What is oxidation cutting?
In oxidation cutting, the steel surface is first heated with a gas flame, usually from a mixture of fuel gas and oxygen. Once the steel has reached the right temperature, a concentrated jet of oxygen is directed at the material. The oxygen causes the iron in the steel to oxidize rapidly, releasing heat and allowing the cutting process to continue through the material.
The oxides formed, together with molten material, are blown away by the oxygen jet. This creates a cut through the sheet metal or steel part.
So it's not just the heat from the flame that cuts the material, but above all the chemical oxidation reaction in combination with the oxygen flow.
How does the process work?
Oxidation cutting takes place in several stages:
1. preheating
First, the steel is heated to its ignition temperature. This is done using a gas flame, where common fuel gases can be acetylene, propane or natural gas.
2. ignition of the material
When the steel surface reaches a sufficiently high temperature, it becomes reactive enough to start oxidizing strongly in contact with pure oxygen.
3. oxygen shear gas
A central oxygen jet opens and reacts with the steel. The oxidation develops extra heat, which helps the process to continue down through the material.
4. Blowing off slag
Oxides and molten material are pushed out of the cutting groove by the oxygen jet. This allows a continuous cut to be formed.
What materials can be cut with oxidation cutting?
Oxidation cutting works best on materials that can oxidize easily and where the oxides can be removed effectively. Therefore, the method is mainly suitable for:
- non-alloy steel
- low alloy steel
- certain structural steels
However, the method is less suitable or even unsuitable for materials such as:
- stainless steel
- aluminum
- copper
- cast iron in some cases
- high alloy steels
The reason is that these materials either form protective oxide layers, dissipate heat too quickly or have chemical properties that make the oxidation reaction itself more difficult.
Common uses
Oxidation cutting is used in many applications where robustness and ability to cut thick material is more important than extreme precision. Examples of applications are:
- manufacture of steel structures
- cutting of heavy plate
- dismantling of steel parts
- maintenance and repair in industry
- shipbuilding
- construction and civil engineering projects
- scrap and recycling management
The method is used both manually and in automated systems, such as CNC cutting tables.
Advantages of oxidation cutting
One of the main advantages of oxidation cutting is that it can handle very thick materials. Where other cutting methods can be costly or technically limited, oxidation cutting is often a practical alternative.
Other advantages are:
Good capacity in thick steel
The method is very well suited for cutting thick sheets and rough details.
Relatively low investment cost
The equipment is often simpler and cheaper than many other thermal cutting systems.
Flexibility
Oxidation cutting can be used both in the workshop environment and in the field.
Simple technique
The process is well-known, robust and proven, making it easy to understand and apply in the right context.
Limitations of the method
Although oxidation cutting is effective, it has several limitations compared to more modern cutting techniques.
Lower precision
The cut is often coarser than with laser cutting or waterjet cutting, for example.
Heat affects the material
As the method applies a lot of heat, a heat-affected zone is created around the cut. This can change the properties of the material locally.
More post-processing
Edge layers, slag and irregularities may mean that the cut part needs to be cleaned or further processed.
Limited choice of materials
The method does not work universally on all metals.
The difference between oxidation cutting and other cutting methods
Oxidizing cutting is clearly different from other common methods in metalworking.
Compared to plasma cutting
Plasma cutting works on more materials, including stainless steel and aluminum. It often gives higher speed in thinner materials and better precision, but oxidation cutting is often more economical in very thick carbon steel.
Compared to laser cutting
Laser cutting provides high accuracy, narrow cuts and fine edges, especially in thinner materials. Oxidation cutting is instead often used when the material thickness is large and the tolerance requirements are less extreme.
Compared to waterjet cutting
Waterjet cutting is a cold method that produces no heat-affected zone. It works on many different materials, but the equipment is more advanced and costly. Oxidation cutting is simpler and often more practical for coarse steel.
What affects cutting quality?
Several factors have a major impact on the results of oxidation cutting:
- the quality and composition of the material
- plate thickness
- condition and size of the nozzle
- the purity of the oxygen
- cutting speed
- correct preheating
- distance between nozzle and material
- operator's experience or machine settings
If the parameters are set correctly, a smooth cut with acceptable edge quality can be obtained. If they are incorrect, the risk of slag, uneven cuts, wide kerfs or incomplete cut-through increases.
Safety in oxidation cutting
As oxidation cutting involves open flame, high temperatures and oxygen, careful safety procedures are required. Fire hazards, sparks, hot surfaces and gas equipment must be properly managed.
Important safety aspects include:
- good ventilation
- proper handling of gas cylinders
- checking hoses, couplings and valves
- use of personal protective equipment
- protection against sparks and the spread of fire
- training in the safe handling of cutting equipment
It is particularly important that oxygen is never handled carelessly, as it can greatly accelerate the progress of a fire in contact with flammable substances.
Executive summary
Oxidizing cutting is an established method for cutting non-alloy and low-alloy steel using a combination of heat and oxygen. It is mainly used where thicker materials need to be processed in a robust and cost-effective way, but it also has limitations in terms of precision, heat impact and material selection.
For many industrial companies, it is therefore important to choose the cutting method based on the material, tolerance requirements and end use. There are several different methods in thermal and mechanical processing, and the choice should always be based on which solution is most suitable for the application in question.
We at Thor Ahlgren do not work with oxidation cutting, However, knowledge of the method can still be valuable when comparing different manufacturing processes and choosing the right processing for a specific need.