Small punch tests to estimate the mechanical properties of steels for steam power plant: II. fracture toughness

摘要

Accurate measurements of the fracture appearance transition temperature and fracture toughnessK{sub}IC are greatly desired for engineering in steam power plant, especially from the standpoint oflife extension. The current toughness of materials at critical locations is a key characteristic necessaryfor the remaining life analysis. For this purpose, small punch test techniques using miniature-sizedspecimens have been investigated on header components. Linear relationships, obtained betweenmechanical characteristics determined from small punch tests and from Charpy tests, have been usedto estimate the fracture appearance transition temperature. Energy based and fracture stressformulations have been applied to estimate the fracture toughness in the upper- and lower-shelfregimes on a class of low alloy steels.