CRYSTALLOGRAPHIC ORIENTATION AND ELEMENTAL SEGREGATION OF FLAKES IN STEELS

An investigation on the crystallographic orientation and elemental segregation of flakes (hairline cracks) has been carried out by means of etching method and electron optical techniques (SEM, TEM, EPMA and AES). The results obtained are as follow:(1) The microappearances of fracture surface of flakes are a mixed fracture mode of quasicleavages and intergranular tearing waves.(2) The direction of the crack propagation of flakes are mostly along {112} planes of ferrite. These planes are also quasicleavage facets. While the orientation of the dendritic surface of flakes are {111} planes.(3) There are positive segregations of P, Mn, Mo, Cr and Si on the fracture surface of flakes, among which the most one is phosphorus.