Tungsten Inert Gas (TIG) or Gas Tungsten Arc welding (GTAW):
It is an arc welding procedure wherein coalescence is produced past times heating the undertaking alongside an electrical arc struck betwixt a tungsten electrode together with the job. The electrodes used inwards this procedure are made of either Tungsten or Thoriated Tungsten. Thoriated Tungsten electrodes run cooler than manifestly tungsten electrodes together with keep foursquare arcing ends but it is to a greater extent than expensive.
Shielding gas:
A Shielding gas (Argon, Helium, Nitrogen, Carbon dioxide or a mixture of gases etc.) is used to avoid atmospheric contamination of the molten weld pool. The inert gas blanket shields the entire weld surface area from the atmospheric ready on eliminating the demand for whatsoever flux. General inert gas used is Argon though Helium or a mixture of the 2 may besides hold upwards used. Influenza A virus subtype H5N1 filler metallic may hold upwards added if required.
Commercial grades (Shielding gas) used for welding are 99.9% pure. Argon is 0.38% heavier than air together with most 10 times heavier than Helium. Both gases ionize when acquaint inwards an electrical arc. This agency that the gas atoms lose unopen to of their electrons that accept a negative charge. These unbalanced gas atoms, properly called positive ions, at nowadays accept a positive accuse together with are attracted to the negative pole inwards the arc.
When the arc is positive together with the move is negative, these positive ions impinge upon the move together with take surface oxides or scale inwards the weld area. Argon is most unremarkably used of the shielding gases. So Argon is suitable for welding thinner material.
Whereas Helium produces a higher arc voltage than Argon. This makes it to a greater extent than suitable for welding heavy sections of metallic that accept high rut electrical conductivity or for automatic welding operations where higher welding speeds required.
TIG Welding Polarity:
The electrical current beginning may hold upwards either DC or air conditioning depending upon application. DC straight off polarity arc is used inwards metals other than aluminium together with magnesium including copper alloys, sort iron, steel together with stainless steel. It gives practiced rut concentration together with produces welds that are deep together with narrow. Welding rates are high together with at that spot is less distortion of base of operations metal. DC opposite polarity is non to a greater extent than oftentimes than non used because it produces shallow together with broad welds. air conditioning arc is used for welding aluminium, magnesium, sort atomic reveal 26 together with a reveal of other metals. Penetration alongside air conditioning arc is midway betwixt the penetration produced past times DC conduct polarity together with DC opposite polarity.
The procedure is most suitable for depression estimate canvas metallic welding together with cannot compete alongside conventional shielded metallic electrode welding for welding of heavier gauges due to the toll of inert gas.
TIG Welding Process:
A high frequency, high voltage (100 kHz to 2 MHz, 2000 volts) depression amperage electrical current render is oftentimes used inwards TIG welding to initiate the arc. This is to avoid the contamination of the electrode caused when the arc is initiated past times brusk circuiting alongside the move piece. When electrode tip reaches inside a distance of three to 2 mm from the job, a spark jumps across the air gap betwixt the electrode together with the job. The air path gets ionized together with arc is established.
The superimposed high frequency electrical current causes a spark to limit the gap betwixt the electrode together with the move piece. If a high frequency beginning is non available the arc tin hold upwards initiated past times scratch starting using copper striker plate to limit electrode contamination. Tungsten inert gas welding tin hold upwards done inwards whatsoever position. Welding speeds of the lodge of 400 to grand mm per infinitesimal accept been attained past times manual process. The procedure tin besides hold upwards adapted to mechanized together with automatic operation.
Advantages:
1. No flux is used, thus at that spot is no danger of flux entrapment when welding fridge together with air conditioner components.
2. Because of clear visibility of the arc together with the job, the operator tin exercise a meliorate command on the welding process
3. This procedure tin weld inwards all positions together with produces polish together with audio welds alongside less spatter.
4. TIG welding is rattling much suitable for high character welding of sparse materials (0.125mm)
5. It is a rattling practiced procedure for welding Nonferrous metals (Aluminum etc.) together with Ferrous metals.
Disadvantages:
1. Tungsten if it transfers to molten weld puddle tin contaminate. It is Hard together with Brittle.
2. Filler rod halt tin drive weld metallic contamination
3. Equipment costs are higher than that for flux shielded metallic arc welding.
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