Characteristics of flame used in gas welding


Flame is responsible for heating the workpiece. until the temperature reaches the melting point while welding. A flame that is good for welding must be drawn in a long, pointed cone from the welding head. The hottest position is about 2 – 10 mm. from the tip of the inner flame and the temperature is up to 3200 ° C. If the flame is not correct, it will affect the welding. and the quality of the weld Incorrect flame characteristics can be classified as follows.

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  1. The flames tilted and the flames burst into flames. The flame emanating from the welding head may be tilted to one side. or split ends, not falling into a cone This can be caused by a number of reasons including: The gas outlet hole is tilted or enlarged to form a bell. Dirt, metal flakes or soot can remain inside and around the tip.

Solution: Clean the tip to remove any remaining dirt. Use the tip of the tip to rub against the hardwood plank back and forth several times while the flame is still on. Various impurities will come off. Do not rub against softwood or painted planks. Because it will cause wood splinter or paint to clog the tip.

Caution: Do not rub the tip against steel, concrete, brick, stone, as this will cause the tip to corrode.

  1. Interrupted flame from the tip of the tip. The welding torch flame is sometimes found to be very intense and cut off from the tip of the tip. can not be welded This is caused by the pressure of the gas passing through the tip being too high. causing high gas flow rates as well

Solution to reduce the pressure of oxygen gas or acetylene gas to be lower than before. by adjusting the gas regulator and adjusting the gas welding nozzle until the welding flame is normal

  1. The flames have water droplets coming out. It was noticeable in the flames, and there was a streak of red droplets on the inside of the flames. This is caused by a higher than normal acetylene gas flow rate or a higher water content in the safety device. causing excess water to flow out with the flame.

Remedy: Disconnect the acetylene gas welding hose from the welding head holder and allow the contaminated and residual water in the wire to be completely removed. and then connect the cable to the mobile phone, connect as usual Then check the water level in the safety device to see if it meets the required level or not. If too little, add If too much, it can be released to the specified level.

  1. The flame is always changing. The flame from the welding torch changes frequently, sometimes spurting, sometimes alternating. Caused by uneven pressure of oxygen gas or acetylene gas. This may be because the gas regulator is not working properly, internal parts are damaged, etc.

The solution is to replace the gas regulator with a new one. How to easily notice that the gas regulator is damaged or not, look at the gauge needle. The pressure gauge moves or vibrates frequently.

  1. Flame changes to oxidizing flame during welding, caused by welding for a long time, causing the tip to be high temperature. This causes oxygen gas and acetylene gas to dissociate normally. The acetylene gas volume decreases but the oxygen gas remains the same, causing the central flame. transformed into an oxidizing flame

Solution: The flame must be re-adjusted by increasing the amount of acetylene gas from the original. Until the flame is converted to a carburizing flame, then slowly reduce the acetylene gas to change to the middle flame as before. Alternatively, pause welding to allow the welding head to cool before connecting.

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