Chapter 3: Resistance to Corrosion and Passivity of 316L Stainless Steel Directionally Solidified Samples

MENDEZ, CLAUDIA MARCELA; COVINICH, MÓNICA MARIELA; ARES, ALICIA ESTHER

Developments in Corrosion Protection

IN TECH d.o.o.

Año: 2014; p. 41 - 63

The three main types of crystalline structure that stainless steel can be classified are Austenitic,Ferritic and Martensitic. Austenite, also known as gamma phase iron (γ-Fe), is a metallic, nonmagnetic allotrope of iron or a solid solution of iron, with an alloying element. According to previous studies in the literature, there are eight separate types of corrosion, with only a few having a major impact on stainless steel (DOD Technical Bulletin ? Corrosion Prevention and Detection). Directional solidification technology is an important research instrumentally to study solidification theory. Because directional solidification can achieve controllable cooling rate with a broad range, solidification structure from near-equilibrium to far-from equilibrium condition can be obtained. A serious of scientific phenomena such as interface evolution, crystal growth instability, solute redistribution, and phase selection during the course have received significant attention in recent years.This work aims to study the overall influence of the variation of the structure (equiaxed, columnar and columnar-to-equiaxed transition, CET) on the corrosion resistance of 316 stainless steel in aqueous 3% NaCl (pH = 5.5) using cyclic potentiodynamic polarization techniques and electrochemical impedance spectroscopy (EIS) and investigate the relationship between the corrosion resistance of material and the secondary dendritic spacing evolution.