黒鉛形状の異なるパーライト地鋳鋼の破面解析

概要

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Tensile, fracture toughness, Charpy impact and rotating-bending fatigue tests were conducted on spheroidal, vermicular and flake graphite of pearlitic cast irons prepared experimentally to the purpose of investigating the relationship between the fracture behavior and the fracture surface appearances. The detailed fracture surface observations was conducted by a scanning electron microscope. A lamellar pattern was characteristically observed on the fatigue fracture surfaces of the spheroidal and vermicular graphite cast irons. However, striations were not clearly recognized. The lamellar pattern was also found on the fracture surface of the matrix of the flake graphite cast iron. The quasicleavage fracture was observed on the tensile and impact fracture surfaces of the spheroidal and vermicular graphite cast irons. However, no lamellar pattern was observed on the tensile or impact fracture surfaces. It was confirmed that the lameller pattern was corresponded to the lameller pearlite. Micro-dimples were also found in the restricted area of matrix fracture surface of the flake graphite cast iron. This fact provides a clue for identifying the fatigue failure in a practical equipment. A stretched-zone-like pattern consisting of quasi-cleavage fracture was observed on the fracture surface of the fracture toughness specimen of spheroidal and vermicular graphite cast irons except the flake graphite cast iron.
社団法人日本材料学会の論文
1985-06-15