CN110625226A - A K-TIG deep penetration welding control system and method under the action of a composite magnetic field - Google Patents

Abstract

The invention discloses a K-TIG deep penetration welding control system and control method under the action of a composite magnetic field. The composite magnetic field is composed of a rotating magnetic field and a longitudinal magnetic field. The composite magnetic field is introduced into the K-TIG deep penetration welding arc. area, so that the welding arc can change its original motion state under the action of the electromagnetic force of the compound magnetic field. The welding control system is mainly composed of a composite magnetic field excitation system and a K-TIG deep penetration welding welding system. The control method is a control method based on the penetration state of the weld surface. The image acquisition sensor collects the penetration state of the back of the weld, and after computer analysis and judgment, automatically adjusts the parameters of the composite magnetic field to ensure that the back of the weld can In a state of good penetration.

Description

A K-TIG deep penetration welding control system and method under the action of a composite magnetic field

technical field

The invention relates to the field of welding technology, in particular to a K-TIG deep penetration welding control system and control method under the action of a composite magnetic field.

Background technique

Compared with traditional TIG welding, K-TIG welding is a new welding method that forms a keyhole through high current to achieve deep penetration welding. It can realize single-sided welding and double-sided forming on the base metal of 3-16mm, and has the advantages of high efficiency, high quality and low cost.

However, during the welding process of K-TIG welding, some welding defects will also appear. For example, undercutting will occur. If the molten pool cools down quickly, it may also cause coarse grains in the weld structure, which will lead to mechanical defects. poor performance etc. Therefore, it is necessary to develop a new welding method to improve the welding defects in the above welding process.

The traditional methods to improve the mechanical properties of the weld are generally to heat the weld after the welding is completed or to add alloy elements during the welding process. Due to welding costs and other reasons, these improvement methods are often limited to the experimental field, and cannot be used applied to the actual production process. Previous studies have shown that introducing a magnetic field in the welding arc region can improve the welding effect, refine the grains and improve its mechanical properties. However, the previous research fields mostly focused on some traditional welding methods, such as TIG welding, MIG welding and so on. However, there are relatively few studies on introducing magnetic field into the field of K-TIG welding. The significant difference between K-TIG welding and these traditional welding methods is that the welding current is relatively large during the welding process, the heat input is relatively high, and the cooling rate is fast, so a relatively large grain structure is often formed. The reason why the magnetic field causes grain refinement is that, on the one hand, the action of the magnetic field will cause the movement of the welding arc, which will then drive the movement of the molten pool; on the other hand, the welding pool will be directly affected by the force under the action of the magnetic field. Therefore, the molten pool is in a dynamic solidification process, which is more conducive to the formation of fine grains. In order to verify the actual effect of the above theoretical research, a set of K-TIG deep penetration welding control system under the action of a composite magnetic field is built in the present invention.

Contents of the invention

In order to solve the above technical problems, the object of the present invention is to provide a K-TIG deep penetration welding control system and method under the action of a composite magnetic field.

The purpose of the present invention is achieved through the following technical solutions:

A K-TIG deep penetration welding control system under the action of a compound magnetic field, including:

The system includes a composite magnetic field excitation system and a K-TIG deep penetration welding system;

The composite magnetic field excitation system is used to generate a rotating magnetic field or/and a longitudinal magnetic field;

The K-TIG deep penetration welding welding system is used to complete the whole welding process of arc starting, welding and arc ending.

Further, the composite magnetic field excitation system includes a mechanical device system and an electric control system;

The mechanical device system is a mechanical component that generates a composite magnetic field, including a longitudinal magnetic field excitation column, a rotating magnetic field excitation column, a gasket, an upper end cover, a lower end cover, a cooling air inlet, a cooling air outlet, and a sleeve;

The electric control system is used to control the parameters in the composite magnetic field, including a three-phase AC converter, a one-way AC converter, a sliding rheostat, a high dynamic camera and an industrial control computer.

Further, the longitudinal magnetic field excitation column and the rotating magnetic field excitation column are used to enhance the magnetic field and conduct magnetism, and the magnetic field generated by the energized coil will guide the welding arc along the longitudinal magnetic field excitation column and the rotating magnetic field excitation column the area in which it is located;

The sealing gasket, the upper end cover, the lower end cover and the sleeve constitute a closed cooling gas circulation space, so that the cooling gas can flow fully and reduce the heat generated by the excitation magnetic column;

The upper end cover, the lower end cover and the sleeve are also used to fix the position of the rotating magnetic field excitation column, so that the rotating magnetic field excitation column is evenly distributed around the lower end cover, and at the same time, the longitudinal magnetic field excitation column is relative to the rotating field excitation column. The position is fixed.

Further, the three-phase AC frequency converter and the sliding rheostat are used to change the rotation frequency of the rotating magnetic field and the magnetic field strength of the magnetic field;

The unidirectional AC frequency converter and the sliding rheostat are used to change the changing frequency and magnetic field strength of the longitudinal magnetic field;

The high dynamic camera and the industrial control computer are used for feedback and control of the whole welding process, and make the weld seam in a state of good penetration during the welding process.

Further, the K-TIG deep penetration welding system includes a welding power supply, a welding torch, a cooling water tank, an argon gas bottle and a welding workpiece;

The welding power supply is used to provide power for the entire welding process;

The welding torch is a special welding torch for K-TIG welding, and the adjustable range is 0-1000A;

The cooling water tank is used to cool the welding torch in time during the welding process;

The argon cylinder is used to provide shielding gas for the whole welding process, and the shielding gas is passed to the surface and bottom of the weld seam to ensure that the weld seam is not oxidized during the welding process.

A welding control method for K-TIG deep penetration welding under the action of a compound magnetic field, comprising:

Grinding and assembling welding workpieces for welding;

Power on the robot motion system;

Teach the welding trajectory according to the actual welding seam position;

Power on the welding system to prepare for welding;

Adjust the image acquisition system so that the image acquisition system is in the camera mode;

The arc is started for welding and collection, and the excitation device is energized for excitation at the moment of arc start;

When the welding is finished, turn off the system power.

Compared with the prior art, one or more embodiments of the present invention may have the following advantages:

(1) In the present invention, the effect of the magnetic field is introduced into the K-TIG deep penetration welding process, which can improve the original welding effect. When K-TIG deep penetration welding is used alone for welding, due to the large welding current, the heat input is large , tends to lead to coarse grains of the weld structure, which in turn leads to poor mechanical properties of the weld, and when a magnetic field acts on the welding area, especially when a compound magnetic field acts on the welding area, it can often improve the stiffness of the welding arc And the vibration effect of the molten pool in the weld is intensified, which can further refine the structure of the weld and improve the mechanical properties of the weld.

(2) use the mechanical device in the present invention to more conveniently carry out the research of welding process under the action of magnetic field. The research on the action effect of the composite magnetic field is completed, and in the present invention, a single test device can be used to generate two different magnetic field forms independently, and also to generate a composite magnetic field in which two magnetic fields are superimposed on each other.

(3) In the present invention, the control of the welding effect can be realized indirectly by controlling the magnetic field parameters. When using the traditional welding method for welding, when welding penetration and incomplete penetration occur, it is often by adjusting the welding current Or the welding speed is adjusted, and when the magnetic field is used for welding, not only can it be adjusted in the traditional way, but also the welding process can be controlled by adjusting the parameters of the magnetic field. The multi-parameter adjustment control method can make the control of the whole welding process more precise.

Description of drawings

Figure 1 is a structural diagram of the K-TIG deep penetration welding control system based on the composite magnetic field;

Fig. 2 is a schematic diagram of the composite magnetic field lines of force;

Fig. 3 is a schematic diagram of the magnetic force lines of the rotating magnetic field;

Fig. 4 is a schematic diagram of longitudinal magnetic field lines of force;

Figures 5a and 5b are internal structural diagrams of the composite magnetic field device;

Figure 6 is an external schematic diagram of the composite magnetic field device;

Fig. 7 is the workflow diagram of this welding system;

Fig. 8 is a feedback control diagram of the welding seam state of the welding system.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the embodiments and accompanying drawings.

As shown in Figure 1, it is the structure of the K-TIG deep penetration welding control system based on the composite magnetic field, including the composite magnetic field excitation system and the K-TIG deep penetration welding welding system;

The composite magnetic field excitation system is used to generate a rotating magnetic field or/and a longitudinal magnetic field;

The K-TIG deep penetration welding welding system is used to complete the whole welding process of arc starting, welding and arc ending.

The composite magnetic field excitation system is the part that generates the magnetic field in the whole welding system. The composite magnetic field excitation system can generate either a rotating magnetic field or a longitudinal magnetic field alone, or a composite magnetic field of the two magnetic fields. The form of the composite magnetic field that generates the magnetic field is shown in Figure 2. The rotating magnetic field and the longitudinal magnetic field generated by the composite magnetic field device are in the same space, and the two overlap each other. Figure 3 shows the form of the magnetic field generated when the rotating magnetic field acts alone. According to the working principle of the three-phase AC asynchronous motor and Faraday's law of electromagnetic induction, when the three-phase alternating current is applied to the excitation column of the rotating magnetic field, the N at both ends of the excitation column The pole and the S pole are in the process of alternating change. Since the magnetic force line is always directed from the N pole to the S pole, the magnetic field generated by it is always in a state of rotational motion. When the connection sequence of any two lines of the excitation column is changed, the rotation The direction of rotation of the magnetic field changes. Figure 4 shows the form of the magnetic field generated by the longitudinal magnetic field device, and most of the magnetic force lines are distributed along the direction parallel to the welding torch.

As shown in Figure 1, the composite magnetic field excitation system also includes two parts: mechanical device system and electric control system. As shown in Figures 5a and 5b, the mechanical device system includes a longitudinal magnetic field excitation column 1, a rotating magnetic field excitation column 2, a gasket 3, an upper end cover 4, a lower end cover 5, a cooling air inlet 6, and a cooling air outlet 7 and sleeve 8. The electronic control system includes three-phase AC inverter, one-way AC inverter, sliding rheostat, high dynamic camera and industrial control computer.

The longitudinal magnetic field excitation column 1 and the rotating magnetic field excitation column 2 mainly play the role of enhancing the magnetic field and conducting magnetism, and the magnetic field generated by the energized coil will guide along the excitation magnetic column to the area where the welding arc is located. Gasket 3, upper end cover 4, lower end cover 5, and sleeve 8 form a closed cooling gas circulation space to ensure sufficient flow of cooling gas, reduce the heat generated by the excitation column, and enable the entire excitation device to work for a long time . At the same time, the upper end cover 4, the lower end cover 5 and the sleeve 8 also play a fixing role, fixing the positions of the six rotating magnetic field excitation columns so that they can be evenly distributed around the circumference, and at the same time ensure that the longitudinal magnetic field excitation columns are excited relative to the rotating magnetic field The position of the column is fixed.

The electronic control system includes three-phase AC inverter, one-way AC inverter, sliding rheostat, high dynamic camera and industrial control computer. Among them, the three-phase AC frequency converter and the sliding rheostat are mainly used to change the magnetic field strength of the rotating magnetic field and the rotating frequency of the magnetic field. The one-way AC frequency converter and the sliding rheostat are mainly used to change the changing frequency and magnetic field strength of the longitudinal magnetic field. The high dynamic camera and industrial control computer are mainly used for feedback control of the whole welding process to ensure that the weld seam can always be in a state of good penetration during the welding process.

As shown in Figure 1, the K-TIG deep penetration welding system includes devices such as a welding power source, a welding torch, a cooling water tank, an argon gas bottle, and a welding workpiece. The welding power supply provides power for the entire welding process, and the welding torch is dedicated to K-TIG welding. The welding torch can be adjusted in the range of 0-1000A; the cooling water tank cools the welding torch in time during the welding process, the cold water in the cooling water tank enters the cooling water circulation inlet of the welding torch after coming out of the outlet of the water tank, and the cold water circulates inside the welding torch After the flow cools down the inside of the welding torch, it becomes hot water from the outlet of the cooling water circulation channel of the welding torch, and enters the cooling water tank again for cooling to become cold water; the argon gas cylinder is used to provide protective gas for the entire welding process, during the welding process At the same time, shielding gas is passed to the surface and bottom of the weld to ensure that the weld is not oxidized.

As shown in Figure 7, the embodiment of the present invention also discloses a control method using the K-TIG deep penetration welding control system under the action of the above-mentioned composite magnetic field, including the following steps:

First, use an angle grinder to grind off the rust on the part of the welding workpiece to be welded, and then use a spot welder to spot weld the two ends of the weld, and finally use a special fixture to assemble the welding workpiece on the welding platform for welding; After power on, teach the welding trajectory according to the actual welding seam position. When teaching the welding trajectory, since it is straight-line welding, it is only necessary to determine the starting point and end point of welding and the height of the welding torch from the welding workpiece. After the teaching is completed, power on the welding system to prepare for welding; adjust the entire image acquisition position and make it in the camera mode. When adjusting the camera image acquisition position, first ensure that the position of the camera will not affect the welding trajectory. After fixing the camera position, adjust the focal length of the camera so that the image can be clearly displayed on the industrial computer. In this process, there is a feedback control mechanism for the weld penetration state (as shown in Figure 8). The state of the molten pool on the surface of the seam, and transmit the collected images to the industrial computer to judge whether the weld is in a state of good penetration. Frequency or strength to ensure that the weld is in a state of good penetration. Due to the influence of strong arc light during the welding process, the aperture of the camera should be adjusted to the minimum, and finally the arc should be started for welding and collected, and the magnetic field frequency or magnetic field strength of the composite magnetic field should be adjusted to ensure that the molten pool is in a good penetration state until the welding is completed Power off each system.

Although the embodiments disclosed in the present invention are as above, the described content is only an embodiment adopted for the convenience of understanding the present invention, and is not intended to limit the present invention. Anyone skilled in the technical field to which the present invention belongs can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed by the present invention, but the patent protection scope of the present invention, The scope defined by the appended claims must still prevail.

Claims (6)

1. A K-TIG deep fusion welding control system under the action of a composite magnetic field is characterized by comprising a composite magnetic field excitation system and a K-TIG deep fusion welding system;

the compound magnetic field excitation system is used for generating a rotating magnetic field or/and a longitudinal magnetic field;

the K-TIG deep fusion welding system is used for completing the whole welding process of arc striking, welding and arc stopping.

2. The K-TIG deep fusion welding control system under the action of the compound magnetic field according to claim 1, wherein the compound magnetic field excitation system comprises a mechanical device system and an electric control system;

the mechanical device system is a mechanical component for generating a composite magnetic field and comprises a longitudinal magnetic field excitation magnetic column, a rotating magnetic field excitation magnetic column, a sealing gasket, an upper end cover, a lower end cover, a cooling air inlet, a cooling air outlet and a sleeve;

the electric control system is used for controlling parameters in the composite magnetic field and comprises a three-phase alternating current frequency converter, a one-way alternating current frequency converter, a sliding rheostat, a high-dynamic camera and an industrial control computer.

3. K-TIG deep fusion welding control system under the action of composite magnetic field according to claim 2,

the longitudinal magnetic field excitation magnetic column and the rotating magnetic field excitation magnetic column are used for playing roles of enhancing a magnetic field and conducting magnetism, and a magnetic field generated by the electrified coil can guide the area where the welding electric arc is located along the longitudinal magnetic field excitation magnetic column and the rotating magnetic field excitation magnetic column;

the sealing gasket, the upper end cover, the lower end cover and the sleeve form a closed cooling gas circulation space, so that the cooling gas can flow sufficiently, and the heat generated by the excitation magnetic column is reduced;

the upper end cover, the lower end cover and the sleeve are also used for fixing the positions of the rotating magnetic field excitation magnetic columns, so that the rotating magnetic field excitation magnetic columns are uniformly distributed around the lower end cover, and meanwhile, the longitudinal magnetic field excitation magnetic columns are fixed relative to the positions of the rotating magnetic field excitation magnetic columns.

4. K-TIG deep fusion welding control system under the action of composite magnetic field according to claim 2,

the three-phase alternating current frequency converter and the sliding rheostat are used for changing the rotating frequency of the rotating magnetic field and the magnetic field intensity of the magnetic field;

the unidirectional alternating current frequency converter and the sliding rheostat are used for changing the change frequency and the magnetic field intensity of the longitudinal magnetic field;

the high-dynamic camera and the industrial control computer are used for feeding back and controlling the whole welding process, and the welding seam is in a good penetration state in the welding process.

5. The K-TIG deep fusion welding control system under the action of the composite magnetic field according to claim 1, wherein the K-TIG deep fusion welding system comprises a welding power supply, a welding gun, a cooling water tank, an argon gas bottle and a welding workpiece;

the welding power supply is used for providing power for the whole welding process;

the welding gun is a special welding gun for K-TIG welding, and the adjustable range is 0-1000A;

the cooling water tank is used for cooling the welding gun in time in the welding process;

the argon bottle is used for providing protective gas for the whole welding process, and the protective gas is introduced to the surface and the bottom of the welding line during the welding process to ensure that the welding line is not oxidized.

6. A K-TIG deep fusion welding control method under the action of a composite magnetic field is characterized by comprising the following steps:

polishing and assembling a welding workpiece for welding;

powering on a robot motion system;

teaching a welding track route according to the actual welding seam position;

powering on a welding system to prepare welding;

adjusting the image acquisition system to enable the image acquisition system to be in a shooting mode;

carrying out welding and acquisition in the arcing process, and energizing an excitation device for excitation at the moment of arcing;

and (5) closing the system power supply after welding.