| When the rapidly solidified standard high Mn steel strips were reheated, the precipitation curve of carbide was likely a C-curve which had the nose at about 600-700℃. The precipitation curve of pearlitic constituents(PC) was also likely a C-curve having the nose at about 600℃. By addition of alloying elements(Cr, V), the temperature ranges of the carbide and PC precipitation were enlarged and the time of their precipitation was earlier. The quantities of the carbide and PC precipitation were increased and were observed much more in the V-added specimen. Regardless of the alloying elements(Cr, V), carbide was formed in the shape of film at the grain boundaries at 500-700℃. With the increase of heating time, the shape of carbide film was grown like plate and subsequently PC nucleus was formed at the plate-like precipitations and grown. The hardness of the (Cr, V) added specimen was higher than that of the standard specimen. The increased hardness was mainly affected by PC rather than carbide. V has more accelerated the formation of carbide and PC than Cr. |
|
