SMALL PUNCH TESTS TO ESTIMATE THE MECHANICAL-PROPERTIES OF STEELS FORSTEAM POWER-PLANT - II - FRACTURE-TOUGHNESS

Accurate measurements of the fracture appearance transition temperatur e and fracture toughness Kic are greatly desired for engineering in st eam power plant, especially from the standpoint of life extension. The current toughness of materials at critical locations is a key charact eristic necessary for the remaining life analysis. For this purpose, s mall punch test techniques using miniature-sized specimens have been i nvestigated on header components. Linear relationships, obtained betwe en mechanical characteristics determined from small punch tests and fr om Charpy tests, have been used to estimate the fracture appearance tr ansition temperature. Energy based and fracture stress formulations ha ve been applied to estimate the fracture toughness in the upper- and l ower-shelf regimes on a class of low alloy steels. (C) 1998 Elsevier S cience Ltd. All rights reserved.