Fabrication of large ingots of high-nitrogen steels by the remelting method of expendable plasmatron

The results are presented of a commercial trial at the 'Dneprospetsstal' works of the technological process for producing high-nitrogen chromium-nickel-manganese steels using the method of consumable plasmatron smelting (CPS), which permitted in smelting hollow ingots, to alloy the metal to a high degree of accuracy up to graded concentrations of nitrogen up to 2 atm (ex). The ingots weighing up to 1000 kg were cast with a good surface, chemical and structural homogeneity, dense macrostructre. The losses of elements having high vapor tension are negligible as compared to the vacuum arc melting. For instance the manganese content in the KH2111G7AN5 steel does not exceed 5%. The experimentally produced metal is characterized by high tensile and plastic properties, their standard being 45 to 55% higher than that of electroslag melted metal. A comparison is given of the economic factors of various technological processes for producing nitrogen-containing steels, which demonstrates a promising potentiality of commercial utilization of the CPS technology. The use of nitrogen-containing stainless steels produced by the CPS technology will permit to decrease considerably the weight of machine parts and metallic structures without decreasing their service life and also to decrease their cost price