of a plasma-welded pipe box corner joint according to claim 1, characterized in that: The length of the steps in the assembly is greater than the thickness of the horizontal plate; the gap between the left or right end of the horizontal plate and the inner side of the vertical plate is less than or equal to 0.5 mm.

3. The bevel structure of a plasma-welded pipe box corner joint according to claim 2, characterized in that: The horizontal plate has symmetrical arc-shaped notches at its left and right ends, with a radius of 8 mm, which penetrate the longitudinal body of the horizontal plate.

4. The bevel structure of a plasma-welded pipe box corner joint according to claim 2, characterized in that: The upper and lower ends of the upright plate have arc-shaped notches at their inner corners, and the arc-shaped notches penetrate the longitudinal body of the upright plate.

5. The bevel structure of a plasma-welded pipe box corner joint according to claim 1, characterized in that: The depth of the steps is 0.5 mm, and the steps are L-shaped.

6. The bevel structure of a plasma-welded pipe box corner joint according to claim 1, characterized in that: The arc-shaped notches at the upper and lower ends of the inner side of the vertical plate and the upper arc-shaped notches at the left and right ends of the horizontal plate form a U-shaped molten pool.

7. The bevel structure of a plasma-welded pipe box corner joint according to claim 1, characterized in that: The bends of the upper and lower steps of the vertical plate connect with the arc-shaped recesses at the lower left and right ends of the horizontal plate to form a molten pool.

8. The bevel structure of a plasma-welded corner joint for a pipe box according to claim 1, characterized in that: The horizontal plate has an arc-shaped notch at the lower or upper part of the left or right ends. The arc-shaped notch at the lower or upper part of the left or right ends of the horizontal plate is connected with the upper and lower steps of the vertical plate to form a molten pool.

9. The bevel structure of a plasma-welded pipe box corner joint according to claim 1, characterized in that: The arc-shaped notches at the lower left and right ends of the horizontal plate connect with the inner side of the vertical plate to form an arc-shaped molten pool.

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