Proceedings of COBEM 2005 18th International Congress of Mechanical Engineering Copyright © 2005 by ABCM November 6-11, 2005, Ouro Preto, MG Determination of the Mechanical Behavior of AISI 304 austenitic stainless steel in Machining Processes João Paulo Pereira Marcicano. Departamento de Eng. Mecatrônica e Sistemas Mecânicos – EPUSP. Av. Prof. Melo Moraes, 2231; 05508-900 marcican@usp.br Luanna Oliveira de Almeida. Departamento de Eng. Mecatrônica e Sistemas Mecânicos – EPUSP. Av. Prof. Melo Moraes, 2231; 05508-900 lumath_oli@hotmail.com Izabel Fernanda Machado. Departamento de Eng. Mecatrônica e Sistemas Mecânicos – EPUSP. Av. Prof. Melo Moraes, 2231; 05508-900 machadoi@usp.br Amauri Hassui Departamento de Eng. Mecatrônica e Sistemas Mecânicos – EPUSP. Av. Prof. Melo Moraes, 2231; 05508-900 ahassui@usp.br Abstract. The mechanical behavior of AISI 304 stainless steel within the practical range of stress, strain, strain rate, and temperature encountered in metal cutting is characterized by Johnson-Cook constitutive equation. The coefficients of constitutive equation are determinated by fitting the data from both quasi-static compression and machining tests. An analytical model based on the plasticity theory and orthogonal cutting is utilized to estimate the effective stress, strain, strain rate, and temperature on the main shear plane. This approach is valid for machining with continuous chips. It was verified good agreement between experimental and estimated values. Keywords: machining, AISI304, Johnson-Cook model 1.Introduction The machining processes have great economic importance in the mechanical industry due mainly to the dimensional precision that can be achieved. The knowledge of the metal cutting processes is essential to development of new tools and machines. Numerical and analytical models have been used with relative success in the modeling of these processes. Information on the mechanical behavior of metals within machining process is of utmost importance in both the analytical and numerical models. However the physical phenomena taking part in metal cutting are numerous and complex. Chip formation is the result of plastic deformation caused by relative motion between the tool and the work piece. Deformations are large and the strain rate reaches 10 6 s -1 . These intense circumstances result in mechanical behavior far from that encountered in conventional material tests. Moreover the sliding at the tool/chip interface happens under very hard conditions of pressure, strain rate and temperature. (Tounsi et al., 2002). According to Altintas (2000) there are basically two types of assumptions in the analysis of the primary shear zone. Merchant (1945) developed an orthogonal cutting model by assuming the shear zone to be a thin plane. Others, such as Lee ,Shaffer and Oxley (1977), based their analysis on a thick shear deformation zone for continuous ship and Okushima (1961) for discontinuous chip formation. Recently Tounsi et all (2002) re-evaluated the mechanics of primary shear zone for continuous chip formation deriving the expressions of the effective stress, strain, strain rate and temperature on the main shear plane. These expressions are deduced from an estimated velocity field derived from strain rate fields observed in experimental work and finite element method results. Guo (2003) presented a method to characterize the mechanical behavior of materials in metal cutting based on Johnson-Cook model. The author deduced the coefficients of equation of Johnson-Cook fitting the data from quasi- static compression and machining tests. The primary shear zone was modeled with Oxley method and the temperatures were estimated with Loewen-Shaw model. In this paper, a methodology to identify the material constants of the Johnson-Cook constitutive equation is presented. It is based on analytical modeling of the primary shear zone, quasi-static compression test, machining tests and numerical minimization. The experimental and model results are compared and discussed.