Technology

Gas Welding

gas welding and measures to prevent danger from reverse fire (Yamato Flashback Arrestor). In principle, gas welding is a welding process that uses the combustion of acetylene gas mixed with oxygen gas. (Oxy-acetylene Welding) Flame from burning at the tip of the welding head, causing the metal to melt and then adding the welding wire to the melting metal well. Gas welding is commonly used for light welding work that uses a thin metal name such as welding for car body repairs, air duct welding. Automobile exhaust pipes or pipe welding in various chemical industries, etc.

Oxy-fuel Gas Welding means welding workpieces by using heat energy from the combustion of fuel gas such as liquefied petroleum gas (LPG), acetylene (C2H2) or hydrogen (H2) and Oxygen (O2) at the gas welding torch (Torch)

Gas Welding Equipment

  1. Gas welding torch (Torch)
  2. Gas lines and oxygen lines (Hoses)
  3. Fuel Gas Cylinder
  4. Oxygen Cylinder
  5. Regulators

1. Principle of gas welding

It is a welding process that uses the combustion of acetylene gas mixed with oxygen gas (Oxy-acetylene). Welding) The flame from burning at the tip of the welding head causes the metal to melt and then fills the welding wire into the melting metal well. When allowed to cool down, the weld line will be as desired. gas welding Commonly used for light welding work. used for welding thin metals, such as welding for car body repairs Air duct welding car exhaust or welding pipes in various chemical industries, etc.

 

2.Tools and equipment in gas welding

In gas welding, the following tools and equipment are required:

2.1. Acetylene tank

Made of steel plate, it is normally used to store acetylene pressure of only 250 Psi because acetylene gas is a fire gas. If stored at high pressure, the gas molecules will be compressed. cause heat or leak easily There is a risk of fire and explosion. Normally, in acetylene tanks, porous material is obtained and contains about 40% aceto, which acetone will help absorb acetylene gas so that the pressure is not too high. The standard acetylene gas tank has a capacity of 40 liters. Can compress 6000 liters of acetylene gas with acetone to help absorb the gas not to make the pressure too high. And on the acetylene barrels there are safety-plugs at the head and bottom of the barrel to prevent explosions from heat and overpressure. During transport of acetylene tanks, the cylinder head valve cover must also be covered to prevent bumps during transport. The thread on the cylinder head valve is used as a left-hand thread and the acetylene tank is often symbolized in red or orange.

2.2. Oxygen tank

Made of steel sheet, about 6.4 mm thick, forged, without joints. strong resistance to high pressure Because it is used to compress oxygen gas at a pressure of 2200-2800 Psi or about 150-170 bar.

Forged brass cylinder head valve The fitting thread on the cylinder head valve is used as a right-hand thread.

Before compressed oxygen gas must be tested for pressure first.

2.3. Pressure Regulators

The pressure relief valve is responsible for adjusting the gas pressure from the storage tank to suit the required pressure and helping to stabilize the pressure at the welding nozzle. Normally, 1 set has 2 gauges: the right gauge measures the gas pressure and the left gauge measures the pressure while working. The acetylene pressure regulator valve and the oxygen gas pressure regulator are different, that is, the connection thread of the acetylene pressure regulator valve is left-hand thread. The pressure used is 0-250 Psi. The oxygen part is a right-hand thread. The pressure range is between 0-3000 Psi.

2.4. Welding head oxy-acetylene (Oxy-acetylene welding torches)

This type of welding head has The main components are the handle, the shut-off valve, the gas mixing chamber and the tip. will adjust the shut-off valve To control the oxygen and acetylene gas from the connecting pipe to the oxygen-acetylene gas mixing chamber. The mixed gas flows out to the tip. made of copper Because copper is heat resistant.

2.5. Iron cleaning holes in the gas welding head (Tip cleaners).

It is a thin wire. There are many sizes to choose from according to different tip sizes. We used this cleaning iron inserted into the gas welding nozzle hole to clean it. When the tip has iron flakes or various soot fragments to be attached

2.6.Gas Hose

There are two types: acetylene chain and oxygen chain.

– Acetylene line will receive acetylene gas from the acetylene tank to the welding nozzle. This wire is red at the end of the pipe with a left-hand threaded nut.

– Oxygen line will receive oxygen gas from the oxygen tank to the welding nozzle. The cable is blue or green at the end of the tube with a right-hand threaded nut.

2.7. Ignition device (Gas Saver SE-ll )

The gas ignition control device is suitable for all types of gasification applications. Ease of use, reduce gas costs and increase productivity.

Can be used with LPG gas, Acetylene and has accessories to control Gas N2

The gas is ignited by the straight Ignition Unit, ensuring that you can truly save gas and do not have to worry about wind power in the coffin.

No problem of clogging the flux in the system.

2.8.Gas welding glasses (Goggles) frame (Frame)

The gas welding goggles are made of plastic with 2 lenses to prevent sparks. Gas welding goggles should be worn while welding. Hot sparks and very bright sparks can cause blindness. The lens used is a light filtering lens coated with a concentrated green substance. From numbers 1-14 depending on usage

Note : Read more about welding work and welding products : https://www.udo.co.th/category_product/กลุ่มลวดเชื่อม

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