An analysis of retained austenite in austempered ductile iron

Abstract

Data from the literature have been analyzed to understand aspects of the retained austenite in austempered ductile irons, especially its relationship with the transformation mechanism of bainite. The final and initial carbon concentrations in austenite, C ␥ and C 0 ␥ , respectively, are important in determining the maximum extent of reaction, and hence, the amount of austenite and bainitic ferrite C ␥ and C 0 ␥ data have been expressed in terms of chemical compositions and reaction temperature, with reasonable agreement between experimental and predicted results. It is demonstrated that, in connection with the lever rule, the calculated C ␥ and C 0 ␥ values can be employed to predict the microstructural constituents of austempered ductile irons.

The rolling/sliding wear performance of high silicon carbide-free bainitic steels

“…They were etched with 2% nital. The procedure for thin foil sample preparation for transmission electron microscopy studies has been described elsewhere [19]. To examine the chemical compositions of the transferred layer, an energy dispersive X-ray (EDX) analysis system on a CAMSACN 200.…”

Investigating the Effect of Auto-Focus and Auto-Threshold Algorithms in Advanced Nodularity Analysis of Austempered Ductile Iron Castings

“…ADI is obtained after a specific heat treatment of SGCI which is known as austempering operation. Austempering process includes two steps: austenization at temperatures around 850 • C to 950 • C, followed by rapid cooling to an isothermal transformation temperature range (220 • C-420 • C) for 1 to 4 h before coming to room temperature [6,7]. A specific microstructure called ausferrite occurs as a result of this austempering heat treatment.…”

Thermal Stability of Austempered Ductile Iron Evaluated in a Temperature Range of 20-300K

“…Control of the heat treatment process, as follows from several investigations, boils down mainly to determining the appropriate amount of austenite in the matrix of the required grade of austempered ductile iron [6,7]. In the light of new investigations carried out by the authors of this article, the above fact may be restated in a manner that is more precise.…”