Assessment of transfer phenomena on steel surface caused by liquid sodium

The mechanism is discussed of the transfer between sodium and steel of iron, alloying elements and interstitial dissolved elements. Temperature dependences are given for solubility of iron, chromium, nickel and carbon in liquid sodium. Main attention is paid to an approximate calculation of the width of carbon steel decarburization. A thermodynamic analysis is made of carbon diffusion flow between steel and sodium. The results of the calculations of decarburization profiles of steel with 0.172 wt.% C, taking into account a 5% and 10% carbon contribution from cementite are shown in graphs. The algebraic grid method was used to solve the diffusion equations. Time-dependent widths of the decarburized layer were determined for steels containing 1.010 and 0.172 wt.% C at temperatures of 943 K and 893 K. Good agreement was observed of the calculated and experimental values. (E.S.)