Machinability study of first generation duplex (2205), second generation duplex (2507) and austenite stainless steel during drilling process

Machinability tests were conducted on duplex alloys SAF 2205 and SAF 2507, while employing austenite stainless steel 316L as a benchmark during drilling. Tool wear, cutting forces and machined surface finish were compared and analysed under similar machining conditions. Both duplex alloys displayed poorer machinability responses, with 2507 being worst. Abrasion and adhesion are the most common wears appeared on the flank and rake faces. Adhesion wear being the most severe on the flank face, was seen to be triggered by built-up edge formation. Duplex alloys 2507 and 2205 both show a higher response to built-up edge formation. Flute damage was found on the drill tool, while drilling both duplex alloys. It was found this damage can lead to catastrophic tool failure. Higher cutting force and poorer surface finish were found for second generation duplex (2507).