Oxy- fuel welding and cutting - Wikipedia, the free encyclopedia. For the song, see Cubanate. French engineers Edmond Fouch. A common propane/air flame burns at about 2,2. K (1,9. 80 . In recent decades it has been obsolesced in most all industrial uses due to various arc welding methods offering more consistent mechanical weld properties and faster application. Gas welding is still used for metal- based artwork and in smaller home based shops, as well as situations where accessing electricity (e. In oxy- fuel welding, a welding torch is used to weld metals. Welding metal results when two pieces are heated to a temperature that produces a shared pool of molten metal. The molten pool is generally supplied with additional metal called filler. Filler material depends upon the metals to be welded. In oxy- fuel cutting, a torch is used to heat metal to its kindling temperature. A stream of oxygen is then trained on the metal, burning it into a metal oxide that flows out of the kerf as slag. Most metals cannot be melted with a single- tank torch. Consequently, single- tank torches are typically suitable for soldering and brazing but not for welding. Oxy- gas torches are or have been used for: Welding metal: see below. Cutting metal: see below. Depositing metal to build up a surface, as in hardfacing. Also, oxy- hydrogen flames are used. A steel circular brush is attached to an angle grinder and used to remove the first layer leaving behind a bumpy surface similar to hammered bronze. This sort of torch can also be used for soldering and brazing. The cylinders are often carried in a special wheeled trolley. There have been examples of oxyhydrogen cutting sets with small (scuba- sized) gas cylinders worn on the user's back in a backpack harness, for rescue work and similar. There are also examples of pressurized liquid fuel cutting torches, usually using gasoline. These are used for their increased portability. Regulator. The flow rate is then adjusted by the operator using needle valves on the torch. Accurate flow control with a needle valve relies on a constant inlet pressure. Most regulators have two stages. The first stage is a fixed- pressure regulator, which releases gas from the cylinder at a constant intermediate pressure, despite the pressure in the cylinder falling as the gas in it is consumed. This is similar to the first stage of a scuba- diving regulator. The adjustable second stage of the regulator controls the pressure reduction from the intermediate pressure to the low outlet pressure. The regulator has two pressure gauges, one indicating cylinder pressure, the other indicating hose pressure. The adjustment knob of the regulator is sometimes roughly calibrated for pressure, but an accurate setting requires observation of the gauge. Some simpler or cheaper oxygen- fuel regulators have only a single stage regulator, or only a single gauge. A single- stage regulator will tend to allow a reduction in outlet pressure as the cylinder is emptied, requiring manual readjustment. For low- volume users, this is an acceptable simplification. Welding regulators, unlike simpler LPG heating regulators, retain their outlet (hose) pressure gauge and do not rely on the calibration of the adjustment knob. The cheaper single- stage regulators may sometimes omit the cylinder contents gauge, or replace the accurate dial gauge with a cheaper and less precise . A double- hose or twinned design can be used, meaning that the oxygen and fuel hoses are joined together. If separate hoses are used, they should be clipped together at intervals approximately 3 feet (1 m) apart, although that is not recommended for cutting applications, because beads of molten metal given off by the process can become lodged between the hoses where they are held together, and burn through, releasing the pressurised gas inside, which in the case of fuel gas usually ignites. The hoses are color- coded for visual identification. The color of the hoses varies between countries. In the United States, the oxygen hose is green, and the fuel hose is red. LPG will damage an incompatible hose, including most acetylene hoses. The threaded connectors on the hoses are handed to avoid accidental mis- connection: the thread on the oxygen hose is right- handed (as normal), while the fuel gas hose has a left- handed thread. The use of worm- drive hose clips or Jubilee clips is specifically forbidden in the UK and other countries. Although it has an upper flammability limit in air of 8. If a detonation wave enters the acetylene tank, the tank will be blown apart by the decomposition. Ordinary check valves that normally prevent back flow cannot stop a detonation wave because they are not capable of closing before the wave passes around the gate. For that reason a flashback arrestor is needed. It is designed to operate before the detonation wave makes it from the hose side to the supply side. Between the regulator and hose, and ideally between hose and torch on both oxygen and fuel lines, a flashback arrestor and/or non- return valve (check valve) should be installed to prevent flame or oxygen- fuel mixture being pushed back into either cylinder and damaging the equipment or causing a cylinder to explode. A Beginner’s Guide to TIG Welding TIG Welding Names TIG Welding, or TIG, is an acronym for “Tungsten Inert Gas” welding. TIG is a commonly used and accepted slag term. The proper terminology is “Gas Tungsten Arc.European practice is to fit flashback arrestors at the regulator and check valves at the torch. US practice is to fit both at the regulator. The flashback arrestor (not to be confused with a check valve) prevents shock waves from downstream coming back up the hoses and entering the cylinder, possibly rupturing it, as there are quantities of fuel/oxygen mixtures inside parts of the equipment (specifically within the mixer and blowpipe/nozzle) that may explode if the equipment is incorrectly shut down, and acetylene decomposes at excessive pressures or temperatures. In case the pressure wave has created a leak downstream of the flashback arrestor, it will remain switched off until someone resets it. Check valve. It is usually a chamber containing a ball that is pressed against one end by a spring. Gas flow one way pushes the ball out of the way, and a lack of flow or a reverse flow allows the spring push the ball into the inlet, blocking it. Not to be confused with a flashback arrestor, a check valve is not designed to block a shock wave. The shock wave could occur while the ball is so far from the inlet that the wave will get past the ball before it can reach its off position. The torch is the tool that the welder holds and manipulates to make the weld. It has a connection and valve for the fuel gas and a connection and valve for the oxygen, a handle for the welder to grasp, and a mixing chamber (set at an angle) where the fuel gas and oxygen mix, with a tip where the flame forms. Two basic types of torches are positive pressure type and low pressure or injector type. It can be identified by having only one or two pipes running to the nozzle, no oxygen- blast trigger, and two valve knobs at the bottom of the handle letting the operator adjust the oxygen and fuel flow respectively. Cutting torch. It is similar to a welding torch, but can be identified by the oxygen blast trigger or lever. When cutting, the metal is first heated by the flame until it is cherry red. Once this temperature is attained, oxygen is supplied to the heated parts by pressing the oxygen- blast trigger. This oxygen reacts with the metal, forming iron oxide and producing heat. It is the heat that continues the cutting process. The cutting torch only heats the metal to start the process; further heat is provided by the burning metal. The melting point of the iron oxide is around half that of the metal being cut. As the metal burns, it immediately turns to liquid iron oxide and flows away from the cutting zone. However, some of the iron oxide remains on the workpiece, forming a hard . It is so- called because the flame at the end looks like a rose bud. A welding torch can also be used to heat small areas such as rusted nuts and bolts. Injector torch. In an injector torch, high- pressure oxygen comes out of a small nozzle inside the torch head which drags the fuel gas along with it, using the venturi effect. Oxy- fuel processes may use a variety of fuel gases, the most common being acetylene. Other gases that may be used are propylene, liquified petroleum gas (LPG), propane, natural gas, hydrogen, and MAPP gas. Many brands use different kinds of gases in their mixes. Acetylene. This is used where acetylene cylinders are not available. The term 'Las Karbit' means acetylene (carbide) welding in Indonesian. Acetylene is the primary fuel for oxy- fuel welding and is the fuel of choice for repair work and general cutting and welding. Acetylene gas is shipped in special cylinders designed to keep the gas dissolved. The cylinders are packed with porous materials (e. This method is necessary because above 2. Pa (3. 0 lbf/in. Acetylene when combined with oxygen burns at 3. As a fuel acetylene's primary disadvantage, in comparison to other fuels, is high cost. As acetylene is unstable at a pressure roughly equivalent to 3. Tests showed that an oxy- gasoline torch can cut steel plate up to 0. In plate thicknesses greater than 0. Another low cost approach commonly used by jewelry makers in Asia is using air bubbled through a gasoline container by a foot- operated air pump, and burning the fuel- air mixture in a specialized welding torch. Hydrogen. It can be used at a higher pressure than acetylene and is therefore useful for underwater welding and cutting. Gas Tungsten Arc Welding Guide Book. 12-09-2016 2/2 Gas Tungsten Arc Welding Guide Book. Other Files Available to Download Oxy-fuel welding (commonly called oxyacetylene welding, oxy welding, or gas welding in the U.S.) and oxy-fuel cutting are processes that use fuel gases and oxygen to weld and cut metals, respectively. GAS PRODUCTS AND SERVICES MANUAL Supagas Shielding Gases Selection Guide To recommend a welding shield gas, use the following steps: NB: If the customer is currently using a competitive gas, refer to gas comparison chart. Towards gas and arc welding techniques when these were developed to useful production and repair methods through the 1930es. A main objective became to develop and maintain a range of welding equipment that. Gas Tungsten Arc Welding (GTAW) See Figure 3 Gas Tungsten Arc Welding (GTAW) is also referred to as tungsten inert gas (TIG) welding. In GTAW, an electric arc is established between the work piece and the. Welding Guide - Free download as PDF File (.pdf), Text File (.txt) or read online for free. A short but comprehensive guide on oxy/acetylene and tig welding. Tungsten and Gas for TIG Welding Metal Aluminum Thickness All. It is a good type of flame to use when heating large amounts of material. The flame temperature is high, about 2,0. Hydrogen is not used for welding steels and other ferrous materials, because it causes hydrogen embrittlement. For some oxyhydrogen torches the oxygen and hydrogen are produced by electrolysis of water in an apparatus which is connected directly to the torch. Types of this sort of torch: The oxygen and the hydrogen are led off the electrolysis cell separately and are fed into the two gas connections of an ordinary oxy- gas torch. Welding, Cutting and Heating guide Revision: B. SET-UP AND SAFE OPERATING PROCEDURES. PDF File: Gas Tungsten Arc Welding Guide Book - MTOM1-PDF-GTAWGB9 2/4 Gas Tungsten Arc Welding Guide Book INTRODUCTION This particular Gas Tungsten Arc Welding Guide Book PDF start with Introduction, Brief Session till the.
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