Upward position welding method for low-temperature nickel alloy steel

Abstract

The invention provides an overhead position welding method for low-temperature nickel alloy steel. The method comprises the specific steps that the thickness of a first to-be-welded part and the thickness of a second to-be-welded part are compared; the weld leg size is calculated based on the minimum thickness value of the first to-be-welded part and the second to-be-welded part; and a welding device is provided, the welding device comprises a welding gun, the welding gun is obliquely arranged, the welding gun moves from the arc starting position to the arc extinguishing position, and meanwhile the welding gun swings in a reciprocating mode in the horizontal direction and the vertical direction so as to weld the first to-be-welded piece and the second to-be-welded piece. By the adoption of the method, manual operation can be avoided, so that dependence on operation skills of welders is reduced, weld joints with more stable quality are obtained, in addition, the labor intensity of workers is reduced, and the construction efficiency is improved.

Description

Technical Field

[0001] The invention relates to the field of ship overhead welding, in particular to an overhead welding method for low-temperature nickel alloy steel. Background Art

[0002] Low-temperature nickel alloy steel is often used in the construction of independent liquid cargo tanks of liquefied gas ships. For example, there are a large number of overhead welds in the construction of independent liquid cargo tanks. Currently, the overhead welding needs to be welded by manual arc welding first, and then the weld is polished with an angle grinder. In the current welding method, the welding quality depends on the skill level of the welder, the weld quality is unstable, the operator's labor intensity is high, and the efficiency of ship construction is seriously affected. Summary of the invention

[0003] In view of the shortcomings of the related art mentioned above, the purpose of the present invention is to provide a low-temperature nickel alloy steel overhead welding method to solve the problems of unstable weld quality, high labor intensity for operators and low efficiency in shipbuilding in the related art.

[0004] To achieve the above-mentioned object and other related objects, the present invention provides a method for welding low-temperature nickel alloy steel in an overhead position, and the specific steps of the method include:

[0005] comparing the thickness of the first workpiece to be welded and the thickness of the second workpiece to be welded;

[0006] Calculating the weld leg size based on the minimum thickness value of the first workpiece to be welded and the second workpiece to be welded;

[0007] A welding device is provided, comprising a welding gun which is arranged in an inclined manner so as to move the welding gun from an arc starting position to an arc extinguishing position and to swing the welding gun back and forth in a horizontal direction and a vertical direction to weld a first workpiece to be welded and a second workpiece to be welded.

[0008] Optionally, the step of calculating the weld foot size is: based on the formula Calculate the size of the weld leg required for welding, where K is the welding height and W is the welding height. F is the welding coefficient, t p is the minimum thickness value between the first and second parts to be welded, d is the weld length, and l is the weld interval.

[0009] Optionally, the minimum height of the solder foot is 5 mm.

[0010] Optionally, when welding the first workpiece to be welded and the second workpiece to be welded, the welding speed decreases as the weld foot height increases.

[0011] Optionally, the welding gun is arranged at preset angles with the horizontal plane and the vertical plane respectively.

[0012] Optionally, when the welding gun is at the arc starting position, the welding gun is at a preset distance from the first workpiece to be welded and the second workpiece to be welded, respectively, and the preset distance between the welding gun and the first workpiece to be welded is smaller than the preset distance between the welding gun and the second workpiece to be welded.

[0013] Optionally, a preset distance between the welding gun and the first workpiece to be welded, and a preset distance between the welding gun and the second workpiece to be welded both increase as the size of the weld foot increases.

[0014] Optionally, the swing amplitude of the welding gun in the horizontal direction and the vertical direction is ±10 mm.

[0015] As described above, the method for welding low-temperature nickel alloy steel in an overhead position of the present invention has the following beneficial effects: by reciprocating the welding gun in the horizontal and vertical directions during welding, the size and shape of the molten pool can be adjusted to make it more uniform, avoiding defects such as pores and inclusions. By adopting the above method for welding, manual operation can be avoided, thereby reducing the dependence on the welder's operating skills, obtaining a weld with more stable quality, and in addition, reducing the labor intensity of personnel and improving construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic flow chart of the overhead welding method for low-temperature nickel alloy steel in an embodiment of the present invention.

[0017] Figure 2 Shown is a schematic diagram of a welding device in an embodiment of the present invention.

[0018] Figure 3 It is a schematic diagram showing that the welding gun is arranged at an angle in the horizontal direction in an embodiment of the present invention.

[0019] Figure 4 It is a schematic diagram showing that the welding gun is arranged at an angle in the vertical direction in an embodiment of the present invention.

[0020] Figure 5 It is a schematic diagram showing the arrangement of a welding gun at an arc starting position according to an embodiment of the present invention.

[0021] Component number description

[0022] 1. Welding gun; 2. Support arm; 3. Track platform; 4. Welding robot; 5. Slide rail; 6. Gas shielded welding machine. DETAILED DESCRIPTION

[0023] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0024] For example, when describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional view showing the device structure will not be partially enlarged according to the general scale, and the schematic view is only an example, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional space dimensions of length, width and depth should be included.

[0025] For ease of description, spatial relational terms such as "under", "below", "below", "below", "above", "on", etc. may be used herein to describe the relationship of one element or feature shown in the drawings to other elements or features. It will be understood that these spatial relational terms are intended to include other directions of the device in use or operation in addition to the directions depicted in the drawings. In addition, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or there can be one or more intervening layers. As used herein, "between..." means including the end point values.

[0026] In the context of the present application, a structure in which a first feature is described as being "above" a second feature may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0027] It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and therefore the illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0028] like Figure 1 As shown, this embodiment discloses an overhead welding method for low-temperature nickel alloy steel, which is used for overhead welding of a first workpiece to be welded and a second workpiece to be welded, wherein the first workpiece to be welded and the second workpiece to be welded are both low-temperature nickel alloy steel, for example, X12Ni5 steel. The overhead welding method for low-temperature nickel alloy steel comprises the following steps:

[0029] comparing the thickness of the first workpiece to be welded and the thickness of the second workpiece to be welded;

[0030] Calculating the weld leg size based on the minimum thickness value of the first workpiece to be welded and the second workpiece to be welded;

[0031] A welding device is provided, comprising a welding gun 1, which is arranged at an angle so that the welding gun 1 moves from an arc starting position to an arc extinguishing position and simultaneously makes the welding gun 1 reciprocate in the horizontal and vertical directions to weld a first workpiece to be welded and a second workpiece to be welded.

[0032] The size of the weld foot is related to the thickness of the weldment. When the thicknesses of the first workpiece to be welded and the second workpiece to be welded are different, the size of the weld foot is determined by the thinner thickness. Since the thickness of the component is thinner, deformation and burn-through problems are prone to occur during welding. Therefore, the upper limit of the weld foot size is determined by comparing the thicknesses of the first workpiece to be welded and the second workpiece to be welded to improve the welding quality.

[0033] like Figure 2 As shown, specifically, the welding device includes a welding gun 1, a support arm 2, a track platform 3, a welding robot 4, a slide rail 5, a gas shielded welding machine 6 and a wire feeder. The support arm 2 is L-shaped, and the support arm 2 is arranged on the track platform 3. The track platform 3 is slidably arranged on the slide rail 5. For example, the bottom of the track platform 3 is provided with a groove structure adapted to the slide rail 5, so that the track platform 3 can slide along the slide rail 5. The welding robot 4 is invertedly connected to the support arm 2, and the welding gun 1 is connected to the welding robot 4. The welding robot 4 is provided with an operating program inside, so that the welding gun 1 can move in a predetermined trajectory to weld the first to-be-welded part and the second to-be-welded part. The gas shielded welding machine 6 is arranged on the track platform 3, and a signal line is connected between the gas shielded welding machine 6 and the welding robot 4. The wire feeder is installed on the welding robot 4 and connected to the gas shielded welding machine 6 through a relay cable. During the welding process, the wire feeder continuously supplies welding wire to the welding gun 1, the gas shielded welding machine 6 is used to provide shielding gas, and the welding robot 4 drives the welding gun 1 to swing back and forth in the horizontal and vertical directions along the preset trajectory to perform welding. It can be understood that the motion trajectory of the welding gun 1 is a spatial trajectory line. For example, the welding material in the welding process is Thermanit 17 / 15TTΦ1.2mm welding wire, and the shielding gas is a mixed gas of 95% argon and 5% carbon dioxide. Since the molten pool is suspended upside down under the weldment during the welding process in the supine position, it is easy to fall due to gravity, resulting in difficulty in droplet transition and weld formation. The higher the temperature of the molten pool, the smaller the surface tension, the more likely it is to produce depressions on the back of the weld, and weld nodules may appear on the front. During welding, by moving the welding gun 1 back and forth in the horizontal and vertical directions, the size and shape of the molten pool can be adjusted to make it more uniform, avoid defects such as pores and inclusions, and thus ensure the welding quality. By adopting the above method for welding, manual operation can be avoided, thereby reducing the dependence on the welder's operating skills and obtaining welds with more stable quality. In addition, the labor intensity of personnel is reduced and the construction efficiency is improved.

[0034] In this embodiment, the step of calculating the solder foot size is: based on the formula Calculate the size of the weld foot required for welding, where K is the welding height. In this embodiment, the minimum welding height is 5 mm, and W F is the welding coefficient, t p W is the minimum thickness of the first welded part and the second welded part, d is the weld length, and l is the weld interval. FIt depends on the product being welded, and 0.13 is selected here; this embodiment adopts continuous welding, so Take 1.

[0035] In this embodiment, when the height of the weld foot is larger, in order to ensure the welding quality, the welding speed decreases as the height of the weld foot increases.

[0036] Select different process parameters according to different weld leg sizes. The specific process parameters are shown in the following table.

[0037] Table 1 Welding process parameters

[0038]

[0039] In other embodiments, when the materials of the first workpiece to be welded and the second workpiece to be welded change, the current, voltage and welding speed in the above process parameters may be changed accordingly.

[0040] like Figure 3 and Figure 4 As shown, in this embodiment, the posture of the welding gun 1 needs to be set before the welding work begins, wherein the welding gun 1 is set at preset angles with the horizontal plane and the vertical plane respectively. By tilting the welding gun 1, the fluidity of the molten pool can be controlled and the arc can be ensured to act directly on the molten pool to prevent the molten pool liquid from sagging.

[0041] like Figure 5 As shown, when the welding gun 1 is in the arc starting position, the welding gun 1 is at a preset distance from the first workpiece to be welded and the second workpiece to be welded, and the preset distance between the welding gun 1 and the first workpiece to be welded is smaller than the preset distance between the welding gun 1 and the second workpiece to be welded. According to the size of the weld leg and the material of the first workpiece to be welded and the second workpiece to be welded, the preset distances between the welding gun 1 and the first workpiece to be welded and the second workpiece to be welded will be changed accordingly. In this embodiment, the preset distance between the welding gun 1 and the first workpiece to be welded and the preset distance between the welding gun 1 and the second workpiece to be welded both increase as the size of the weld leg increases. The arc starting position setting of the welding gun 1 is shown in the following table.

[0042] Table 2 Arc starting position of welding gun 1

[0043] Serial number Welding foot size c / mm d / mm 1 5 0 4 2 5.5 0.3 4.5 3 6 0.6 5 4 6.5 0.9 5.5 5 7 1.2 6

[0044] Among them, when the distance between the welding gun 1 and the first workpiece to be welded is a preset distance, the distance between the welding rod and the first workpiece to be welded is c, and when the distance between the welding gun 1 and the second workpiece to be welded is a preset distance, the distance between the welding rod and the second workpiece to be welded is d.

[0045] In this embodiment, the movement form of the welding gun 1 is a spatial motion trajectory, that is, the welding gun 1 is a compound motion in the horizontal direction and in the vertical direction. From the perspective of the motion trajectory in the horizontal direction or in the vertical direction alone, when the welding gun 1 moves in a straight line from the arc starting position to the arc extinguishing position, the welding gun 1 will continuously swing back and forth in the horizontal direction. At this time, the welding gun 1 is equivalent to a V-shaped motion trajectory in the horizontal direction. Similarly, the welding gun 1 is also a V-shaped motion trajectory in the vertical direction. It should be noted that during the swinging process of the welding gun 1, the tilting angle of the welding gun 1 remains unchanged.

[0046] In this embodiment, the swing amplitude of the welding gun 1 in the horizontal direction and the vertical direction is ±10mm. For example, when the welding foot size is 5mm, the starting distance between the welding gun 1 and the first workpiece to be welded is 0, and the starting distance between the welding gun 1 and the second workpiece to be welded is 4mm. When welding starts, the welding gun 1 can first move toward the second workpiece to be welded in the horizontal direction, and the maximum distance of the movement is 10mm, and then the welding gun 1 moves away from the second workpiece to be welded, and the maximum distance of the movement is also 10mm, wherein the positive sign can indicate the direction in which the welding gun 1 moves toward the second workpiece to be welded, and the negative sign can indicate the direction in which the welding gun 1 moves away from the second workpiece to be welded.

[0047] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for welding low-temperature nickel alloy steel in an overhead position, used for welding a first workpiece to be welded and a second workpiece to be welded in an overhead position, characterized in that: The specific steps of the method include: comparing the thickness of the first workpiece to be welded and the thickness of the second workpiece to be welded; Calculating the weld leg size based on the minimum thickness value of the first workpiece to be welded and the second workpiece to be welded; A welding device is provided, comprising a welding gun which is arranged in an inclined manner so as to move the welding gun from an arc starting position to an arc extinguishing position and to swing the welding gun back and forth in a horizontal direction and a vertical direction to weld a first workpiece to be welded and a second workpiece to be welded.

2. The method for welding low temperature nickel alloy steel in an overhead position according to claim 1, characterized in that: The steps for calculating the weld foot size are: based on the formula Calculate the size of the weld leg required for welding, where K is the welding height and W is the welding height. F is the welding coefficient, t p is the minimum thickness value between the first and second parts to be welded, d is the weld length, and l is the weld interval.

3. The method for welding low temperature nickel alloy steel in an overhead position according to claim 2, characterized in that: The minimum height of the soldering foot is 5mm.

4. The method for welding low temperature nickel alloy steel in an overhead position according to claim 2, characterized in that: When welding the first workpiece to be welded and the second workpiece to be welded, the welding speed decreases as the weld leg height increases.

5. The method for welding low temperature nickel alloy steel in an overhead position according to claim 1, characterized in that: The welding gun is arranged at preset angles with the horizontal plane and the vertical plane respectively.

6. The method for welding low temperature nickel alloy steel in an overhead position according to claim 1, characterized in that: When the welding gun is at the arc starting position, the welding gun is at a preset distance from the first workpiece to be welded and the second workpiece to be welded, respectively, and the preset distance between the welding gun and the first workpiece to be welded is smaller than the preset distance between the welding gun and the second workpiece to be welded.

7. The method for welding low temperature nickel alloy steel in an overhead position according to claim 6, characterized in that: The preset distance between the welding gun and the first workpiece to be welded and the preset distance between the welding gun and the second workpiece to be welded both increase as the size of the weld leg increases.

8. The method for welding low temperature nickel alloy steel in an overhead position according to claim 1, characterized in that: The swing amplitude of the welding gun in the horizontal and vertical directions is ±10mm.

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