Fracture toughness of MANET II steel

The effect of ageing on the tensile properties and fracture toughness of a 12Cr-1Mo-Nb-V steel, MANET II, was investigated. Tensile specimens and compact tension (CT) specimens were aged at 550 degrees C for 1000 h. The fracture toughness was evaluated according to the American ASTM, 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 toughness J(Ic) and the tearing modulus T were reduced due to the ageing treatment. The results are discussed in the light of the chemical composition and the fracture surface morphology. (C) 1998 Published by Elsevier Science Limited. All rights reserved.