Microstructural study in graphitised hypereutectoid cast and commercial steels

Abstract

In the present paper, past research work with new and/or improved processes for willing graphitisation in steels is reviewed. Experiments were carried out to study the carbide dissociation in two different hypereutectoid steels (cast and commercial steels) during graphitisation process by annealing primary martensitic structures at 670°C. Graphite phase evolution during graphitisation treatment was investigated by light optical and scanning electron microscopy and energy dispersive X-ray analyses. It has been reported with promising results that a uniform distribution of alloying elements is found around the graphite particles, which resulted in cast steel. Furthermore, graphite particles in the cast steel were observed to be larger and more spherical than that in commercial steel, which seems to be due to lower Mn/S ratio in cast steel composition.

A study on graphitisation acceleration during annealing of martensitic hypereutectoid steel

“…The details of microstructure and morphology of graphite particles have been described elsewhere [19,20]. The same structures also are observed in pearlitic/cementitic and spheroidized specimens (specimens No.…”

Secondary graphitization kinetics in a gray cast iron

“…This secondary graphitization can be the cause of failure in creep resistant steels subjected to extended times (years) of service at high temperatures [4]. There are also graphitic steels grades, where the secondary graphitization is part of the normal processing [5][6][7]. The morphology of graphite in steels is of the nodular or multifaceted type, similar to cast irons.…”

Compósitos ferro-grafita para componentes de motores com propriedades tribológicas melhoradas.

“…Porém, em algumas circunstâncias os efeitos da morfologia desta grafita podem ser benéficos a algumas propriedades mecânicas [3]. Mais recentemente uma série de aços contendo dispersões de grafita obtidas por precipitação no estado sólido tem sido descritos na literatura [4][5][6][7]. A nucleação da grafita no estado sólido em aços foi estudada em detalhes por Edmonds [8].…”