Role of Bulky Retained Austenite in Austempered Ductile Iron

2017 ◽  
Vol 1142 ◽  
pp. 19-22 ◽  
Author(s):  
Chen Yang ◽  
Xi Xi Cui ◽  
Zhen Bo Zhao ◽  
Gao Hua ◽  
Cheng Liu
Keyword(s):  
Fatigue Resistance ◽  
Ductile Iron ◽  
Retained Austenite ◽  
Room Temperature ◽  
Austempered Ductile Iron ◽  
The Poor

In this investigation, the characteristics of bulky retained austenite in an austempered ductile iron are evaluated in two tempered conditions. which were intially tempered at 200oC for 1h before cooling to room temperature, and then tempered at 350oC for 1h. The result shows that the hardness within retained austenite areas is distributed unevenly with a range from 423 HV to 897 HV, which is attributed to the transformation from austenite to martensite during austempering. Also, the mechanism regarding the quenched marteniste formation is discussed. The poor fatigue resistance of ADI is hypothesized to be due to the amount of austenite transformed to martensite.

scholarly journals The role of sampling position on fatigue of austempered ductile iron

2010 ◽  
Vol 2 (1) ◽  
pp. 1337-1341 ◽  
Author(s):  
M. Wohlfahrt ◽  
C. Oberwinkler ◽  
S. Tunzini ◽  
A. Rauscher ◽  
R. de la Prida Caballero ◽  
...  
Keyword(s):  
Ductile Iron ◽  
Austempered Ductile Iron ◽  
Sampling Position

scholarly journals Phase Transition Kinetics in Austempered Ductile Iron (ADI) with Regard to Mo Content

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5266
Author(s):  
Martin Landesberger ◽  
Robert Koos ◽  
Michael Hofmann ◽  
Xiaohu Li ◽  
Torben Boll ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
Neutron Diffraction ◽  
Ductile Iron ◽  
Retained Austenite ◽  
Length Change ◽  
Atom Probe ◽  
Carbon Accumulation ◽  
Austempered Ductile Iron ◽  
Mo Content

The phase transformation to ausferrite during austempered ductile iron (ADI) heat treatment can be significantly influenced by the alloying element Mo. Utilizing neutron diffraction, the phase transformation from austenite to ausferrite was monitored in-situ during the heat treatment. In addition to the phase volume fractions, the carbon enrichment of retained austenite was investigated. The results from neutron diffraction were compared to the macroscopic length change from dilatometer measurements. They show that the dilatometer data are only of limited use for the investigation of ausferrite formation. However, they allow deriving the time of maximum carbon accumulation in the retained austenite. In addition, the transformation of austenite during ausferritization was investigated using metallographic methods. Finally, the distribution of the alloying elements in the vicinity of the austenite/ferrite interface zone was shown by atom probe tomography (APT) measurements. C and Mn were enriched within the interface, while Si concentration was reduced. The Mo concentration in ferrite, interface and austentite stayed at the same level. The delay of austenite decay during Stage II reaction caused by Mo was studied in detail at 400 °C for the initial material as well as for 0.25 mass % and 0.50 mass % Mo additions.

Characteristics of the Transformation of Retained Austenite in Tempered Austempered Ductile Iron

2017 ◽  
Vol 26 (5) ◽  
pp. 2095-2101 ◽  
Author(s):  
Bingxu Wang ◽  
Gary Barber ◽  
Xichen Sun ◽  
Michael Shaw ◽  
Phil Seaton
Keyword(s):  
Ductile Iron ◽  
Retained Austenite ◽  
Austempered Ductile Iron

Influence of TiN coating thickness on the rolling contact fatigue resistance of austempered ductile iron

Wear ◽  
2016 ◽  
Vol 350-351 ◽  
pp. 82-88 ◽  
Author(s):  
Diego Alejandro Colombo ◽  
María Dolores Echeverría ◽  
Ricardo Cesar Dommarco ◽  
Juan Miguel Massone
Keyword(s):  
Fatigue Resistance ◽  
Coating Thickness ◽  
Ductile Iron ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Austempered Ductile Iron ◽  
Tin Coating ◽  
Contact Fatigue Resistance

Role of pre-formed martensite on transformation of austempered ductile iron

2017 ◽  
Vol 33 (15) ◽  
pp. 1819-1828 ◽  
Author(s):  
Cheng Liu ◽  
Chen Yang ◽  
Limin Yuan ◽  
Derek O. Northwood
Keyword(s):  
Ductile Iron ◽  
Austempered Ductile Iron

Rolling contact fatigue resistance of PVD CrN and TiN coated austempered ductile iron

Wear ◽  
2013 ◽  
Vol 308 (1-2) ◽  
pp. 35-45 ◽  
Author(s):  
Diego Alejandro Colombo ◽  
María Dolores Echeverría ◽  
Sebastián Laino ◽  
Ricardo Cesar Dommarco ◽  
Juan Miguel Massone
Keyword(s):  
Fatigue Resistance ◽  
Ductile Iron ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Austempered Ductile Iron ◽  
Contact Fatigue Resistance

Microstructure Evolution during Strain-Induced Transformation of Austenite in an Austempered Ductile Iron (ADI)

2021 ◽  
Vol 1016 ◽  
pp. 1199-1204
Author(s):  
R. Raghavendran ◽  
Anil Meena ◽  
Murugaiyan Amirthalingam
Keyword(s):  
Phase Transformation ◽  
Thermomechanical Treatment ◽  
Ductile Iron ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Thermomechanical Processing ◽  
Base Material ◽  
High Volume ◽  
Austempered Ductile Iron ◽  
Conventional Heat Treatment

Microstructural evolution during the strain-induced phase transformation of austenite in an Austempered ductile iron (ADI) under various thermomechanical processing conditions is studied in the present study. An alloyed ductile iron is taken as the base material, and thermomechanical treatment is carried out on a Gleeble 3800 thermomechanical simulator coupled with dilatometry. The effect of deformation on the austempering process has been studied by microstructure characterization using optical microscopy (OM), scanning electron microscopy (SEM), and X-ray diffraction (XRD) techniques. The variations in retained austenite volume fraction and its carbon content with respect to different austempering times are analyzed to study the effect of strain-induced transformation of austenite. It has been observed that the thermomechanical treatment significantly influences the phase transformation kinetics during the austempering process. The thermomechanical treatment produced a martensite free ausferritic microstructure for all austempering times with a high volume fraction of carbon enriched retained austenite as compared to the conventional heat treatment.

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