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Plasma arc cutting
Plasma Arc Cutting
PAC - “Plasma Arc Cutting” produces a good quality cut using a Plasma jet at high speed and high temperature as a thermal source.
The term Plasma indicates a gaseous element becoming ionized and thereby an electric conductor.
This element can transfer a high quantity of energy from an electric power source to the piece of metal to be cut by an electric conductor. The jet passes through a nozzle, specially calibrated for the purpose, in order to heighten the thermal and kinetic characteristics.
The Plasma cut can be of a conventional type, dual gas or with a shield or injection of water.
The constant need to improve quality and increase speed has resulted in remarkable developments in Plasma technology.
The use of new components, gases and gas blends has made it possible to reduce the area in which the plasma jet is concentrated to approximately a tenth of that of conventional Plasma.
As a result, it is possible to obtain quality cuts with reduced wall angles, high precision hole cutting even for small diameters and a reduction in the formation of flashes and irregularities. The development of this technology is also a result of the gases and gas blends specifically studied and developed for these processes.
For ferrous metals below 30mm thick, plasma cutting is quicker than oxy-acetylene cutting and, for this reason, tends to be the cheaper alternative in many industrial applications.
Plasma cutting is a growth area which today is increasingly being used in different sectors for the cutting of medium-large thicknesses of a range of metals:
Whilst with conventional Plasma a single stream is used to produce the jet and cool the torch, others make use of two gas streams or separate gas mixtures from the Stargas® range:
- Plasma Gas: Highly ionized and capable of generating high energy Plasma jets.
- Assist Gases: have the job of helping to remove the metal changed to a liquid state from the cutting area and of screening, and therefore protecting, the surface of the cut from the surrounding atmosphere.
Use of technical gases and gas mixtures, and their development, has enabled a marked improvement in the quality of plasma cutting, increasing its speed and allowing it to gain important market share.
Gases normally used in plasma cutting are:
- Compressed Air: its use, because of the impurities present in compressed atmospheric air, brings a net reduction to the life of those parts of the torches which are subject to wear and tear, leads to the creation of nitrides in the cutting of ferrous steels and oxidation in stainless steels.
- Nitrogen: has a high capacity for inertising and is used for high speed cutting and without oxidation.
- Hydrostar Mixtures: used as plasma gas in so called “high definition” plants, they make it possible to take maximum advantage of the disassociative and reassociative properties of Hydrogen, contributing to significant improvements in the qualitative parameters of the cut. The most widely used are Hydrostar H-35 and Hydrostar H5N.
- Oxygen: is a good energy carrier and is used to cut carbon and low alloyed steels. Thanks to the effect of its exothermic reaction with iron, it is able to achieve regular, glittering cuts, without slag or dribbles and at increased cutting speeds.
Apart from gas products, today SIAD also offers a complete range of materials and accessories for cutting, gas centralization and, through its own partners, even automated cutting plants. The SIAD offer includes, furthermore, services such as technical theory/practical training courses to cater for all needs.