Effect of Temperature and Speed on the Formation of Strain-Induced Martensite in AISI 304L and 316L Stainless Steels Subjected to Standardized Tensile Tests

With the intention of evaluating the differences in results due to variations in test parameters within ranges standardized by ASTM and ISO, the effect of test speed and temperature were studied for two metastable austenitic stainless steels (grades AISI 304L and AISI 316L). Tensile tests were conducted between 10 °C and 35 °C, strain rates between 2.5 × 10⁻⁴ and 3 × 10⁻⁴ s⁻¹, and post-yield strain rates between 8.3 × 10⁻⁴ and 7.5 × 10⁻³ s⁻¹. The tendency for the generation of martensitic phase due to plastic deformation within these ranges was measured, as well as the α′-martensite content as a function of distance from the fracture zone, modeled as a potential function with a negative exponent. Within the narrow standard parameter ranges tested, a significant trend toward martensitic transformation was found in the AISI 304L alloy, with variations in strength of over 200 MPa (approximately 30 pct between limit parameters), while the AISI 316L alloy showed strength differences of up to 70 MPa (more than 10 pct).