Title: Characterisation of surface martensite-austenite transformation during finish turning of an AISI S15500 stainless steel

Authors: Alexandre Mondelin; Joël Rech; Eric Feulvarch; Michel Coret

Addresses: Université de Lyon, ENISE, LTDS, UMR CNRS 5513, 58 Rue Jean Parot, 42023 Saint-Etienne, France; Université de Lyon, INSA, LaMCoS, UMR CNRS 5259, 27 Avenue Jean Capelle, 69621 Villeurbanne, France ' Université de Lyon, ENISE, LTDS, UMR CNRS 5513, 58 Rue Jean Parot, 42023 Saint-Etienne, France ' Université de Lyon, ENISE, LTDS, UMR CNRS 5513, 58 Rue Jean Parot, 42023 Saint-Etienne, France ' École Centrale de Nantes, GeM, UMR CNRS 6183, 1 rue de la Noë BP 92101, 44321 Nantes cedex 3, France

Abstract: During machining, extreme temperature conditions appear in the cutting zone (from 700 to 1,000°C with heating rates around 10⁶ °C/s). Consequently, the metallurgical models used to simulate the impact of the manufacturing process must be adapted to this fast thermal kinetics. Stress-free dilatometry tests have been performed to determine the austenisation kinetics of an AISI S15500 martensitic stainless steel and to identify a phenomenological model. Experimental heating rates vary from 6 °C/s to 11,000 °C/s. The metallurgical model calibrated for high heating rates, has been applied to a typical machining thermal cycle. It has been shown that martensite→austenite transformation does not have the time to significantly occur during the finish turning of AISI S15500 under standard cutting conditions. This result has been confirmed using retained austenite measurements in the machined surface layer.

Keywords: dilatometry; martensite-austenite transformation; high heating rate; turning; metallurgical modelling; surface integrity; surface transformation; martensitic stainless steel; austenisation kinetics.

DOI: 10.1504/IJMMM.2014.059190

International Journal of Machining and Machinability of Materials, 2014 Vol.15 No.1/2, pp.101 - 121

Received: 14 Jan 2013
Accepted: 23 Jul 2013
Published online: 13 May 2014 *

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