On the use of a new ultrahigh-strength Cr-Mn austenitic stainless steel in gas turbine's exhaust systems

The local substitution of AISI 316L stainless steel grade type by a new ultrahigh-strength Cr-Mn austenitic stainless steel was assessed in order to eliminate the high temperature fatigue crack propagation, mainly due to thermal shock, that has been verified in some exhaust systems of naval gas turbines. Results obtained in tensile and fatigue strength tests, carried out in base materials and dissimilar butt-welded joints, at 24, 350 and 500 degrees C, are presented. Cyclic mechanical properties and thermal shock resistance values were calculated and compared, together with the pitting corrosion resistance of the two materials under study. (C) 2011 Published by Elsevier Ltd. Selection and peer-review under responsibility of ICM11