Observation and Analysis About the Fracture of Low Carbon Ductile Iron

Using the scanning electronic microscope(SEM), orienting to the low carbon ductile iron with pearlite matrix, ferrite matrix and Quasi-as-cast bainite matrix, the analysis and research have been done about the tensile fracture's shape and appearance of low carbon ductile iron. The result indicates that the fracture of pearlite low carbon ductile iron belongs to brittle fracture; toughness puteus increasing and cleavage pattern decreasing obviously in the fracture of Quasi-as-cast bainite low carbon ductile iron, it belongs to the toughness-brittle hybrid fracture; that of ferrite low carbon ductile iron completely present the characteristic of brittle fracture. The research also indicates that in the process of pyro-austenite cooling rapidly to the bainite transforming temperature, it is impossible for ADI to forming austenite dendrite, as well as the shrinkage area among the dendrite. So, on the premiss of good intensity, ADI advances the toughness and plasticity of the materials.