Difference:
1, the gas used is different: the former Ar gas, the latter CO2.
2, different uses. The former can be welded almost around the welded structure, the latter can not be used for pressure vessels.
3, different welding materials: the former is divided into tungsten argon arc welding, fusion pole argon arc welding; the latter only fusion pole.
4, one is the wire as the electrode, and is constantly melting to fill the molten pool, condensing to form a weld; the other is the use of shielding gas, with the application of melting electrode tig welding technology, the shielding gas has been developed from a single argon a variety of gas mixtures for a wide range of applications, such as argon or helium for the shielding gas is known as the melting electrode inert gas shielded arc welding (referred to as the MIG welding in the international arena).
5, inert gas and oxidizing gas (O2, CO2) mixture of gas as a shielding gas, or CO2 gas or CO2 + O2 mixture of gas as a shielding gas, collectively referred to as the melting electrode reactive gas shielded arc welding (in the international abbreviation for MAG welding).
6, from its mode of operation, the most widely used is the semiautomatic melting electrode argon arc welding and argon-rich mixed gas shielding welding, followed by automatic melting electrode argon arc welding.
Advantages and disadvantages:
①Molten electrode inert gas shielding welding: argon or helium as a shielding gas. Inert shielding gas does not participate in the metallurgical reaction of the molten pool, suitable for a variety of high quality requirements or easy to oxidize metal materials, such as stainless steel, aluminum, titanium, zirconium, etc., but the cost is higher.
② Carbon dioxide gas shielded welding: carbon dioxide as a protective gas. Carbon dioxide at high temperatures will decompose oxygen into the molten pool, so it is necessary to add the appropriate amount of manganese, silicon and other deoxidizers in the wire. The main advantage of this protection welding is lower cost, but can only be used for carbon steel and low alloy steel welding.
3 mixed gas shielded welding: shielding gas to argon as the main, add the appropriate amount of carbon dioxide (15 ~ 30%) or oxygen (0.5 ~ 5%). Compared with carbon dioxide gas shielded welding, this shielding welding welding specifications wider, better shaped, better quality; compared with fusion inert gas shielded welding, the molten pool is more active, better metallurgical response.
Expanded information:
CO2 shielded arc welding is known as carbon dioxide gas shielded arc welding. The shielding gas is carbon dioxide (sometimes a mixture of CO2 + Ar), mainly used for manual welding. Due to the special effects of the thermophysical properties of carbon dioxide gas, the use of conventional welding power supply, the wire end of the molten metal is not possible to form a balanced axial free transition, usually need to be used to short-circuit and the droplet necking burst.
Therefore, compared with the MIG welding free transition, more spatter. However, if the use of high-quality welding machine, the right choice of parameters, you can get a very stable welding process, so that the spatter is reduced to a minimum.
Because the shielding gas used is inexpensive, the use of short-circuit transition when the weld is well formed, coupled with the use of deoxidizing flux-containing wire can be obtained without internal defects in the quality of the welded joints. Therefore, this welding method has become one of the most important welding method of ferrous materials.
Cold welding machine for intelligent repair machinery and equipment products, is for the majority of mold industry, foundry, electrical manufacturing, medical equipment, automotive, shipbuilding, boilers, construction, steel, bridge construction and other industries to improve the production, has a wide range of applicability. In the country is the majority of small and medium-sized enterprises preferred repair equipment.
Principle of repair
Intelligent cold welding machine is through the microelectric instantaneous discharge generated by the high thermal energy of the special wire fusion to the broken parts of the workpiece, and the original substrate firmly fused, after welding only after very little grinding and polishing post-processing.
Working Principle
Intelligent Repair Cold Welder is based on the principle of utilizing a charging capacitor to discharge the electrode with a cycle of 10-3 to 10-1 seconds and an ultra-short time of 10-6 to 10-5 seconds. The contact area between the electrode material and the workpiece will be heated to 8,000 to 25,000°C, and the molten metal in the state of plasma ionization transitions to the surface layer of the workpiece in a metallurgical manner. The coating or cladding layer that is overlaid onto the surface of the workpiece, due to the alloying effect with the base material, diffuses into the interior of the workpiece, melts and infiltrates, forming a diffusion layer, and obtains a high-strength bond.
Realization of Cold Welding
The discharge time (Pt) is extremely short compared to the time between the next discharge (It), and the machine has enough relative stopping time for the heat to diffuse to the outside world through the basic body of the workpiece, so there is no heat buildup in the processed part of the workpiece. The temperature of the electrode tip can reach about 25,000°C due to instantaneous melting, even though the workpiece is heated almost at room temperature.
Bonding Strength
When using the Intelligent Repair Cold Welder for repair overlay welding, why is the bonding strength so high when the heat input is low. This is because the welding electrode instantly produces a molten droplet of metal that transitions to the contact area with the base metal, and at the same time, due to the high temperature of the plasma arc, the surface layer develops deep into a strong, solid diffusion layer like a root. It shows high bonding and will not come off.
Advantages
1, reasonable design, free adjustment. According to different metal materials can choose different gear discharge frequency, in order to achieve the best repair effect.
2. Small heat-affected area. There is no heat input during the instantaneous process of cladding, so there is no deformation, biting edge and residual stress. There is no local annealing and no need for re-heat treatment after repair.
3, very small welding impact, the welding machine in the welding process to overcome the common argon arc welding on the workpiece periphery to produce the phenomenon of impact. There is no margin of the workpiece processing surface can also be repaired.
4, repair high precision: Surfacing thickness from a few microns to a few millimeters, just grinding, polishing.
5, fusion bonding strong high: due to the full penetration of the workpiece surface material to produce extremely strong bonding force.
6, easy to carry: light weight (28 kg), 220V power supply, no working environment requirements.
7, economy: in the field immediately repair, improve productivity and cost savings.
8, a machine multi-purpose: can be surfacing, surface strengthening and other functions. By adjusting the discharge power and discharge frequency, it can obtain the required thickness of surfacing and enhanced finish.
9, the hardness of the cladding layer and the diversity of filler material:
Argon arc welding in the main circuit, auxiliary power supply, drive circuits, protection circuits and other aspects of the working principle is the same as the hand arc welding. No more description here, but focus on the unique control functions of the argon arc welding machine and the arc circuit function.
Argon arc welding according to the different electrodes are divided into melting pole argon arc welding and non-melting pole argon arc welding two kinds.
Non-molten pole
Working principle and characteristics: non-molten pole tig welding is the arc in the non-molten pole (usually tungsten pole) and the workpiece between the combustion, in the welding arc around the flow of an inert gas (commonly used argon) does not have a chemical reaction with the metal, the formation of a protective shield, so that the tungsten end of the extreme part of the tungsten pole, arc and the molten pool and the neighboring heat-affected areas of the high-temperature metal does not come into contact with the air, can prevent the oxidation and absorption of harmful gases. Oxidation and absorption of harmful gases. Thus forming a dense welded joint, its mechanical properties are very good.
Molten Pole
Working Principle and Characteristics : The wire is fed through the wire wheel, and the conductive nozzle conducts electricity, generating an arc between the base material and the wire, melting the wire and the base material, and protecting the arc and the molten metal with the inert gas argon to carry out the welding.
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