A thermal cutting process that utilizes fuel gas and oxygen in order to penetrate through a variety of materials is known as the oxy-fuel cutting procedure. The gases used for this process are considered to be the following.
- Natural gas
- MAPP, etc.
The oxyfuel process is an operation that is the most followed industrial cutting process that is being used worldwide. It is used to cut thick materials from 0.5mm to 250mm with different types of equipment that are used manually as well as systematically. These equipment contain several design options that are relatively inexpensive in terms of performance. This not only increases the cutting quality enhancement but also improves the cutting speed of the material.
The Fundamental Procedure Of Oxy-Fuel Cutting
The first step in the oxyfuel cutting procedure requires a mixture of oxygen and gas to help preheat the metal or steel in its ignition form. The preheating metal process is also known as the oxidation process. The temperature in order to preheat the metal effectively should be around 700 °C to 900 °C, preferably well below its melting point.
This step then leads to an exothermic chemical reaction in between the oxygen, acetylene, and the metal where a jet of pure gas is released into the preheated area. Furthermore, the form which metal obtains is of iron oxide and slag where the slag is blown away with the jet’s assistance. It is done to ensure that the jet has been penetrating the material and is cutting it efficiently.
Basic Oxy-Fuel Cutting Requirements
- The temperature used for igniting any material such as metal, steel, etc must be below its melting point. The reasoning behind this strategy is to make sure that the material does not melt or flow in its ignition period, before the actual procedure of cutting.
- It is important to ensure that the temperature of the oxidation melting process is below than its surrounding materials so that it cannot be blown away or melted by the oxygen and other gases.
- The chemical reaction between the oxygen jet and metal should be efficient enough to maintain the temperature of ignition accurately.
- It is necessary for a minimum reaction of gases to be produced for the dilution of oxy-fuel cutting.
Moreover, it is recommended to inject powder into the heated flame to produce a low melting point or to control the oxide melting point that is formed by stainless steel, non-ferrous metals, and cast iron. The purpose, as mentioned above, is to not let the material melt itself.
Furthermore, the speed and quality of oxy-fuel cutting also depend upon the purity of the oxygen stream. Therefore, the nozzle is used to protect the oxidation process from the outside air.
Apart from that, the characterization and choice of fuel gases are significant in the process of combustion. These gases must be characterized by:
- Their flame temperature
- Their ratio with oxygen
- Their amount required for combustion (which needs to be neutral)
- The heat required for combustion
For more information, checkout Messer oxy-fuel cutting options, advantages, and disadvantages.