2014 Volume 100 Issue 10 Pages 1274-1280
The authors proposed a three dimensional model to explain microscopic behavior of cleavage crack propagation in steel, which was validated by experimental results, in the previous paper. Purpose of this paper is to explore further into microscopic cleavage crack propagation behavior in steels having anisotropy using the proposed model. Charpy impact testing and small size crack arrest testing were conducted for observing anisotropy of cleavage fracture toughness and it was confirmed that R direction has lower toughness than LT and TL directions. And simulation was also conducted using the data of crystal orientation, which was derived from Electron Back Scattering Diffraction analysis. The comparison between the experiment and the simulation showed good agreement and the lowest toughness in the R direction was explained by a concentration of {100} planes in that direction.