Learn about TIG welding and choose a more suitable TIG welding machine

10 Mar 2022

I believe everyone is familiar with TIG welding, but let you classify TIG welding, would you? What does the model on the TIG welding machine represent? What is the composition of the welding machine that can be used normally? How many types of argon arc welding guns are there? What is the order of its assembly? How does the air supply system and the water cooling system operate? With these questions, let's talk to you one by one.

First, let's talk about the classification and model preparation of tungsten argon arc welding. The classification of tungsten argon arc welding, the first type is divided into manual welding and automatic welding according to the operation mode; the second type can be divided into AC, DC, AC and DC dual-purpose and pulse power supply according to the type of current; the third type is classified according to special The use requirements can be divided into tungsten argon arc spot welding machine, hot wire tungsten argon arc welding machine and plate pulse argon arc welding machine. And the model of tungsten argon arc welding machine, according to GB/T10249-2010 "Welding Machine Model Compilation Method", the first character in the product model of tungsten argon arc welding machine is represented by the first letter "W" in Chinese Pinyin; The two-character position represents the name of the subclass, mainly automatic welding, manual welding, tack welding and others, which are respectively represented by the first capital letters "Z", "S", "D" and "Q" in Chinese Pinyin; the third character Auxiliary features (types of current), mainly including AC, AC and DC, pulse and DC, are represented by the first letters of Chinese Pinyin "J", "E" and "M", the flow is omitted and not written; the fourth character Indicates the serial number (product variety), which mainly include all-position welding car type, horizontal arm type, machine tool type, rotary welding head type, desktop type, welding robot, displacement type and vacuum inflatable type, etc., respectively use "1" "2" "3", "4", "5", "6", "7" and "8"; the number after the horizontal bar represents the basic specification (rated current); if a horizontal bar and a number are added after the basic specification, it is a derivative code, derived Codes are arranged in alphabetical order of Chinese Pinyin. For example: the manual AC model of tungsten argon arc welding machine commonly used in automatic welding is WSJ-400-1, manual AC and DC is WSE5-315, manual DC is WS-300, automatic AC and DC is WZE-500 and manual pulse is WSM -250.

Next, let's talk about the welding power source in the components of the welding machine. Manual tungsten argon arc welding machine is composed of welding power source, arc striking and arc stabilization device, welding torch, gas supply system, water supply system and welding control device; automatic tungsten argon arc welding machine also includes welding trolley traveling mechanism and wire feeding device . The power supply of tungsten argon arc welding machine includes DC power supply, AC power supply, AC and DC dual-purpose power supply and pulse power supply. Whether it is DC or AC tungsten arc welding, it is required to select an arc welding power source with a steep drop (constant current) external characteristic. The purpose of this selection is to reduce or eliminate current fluctuations caused by changes in arc length. At present, arc welding transformers and thyristor arc welding rectifiers are commonly used. The no-load voltage of arc welding rectifier is generally not less than 70V. It is not much different from the electrode arc welding machine in structure, and can be used in general, but the external characteristics are more steep. The DC welding power source has two connection methods: positive polarity and reverse polarity, referred to as DC positive connection and DC reverse connection. The workpiece is connected to the positive pole of the power supply, and the tungsten pole is connected to the negative pole of the power supply, which is called DC positive connection (see Figure 1-1). Since the tungsten electrode is the cathode and the temperature of the arc cathode is low, the tungsten electrode burns less and the allowable current is large; at the same time, the workpiece is connected to the anode, which generates a large amount of heat, has a strong ability to emit electrons, and has stable arc combustion and large penetration. Generally, low carbon steel, stainless steel and its alloys are welded by DC positive connection. The workpiece is connected to the negative pole of the power supply, and the tungsten pole is connected to the positive pole of the power supply, which is called DC reverse connection (see Figure 1-2). Because the tungsten pole is anodic arc, the temperature is high, so the tungsten pole has a large burning loss and a small allowable current; at the same time, the workpiece is connected to the cathode to generate less heat, which affects electron emission, resulting in unstable arc and small penetration, so argon arc welding is rarely used. Connection. Although this connection method can remove the oxide film formed on the surface of easily oxidizable metals such as aluminum and magnesium, and has the effect of cathode cleaning, the AC welding power source should be preferred for welding aluminum, magnesium and their alloys.

Then talk about the welding gun that is part of the welding machine. Construction and assembly of the welding torch: The function of the argon arc welding torch is to hold the tungsten electrode, conduct the welding current and deliver the argon gas. The welding gun should have the characteristics of light weight, easy disassembly and assembly, good electrical conductivity and gas fluidity, and at the same time, it should also meet the requirements of good insulation between the nozzle and the tungsten electrode. The structure of the welding torch consists of a nozzle, an electrode jacket, a welding torch body, a tungsten electrode clamp, a tungsten electrode, an electrode cap, a cable and a power interface (see Figure 2). In particular, the assembly order of the argon arc welding torch cannot be reversed, and the order of installation is as follows: The first step is to install the electrode cover first. The electrode jacket and tungsten electrode clamp should be selected according to the diameter of the tungsten electrode, and it is required to tighten and not loosen. If the electrode jacket is not screwed in place and the electrode cap is not pressed tightly against the tungsten electrode clip, it will cause the tungsten electrode to fall off, or the tungsten electrode clip will heat up during welding, causing the tungsten electrode to fall off and fall into the molten pool, resulting in tungsten clipping defects. The second step is to tighten the nozzle, which is easier to operate when using a crank welding. The third step is to release the tungsten electrode and the tungsten electrode clip. The fourth step is to tighten the electrode cap. Once the electrode cap is loose, it can cause burns due to overheating of the electrode jacket. The fifth step, during the assembly process of the welding torch, all the connection parts and fixed parts should be fully tightened. Once loose, the parts will be burnt due to heat, resulting in air leakage and water leakage. In addition, the tungsten electrode should extend out of the nozzle. If the tungsten electrode tip is retracted inside the porcelain nozzle, the arc heat will damage the nozzle. The welding torch is also divided into: the welding torch is divided into two types: air-cooled and water-cooled. The air-cooled argon arc welding torch is supplied with argon gas to take away part of the heat of the welding torch. The allowable current of the air-cooled argon arc welding torch is small, and when the welding current is less than 100A, the air-cooled welding torch can generally be used (see Figure 3-1). The water-cooled welding torch is a dual cooling method of air cooling and water cooling. The water cooling system circulates through the water pump, and the water flow takes away the heat of the cable and the welding torch, so as to avoid the conductive part of the welding torch from being burned out. The allowable current of the water-cooled argon arc welding torch is large. Generally, when the welding current is >100A, the water-cooled welding torch is mostly used (see Figure 3-2).

Finally, let's talk about the gas supply system, water cooling system and welding program control device of the welding machine. The first is the air supply system. It is composed of argon cylinder, gas regulator, solenoid valve and gas pipe (see Figure 4). Its function is to control the on-off of solenoid valve, gas indicator light, advance and lag gas supply time and gas inspection through electronic circuit. , The conversion control of the welding state to ensure that the qualified argon gas is smoothly sprayed from the nozzle of the welding torch at a suitable flow rate during welding. The second is the water cooling system. Its function is to use water circulation to cool the tungsten electrode and the welding torch. Welding guns with welding current >100A are generally water-cooled, and the water flow is controlled by a water pressure switch or manually (see Figure 5). The third type is the welding program control device. The device can realize the adjustable control of each program and welding parameters in the welding process. The device should meet the following requirements: Argon gas should be delivered 1.5~4s in advance before welding to remove the air in the trachea and the welding area. Automatically connect and cut off arc ignition and arc stabilization circuits. Control the on-off of the welding power source. The welding current is automatically attenuated before the end of welding to prevent crater cracks. ) Stop supplying argon with a delay of 5~15s after welding to protect the tungsten electrode and molten pool.

There are so many tungsten argon arc welding machines on the market, how should we choose? I recommend to you our Kingsiri brand argon tungsten arc welding machine. The first feature is that it has complete functions. It can be used for DC argon arc welding, DC pulse TIG, arc welding, and cold welding. Second, the panel is rich in content and one key Precise adjustment function, save work preparation time; Feature 3, easy to start arc, manual arc welding has the function of adjusting the arc current and forced current; All parameters can be accurately preset, including current, pulse frequency, gas stop time; feature five, good anti-interference performance, the screen display will not jump to and fro; feature six, our tungsten argon arc welding machine All special electrodes can be welded, and the welding effect is good. You can't go wrong with our Kingsiri welding machines!

Keywords: welding machine

Originally published 10 Mar 2022, updated 10 Mar 2022.

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