<p>The conversion of plastic work during deformation into thermal energy leads to temperature variations along tensile specimens, creating thermal inhomogeneities that significantly influence test results, particularly in metastable austenitic stainless steels, which undergo temperature-dependent phase transformations. These heterogeneities must be considered for accurate modelling of material behavior. This study aims to exploit the inherent thermal and strain rate heterogeneities in tensile test specimens to reduce the experimental effort required for thermomechanical characterization. Two series of tensile tests were performed: one at room temperature and another using locally heated specimens to establish controlled temperature gradients. The novelty of the approach lies in using a single test with spatially varying conditions to extract multiple stress-strain responses, each corresponding to distinct thermomechanical states. Quantitative analyses of local stress, strain, strain rate, temperature, and martensite evolution show that the method provides stress-strain data across a wide range of conditions. From just a few tests, we obtained equivalent data that would traditionally require numerous experiments, capturing strain rates from 0 to 0.6 s⁻¹ and temperatures from 30 to 120 °C. The martensite fraction varied locally as a function of strain, temperature, and strain rate, enabling insight into its coupled thermomechanical evolution.</p>