Effect of Warm Rolling on the Corrosion and Mechanical Properties of UNS S32205 Duplex Stainless Steel

Abstract

Duplex stainless steel (DSS) has been considered as an excellent alternative for applications where high corrosion resistance and high mechanical strength are required. Therefore, microstructure and properties of DSS remain topics of much interest. For this purpose, the effect of warm-rolling was studied in a duplex stainless steel. The focus of this work was 2205 which is one of the most useful type of DSS. Although evolution of microstructure, texture and tensile properties during warm rolling of DDS have been reported, there is no study on the effect of warm rolling on corrosion resistance of 2205 DSS. In this context, the objective of this work is to evaluate microstructure, texture and mechanical and corrosion properties of UNS S32205 DSS after warm rolling. The duplex stainless steel was warm-rolled at 600°C up to 60 and 80% thickness reduction and submitted to electrochemical tests. The electrochemical behaviour of warm-rolled 2205 in the chlorine ion environment was evaluated using cyclic potentiodynamic polarization (CPP) and electrochemical impedance spectroscopy (EIS). The samples exhibited an excellent corrosion resistance in 3.5% NaCl solution. The study showed that the thermomechanical treatment used favoured the formation of the passive film and led to a greater polarization resistance. This behaviour is consistent with the pits density observed by scanning electron microscopy (SEM) and the crystallographic microtexture of the steel.

Electrochemical corrosion behavior and microstructural characteristics of electron beam welded UNS S32205 duplex stainless steel

“…It has been reported that the change in the value of Q for the passive layer is an indicator of a change in the thickness of the passive film. [ 42 ] The passive layer thickness is inversely proportional to Q . [ 43 ] Thus, the base metal passive layer thickness was the highest, and it was adversely affected by both EB and GTA welding.…”

“…A thicker passive film layer provides more effective protection against corrosion for similar chemical composition. [ 42 ] The magnitude of parameter “ n ” represents the corrosion process on the surface of the test specimen. The smaller the value, the greater the surface heterogeneity.…”

Strain Rate Sensitivity Analysis of Duplex and Superduplex Steels in Tensile Tests

“…Many studies have been performed about microstructural and metalurgical aspects of these alloys (weldability, aging, heat treatments, phases, etc. for instance see [2][3][4][5][6][7][8][9][10][11][12] , but only a few about the phenomenological aspects of the macrossopic mechanical behavior, mainly concerned with Finite Element simulations 9,10 . It is not the goal of the present paper to perform an extensive review of these studies, but the previously mentioned references give a reasonable idea of the research in thie area.…”