Methods of Cutting Mild Steel

Various methods exist for cutting mild steel. Waterjet, plasma, laser cutting and power tools are amongst several ways of cutting mild steel. The best method for a given situation depends largely on the thickness and configuration of the steel being cut.

The water jet method can be used to cut straight through mild steel sheet, mild steel plate or mild steel tube. In principle, a waterjet works much like the natural water erosion that occurs over time. A water jet cutter uses a thin stream of water at very high pressures, usually between 33,000 and 75,000 PSI, to cut through steel. Sometimes an abrasive substance, such as aluminium oxide or garnet is mixed with the water stream. In cases where the material being cut is sensitive to high temperatures, water jet cutting is the preferred method since it does not create a heat-affected zone (HAZ). Waterjet is not a very quick method of cutting, so it is not preferred when speed is required.

Plasma cutting can be used to cut mild steel and other materials of various thicknesses. An inert gas is forced through the plasma torch nozzle at high speed. An electric spark ionises the gas running through the torch nozzle and creates an arc. This turns some of the gas into plasma, which melts the material being cut. This process is quick enough to force the molten metal away from the cut, creating a relatively clean slice in the mild steel.

Laser cutting has been used mainly for industrial applications, but hobbyists, small businesses and schools are also starting to use this method. In laser cutting, a computer controls the laser and directs the cutting pattern. Where the laser is directed, the material is blown away, burns, vaporises or melts, depending on the type of laser cutter. The more powerful lasers can cut through steel up to 3.429 cm think. Laser cutting is suitable for making straight cuts in mild steel sheet and mild steel tube. Because of its precision, laser cutting is also the best method for cutting intricate patterns or designs in the metal.

Another option for cutting mild steel is to use power tools. Most power tools are available in cordless or corded varieties. Corded tools are more powerful and therefore probably better for cutting steel. A circular saw fitted with carbide tips should be able to cut straight through mild steel tube or even fairly thick mild steel plate. This method will result in a lot of metal shavings, so personal protective equipment is a must.

Each of the methods discussed above is effective for cutting mild steel. When cutting steel 2.54 cm or less thick or when cutting according to a pattern, laser cutting is advisable. Where high cutting temperatures are a problem, waterjet is the preferred method. When attempting to make a straight cut in thicker mild steel plate, plasma cutting works better. Especially in a small shop or at home, a corded circular saw with carbide tips will do for making straight cuts in mild steel sheet or mild steel tube.