Different types of gas welding flames and their applications

Today I will be discussing the three basic types of gas welding flames. Previously, an article was published on the components of gas welding.

Gas welding flames and their applications


Types of gas welding flames

Gas welding which is also known as oxyacetylene or oxy-fuel welding uses three controlled flames to carry out any type of operation. These flames include neutral, oxidizing, and carburizing flame.

Neutral flame

Gas welding Neutral flame

In this gas welding flame, oxygen and acetylene are released at a one-to-one ratio. That is, an equal amount of oxygen and acetylene is released. It absorbs additional oxygen from the air as it provides complete combustion. A neutral flame is fine, clear, and well-defined. It is generally preferred for welding. it produces a luminous cone indicating the completion of the flame.

Read more: Safety precautions in a gas welding workshop

Neutral flames are used to weld both ferrous and nonferrous metals such as mild steel, cast iron, copper, stainless steel, aluminum, etc. welder are expected to adjust to neutral before any other flame. The flame is indicated from its inner cone consisting of a luminous cone that is bluish-white. It is also known for its surroundings showing a light blue flame sheath or envelope. Neutral flame, which is also known as a balanced flame which is achieved by releasing excess acetylene. A flame with feather extension of inner cone is produce, increasing the oxygen valve will produce the flame. Immediately oxygen gas, the acetylene flame feather disappears and neutral flame remains. The inner core tip temperature is approximately 585-degree Fahrenheit, whilst, end of its outer sheath or envelope temperature drops to approximately 2300-degree Fahrenheit.

Carburizing flame

Carburizing flame

In this oxyacetylene flame, excess acetylene is supply. Its inner core has a feather edge extending beyond it, this white feather is also known as acetylene feather. This acetylene is 2x if it’s twice as long as the inner cone, helping to know the amount of acetylene supply. Carburizing flame may add carbon to the welded metal of one volume. It is performed by adjusting to a neutral flame before increasing the acetylene valve. The inner core will change showing an acetylene streamer or “feather” at its end. The level of carburization flame is determined from the length of the streamer. The streamer should not be more than half the length of the inner core.

Read more: Different Types of Gas welding equipment

Carburizing flame is clearly recognized by three flame zones:

  1. A clearly defined bluish-white inner cone
  2. White immediately cone indicating the amount of excess acetylene
  3. A light blue outer flare envelope.

This flare burns with a coarse rushing sound. The inner cone tip temperature is approximately 3700-degree Fahrenheit. If a carburizing flame is used for welding, carbon absorbs from the flame, causing metals to boil. This metal is not clear as it boils, obtains high carbon steel, becomes brittle, and subject to cracking.

Oxidizing flame

Oxidizing flameRead more: Understanding metal inert gas welding (MIG), and its applications?

this is the third oxyacetylene flame. It is obtained when oxygen is slightly more than one volume, mixed with one volume of acetylene. Just as it is done in carburizing flame, the torch is adjusted to a neutral flame. The oxygen valve will then be increased until the inner core is shortened to about one-tenth of its original length. The flame tends to be slightly purple and the inner cone is pointed if the flame is properly adjusted. This flame is also known for its clear hissing sound.

The temperature of the oxidizing flame is approximately 6300-degree Fahrenheit at its inner core tip. It is used to weld metals such as zinc, copper, manganese steel, and cast iron. Applying this flame to steel causes its molten metal to form and spark off, indicating excess oxygen is supply to the steel. It is not used for welding steel because it causes it to be porous, oxidized, and brittle.

Read more: Understanding tungsten inert gas welding (TIG)

That is all for this article, where the three basic types of gas welding flame are being discussed. I hope you enjoyed the reading, if so, kindly share with other students. Thanks for reading, see you next time!


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