A method for adjusting MIG welding process parameters of an aluminum alloy

Abstract

The application provides an adjusting method of aluminum alloy MIG welding process parameters, and relates to the technical field of welding.The aluminum alloy MIG welding process is taken as a benchmark when the environmental temperature is controlled to be 20 DEG C, when the environmental temperature T deviates from 20 DEG C, the arc starting delay is adjusted to t4, and the time in the initial stage of arc starting is adjusted to t6, so that the stable heat input of the welding molten pool in the arc starting stage is ensured, and thus the welding quality of the aluminum alloy product is ensured.In addition, when the environmental temperature T deviates from 20 DEG C, the welding current decay time is adjusted to t5, so that the stability of the welding molten pool in the welding current decay stage is ensured, and thus the welding quality of the aluminum alloy product is ensured.The method of the application can adjust the MIG welding process parameters of the aluminum alloy when the environmental temperature deviates from 20 DEG C, and can avoid the problems of surface non-fusion, back penetration, surface blackening and spatter of the aluminum alloy welding product.

Description

Technical Field

[0001] This invention relates to the field of welding technology, and more specifically, to a method for adjusting the process parameters of MIG welding of aluminum alloys. Background Technology

[0002] Melt Inert Gas (MIG) welding technology for aluminum alloys is widely used in industries such as aerospace, rail vehicles, and new energy vehicle manufacturing. In MIG welding of aluminum alloys, the workpiece itself acts as the positive electrode, the welding wire as the negative electrode, and a direct current arc is used as the welding heat source. Under the protection of an inert gas, the welding wire electrode generates an arc, allowing the workpieces in the molten pool to melt and mix together. However, the aluminum alloy MIG welding process is very sensitive to heat input. If the heat input is too high, the weld may have excessive penetration, resulting in back penetration; if the heat input is too low, the weld may have surface incompatibility, blackening, and spatter. Currently, constant temperature workshops (20±5℃) are commonly used to eliminate environmental temperature variations, but these workshops require significant investment. Non-constant temperature workshops experience greater environmental temperature fluctuations, leading to uncontrollable welding quality in aluminum alloys. Therefore, when the ambient temperature deviates from 20℃, some process parameters in the aluminum alloy MIG welding process need to be adjusted to avoid the aforementioned problems. Summary of the Invention

[0003] The problem solved by this invention is: how to adjust the MIG welding process parameters of aluminum alloys when the ambient temperature deviates from 20°C, so as to avoid problems such as surface non-fusion, back penetration, surface blackening, and spatter in aluminum alloy welded products.

[0004] To address the above problems, this invention provides a method for adjusting the process parameters of aluminum alloy MIG welding, comprising:

[0005] Step S1: Control the ambient temperature to 20℃, and obtain standard MIG welding process parameters that can ensure the quality of aluminum alloy welded products through multiple aluminum alloy MIG welding experiments; the standard MIG welding process parameters include 20℃ arc start delay t1, 20℃ arc start initial stage time t2, and 20℃ welding current decay time t3.

[0006] Step S2: Based on t1, t2, K1 and K2, obtain the arc ignition delay t4 and the initial arc ignition time t6 when the ambient temperature is T; based on the ambient temperature T, obtain the welding current decay time t5 when the ambient temperature is T; where K1 is the thermal radiation coefficient of aluminum alloy at 20℃ and K2 is the thermal radiation coefficient of aluminum alloy at temperature T.

[0007] Step S3: When performing aluminum alloy MIG welding, if the ambient temperature T deviates from 20℃, adjust the arc ignition delay to t4, the initial arc ignition stage time to t6, and the welding current decay time to t5.

[0008] Optionally, in step S1, obtaining the arc initiation delay t4 and the initial arc initiation time t6 at ambient temperature T based on t1, t2, K1, and K2 includes:

[0009] Based on t1, t2, K1 and K2, the arc ignition delay t4 and the initial arc ignition time t6 when the ambient temperature is T are obtained by equations (1) and (2).

[0010] Wherein, equation (1) is:

[0011] t2×K1=t6×K2;

[0012] Equation (2) is:

[0013] t4 = t6 + t1 - 2t2.

[0014] Optionally, in step S2, obtaining the welding current decay time t5 at an ambient temperature of T based on the ambient temperature T includes:

[0015] Based on the ambient temperature T, the welding current decay time t5 at ambient temperature T is obtained by equation (3); wherein, equation (3) is:

[0016] t5 = 0.6 - 0.07T.

[0017] Optionally, T is 0°C to 40°C.

[0018] Optionally, the aluminum alloy is selected from one of 6061 aluminum alloy, 6060 aluminum alloy, 6082 aluminum alloy and 6063 aluminum alloy.

[0019] Optionally, in step S1, the criterion for judging the quality of the aluminum alloy welded product is: the aluminum alloy welded product does not exhibit surface non-fusion, back penetration, surface blackening, or spatter.

[0020] Optionally, in step S1, controlling the ambient temperature to 20°C and obtaining standard MIG welding process parameters that ensure the quality of aluminum alloy welded products through multiple aluminum alloy MIG welding experiments includes:

[0021] The ambient temperature was controlled at 20℃, and more than 100 aluminum alloy MIG welding experiments were conducted. The process parameters used in the qualified aluminum alloy welding products were statistically analyzed and the average value was taken.

[0022] Optionally, in step S2, both K1 and K2 are measured by Fourier transform infrared spectroscopy.

[0023] Optionally, the aluminum alloy MIG welding process includes an arc initiation stage, a welding current decay stage, a main welding stage, and an arc termination stage.

[0024] Optionally, the welding current during the arc initiation stage is I1, and the welding current during the main welding stage is I0; the ratio of I1 to I0 is 1.05 to 1.50.

[0025] Compared with related technologies, this invention uses aluminum alloy MIG welding at an ambient temperature of 20°C as a benchmark. Based on the arc initiation delay t1 at 20°C, the initial arc initiation stage time t2 at 20°C, the thermal radiation coefficient of the aluminum alloy at 20°C, and the thermal radiation coefficient of the aluminum alloy at temperature T, the arc initiation delay t4 and the initial arc initiation stage time t6 at ambient temperature T are obtained. When the ambient temperature T deviates from 20°C, the arc initiation delay is adjusted to t4, and the initial arc initiation stage time is adjusted to t6 to ensure stable heat input to the weld pool during the arc initiation stage, thereby ensuring the welding quality of the aluminum alloy product. Furthermore, when the ambient temperature T deviates from 20°C, the welding current decay time is adjusted to t5 to ensure the stability of the weld pool during the welding current decay stage, thereby ensuring the welding quality of the aluminum alloy product. Using the method of this invention, when the ambient temperature deviates from 20°C, the MIG welding process parameters of the aluminum alloy are adaptively adjusted, which can avoid problems such as surface incompatibility, back penetration, surface blackening, and spatter in the welded aluminum alloy products. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the method for adjusting the process parameters of aluminum alloy MIG welding in an embodiment of the present invention;

[0027] Figure 2 The image shows the aluminum alloy welded product obtained in Example 2;

[0028] Figure 3 Image of the aluminum alloy welded product prepared in Comparative Example 1;

[0029] Figure 4 Image of the aluminum alloy welded product obtained in Comparative Example 2;

[0030] Figure 5 Image of the aluminum alloy welded product prepared in Comparative Example 3;

[0031] Figure 6 This is an image of the aluminum alloy welded product obtained in Comparative Example 4. Detailed Implementation

[0032] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0033] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0034] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first," "second," etc., mentioned in this invention are used to distinguish different objects, not to describe a specific order or hierarchy. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0035] The process of MIG welding of aluminum alloys includes the arc initiation stage, the welding current decay stage, the main welding stage, and the arc termination stage. The arc initiation stage in MIG welding refers to the transition from the contact of the welding wire with the workpiece to the stable combustion of the arc. The arc initiation delay refers to the time of the arc initiation stage. The welding current decay time is the time of the welding current decay stage.

[0036] The arc ignition stage is divided into the initial arc ignition stage and the arc stabilization stage. The initial stage is from the start of welding to the formation of a stable molten pool. In the initial stage, the heat absorbed by the aluminum alloy base material mainly comes from thermal radiation. Therefore, the thermal radiation coefficient of the aluminum alloy base material has a significant impact on the formation of the weld pool. In the arc stabilization stage, as the welding wire continuously melts into the molten pool, the heat absorbed by the aluminum alloy base material mainly comes from thermal conduction. The temperature of the base material around the molten pool reaches over 200℃, and the temperature of the molten pool is approximately 600℃. The temperatures of the base material and the molten pool are much higher than the ambient temperature. Therefore, the ambient temperature has a very small impact on the weld pool during the arc stabilization stage. Thus, the time required for the arc stabilization stage remains essentially unchanged when the ambient temperature changes.

[0037] To ensure the welding quality of aluminum alloy products, when the ambient temperature changes, the heat absorption Q1 during the initial stage of arc initiation needs to remain constant to ensure a stable heat input to the weld pool. The formula for calculating Q1 is as follows:

[0038] Q1=q×t 初始 ×K;

[0039] Where q is the arc heating density during the arc initiation stage, and t 初始 The initial arc initiation stage time is denoted by K, and K is the thermal radiation coefficient of the aluminum alloy. Since the thermal radiation coefficient of the aluminum alloy varies at different temperatures, the initial arc initiation stage time should also change when the ambient temperature changes. Since the arc stabilization stage time remains basically unchanged, the arc initiation delay and the initial arc initiation stage time can be adjusted to ensure that the heat absorption of thermal radiation in the initial arc initiation stage remains unchanged, thereby ensuring the welding quality of aluminum alloy products.

[0040] Under normal conditions, during MIG welding of aluminum alloys, the ratio of the welding current I1 during the arc initiation phase to the welding current I0 during the main welding phase is 1.05 to 1.5. The stage where the welding current changes from I1 to I0 after the arc initiation phase is the welding current decay phase. Studies have found that when the ambient temperature changes, the time t of the welding current decay phase needs to be adjusted. 衰减 Adjustments are made accordingly to ensure the stability of the molten pool, thereby ensuring the welding quality of aluminum alloy products. The empirical formula used for adjusting the welding current decay stage is t. 衰减 =0.6-0.07T, where T is the ambient temperature.

[0041] In summary, when performing MIG welding of aluminum alloys, the arc ignition delay, the initial arc ignition time, and the welding current decay time can be adjusted to avoid problems such as surface non-fusion, back penetration, surface blackening, and spatter in the welded aluminum alloy products.

[0042] Based on the above considerations, such as Figure 1 As shown, a method for adjusting aluminum alloy MIG welding process parameters according to an embodiment of the present invention includes:

[0043] Step S1: Control the ambient temperature to 20℃, and obtain standard MIG welding process parameters that can ensure the quality of aluminum alloy welded products through multiple aluminum alloy MIG welding experiments; the standard MIG welding process parameters include 20℃ arc start delay t1, 20℃ arc start initial stage time t2, and 20℃ welding current decay time t3.

[0044] Step S2: Based on t1, t2, K1 and K2, obtain the arc ignition delay t4 and the initial arc ignition time t6 when the ambient temperature is T; based on the ambient temperature T, obtain the welding current decay time t5 when the ambient temperature is T; where K1 is the thermal radiation coefficient of aluminum alloy at 20℃ and K2 is the thermal radiation coefficient of aluminum alloy at temperature T.

[0045] Step S3: When performing aluminum alloy MIG welding, if the ambient temperature T deviates from 20℃, adjust the arc ignition delay to t4, the initial arc ignition stage time to t6, and the welding current decay time to t5.

[0046] This invention uses aluminum alloy MIG welding at an ambient temperature of 20°C as a benchmark. Based on the arc initiation delay t1 at 20°C, the initial arc initiation stage time t2 at 20°C, the thermal radiation coefficient of the aluminum alloy at 20°C, and the thermal radiation coefficient of the aluminum alloy at temperature T, the arc initiation delay t4 and the initial arc initiation stage time t6 at ambient temperature T are obtained. When the ambient temperature T deviates from 20°C, the arc initiation delay is adjusted to t4, and the initial arc initiation stage time is adjusted to t6 to ensure stable heat input to the weld pool during the arc initiation stage, thereby ensuring the welding quality of the aluminum alloy product. Additionally, when the ambient temperature T deviates from 20°C, the welding current decay time is adjusted to t5 to ensure the stability of the weld pool during the welding current decay stage, thereby ensuring the welding quality of the aluminum alloy product. Using the method of this invention, when the ambient temperature deviates from 20°C, the MIG welding process parameters of the aluminum alloy are adaptively adjusted, which can avoid problems such as surface incompatibility, back penetration, surface blackening, and spatter in the welded aluminum alloy products.

[0047] In some embodiments of the present invention, in order to ensure the welding quality of aluminum alloy products, it is necessary to keep the heat absorption Q1 of thermal radiation in the initial stage of arc initiation constant when the ambient temperature changes. Based on this principle, in step S1, obtaining the arc initiation delay t4 and the initial arc initiation time t6 at an ambient temperature of T based on t1, t2, K1, and K2 includes:

[0048] Based on t1, t2, K1 and K2, the arc start delay t4 when the ambient temperature is T is obtained by equation (1);

[0049] Wherein, equation (1) is:

[0050] t2×K1=t6×K2;

[0051] Equation (2) is:

[0052] t4=t6-t2+t1-t2=t6+t1-2t2.

[0053] In some embodiments of the present invention, step S2, which involves obtaining the welding current decay time t5 at an ambient temperature of T, includes:

[0054] Based on the ambient temperature T, the welding current decay time t5 at ambient temperature T is obtained by equation (3); wherein, equation (3) is:

[0055] t5 = 0.6 - 0.07T; this formula is an empirical formula summarized from experiments.

[0056] In some embodiments of the present invention, T is 0°C to 40°C.

[0057] In some embodiments of the present invention, the aluminum alloy is selected from one of 6061 aluminum alloy, 6060 aluminum alloy, 6082 aluminum alloy and 6063 aluminum alloy.

[0058] In some embodiments of the present invention, in step S1, the criteria for judging the quality of the aluminum alloy welded product are: the aluminum alloy welded product does not exhibit surface non-fusion, back penetration, surface blackening, or spatter.

[0059] In some embodiments of the present invention, step S1, which involves controlling the ambient temperature to 20°C and obtaining standard MIG welding process parameters that ensure the quality of aluminum alloy welded products through multiple aluminum alloy MIG welding experiments, includes:

[0060] The ambient temperature was controlled at 20℃, and more than 100 aluminum alloy MIG welding experiments were conducted. The process parameters used in the qualified aluminum alloy welding products were statistically analyzed and the average value was taken.

[0061] In some embodiments of the present invention, in step S2, K1 and K2 are both measured by Fourier transform infrared spectroscopy.

[0062] In some embodiments of the present invention, the welding current during the arc initiation stage is I1, and the welding current during the main welding stage is I0; the ratio of I1 to I0 is 1.05 to 1.50.

[0063] The present invention will be further described below with reference to specific embodiments.

[0064] Example 1

[0065] The ambient temperature was controlled at 20℃, and 100 MIG welding experiments were conducted using 6061 aluminum alloy to obtain aluminum alloy welded products. The process parameters used for the qualified aluminum alloy welded products were statistically analyzed and averaged. The statistics showed that when the welding temperature was 20℃, the optimal welding current during the MIG welding process was 220A during the arc initiation phase, 170A during the main welding phase, 0.9m / min during the welding speed, 0.5s during the arc initiation delay, 0.15s during the initial arc initiation phase, and 0.46s during the welding current decay time. The aluminum alloy welded products obtained using the above process parameters were of qualified quality.

[0066] Tests showed that the thermal emissivity of 6061 aluminum alloy is 0.14 at 20℃ and 0.07 at 0℃.

[0067] Example 2

[0068] According to the method provided by the present invention, the arc ignition delay at an ambient temperature of 0°C is 0.65s, the initial arc ignition stage time at an ambient temperature of 0°C is 0.3s, and the welding current decay time at an ambient temperature of 0°C is 0.6s.

[0069] The ambient temperature was controlled at 0℃, and MIG welding was performed using 6061 aluminum alloy to obtain aluminum alloy welded products. During the MIG welding process, the arc ignition delay was adjusted to 0.65s, the initial arc ignition time was adjusted to 0.3s, and the welding current decay time was adjusted to 0.6s, while keeping other process parameters the same as in the example.

[0070] Comparative Example 1

[0071] The difference from Example 2 is that the arc initiation delay is adjusted to 0.55s and the time of the initial stage of arc initiation is adjusted to 0.2s.

[0072] Comparative Example 2

[0073] The difference from Example 2 is that the arc initiation delay is adjusted to 0.95s and the time of the initial stage of arc initiation is adjusted to 0.6s.

[0074] Comparative Example 3

[0075] The difference from Example 2 is that the welding current decay time is adjusted to 0.2s.

[0076] Comparative Example 4

[0077] The difference from Example 2 is that the welding current decay time is adjusted to 0.8s.

[0078] Experimental Example

[0079] The quality of the aluminum alloy welded products obtained in Example 2 and Comparative Examples 1 to 4 was observed, and the results are shown in the figure. Figures 2 to 6 ,from Figure 2 It can be seen that the aluminum alloy product obtained in Example 2 is of good quality, with no surface incompatibility, back-through defects, surface blackening, or spattering. Figure 3 It can be seen that the aluminum alloy product obtained in Comparative Example 1 exhibits surface incompatibility and blackening. From Figure 4 It can be seen that the aluminum alloy product prepared in Comparative Example 2 exhibits a back-view design. From... Figure 5 It can be seen that the aluminum alloy product obtained in Comparative Example 3 exhibits spattering. From... Figure 6 It can be seen that the aluminum alloy product prepared in Comparative Example 4 has a back-view design.

[0080] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A method for adjusting process parameters in aluminum alloy MIG welding, characterized in that, include: Step S1: Control the ambient temperature to 20℃, and obtain standard MIG welding process parameters that can ensure the quality of aluminum alloy welded products through multiple aluminum alloy MIG welding experiments; the standard MIG welding process parameters include 20℃ arc start delay t1, 20℃ arc start initial stage time t2, and 20℃ welding current decay time t3. Step S2: Based on t1, t2, K1, and K2, obtain the arc ignition delay t4 and the initial arc ignition time t6 at ambient temperature T; based on ambient temperature T, obtain the welding current decay time t5 at ambient temperature T; where K1 is the thermal radiation coefficient of aluminum alloy at 20℃, and K2 is the thermal radiation coefficient of aluminum alloy at temperature T; the step of obtaining the arc ignition delay t4 and the initial arc ignition time t6 at ambient temperature T based on t1, t2, K1, and K2 includes: Based on t1, t2, K1 and K2, the arc ignition delay t4 and the initial arc ignition time t6 when the ambient temperature is T are obtained by equations (1) and (2). Wherein, equation (1) is: t2×K1=t6×K2; Equation (2) is: t4 = t6 + t1 - 2t2; The process of obtaining the welding current decay time t5 at ambient temperature T includes: Based on the ambient temperature T, the welding current decay time t5 at ambient temperature T is obtained by equation (3); wherein, equation (3) is: t5 = 0.6 - 0.07T; Step S3: When performing aluminum alloy MIG welding, if the ambient temperature T deviates from 20℃, adjust the arc ignition delay to t4, the initial arc ignition stage time to t6, and the welding current decay time to t5.

2. The method for adjusting the process parameters of aluminum alloy MIG welding according to claim 1, characterized in that, T ranges from 0°C to 40°C.

3. The method for adjusting the process parameters of aluminum alloy MIG welding according to claim 1, characterized in that, The aluminum alloy is selected from one of 6061 aluminum alloy, 6060 aluminum alloy, 6082 aluminum alloy and 6063 aluminum alloy.

4. The method for adjusting the process parameters of aluminum alloy MIG welding according to claim 1, characterized in that, In step S1, the criteria for judging the quality of the aluminum alloy welded product are: the aluminum alloy welded product does not exhibit surface non-fusion, back penetration, surface blackening, or spatter.

5. The method for adjusting the process parameters of aluminum alloy MIG welding according to claim 1, characterized in that, In step S1, controlling the ambient temperature to 20°C and obtaining standard MIG welding process parameters that ensure the quality of aluminum alloy welded products through multiple aluminum alloy MIG welding experiments includes: The ambient temperature was controlled at 20℃, and more than 100 aluminum alloy MIG welding experiments were conducted. The process parameters used in the qualified aluminum alloy welding products were statistically analyzed and the average value was taken.

6. The method for adjusting the process parameters of aluminum alloy MIG welding according to claim 1, characterized in that, In step S2, K1 and K2 are both measured by Fourier transform infrared spectroscopy.

7. The method for adjusting the process parameters of aluminum alloy MIG welding according to claim 1, characterized in that, The aluminum alloy MIG welding process includes the arc initiation stage, the welding current decay stage, the main welding stage, and the arc termination stage.

8. The method for adjusting the process parameters of aluminum alloy MIG welding according to claim 7, characterized in that, The welding current during the arc initiation stage is I1, and the welding current during the main welding stage is I0; the ratio of I1 to I0 is 1.05 to 1.50.

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