Investigation on Behavior of Grain Growth in Superaustenitic Stainless Steel 654SMO.

Superaustenitic stainless steel 654SMO was used as the experimental material to investigate the effect of heating temperatures and holding times on grain growth behavior in the temperature range of 1150-1250 °C and holding time ranging from 15 to 60 min. The contour maps of grain size and grain growth rate as a function of temperatures and times were plotted. The results of this study suggest that grains grow with parabolic trend. Grain size and its growth rate increase with increasing heating temperature, the former also increases with holding time, while the latter decreases with holding time. Both grain size and grain growth rate are more sensitive to holding time than solution temperature at temperatures below 1200 °C, which is contrary to that of at temperatures above 1200 °C. The growth behavior of grains in the tested steel is illustrated by a modified mathematical model deduced on the basis of previous empirical models, and this modified grain growth model can fit well with the experimental grain growth data obtained during solution treatment. [ABSTRACT FROM AUTHOR]