Abstract

CASTRO, Cynthia Serra Batista; SALES, Luciana Spíndola  and  GONZALEZ, Berenice Mendonça. Envelhecimento em um aço inoxidável AISI 304 contendo martensita induzida por deformação. Rem: Rev. Esc. Minas [online]. 2007, vol.60, n.1, pp. 111-115. ISSN 0370-4467.  http://dx.doi.org/10.1590/S0370-44672007000100017.

Strain aging of martensite in austenitic stainless steel AISI 304, 25% pre-deformed at -5ºC, was studied to determine phenomenological aspects and mechanisms of strain aging. Under these conditions, the result was a martensite volume fraction of 60%. Ageing treatments were performed from 80 to 160ºC during 1 to 400 minutes. Yield strength increases with the increase of aging time and temperature, saturation being reached in about 20 minutes at 160ºC. A time exponent of ½ was found for the equation that describes the kinetics of the process. This value was associated to the formation of e precipitates. The value of the activation energy (65kJ/mol) was related to the diffusion of carbon in martensite.

Keywords : Strain induced martensite; strain ageing; e carbide.