Advantages of Plasma Cutting in Superheated Water Vapor at Metallurgical Enterprises

Abstract

Currently air plasma cutting is applied for cutting the tube ends at metallurgical enterprises. Plasma cutting process is accompanied
by the release of metallic dust and harmful emissions (NO, NO2, CO, O3) in the environment. During cutting the cutting
edges become saturated with nitrogen and oxygen and carburized. These phenomena promote increase of metal hardness of
the cut surface and machining of pipe ends becomes complicated. To solve these problems, it is proposed to use superheated
vapor as plasma-producing media. Comparative research of ecological data and metallographic study of metal surface of the
cutting edge were conducted. According to the research data, concentration of dust and gases is by 50-60% less during cutting
in water vapor as compared with the air plasma cutting; but when using protective water vapor curtain around the open portion
of the arc this concentration is reduced to 70-75%. The depth of the heat-affected zone (HAZ) is reduced 3-3,5 times, and of
the cast section 2,6-3 times. The microhardness of the metal surface in water vapor is reduced 1.7-2 times.