Gas metal arc welding bottoming layer welding process

Abstract

The invention particularly relates to a gas metal arc welding bottoming layer welding process. The method specifically comprises the steps that S1, the groove position of a welding base material is cleaned to remove impurities influencing the welding performance; s2, welding of a base coat is carried out, wherein the three steps of arc starting, welding of the base coat and arc stopping are included; according to the method, the welding parameters (when the gap width (the swing width) and the welding position change, the optimal welding quality or state is achieved by controlling or adjusting the current, the voltage, the radian, the time delay on the two sides and the change of the Y value) are accurately controlled by optimizing the bottom layer welding process, the specific arc starting and arc stopping methods are adopted, the welding quality is effectively improved, and the welding quality is improved. The welding defects are reduced, meanwhile, the welding efficiency and the operation safety are improved, the welding time is shortened by reasonably controlling the thickness of the truncated edge, and the welding efficiency is improved.

Description

Technical Field

[0001] The present application belongs to the field of welding technology, and specifically relates to a gas metal arc welding base layer welding process. Background Art

[0002] The weldability of metal materials refers to the adaptability of metal materials to welding processing, that is, the difficulty of obtaining high-quality welded joints under certain welding process conditions (welding method, welding materials, welding process parameters and structural form, etc.), also known as weldability. The common welding method is gas metal arc welding (GMAW), also known as gas metal arc welding (MIG welding), which is a welding method that uses a continuous wire feeding electrode and inert gas protection to achieve metal connection. This process is characterized by high efficiency, versatility and ease of use, and is widely used in the welding of various metal materials. Weldability is not only related to the chemical composition and properties of the parent material itself, but also to the welding materials and process methods. With the continuous emergence of new welding methods, welding materials, and process measures, some metal materials that were originally unweldable or difficult to weld may now become weldable or easy to weld. Among them, the base layer is a very important step in the welding process, especially in the multi-layer and multi-pass welding process. It refers to the first layer of weld formed between the two parts to be connected. The base layer helps determine the shape and size of the final welded part and ensures that the subsequent welding layers are carried out according to the design requirements. A good base layer can evenly distribute stress, thereby reducing deformation during welding. The quality of the base layer directly affects the quality of the entire weld, including its strength, durability and corrosion resistance. For applications that require waterproofing or airtightness, the base layer provides a preliminary sealing barrier. The base layer provides a stable foundation for subsequent filling layers and cover layers, which helps to ensure the consistency of the overall welding quality. Announcement No. CN108608093A discloses a duplex stainless steel vertical butt automatic welding method, involving a CO2 welding gun base layer with welding process parameters of 150-160A welding current, 22-24V welding voltage, and 100-110mm / min welding speed, but it does not involve the welding gun's swing width (X value) and the welding gun's movement distance (Y value), but in actual welding, the welding gun's swing width and the welding gun's movement distance directly affect the quality of welding. At present, when welding the base layer, the actual operation still needs to rely on the welding master's many years of experience to adjust the welding parameters at all times. The learning of these experiences not only takes a lot of time, but also varies from person to person in the learning process. These problems may affect the quality of the weld, welding efficiency and the performance of the final product. In the process of base layer welding, the swing width (X value) of the welding gun and the movement distance (Y value) of the welding gun perpendicular to the welding direction are crucial to the weld formation. However, in the existing process, these parameters are often set according to experience and lack scientific basis, resulting in the weld size and shape being difficult to control. On the other hand, in common welding processes, narrow gaps (welds) appear more frequently, and the common weld width is mostly 0 to 7 mm, of which 3 to 4 mm is the most common. For welds of this width, it is urgent to propose a universal base layer welding process.

[0003] Therefore, in view of the problems that the swing width (X value) of the welding gun and the movement distance (Y value) of the welding gun perpendicular to the welding direction in the existing base layer welding process rely entirely on experience, it is urgent to propose a metal electrode gas shielded welding base layer welding process to solve the current problems. Summary of the invention

[0004] In view of the problems in the existing base layer welding process that the swing width X value of the welding gun and the movement distance Y value of the welding gun perpendicular to the welding direction are completely dependent on experience, the present application proposes a base layer welding process of metal arc welding.

[0005] The specific scheme of this application is as follows:

[0006] A gas metal arc welding base layer welding process comprises the following steps:

[0007] Step S1. Substrate treatment: cleaning the groove of the welding substrate to remove impurities that affect welding performance;

[0008] Step S2. Welding: includes three steps: arc starting, base layer welding and arc ending; during the base layer welding, the distance that the welding gun moves along the weld direction each time it swings along the welding direction is 0.3-2.4 mm, and the swing width of the welding gun is 0-7 mm; the weld width between the welding substrates is 0-7 mm, wherein the swing width of the welding gun is denoted as K1, and the weld width is denoted as K2, wherein K1>K2.

[0009] Preferably, the width of the weld between the welding substrates is 3 to 4 mm.

[0010] Preferably, the blunt edge thickness of the welding substrate is d, 0≤d≤3mm.

[0011] Preferably, the conditions for the base layer welding are: when the blunt edge thickness d=0mm, the voltage of the base layer welding is 15-20V and the current is 60-120A; when the blunt edge thickness 0<d≤3mm, the voltage of the base layer welding is 15-22V and the current is 60-150A.

[0012] Preferably, during the base layer welding, the welding gun moves in a positive crescent shape from the lower part to the upper part of the weld.

[0013] Preferably, during the base layer welding, the angle between the welding gun and the direction along the weld is 70 to 90 degrees, and the arc of the positive crescent shape is 50 to 130 degrees.

[0014] Preferably, during the base layer welding, the stop time of each swing of the welding gun is 200 to 500 ms.

[0015] Preferably, when the arc is started, the welding gun moves along the fold line to the weld gap; when the arc is closed, the arc swing is changed to the fold line swinging in place 1 to 2 times, and then the fold line swings forward 1 to 3 times before closing and extinguishing the arc.

[0016] Preferably, the thickness of the welding substrate is greater than 5 mm.

[0017] The beneficial effects of this application are as follows:

[0018] The base layer welding process of the present application is designed to ensure high-quality, efficient and reliable welding results through a series of optimized steps and parameter settings.

[0019] (1) This application cleans the groove thoroughly before welding, which can effectively remove impurities that affect welding performance and reduce the occurrence of welding defects such as pores and cracks. By regulating the voltage and current during base layer welding, as well as the voltage adjustment during arc starting and arc ending (1 to 3V higher than the base layer welding voltage), a stable arc and good penetration are ensured, thereby improving the quality of the weld.

[0020] (2) The present application adopts an arc starting method of zigzag motion to the weld gap and an arc ending method of straight line swing plus zigzag motion, which helps to smoothly establish and end the welding process. The welding gun of the present application moves in a crescent shape from the lower part of the weld to the upper part, and maintains an angle of 70 to 90 degrees and an arc of 50 to 130 degrees. This welding path is not only conducive to observing the molten pool, but also can evenly heat the parent material and promote good fusion of the metal, thereby speeding up the welding speed. The present application appropriately adjusts the swing width and movement distance of the welding gun according to demand: the swing width (X value) of the welding gun is set to 0 to 7 mm, and the movement distance (Y value) is 0.3 to 2.4 mm. Selecting an appropriate swing width according to the actual width of the weld will neither waste material due to excessive filling nor cause weld defects due to insufficient filling.

[0021] (3) The present application can ensure the welding quality and improve the welding efficiency by reasonably controlling the thickness of the blunt edge to 0≤d≤3mm and appropriately changing the voltage and current according to the thickness of the blunt edge. When the thickness of the blunt edge is 0mm, the voltage and current are reduced to prevent burn-through and the need for repair welding. When the thickness of the blunt edge increases, the voltage and current are appropriately increased to reduce the welding time and improve the welding efficiency. At the same time, the filling amount during the cover can be reduced to save welding materials.

[0022] (4) The present application sets the side stop time during base layer welding to 200 to 500 ms, giving the weld sufficient time to cool and solidify, thereby enhancing the mechanical strength of the weld. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Attached Figure 1 This is a schematic diagram of the base layer welding process of this application;

[0024] Attached Figure 2 This is a schematic diagram of the welding gun's swing width and welding gun's running distance in the base layer welding process of this application.

[0025] Description of reference numerals:

[0026] 1. Welding base material a; 2. Welding base material b; 3. Welding gun; X, welding gun swing width; Y, welding gun movement distance; d, blunt edge. DETAILED DESCRIPTION

[0027] In order to further explain the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the following is a detailed description of the specific implementation methods, structures, features and effects of the present application in combination with the preferred embodiments. It should be noted that, based on many years of work experience, the applicant has found that there is a certain functional relationship between the swing width (X value) of the welding gun and the movement distance (Y value) of the welding gun, and this functional relationship is opposite. When the swing width of the welding gun increases, it means that the weld of the welding substrate increases, and the movement distance (Y value) of the welding gun needs to be appropriately reduced. After many experiments, the applicant found that there is a linear relationship between the swing width (X value) of the welding gun and the movement distance (Y value) of the welding gun, that is, Y = -0.3X + 2.4. The present application is welded by a machine. The welding machine is connected to the circuit, and the welding instructions (thickness of the welding substrate, material of the welding substrate, width of the weld, blunt edge thickness, welding speed) are input in advance. The machine performs welding according to the input welding instructions. In order to test the needs, a steel plate with uniform specifications (5cm*5cm) is prepared in advance, and the diameter of the welding wire is 1cm.

[0028] Example 1

[0029] See also Figures 1-2 This embodiment provides a base layer welding process for a thin plate, wherein the welding substrate a1 and the welding substrate b2 are both low-carbon steel plates with a thickness of 6 mm, a weld width of 3 mm, and a blunt edge d thickness of 0 mm.

[0030] Steps:

[0031] Step S1: Use a wire brush and acetone to clean the groove of the welding substrate to ensure that impurities such as oil, rust and scale are removed.

[0032] Step S2: Base layer welding

[0033] Arc starting: The welding gun 3 is connected to the power supply, the arc starting voltage is set to 16V, the angle between the welding gun 3 and the weld is 80°, and the welding gun 3 moves along the broken line to the weld gap.

[0034] Base layer welding: adjust the voltage of welding gun 3 to 15V, the current to 60A, the angle between welding gun 3 and the weld axis to 80°, the movement trajectory of welding gun 3 is a positive crescent shape, and the arc is 90°. The swing width (X value) of welding gun 3 is 3.5mm, and the movement distance (Y value) is 1.35mm. During the welding process, the movement speed of the welding gun is 12cm / min, and the side stop time is 200ms during the welding process to ensure that the molten pool is fully filled.

[0035] Arc extinguishing: When welding to the end of the weld, the voltage is adjusted to 16V, the welding gun 3 first swings in a straight line once, then moves in a zigzag line twice, and finally extinguishes the arc.

[0036] The weld formed is uniform in shape, smooth in surface, and has no obvious depressions or protrusions; the actual welding time is 10.5s less than the theoretical welding time.

[0037] Example 2

[0038] See also Figures 1-2 This embodiment provides a base layer welding process for medium and thick plates, wherein the welding substrate a1 and the welding substrate b2 are both medium carbon steel plates with a thickness of 8 mm, a weld width of 4 mm, and a blunt edge d thickness of 1 mm.

[0039] Steps:

[0040] Step S1: Use a wire brush and acetone to clean the groove of the welding substrate to ensure that impurities such as oil, rust and scale are removed.

[0041] Step S2: Base layer welding

[0042] Arc starting: The welding gun 3 is connected to the power supply, the arc starting voltage is set to 21V, the angle between the welding gun 3 and the weld is 85°, and the welding gun 3 moves along the broken line to the weld gap.

[0043] Base layer welding: adjust the voltage of welding gun 3 to 18V, the current to 100A, the angle between welding gun 3 and the weld axis to 85°, the movement trajectory of welding gun 3 is a positive crescent shape, and the arc is 110°. The swing width (X value) of welding gun 3 is 5mm, and the movement distance (Y value) is 0.9mm. During the welding process, the wire diameter is 1.0mm, the movement speed of the welding gun is 12cm / min, and the side stop time is 300ms during the welding process to ensure that the molten pool is fully filled.

[0044] Arc extinguishing: When welding to the end of the weld, the voltage is adjusted to 20V, the welding gun 3 first swings in a straight line twice, then moves in a zigzag line three times, and finally extinguishes the arc.

[0045] The weld formed is uniform in shape, smooth in surface, without obvious depressions or protrusions, and the actual welding time is 11.4s less than the theoretical welding time.

[0046] Example 3

[0047] See also Figures 1-2 This embodiment provides a thick plate base layer welding process, wherein the welding substrate a1 and the welding substrate b2 are both low-carbon steel plates with a thickness of 10 mm, a weld width of 5 mm, and a blunt edge d thickness of 2 mm.

[0048] Steps:

[0049] Step S1: Use a wire brush and acetone to clean the groove of the welding substrate to ensure that impurities such as oil, rust and scale are removed.

[0050] Step S2: Base layer welding

[0051] Arc starting: The welding gun 3 is connected to the power supply, and the welding power supply voltage is set to 25 V. The angle between the welding gun 3 and the weld is 90°, and the welding gun 3 moves along the broken line to the weld gap.

[0052] Base layer welding: adjust the voltage of welding gun 3 to 22V, the current to 120A, the angle between welding gun 3 and the weld axis to 90°, the movement trajectory of welding gun 3 is a positive crescent shape, and the arc is 130°. The swing width (X value) of welding gun 3 is 6mm, and the movement distance (Y value) is 0.6mm. During the welding process, the wire diameter is 1.0mm, the movement speed of the welding gun is 12cm / min, and the side stop time is 350ms during the welding process to ensure that the molten pool is fully filled.

[0053] Arc extinguishing: When welding to the end of the weld, the voltage is adjusted to 25V, the welding gun 3 first swings in a straight line for 2 times, then moves in a zigzag line for 3 times, and finally extinguishes the arc.

[0054] The weld formed is uniform in shape, smooth in surface, and has no obvious depressions or protrusions; the actual welding time is 9.5s less than the theoretical welding time.

[0055] Example 4

[0056] See also Figures 1-2 This embodiment provides a base layer welding process for substrates with inconsistent thickness, wherein the thickness of the welding substrate a1 is 6 mm, the welding substrate b2 is a low-carbon steel plate with a thickness of 8 mm, the weld width is 3.5 mm, and the blunt edge d is 3 mm thick.

[0057] Steps:

[0058] Step S1: Use a wire brush and acetone to clean the groove of the welding substrate to ensure that impurities such as oil, rust and scale are removed.

[0059] Step S2: Base layer welding

[0060] Arc starting: The welding gun 3 is connected to the power supply, and the welding power supply voltage is set to 23 V. The angle between the welding gun 3 and the weld is 80°, and the welding gun 3 moves along the broken line to the weld gap.

[0061] Base layer welding: adjust the voltage of welding gun 3 to 22V, the current to 150A, the angle between welding gun 3 and the weld axis to 80°, the movement trajectory of welding gun 3 is a positive crescent shape, and the arc is 50°. The swing width (X value) of welding gun 3 is 4mm, and the movement distance (Y value) is 1.2mm. During the welding process, the wire diameter is 1.0mm, the movement speed of the welding gun is 12cm / min, and the side stop time is 500ms during the welding process to ensure that the molten pool is fully filled.

[0062] Arc extinguishing: When welding to the end of the weld, adjust the voltage of welding gun 3 to 23V, and first swing the welding gun 3 in a straight line once, then move in a zigzag line twice, and finally extinguish the arc.

[0063] The weld formed is uniform in shape, smooth in surface, and has no obvious depressions or protrusions.

[0064] Comparative Example 1

[0065] The difference between this comparative example and Example 1 is that the welding voltage is 16 V. The weld seam is unevenly shaped, with obvious depressions or protrusions on the surface.

[0066] Comparative Example 2

[0067] The difference between this comparative example and Example 1 is that the swing width (X value) of the welding gun 3 is 8 mm, and the movement distance (Y value) is 3 mm. The weld seam is unevenly shaped, with obvious depressions or protrusions on the surface.

[0068] Comparative Example 3

[0069] The difference between this comparative example and Example 1 is that the blunt edge thickness is 0 mm. The weld seam is unevenly shaped, with obvious depressions or protrusions on the surface.

[0070] Comparative Example 4

[0071] The difference between this comparative example and Example 3 is that the blunt edge thickness is 5 mm. The weld seam is unevenly shaped, with obvious depressions or protrusions on the surface.

[0072] The present application optimizes the base layer welding process, including cleaning, precise control of welding parameters (when the gap width (swing width) and welding position change, the best welding quality or state is achieved by controlling or adjusting the current, voltage, arc, delay on both sides and changes in the Y value), using specific arc starting and arc ending methods, and flexibly adjusting the movement path of the welding gun, which effectively improves the welding quality, reduces welding defects, and improves welding efficiency and operational safety, and is suitable for high-quality welding requirements of welds of different widths; by reasonably controlling the blunt edge thickness to 0≤d≤3mm, and appropriately changing the voltage and current according to the blunt edge thickness, the welding quality can be guaranteed and the welding efficiency can be improved. When the thickness of the blunt edge is 0mm, the voltage and current are reduced to prevent burn-through and the need for repair welding. When the thickness of the blunt edge increases, the voltage and current are appropriately increased, which can reduce the welding time and improve the welding efficiency. At the same time, the filling amount during covering can be reduced, saving welding materials.

[0073] The above is only a preferred embodiment of the present application and does not constitute any form of limitation to the present application. Although the present application has been disclosed as a preferred embodiment as above, it is not intended to limit the present application. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present application. However, any modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.

Claims

1. A gas metal arc welding base layer welding process, characterized in that: The following steps are included: Step S1. Substrate treatment: cleaning the groove of the welding substrate to remove impurities that affect welding performance; Step S2. Welding: includes three steps: arc starting, base layer welding and arc ending; during the base layer welding, the distance that the welding gun moves along the weld direction each time it swings along the welding direction is 0.3-2.4 mm, and the swing width of the welding gun is 0-7 mm; the weld width between the welding substrates is 0-7 mm, wherein the swing width of the welding gun is denoted as K1, and the weld width is denoted as K2, wherein K1>K2.

2. A gas metal arc welding base layer welding process according to claim 1, characterized in that: The blunt edge thickness of the welding substrate is d, 0≤d≤3mm.

3. A gas metal arc welding base layer welding process according to claim 2, characterized in that: The conditions for the base layer welding are: when the blunt edge thickness d=0mm, the voltage of the base layer welding is 15-20V and the current is 60-120A; when the blunt edge thickness 0<d≤3mm, the voltage of the base layer welding is 15-22V and the current is 60-150A.

4. The gas metal arc welding base layer welding process according to claim 1, characterized in that: During the base layer welding, the welding gun moves from the lower part to the upper part of the weld in a positive crescent shape.

5. The gas metal arc welding base layer welding process according to claim 1, characterized in that: During the base layer welding, the angle between the welding gun and the direction along the weld is 70-90°, and the arc of the positive crescent is 50-130°.

6. A gas metal arc welding base layer welding process according to claim 1, characterized in that: During the base layer welding, the stop time of each swing of the welding gun is 200 to 500 ms.

7. A gas metal arc welding base layer welding process according to claim 1, characterized in that: When the arc is started, the welding gun moves along the broken line to the weld gap; when the arc is closed, the arc swing is changed to the broken line swinging in place 1 to 2 times, and then the broken line swings forward 1 to 3 times before closing and extinguishing the arc.

8. The gas metal arc welding base layer welding process according to claim 1, characterized in that: The thickness of the welding substrate is greater than 5 mm.

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