Analysis of martensitic transformation and residual stress in a stainless steel 304L

Full text: The relationship between plastic deformation and the strain induced phase transformation, that provides a practical route to the development of new engineering materials with excellent mechanical properties, characterize the TRIP effect "Transformation Induced Plasticity". Among the stainless steels, the 304 L austenitic steel is susceptible to transformation austenite-martensite from tensile tests at room temperature by increments of plastic deformation [1]. It is of great technological and scientific interest the knowledge of the evolution of phase transformation and residual stress from different levels and rates of deformation imposed to the material. It is also important to evaluate the interference of metallographic preparation in quantitative analyzes of this steel. The main techniques used consisted of X-Rays Diffraction and Ferritoscopy for the quantitation phase, and DRX to residual stress analysis also. As observed, the phase transformation quantification has not suffered significant influence of the metallographic preparation and evolved from increments of plastic deformation due to different stop charges and strain rates, leading to a further strengthening of the matrix. The residual stress resulting from the martensitic transformation was susceptible to the metallographic preparation and increased its value on comparison to sample without metallographic preparation. It was also observed that the residual stress decreased with the increase of fraction transformed. References: [1] IAWAMOTO, T.; TSUTA, T.; TOMITA, Y.; Investigation on Deformation Mode Dependence of Strain-Induced Martensitic Transformation in TRIP Steels and Modelling of Transformation Kinetics, Elsevier Science, Vol. 40, pp.173-182, 1998. (author)