Abstract：Abstract： The comparative study on hot tensile properties of a 21Cr-11Ni-1.5Si-N austenitic heat-resistant steel with and without yttrium have been investigated by using Gleeble-3800 thermal-mechanical simulator within the temperature range of 750~1200℃ and the stain rate 0.005s-1, the effect of yttrium and corresponding mechanism have been analyzed and discussed. The results show that hot ductility and tensile strength of test steel are increased as the addition of yttrium can refine grain sizes and strengthen grain boundary over 750 ℃ to 850℃. Hot ductility of test steel with yttrium is close to that of test steel without yttrium at the temperature range of 850~1050℃ and is improved significantly at temperature between 1050℃ and 1200℃, because yttrium can suppress dynamic recrystallization and recrystallized grain growth. Additionally, highly stable fibrous structures which are difficult to eliminate according to heat treatment and dynamic recrystallization are distributed in matrix of test steel with yttrium after hot working. A number of fine grains around fibrous structures have been observed.
2011, Vol. 46 
