### Abstract

Computer image processing technology has been applied to cleavage fracture surface analysis and an algorithm for the estimation of 3-dimensional cleavage facet boundaries and 3-dimensional facet areas has been developed. An angle α_{i,j} between relative normal vectors of one mesh P_{i,j} and adjacent mesh plane P_{i+1,j} was calculated and the α_{1,j} was compared to the threshold one α_{th}. If α_{i,j} is larger than α_{th} and the α_{i+1,j} calculated between the mesh planes P_{1+1,j} and P_{i+2,j} along X axis is smaller than α_{th,} the P_{i+1,j} mesh plane was the facet boundary. The same calculation was continued along both X- and Y-axes, and facet numbers being contained in the analyzed area were obtained. After the estimation of facet boundaries, 3-dimensional facet areas were calculated by dividing the 2-dimensional facet areas by cos β_{k} which is the angle between average normal vector of facet and vertical vector. By this algorithm, the cleavage fracture surfaces were analyzed of JIS SS41 and HT80 steels and the effect of the threshold angles α_{th} is discussed using the facet numbers estimated, the distribution of the values of α, and the 3-dimensional facet areas. The method is useful to analyze cleavage facet size and discuss the relationship between the cleavage fracture and microstructures such as ferritic grain size and prior austenitic grain.

Original language | English |
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Pages (from-to) | 552-558 |

Number of pages | 7 |

Journal | ISIJ International |

Volume | 30 |

Issue number | 7 |

Publication status | Published - 1990 |

Externally published | Yes |

### ASJC Scopus subject areas

- Metals and Alloys

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## Cite this

*ISIJ International*,

*30*(7), 552-558.