Gas Metal Cutting - Types and Features

Gas metal cutting can rightly be considered one of the simplest, fastest, and most affordable cutting methods.

This technology does not require complex preparatory work, takes minimal time, and ensures high quality of the final product. Gas cutting offers several advantages and can be performed in different variations suitable for various working conditions and parameters.

Gas Cutting: Key Features of the Technology

The gas cutting process can be explained by the fact that the cut occurs due to the combustion of excess material in the gas flame. When this process is examined in detail, all its technological nuances become clear.

The main tool for gas cutting is a gas torch, which performs several important functions simultaneously:

• regulates the proportions of the oxygen and gas mixture;
• ensures the ignition of the gas;
• controls the oxygen supply.

Gas metal cutting belongs to thermal processing methods. This technology allows for the efficient cutting of metal blanks of various thicknesses. An important advantage of gas cutting is its energy independence – it is autonomous and can be used in any conditions. This feature is crucial when cutting is impossible due to a lack of electricity or other external restrictions. The gas torch works efficiently even in the field, far from infrastructure and power sources.

With a professional approach, the gas cutting process proceeds smoothly. The blank is heated by an acetylene-oxygen flame along a predefined contour, after which a pressurized gas stream is directed at the material. Under the flame's influence, the metal heats up, and the oxides formed are removed by the kinetic energy of the stream.

For the gas torch to operate stably, a high thermal power source is required. The metal blank is heated to the required threshold, causing the metal to burn and release a significant amount of heat.

Technology Limitations

Gas cutting is not suitable for all metals due to certain technological limitations, specifically:

• The oxidation temperature of the metal must be lower than its melting temperature.
• Additionally, the melting temperature should exceed the temperature of the formed oxides.
• The metal must also have low thermal conductivity and good oxide fluidity.

Due to these requirements, not all metals can undergo gas cutting.

Metals Suitable for Gas Cutting

Gas cutting is versatile and allows for the quick and cost-effective cutting of various types of metals. However, there are exceptions: a gas torch is not used for cutting copper, brass, aluminum, and stainless steel, except when additional processing methods or fluxes are used.

Advantages and Disadvantages of Gas Cutting

The advantages of gas cutting include:

• the ability to perform cuts of varying complexity;
• efficient work with metals of any thickness;
• the ability for surface cutting;
• high speed of work execution;
• process autonomy;
• versatile application;
• cost-effective quality-to-price ratio.

The main disadvantages of the technology are:

• requires experience and professional skills;
• low safety level;
• insufficient cutting accuracy.

Despite these drawbacks, the accessibility of gas cutting makes it one of the most popular metal cutting methods.

Types of Gas Cutting and Their Classification

Gas cutting comes in several types that differ based on the characteristics of the gas stream. The following gas cutting methods are distinguished:

• Through (separating) cutting.
• Surface cutting (for removing the top layer of metal).
• Oxygen lance cutting (for creating holes).

High-Speed Through Cutting

Ensures complete separation of parts of the blank using the torch flame. This method uses triple nozzles with holes arranged in a triangle shape. The main stream performs the cut, while auxiliary streams clean the edges. This method offers high work speed, though the cut is wide and unsuitable for complex shapes.

Gas Cutting with Flux

Used for cutting alloy steels. Powdered flux releases additional heat during combustion, necessary for the torch’s stable operation. Flux is supplied through a special flux accumulator. This method is suitable for cutting cast iron, chromium, and chrome-nickel steels. For working with copper and aluminum alloys, preliminary mechanical processing is required.

Surface Gas Cutting

Used for removing the top layer of metal. The torch is positioned at an angle of 15-40 degrees, and the fuel mixture is supplied at low speed. This allows the metal on the surface to burn in the flame.

Oxygen Lance Method

Allows the creation of holes not only in metal but even in reinforced concrete. This method uses a small-diameter tube (up to 35 mm), which is heated, turning the gas mixture into a flame "lance" to penetrate the hole.