Siberian State Industrial University (Novokuznetsk, Russia):

Kozyrev N. A., Dr. Eng., Prof., Head of the Chair of Material Science, Casting and Welding. e-mail: kozyrev_na@mtsp.sibsiu.ru
Umanskiy A. A., Cand. Eng., Ass. Prof., Chair of Ferrous Metals. e-mail: umanskii@bk.ru

EVRAZ ZSMK JSC (Novokuznetsk, Russia):

Boykov D. V., Cand. Eng., Head of Steelmaking Dept. e-mail: Dmitry.Bojkov@evraz.com

At the present level of development of production technology of rail steel, increased concentration of brittle desctucted oxide inclusions in metal can be considered as the main reason for the decline of rail service durability. Content of these oxide inclusions, in their turn, is directly determined by the concentration of oxygen in the primary rail steel. According to the results of statistical studies conducted at EVRAZ ZSMK, it was found out that increase of duration of steel purging by inert gas during ladle treatment is an eff ective method of lowering of oxygen content in rolled rails. Experimental testing of the ladle treatment technology for rail steel with increased duration of inert gas purging (minimum 100 min.) has displayed reduction in the total content of free oxygen and oxygen bound to brittle destructed nonmetallic inclusions in rails by 2 ppm, as well as decrease of the length of lines of non-metallic inclusions by 0.004 mm. Improvement of the mechanical properties of the rails before quenching has been also recorded. However, usage of this technology is accompanied with increase of steel production cost due to elevation of specifi c consumption of argon and electric power.

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