Corrosión en Acero AISI 420 con Distintos Tratamientos Térmicos

P. BENEDETTI, W. TUCKART, J. INSAUSTI Y L. IURMAN

San Nicolás, Argentina.

Congreso; 2º Conferencia sobre Usos del Acero; 2005

Instituto Argentino de Siderurgia

The  tribology properties of stainless steel are improved by ion nitriding treatment. These properties are also improved by  the heat  treatment  imposed. However,  the improvement in wear can lead to a reduction in corrosion resistance.  At the present work, circular sectors of AISI 420 stainless steel with different  heat  treatments  were  tested  in accordance with the ASTM B-117-94 Standard (accelerated corrosion test) after being subjected to sliding tests in an AMSLER machine.   The first group of samples corresponds to as received material - ion nitrided - sliding tested and corrosion tested.   The second group of samples was quenched and tempered (673 K) –(with and without) ion nitriding- sliding tested and corrosion tested.   The third group  was quenched and tempered (943 K) –(with and without) ion nitriding- sliding tested and corrosion tested.   The ion nitriding conditions for the samples were 0.15 MPa and 25% N2, 75% H2 during 20 Hs at 673 K. Corrosion tests were made in saline fog camera with an approximated 1 M concentration of NaCl.   Qualitative analysis at different interval times  was made by  surface  image  photography. Morphology and topography changes due to the corrosion process were analyzed by scanning electronic microscopy (SEM).   Specimens that were quenched and tempered (673 K) with ion nitriding presented a lesser weight loss and in general the morphology of all the samples showed a uniform corrosive attack.. The main conclusion is that the ion nitriding did not affect the corrosion resistance of the tested samples.