The effect of ageing on the tensile properties and fracture toughness
of a 12Cr-1Mo-Nb-V steel, MANET II, was investigated. Tensile specimen
s and compact tension (CT) specimens were aged at 550 degrees C for 10
00 h. The fracture toughness was evaluated according to the American A
STM, European ESIS and Japanese JSME standards. Fracture surfaces were
examined using scanning electron microscopy. The results showed that
ageing did not affect the tensile properties. However, the fracture to
ughness J(Ic) and the tearing modulus T were reduced due to the ageing
treatment. The results are discussed in the light of the chemical com
position and the fracture surface morphology. (C) 1998 Published by El
sevier Science Limited. All rights reserved.