Effects of Cr - Ni 18/9 Austenitic Cast Steel Modification by Mischmetal

Abstract

This paper presents the results of Cr - Ni 18/9 austenitic cast steel modifications by mischmetal. The study was conducted on industrial melts. Cast steel was melted in an electric induction furnace with a capacity of 2000 kg and a basic lining crucible. .The mischmetal was introduced into the ladle during tapping of the cast steel from the furnace. The effectiveness of modification was examined with the carbon content of 0.1% and the presence of δ ferrite in the structure of cast steel stabilized with titanium. The changes in the structure of cast steel and their effect on mechanical properties and intergranular corrosion were studied. It was found that rare earth metals decrease the sulfur content in cast steel and above all, they cause a distinct change in morphology of the δ ferrite and non-metallic inclusions. These changes have improved mechanical properties. R02, Rm, and A5 and toughness increased significantly. There was a great increase of the resistance to intergranular corrosion in the Huey test. The study confirmed the high efficiency of cast steel modification by mischmetal in industrial environments. The final effect of modification depends on the form and manner of placing mischmetal into the liquid metal and the melting technology, ie the degree of deoxidation and desulfurization of the metal in the furnace.

Changes in Abrasion Resistance of Cast Cr-Ni Steel as a Result of the Formation of Niobium Carbides in Alloy Matrix

“…Similar results of microscopic examinations were obtained by the authors in studies [ 6 , 7 , 8 , 9 , 10 ]. For example, in study [ 6 ], in addition to the characteristics of the microstructure of selected cast Cr-Ni steel grades, the results of hardness and impact strength measurements at −40 °C and +20 °C were presented.…”

“…For example, in study [ 6 ], in addition to the characteristics of the microstructure of selected cast Cr-Ni steel grades, the results of hardness and impact strength measurements at −40 °C and +20 °C were presented. On the other hand, [ 7 ] gave the results of the modification of cast austenitic Cr-Ni 18-9 steel with mischmetal (Rare Earth Metals) in the ladle and its impact on the microstructure. The tests were carried out on industrial melts in which the delta ferrite structure was obtained with the carbon content of 0.1%.…”