Toughness losses in low alloy steels at high temperatures: an appraisal ofcertain factors concerning the small punch test

The present paper deals, at length, with a number of aspects of the novel u sage of miniature disc specimens to ascertain the loss of toughness in cert ain critical engineering components which operate at elevated temperatures. This type of test is commonly known as the small punch, SP, test. Details of the experimental methodology are introduced together with a critical app raisal of the relationship between SP transition temperature, T-SP, and the more conventional Charpy fracture appearance transition temperature, FATT, obtained from large test specimens. Essentially it was demonstrated that a non-linear expression better described the T-SP-FATT trends published in t he literature, viz. FATT = C/T-SP(2) When the T-SP-FATT trends of the various steel classes were concerned separ ately an encouraging picture emerged in that a reasonable amount of the rep orted data exhibited good agreement with the predicted effects of grain siz e. Finally, the fractographic characteristics of the SP test and the Charpy test were compared and contrasted. (C) 1998 Elsevier Science Ltd. All righ ts reserved.