Effects of Ferrite Grain Size, Notch Acuity and Notch Length on Brittle Fracture Stress of Notched Specimens of Low Carbon Steel

The effects of ferrite grain size, notch acuity and notch length on brittle fracture stress and fracture toughness of notched specimens were experimentally studied at −196°C for a low-carbon steel. For the case of smaller notch root radius, fracture stress and fracture toughness are not so much conspicuously affected by ferrite grain size. The effect of ferrite grain size will increase with increase of notch root radius. Fracture stress and fracture toughness will decrease with increase of d−12 (d = grain size diameter) a smaller range of d−12, and increase nearly linearly with increase of d−12 in larger range of d−12, and, thus have minimum at some value of d−12.