Austempered Ductile Iron (ADI) is a type of nodular, ductile cast iron subjected to heat treatments — austenitising and austempering. Whilst machining is conducted prior to heat treatment and offers no significant difficulty, machining post heat treatment is demanding and often avoided. Phase transformation of retained austenite to martensite leading to poor machinability characteristics is a common problem experienced during machining. Study of phase transformations is an investigative study on the factors — plastic strain (εp) and thermal energy (Q) which effect phase transformations during machining. The experimental design consists of face milling grade 1200 at variable Depth of Cut (DoC) range from 1 to 4 mm, coolant on/off, at constant speed, 1992 rpm and feed rate, 0.1 mm/tooth. Plastic strain (εp) and martensite content (M) at fracture point for each grade was evaluated by tensile testing. The effect of thermal energy (Q) on phase transformations was also verified through temperature measurements at DoC 3 and 1 mm using thermocouples embedded into the workpiece. Finally, the amount of plastic strain (εp) and thermal energy (Q) responsible for a given martensite increase (M) during milling was related and calculated using a mathematical function, M = f (εp, Q). The future work of the thesis involves an in-depth study on the new link discovered through this research: mathematical model relating the role of plastic strain and thermal energy in martensite formation.
- Manufacturing Engineering Division
Recent Advances in Machining of Austempered Ductile Iron to Avoid Machining Induced Microstructural Phase Transformation Reaction
- Views Icon Views
- Share Icon Share
- Search Site
Polishetty, A, & Littlefair, G. "Recent Advances in Machining of Austempered Ductile Iron to Avoid Machining Induced Microstructural Phase Transformation Reaction." Proceedings of the ASME 2014 International Manufacturing Science and Engineering Conference collocated with the JSME 2014 International Conference on Materials and Processing and the 42nd North American Manufacturing Research Conference. Volume 1: Materials; Micro and Nano Technologies; Properties, Applications and Systems; Sustainable Manufacturing. Detroit, Michigan, USA. June 9–13, 2014. V001T01A001. ASME. https://doi.org/10.1115/MSEC2014-3903
Download citation file: