Effect of acetic acid on corrosion behavior of AISI 201, 304 and 430 stainless steels

Abstract

AbstractAustenitic stainless steels are often used to handle organic acids such as acetic acid (CH3COOH), which are extensively used in food contact applications and chemical industries for manufacturing medicines, nutrition and various chemical amalgams. In the present investigation an attempt has been made to compare the corrosion behavior of Cr–Ni (AISI type 304), Cr–Mn–Ni (type 201) and Cr (type 430) stainless steel for economical replacement of higher cost Cr–Ni grade. Immersion testing was performed at room temperature and boiling temperature in acetic acid. Atomic absorption spectroscopy was carried out to evaluate metal ion concentration in the immersion solution. The surface morphology of pit formation was characterized using scanning electron microscopy coupled with energy dispersive X-ray spectroscopy. The effect of elemental leaching on electrical conductivity of the immersion solution was evaluated and correlated with pH measurements. A new mechanism has been proposed for the pit formation due to manganese sulfide inclusions. The replacement compatibility was further confirmed with anodic polarization testing and a successful replacement was established for room temperature applications.