Oxy-Fuel | What is Oxy-Fuel Welding & Cutting?
What is Oxy-Fuel Welding & Cutting?
Some Basics that you need to know about Oxy-fuel welding and cutting
Oxygen (O₂) is a molecule that constitutes approximately 21% of Earth’s air. Oxygen’s boiling point -183°C and its melting point is −218.8°C, at normal atmospheric pressure. Oxygen is a colorless, odorless, and tasteless gas essential to living organisms. It is valued for its strong oxidizing and life-sustaining properties. Oxygen and practically any other element react to create compounds. In many cases, the reaction of Oxygen with other elements generates heat and light, called combustion.
The process of separating liquid Oxygen directly from the air:
- Oxygen is produced industrially by the fractional distillation of liquid air in a cryogenic air separation unit, a process that separates liquid Oxygen directly from the air.
- Using the same method, Nitrogen and Argon are also produced.
Oxygen can also be produced by using the principle of Water electrolysis:
- Oxygen and Hydrogen, the two components of Water (H2O), are separated from each other by passing a high electrical current through an electrolyte.
- Once each gas is separated, they are then purified and stored separately.
The Usage of AHG’s pure gasses in the welding industry:
- AHG’s pure gases are commonly used in the welding industry, and the correct combination of gases is crucial to the quality and productivity of your work.
- The correct choice of welding gas will protect the weld metal from the surrounding air and ensure a better result.
- Oxy-fuel welding and oxy-fuel cutting are processes that use fuel gases (or liquid fuels) and oxygen to weld or cut metals.
- The process utilizes pure oxygen, instead of air, is used to increase the flame temperature to allow localized melting of the workpiece material (e.g. steel) in a room environment.
To give an example of the difference between using air and using oxygen, a common propane/air flame burns at about 1,950 °C and a propane/oxygen flame burns at about 2,250 °C.
Oxy-fuel cutting is the most widely applied process for cutting steel:
- It is a chemical reaction between oxygen and metal.
- The preheating flame is used to raise the surface temperature of the steel, and the oxygen is then directed to the heated area in a direct and high-pressure stream.
- As the steel is oxidized, it is blown away to form the cavity in what is typically referred to as “slag”.
- This is why the resulting chemical reaction is referred to as rapid rusting.
- Oxy-fuel cutting provides an excellent cut quality with low investment costs.
- The purity of the oxygen used in the cutting process is what determines the cutting speed that can be achieved.
- The higher the purity of the oxygen, the faster the metal can be cut. Acetylene is the most commonly used fuel for oxy-fuel cutting and welding.
- Acetylene produces the hottest and most concentrated primary flame.
- Propane is also commonly used, although compared to acetylene, propane generates less heat in the primary flame.
An important note, oxygen is not the fuel. It is what chemically combines with the fuel to produce the heat for welding. This is called ‘oxidation’, but the more specific and more commonly used term in this context is ‘combustion’.
AHG gas division offers a full range of specialized and industry-standard gases:
These are available in a wide range of cylinder sizes to meet your needs. AHG’s Welding division supplies a wide range of metal fabrication equipment.
Welding and Cutting guidelines:
- When welding or cutting, ensure that you or your employees Read the MSDS and labels for all of the materials you work with.
- Wear the proper personal protective equipment.
- Store compressed gas cylinders in cool, dry, well-ventilated areas, away from incompatible materials and ignition sources.
- Ensure that the storage temperature does not exceed 52°C (125°F).
- Store, handle and use compressed gas cylinders securely fastened in place in the upright position. Never roll, drag, or drop cylinders or permit them to strike each other.
- Know all of the hazards (fire/explosion, health, chemical reactivity, corrosivity, pressure) of the materials you work with.
- Leave the cylinder valve protection cap in place until the cylinder is secured and ready for use.