Oxygen cutting: Types and processes

Oxygen cutting 

The oxygen cutting process is the most common (metal severing ) process used by industries in daily practice. 

Definition

Oxygen cutting is a group of metal cutting processes in which the decomposition or removal of metals is carried out through a chemical reaction of oxygen with the base metal at elevated temperatures.

Generally in this process, the required temperature is being maintained through a gas flame obtained from the combustion of acetylene, hydrogen, propane, etc.

 The chemical reaction of oxygen with the base metal 

Fe +O ➝FeO + Heat (276 KJ)

3Fe+2O₂ ➝Fe₃O₄ +Heat (1120 KJ)

Types of oxygen cutting processes

There are many methods used in oxygen cutting process, such as 

• Oxy-fule gas cutting or Flame cutting
• Oxygen Arc cutting
• Chemical Flux cutting or Injection cutting
• Metal Powder cutting
• Oxygen-Lance cutting

Oxy-fuel Gas cutting 

Oxy-Fuel Gas Cutting Process is also called Flame Cutting Process. It is a process of gas cutting metal, which effected by the chemical reaction of oxygen with the base metal at elevated temperatures. The required temperature is being maintained through a gas flame derived from the combustion of fuel gas.

 Equipment used in Oxy-Acetylene Metal Cutting Process

• Cutting torch
• Oxygen and acetylene gas cylinders
• Oxygen and acetylene hose and fittings
• Regulators
• Flame striker
• Flame 

                                                 

Cutting torch

Cutting a torch made of a yellow brass body. It combines acetylene and oxygen and carries the gas mixture into the holes where it is ignited to produce flames. The cutting torch differs in some ways from the Oxy-fuel gas welding torch because it has an extra pass for the flow of high-pressure cutting oxygen and it has a tip with a centrally located hole and several others located around the central one in a circular pattern. Small orifices.

The act of cutting off the oxygen takes place in the central pore from which it emerges, it oxidizes the metal and blows away from an open slot (kerf).

Types of cutting torches                                                  

There are two types of cutting torches

Injector type, 

In these types of torches, acetylene is transported to the torch at pressures below 1 PSIG. Acetylene is drawn into the torch with the help of an injector. For preheating flames, acetylene and oxygen are added to the tip of the cutting torch.

Equal pressure type

 In these types of torches, oxygen and acetylene are distributed at pressures above 1 PSIG.

The mixture of gases is inside the torch (and not in the tip)

Torch Tip 

The tip of the torch is usually made of copper alloy material and is available in many designs and sizes, it is tightened through the tip nut inside the torch. It has a hole in the middle and around it There are small holes which are circular in shape.

The design of the tips (ie, the size and number of preheating flame ports and the size of the central orifice) varies for different metal thickness cuts and also depends on the material and its surface condition.

Next issue: Types of  Flame cutting