Effect of the Coarsening of Austenite Grain on the Microstructure and Corrosion Behavior of a Cold Rolled AISI 316Ti Stainless Steel

The effect of coarsening of austenite grain on microstructure and corrosion behavior of AISI316Ti austenitic stainless steel, during cold rolling, has been investigated. The AISI 316Ti austenitic stainless steel has been heated at 1100??C for 3 hours, resulting in an average austenite grain size growth of 5 times. The steel was then cold-rolled at 20, 37, 56, and 88% deformation degrees. The characterization of the microstructure has been assessed using optical microscopy, scanning electron microscopy, and X-ray diffractometry. Electrochemical properties have been evaluated by using a scanning Kelvin probe (SKP). Microstructural analysis showed that cold deformation without prior heating leads to the growing formation of strain-induced ?????-martensite, as cold deformation increases. But, the microstructure obtained after subsequent cold rolling and preheat treatment was almost exempt from induced ?????- martensite. The grain growth due to heat treatment, the effective titanium content of austenite, and the strain rate during cold rolling steps are factors that influence the strain-induced ?????-martensite transformation. SKP, in air, demonstrated that the plastic deformation decreased the ability to passivation of the surface. The results obtained show that at high cold rolling, the heat treatment before the cold rolling can improve the electrochemical behavior of AISI 316Ti austenitic stainless steel.