2004 Volume 90 Issue 10 Pages 788-794
Tin (Sn) in steels is a tramp element and promotes copper (Cu) to cause surface cracking at high temperature. But the detail has not been clear enough. In this study, Fe-0.05mass%C-3mass%Sn and Fe-0.05mass%C-0.3mass%Sn steels were investigated to clarify the effects of tin, manganese and sulfur on the precipitation behavior of tin, copper and MnS at high temperature. Under the two heat treatment conditions, the in-situ observations were carried out using a confocal scanning laser microscope. The first condition was a continuous cooling procedure and the second was an annealing procedure at 1423K. After the observation the precipitates were analyzed by SEM and 200 kV FE-TEM. As a result, in Fe-0.05mass%C-3mass%Sn steels the tin carbides were found as Fe3SnC mainly at the grain boundary. In Fe-0.05mass%C-0.3mass%Sn steels tin precipitates were not found at all. (Mn, Cu)S and fine CuS precipitates were found only inside the grains.
