Plasma Cutting Alloy SteelAlloy steel is a name applied to a range of alloys with different characteristics depending on the specific alloy. The alloy steels most frequently encountered are Ni steel, Cr-Mo and Cr-Mo-V steels, and some high strength alloys containing Cr, Ni, Mo and other elements. Alloy steels frequently need to be cut to size or shape and the plasma process will cut at high speeds and so is being used more frequently. Some alloy steels have high carbon equivalents and are very hardenable. This renders them prone to cracking and preheat may be needed to prevent this. The process is normally mechanised and may use a single cutting head or multiple cutting heads. The whole cutting system may also be fitted to numerical control equipment. For plasma cutting steel the plasma gas is normally argon/hydrogen or nitrogen/argon mixtures but may also be compressed air. While cut edges are smooth, if not parallel, the HAZ produced by plasma cutting usually needs further dressing by grinding prior to welding to remove hardened zones and any possible damage or small cracks in the in the cut surfaces. The main safety issues are electrical, radiation, heat, possible noise and welding fume containing particulate and oxides of nitrogen. Cutting under water will suppress emission of fume, noise, and radiation.
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