The working principle of argon arc welding machine, the principle of argon arc welding

According to the different electrodes, TIG welding can be divided into two types: MIG welding and non-MIG welding.

Non-melting electrode. Working principle and characteristics: non-melting electrode argon arc welding is the arc between the non-melting electrode (usually tungsten electrode) and the workpiece burning, around the welding arc flows through an inert gas that does not react with the metal (argon gas is commonly used), forming a protective gas hood, so that the tungsten terminal, the arc and the molten pool and the high-temperature metal adjacent to the heat-affected zone are not in contact with the air, which can prevent oxidation and absorb harmful gases.

The result is a dense welded joint with very good mechanical properties.

Melting electrode. Working principle and characteristics: The welding wire is fed through the wire wheel, and the contact tip conducts electricity, generating an arc between the base metal and the welding wire, melting the welding wire and the base metal, and using inert gas argon to protect the arc and molten metal for welding.

The difference between it and tungsten argon arc welding: one is that the welding wire is used as an electrode, and is continuously melted and filled into the molten pool, and the weld is formed after condensation; The other is the use of shielding gas, with the technical application of MIG-MIG welding, shielding gas has developed from a single argon gas to a variety of mixed gases are widely used, such as argon or helium as shielding gas, called MIG arc welding (MIG welding in the world); When the mixture of inert gas and oxidizing gas (O2, CO2) is used as the shielding gas, or when the CO2 gas or CO2+O2 mixture is used as the shielding gas, it is collectively referred to as MIG arc welding (referred to as MAG welding in the world). From the perspective of its operation mode, the most widely used at present is semi-automatic melting pole argon arc welding and argon-rich mixed gas shielded welding, followed by automatic melting pole argon arc welding.

The working principle of tungsten argon arc welding equipment and its advantages and disadvantages.

In our country, welding operations need to be licensed, welders are the type of work that belongs to the access category, in the professional qualifications of skilled personnel, only five of the 81 types of work in the access category, welders are one of them, and the actual situation is that most of the industry practitioners are unlicensed operations. With the continuous standardization of technology and the relevant requirements of the industry, more and more people want to take a welding certificate, the advantage of the certificate is still very large, first of all, the salary of the certificate and the non-certificate are very different, often able to reach more than double or higher level. Therefore, the issue of short-term welder training has naturally become a concern for practitioners.

Welding as an industrial "tailor" is a very important means of processing in industrial production, the quality of welding plays a decisive role in the quality of the product, so, what is the future development of welding technology?

Industry outlook. With the development of production, welding is widely used in aerospace, aviation, nuclear industry, shipbuilding, construction and machinery manufacturing and other industrial sectors, in China's economic development, welding technology is an indispensable means of processing. After entering the 21st century, welding is an important part of the manufacturing industry, and the rapid development, so it has brought unprecedented development opportunities to the welding industry.

At present, China consumes 300 million tons of steel every year (about tons of welded structure), and needs about 750,000 welding machines, and the welding industry will continue to grow in the next 8 10 years.

The working principle of tungsten argon arc welding equipment and its advantages and disadvantages.

The principle of electrode arc welding is to use the arc heat generated between the electrode and the weldment to heat the electrode and the weldment to a molten state, and the molten droplet after the end of the electrode is melted and the molten base metal are fused together to form a molten pool. As the arc moves forward, the molten pool liquid metal gradually cools and crystallizes, forming a weld.

Compared with submerged arc automatic welding, electrode arc welding has the following characteristics:

1) The energy of the welding line is small, the metal grains of the weld are fine, and the mechanical properties of the welded joint are good.

2) Easy to operate, strong adaptability, suitable for welding of different steel grades, various positions and various structures.

3) The equipment is simple and the investment is small.

4) Low production efficiency.

5) The labor intensity of welders is high.

6) Welder skills determine welding quality.

Working principle: The arc of argon arc welding adopts the arc starting method of high-voltage breakdown, first between the electrode needle (tungsten needle) and the workpiece, high frequency and high pressure are applied to break down argon gas to make it conductive, and then supply continuous current to ensure the stability of the arc.

When welding, the welding rod and the workpiece are in contact to ignite the arc, and then the welding rod is lifted and kept at a certain distance, and the arc burns stably under the appropriate arc voltage and welding current provided by the welding power supply, resulting in high temperature, and the welding rod and welding part are locally heated to a melting state. The molten metal at the end of the electrode and the metal of the weldment being melted are fused together to form a molten pool.

In welding, the arc moves with the electrode, and the liquid metal in the molten pool gradually cools and crystallizes to form a weld, and the two weldments are welded together.

TIG welding is divided into two types: MIGG welding and non-MIGG welding, and the two principles are elaborated respectively, as follows:

The principle of non-melting electrode: the arc burns between the non-melting electrode and the workpiece, and an inert gas that does not react with the metal flows around the welding arc to form a protective gas hood, so that the tungsten terminal, the arc and the molten pool and the hot metal adjacent to the heat-affected zone are not in contact with the air.

The principle of the melting electrode: the welding wire is fed through the wire wheel, and the contact tip conducts electricity, which generates an arc between the base metal and the welding wire, so that the welding wire and the base metal are melted, and the inert gas argon is used to protect the arc and molten metal for welding.

TIG welding is divided into two types: MIGG welding and non-MIGG welding, and the two principles are elaborated respectively, as follows:

The principle of non-melting electrode: the arc burns between the non-melting electrode and the workpiece, and an inert gas that does not react with the metal flows around the welding arc to form a protective gas hood, so that the tungsten terminal, the arc and the hot metal in the molten pool and the adjacent heat-affected zone are not in contact with the air.

The principle of melting Cong Changji: the welding wire is fed through the wire wheel, and the contact tip conducts electricity, which generates an arc between the base metal and the welding wire, so that the welding wire and the base metal are melted, and the inert gas argon is used to protect the arc of the electric draft and the molten metal for welding.

The welding process of using the heat generated by arc discharge (commonly known as arc combustion) melts the electrode and the workpiece into each other and forms a weld after condensation, so as to obtain a strong joint. Using the arc as the heat source, the physical phenomenon of air discharge is used to convert the electrical energy into the thermal energy and mechanical energy required for welding, so as to achieve the purpose of connecting metals.

One of the strongest types of gas discharges is self-sustaining discharge. When the power supply provides a large power of electric energy, if the voltage between the poles is not high (about tens of volts), the gas or metal vapor between the poles can continue to pass a strong current (a few amperes to tens of amperes), and emit a strong brilliance, producing high temperature (thousands to tens of thousands of degrees), which is the arc discharge deficit to call electricity. The arc is a common type of hot plasma (see Plasma Applications).

Because the voltage of the welding machine is relatively low, the voltage of the welding machine is about 50 volts when there is no load, and the voltage of the welding machine is about 25 volts when welding. Compared with the voltage of more than 50 volts, the resistance value of the human body is relatively large, and the voltage will not penetrate, so it will not electrify people.

1.Check and confirm that the power supply and voltage meet the requirements, and the grounding device is safe and reliable.

2.The air pipe and water pipe should be inspected and confirmed to be free from external pressure and leakage.

3.The polarity should be determined first according to the performance, size and shape of the material, and then the voltage and argon flow rate should be determined.

4.The fittings of the installed argon pressure reducing valve must not be greased. After installation, tests should be carried out and unobstructed and air leaks should be confirmed.

5.The cooling water should be kept clean, and the flow of the cooling water should be normal during the welding process of the water-cooled welding machine, and the water should not be broken for welding.

6.The high-frequency protection device of the high-frequency arc welding machine should be good, and it can also be protected by reducing the frequency; No short circuit shall occur, and the interlocking switch in the power line of the oscillator shall prohibit tapping.

7.When using argon arc welding, the operator should wear a gas mask, and the grinding of thorium and tungsten electrode should be equipped with an exhaust device, and it should be placed in a lead box during storage. The thickness of the tungsten electrode should be determined according to the welding thickness, and the power supply must be cut off when the tungsten electrode is replaced.

When grinding the tungsten electrode, the operator must wear gloves and masks, and the dust from the grinding should be removed in time, and the tungsten electrode should not be carried with him.

8.Other mechanical equipment that should not be installed in the vicinity of the welding machine should not be installed, and flammable and explosive materials should not be placed. The workplace should have good ventilation measures.

9.Argon cylinders and argon cylinders should not be too close to the welding site, and should be placed upright and fixed, not upside down.

10.Welding operators and cooperating personnel must wear labor protection equipment according to regulations, and must take safety measures to prevent accidents such as electric shock, falling from height, gas poisoning and fire.

11.The electric welding machine used on site should be equipped with rainproof, moisture-proof and sun-proof measures, and should be equipped with corresponding fire-fighting equipment.

12.When welding at height, safety belts must be fastened, fire prevention measures should be taken around and below the welding, and there should be special supervision.

13.When cleaning the weld, protective glasses should be worn and the head should be kept away from the direction of the knock splash.

14.After operation, cut off the power supply, turn off the consumption and air supply. Welding personnel must take off their work clothes in time to clear their hands and faces and exposed **.

1. The argon arc welding must be operated by a special person.

2. Check whether the equipment and tools are in good condition before work.

3. Check whether the welding power supply, the control system has a grounding wire, and the transmission part is lubricated. The rotation should be normal, and the argon and water sources must be unblocked. If there is any water leakage, it should be repaired immediately.

4. Check whether the welding torch is normal and whether the ground wire is reliable.

5. Check whether the high-frequency arc striking system and welding system are normal, whether the wire and cable joints are reliable, and check whether the adjustment mechanism and wire feeding mechanism are in good condition for automatic wire argon arc welding.

6. Select the polarity according to the material of the workpiece, connect the welding circuit, use DC positive connection for general materials, and reverse connection or AC power supply for aluminum and aluminum alloy.

7. Check whether the welding groove is qualified, there shall be no oil stain and rust on the surface of the groove, and the oil and rust should be removed within 200mm on both sides of the weld.

8. Check the reliability of the fetal tool, and check the preheating equipment and temperature measuring instrument if the weldment needs to be preheated.

9. The argon arc welding operation button should not be far away from the arc, so that it can be closed at any time in the event of a failure.

10. When using high-frequency arc striking, it is necessary to check whether there is leakage.

11. If the equipment fails, the power should be cut off for maintenance, and the operator shall not repair it by himself.

12. It is not allowed to be naked and naked in other parts near the arc, and it is not allowed to smoke or eat near the arc, so as to avoid ozone and smoke inhalation into the body.

13. When grinding thorium tungsten electrode, you must wear masks and gloves, and abide by the operating procedures of the grinder. It is best to use cerium tungsten electrode (the radiation dose is smaller). The grinder must be equipped with an exhaust device.

14. Operators should wear electrostatic dust masks at all times. Minimize the time of high-frequency electrical action during operation. Continuous work shall not exceed 6 hours.

15. The argon arc welding work site must be well ventilated. Ventilation and detoxification equipment should be started during work. When the ventilation device fails, it should stop working.

16. Argon cylinders are not allowed to be smashed, and there must be a bracket for vertical placement, and they are more than 3 meters away from open flames.

17. When argon arc welding is carried out inside the container, a special mask should be worn to reduce the inhalation of harmful smoke. There should be a person outside the container to supervise and cooperate.

18. Thorium tungsten rods should be stored in a lead box to avoid injury due to the radioactive dose exceeding the safety regulations when a large number of thorium tungsten rods are concentrated together.

Cleaning width: It is to adjust the positive and negative width of the square wave output, the smaller the value, the more positive the output of the welding gun, the narrower the weld bead, the deeper the molten pool, the greater the loss of tungsten electrode (easy to burn tungsten electrode); The higher the value, the more negative the torch output, the wider the weld bead, the shallower the weld pool, and the smaller the tungsten electrode loss.

The thyristor argon arc welding machine generally uses a controlled square wave to control the output of the welding machine, and its output is also a square wave.

The argon arc welding machine is a machine that uses argon arc welding, which adopts the arc starting method of high-pressure breakdown. Argon arc welding is tungsten inert gas arc welding, which refers to the welding method of using industrial tungsten or active tungsten as a non-melting electrode and inert gas (argon) as protection, referred to as TIG.

Generally, it is used for 6 lomm thin plate welding and thick plate single-sided welding and double-sided bottom welding. Commonly used welding machines are domestic YC-150 manual tungsten argon arc welding machine.

Non-melting pole TIG welding.

Non-melting electrode argon arc welding is the arc between the non-melting electrode (usually tungsten electrode) and the workpiece burning, around the welding arc flows through an inert gas that does not react with the metal (argon is commonly used), forming a protective gas hood, so that the tungsten terminal head, arc and molten pool and the metal that has been at high temperature do not contact with the air, can prevent oxidation and absorb harmful gases. The result is a dense welded joint with very good mechanical properties.

Melting pole argon arc welding.

The welding wire is fed through the wire wheel, and the contact tip conducts electricity, which generates an arc between the base metal and the welding wire, melts the welding wire and the base metal, and uses inert gas argon to protect the arc and molten metal for welding.

The difference between it and tungsten argon arc welding: one is that the welding wire is used as an electrode, and is continuously melted and filled into the molten pool, and the weld is formed after condensation; The other is the use of shielding gas, with the application of melting pole argon arc welding technology, shielding gas has developed from a single argon gas to a variety of mixed gases are widely used, such as AR 80% + CO220% argon-rich shielding gas.

Usually the former is called MIG and the latter is called MAG. From the perspective of its operation mode, the most widely used is semi-automatic melting pole argon arc welding and argon-rich mixed gas shielded welding, followed by automatic melting pole argon arc welding.