Plasma or Gas Cutting: What is the Difference and Which to Choose
Two main industrial methods for cutting sheet metal — the difference in thickness range, speed, accuracy, and cost.
How plasma cutting works
Plasma cutting uses a jet of ionized gas heated by an electric arc to 20,000-30,000°C — the plasma melts through the metal at the cut line, and the gas flow blows the molten metal out of the kerf. It requires no preheating and works on any electrically conductive metal, including stainless steel and aluminum.
How gas (oxy-fuel) cutting works
Gas cutting burns metal in a stream of pure oxygen after preheating the cut area with a fuel-gas flame to the ignition temperature of steel. Metal in the cut zone burns, and the resulting oxides are blown out by the oxygen jet. The method only works on carbon and low-alloy steel — stainless steel and aluminum cannot be cut this way.
Metal thickness and cut accuracy
Plasma cutting is effective on metal up to roughly 40-50 mm, producing a narrower, more accurate cut with a smaller heat-affected zone and minimal sheet distortion, especially under 20-25 mm.
Gas cutting handles substantially greater thicknesses — up to 60-100 mm and beyond — where plasma no longer cuts through efficiently, but leaves a wider kerf and a more pronounced heat-affected zone at the edge.
Speed and cost
On metal up to 20-30 mm, plasma cutting is several times faster than gas cutting, lowering the cost per cut for medium and thin sheet in production runs. On thick metal, gas cutting is often more economical, and at very large thicknesses it remains virtually the only practical thermal cutting method.
Which metals each method cuts
Plasma cutting works on any electrically conductive metal: carbon and alloy steel, stainless steel, aluminum, copper, brass. Gas cutting is limited to carbon and low-alloy steel — stainless and aluminum require a different method.
How a plant chooses a cutting method
In practice, the method is chosen per part: metal thickness and grade, required edge accuracy, batch size and lead time. For carbon steel structures thicker than 40-50 mm, gas cutting is typically used; for medium sheet and parts where accuracy matters, plasma is used.
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