Three-dimensional diffusion model for austenitisation of ferritic spheroidal graphite irons

Abstract

A mathematical model has been developed for studying the diVusion kinetics of carbon during the austenitisation of a ferritic ductile iron. In modelling the diVusion process, the finite diVerence method was used and the diVusion equation was solved using the Crank-Nicolson (implicit) form. T he results obtained were compared with those from the conventional error function estimates. For short diVusion distances, that is, spheroidal graphite irons with a high nodule count, the diVusion times required to attain carbon equilibrium suggested by the finite diVerence and error function methods were similar. For medium to low nodule counts, the times predicted by the error function estimate were less than those suggested by the finite diVerence analysis.MST /4134

A Dilatometry Study of the Austenitization and Cooling Behavior of Ductile Iron Meant for the Production of Austempered Ductile Iron (ADI)

“…An in-depth coverage of the interplay between these factors and the austenitization time is provided by Zimba et al [14] elsewhere. An in-depth coverage of the interplay between these factors and the austenitization time is provided by Zimba et al [14] elsewhere.…”

Bainite transformation time model optimization for Austempered Ductile Iron with the use of heuristic algorithms

“…-improving efficiency in solving complex problems; -finding a solution along the most likely path while avoiding less promising paths; -avoiding checking so-called "dead ends", for example, by using previously acquired information; -formulation of simple criteria for selecting directions of conduct without unequivocally defining good and bad states (Boccardo et al, 2015;Hepp et al, 2012;Zimba et al, 1999).…”

“…However, the application of optimization in the metal casting sector is significantly limited. In the case of ADI manufacturing, one can only find the results of studies from a few research centers in the literature, where authors have attempted to model changes in the microstructure of ductile iron in order to obtain ADI (Boccardo et al, 2015;Hepp et al, 2012;Zimba et al, 1999). The model developed by Zimba (Zimba et al, 1999) concerned the austenitic transformation of cast iron with a ferritic matrix.…”

“…In the case of ADI manufacturing, one can only find the results of studies from a few research centers in the literature, where authors have attempted to model changes in the microstructure of ductile iron in order to obtain ADI (Boccardo et al, 2015;Hepp et al, 2012;Zimba et al, 1999). The model developed by Zimba (Zimba et al, 1999) concerned the austenitic transformation of cast iron with a ferritic matrix. This model makes it possible to calculate changes in the carbon concentration in austenite over time, depending on the size of the so-called ferritic cells of ductile iron.…”

Phase Transformation of an Austempered Ductile Iron during an Erosion Process

“…[1][2][3][4] Reports on ADI wear, including abrasive wear, 5,6) sliding wear, 7) rolling wear 8) and gear-wear, 9) reveal the common result that the high carbon austenite content will decrease through transformation into the martensite phase. This raises the hardness of the eroded-surface and reduces the fracture toughness of the material.…”