Oxy-fuel welding and cutting
摘要和引言有什么区别Oxy-fuel welding (commonly called oxyacetylene welding, oxy welding, or gas welding in the U.S.) and oxy-fuel cutting are process that u fuel gas and oxygen to weld and cut metals, respectively. French engineers Edmond Fouche and Charles Picard were the first to develop a oxygen-acetylene welding machine in 1903.
Oxy-fuel is one of the oldest welding process, though in recent years it has become less popular in industrial applications. However, it is still widely ud for welding pipes and tubes, as well as repair work. It is also frequently well-suited, and favored, for fabricating some types of metal-bad artwork. Oxyfuel equipment is versatile, lending itlf not only to some sorts of iron or steel welding but also to brazing, braze-welding, metal heating (for bending and forming), and also oxyfuel cutting.
In oxy-fuel welding, a welding torch is ud 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 cutting torch is ud to heat metal to kindling temperature. A stream of oxygen then trained on the metal combines with the metal which then flows out of the cut (kerf) as an oxide sla
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Torches that do not mix fuel with oxygen (combining, instead, atmospheric air) are not considered oxy-fuel torches and can typically be identified by a single tank (Oxy-fuel welding/cutting generally requires two tanks, fuel and oxygen). Most metals cannot be melted with a single-tank torch. As such, single tank torches are typically ud only for soldering and brazing, rather than welding.
Note: Sometimes a metal-cutting torch is colloquially called a "gas-axe", "smoke wrench", "hot wrench", "blue wrench" or "hot blue spanner" (in Britain). Colloquially, many people mistakenly call a welding torch a blowtorch. In the USA the word blowtorch is also ud for what in Britain is called a blowlamp.
Us
Oxy-gas torches are ud for or have been ud for:
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∙Welding metal: e below.
∙Cutting metal: e below.
∙Also, oxy-hydrogen flames are ud:
o In Stone Work for "flaming" where the stone is heated and a top layer crackles and breaks. A steel circular brush is attached to an angle
grinder and ud to remove the first layer leaving behind a bumpy
surface similar to hammered bronze.
o In the glass industry for "fire polishing".
o In jewelry production for "water welding" using a "water torch".
应急演练总结报告
o Formerly, to heat lumps of quicklime to obtain a bright white light called limelight, in theatres or optical ("magic") lanterns.
o Formerly, in platinum works, as platinum is only fusible in the oxy-hydrogen flame and in an electric furnace.
Apparatus
酌金馔玉The apparatus ud in gas welding consists basically of an oxygen source and a fuel gas source (us
ually cylinders), two pressure regulators and two flexible hos (one of each for each cylinder), and a torch. This sort of torch can also be ud for soldering and brazing. The cylinders are often carried in a special wheeled trolley. There have been examples of oxyhydrogen cutting ts with small (scuba-sized) gas cylinders worn on the ur's back in a backpack harness, for rescue work and similar.
There are also examples of pressurized liquid fuel cutting torches, usually using gasoline. The are ud for their incread portability.
Regulator
The regulator is ud to control pressure from the tanks by reducing pressure and regulating flow rate. Oxy-gas regulators usually have two stages: The first stage of the regulator releas the gas at a constant rate from the cylinder despite the pressure in the cylinder becoming less as the gas in the cylinder is ud, as in the first stage of a scuba-diving regulator. The cond stage of the regulator controls the pressure reduction from the intermediate pressure to low pressure. It is constant flow. The valve asmbly has two pressure gauges, one indicating cylinder pressure, the other indicating ho pressure.
Some oxy-gas regulators only have one stage, and one pressure gauge, and in them the gas flow becomes less as the cylinder pressure drops.
Gas hos
The hos ud are specifically designed for welding and cutting. The ho is usually a double-ho design, meaning that there are two hos joined together. The oxygen ho is green and the fuel ho is red. The type of gas the ho will be carrying is important becau the connections will have different threads for different types of gas. Fuel gas (red) will u left-hand threads and a groove cut into the nut, while the oxygen (green) will u right-hand threads. This is a safety precaution to prevent hos from being hooked up the wrong way.
There are basically two types of connections that can be ud. The first is using a jubilee clip. The cond option is using a crimped connector. The cond option is probably safer as it is harder for this type of connection to come loo. The hos should also be clipped together at intervals approximately 3 feet apart.
Non-return valve
Between the regulator and ho, and ideally between ho and torch on both oxygen and fuel lines, a flashback arrestor and/or non-return valve should be installed to prevent flame or oxygen-fuel mixture being pushed back into either cylinder and damaging the equipment or making a cylinder explode.
多少天过年The flashback arrestor (not to be confud with a check valve) prevents the shock waves from downstream coming back up the hos 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 decompos at excessive pressures or temperatures. The flashback arrestor will remain switched off until someone rets it, in ca the pressure wave created a leak downstream of the arrestor.
Check valve
A check valve lets gas flow in one direction only. Not to be confud with a flashback arrestor, a check valve is not designed to block a shock wave. The pressure wave could occur while the ball is so far from the inlet that the pressure wave gets past before the ball reaches its off position. A check
老师为什么valve is usually a chamber containing a ball that is presd against one end by a spring: gas flow one way pushes the ball out of the way, and no flow or flow the other way lets the spring push the ball into the inlet, blocking it.
Torches
The torch is the part 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, a mixing chamber (t at an angle) where the fuel gas and oxygen mix, with a tip where the flame forms.
Welding torch
A welding torch head is ud to weld metals. It can be identified by having only one or two pipes running to the nozzle and no oxygen-blast trigger and two valve knobs at the bottom of the handle letting the operator adjust the oxygen flow and fuel flow.
