Relationship between fracture topography and fracture toughness of a high strength steel

Abstract

The relationship between fracture topography and the plane strain fracture toughness of Comsteel En25 tempered at nine different temperatures and with crack planes in the R-L, R-C and L-R orientations has been studied. The results show that fracture toughness is qualitatively relatable to the fracture morphology. Due to the shape and alignment of the elongated MnS inclusions, fracture toughness in the L-R orientation was found to be 1.8 times those in the other two orientations. Terrace-type fracture prevailed in the R-L orientation, but this frequently was observed to change to zigzag type fracture in the R-C orientation. However, both these fracture mechanisms were absent in the L-R orientation. © 1985 Chapman and Hall Ltd.