Evolution of microstructure and corrosion behavior in 2205 duplex stainless steel GTA-welding jointby Shaoning Geng, Junsheng Sun, Lingyu Guo, Hongquan Wang

Journal of Manufacturing Processes

Text

Journal of Manufacturing Processes 19 (2015) 32–37

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Journal of Manufacturing Processes j ourna l ho me pa g e: www.elsev ier .com/ locate /manpro

Technical paper

Evoluti av stainle

Shaoning ng

Key Laboratory n), Sh a r t i c l

Article history:

Received 9 Jan

Received in re

Accepted 24 M

Keywords: 2205 duplex s

Tungsten iner

Microstructur

Microhardnes

Corrosion beh nd co l join tigate etal e, wh the m pitate it re ing fu ce mo factu 1. Introduction

Duplex stainless steels (DSS) are widely used in the paper and pulp, oil an lent mecha strength, go ing, pitting dependent proper bala engineering method an ing the fusi thermal cyc to the appe decreases t bility to loc significance ior of 2205

It is wel joint are no uniform du every differ erties and c ∗ Correspon

E-mail add into three zones, i.e. weld metal zone (WMZ), high temperature heat affected zone (HT-HAZ), low temperature heat affected zone (LT-HAZ). So far, lots of researchers have investigated the prophttp://dx.doi.o 1526-6125/© d gas, petrochemical industries due to their excelnical properties and corrosion resistance, such as high od toughness and resistance to stress corrosion crackand crevice corrosion [1–4]. These good properties are on their chemical composition (Cr, Mo, N and Ni) and nce between ferrite () and austenite () phase [5,6]. In applications, fusion welding is a common processing d often used in manufacturing of DSS. However, duron welding, the weldment is subjected to the welding le which will upset the balance of / phase and lead arance of detrimental phases [7] and consequently, it he mechanical properties and increases the susceptialized corrosion dramatically. Therefore, it has great to investigate the microstructure and corrosion behavDSS weld joint. l-known that the changes in microstructures of a weld n-uniform because the temperature distribution is nonring the welding thermal cycle [8], which indicates that ent zone of a weld joint has different mechanical proporrosion behavior. In general, a weld joint can be divided ding author. Tel.: +86 159 64538306; fax: +86 531 88392315. ress: mstsun@sdu.edu.cn (J. Sun). erties of WHZ or HT-HAZ alone. Kang and Lee [6] investigated the relationship between the pitting corrosion behavior and the ferriteaustenite phase ratio of WMZ by changing the chromium element.

Zhang et al. [9] reported the effect of tungsten inert gas welding and post-weld heat treatment on the pitting corrosion behavior of WMZ. Yang et al. [4] studied the effect of large heat input on the microstructure and corrosion behavior in the Gleeble simulated HT-HAZ. Liou et al. [10] investigated the effects of nitrogen content and cooling rate on the microstructure and stress corrosion cracking (SCC) behavior in the simulated HT-HAZ of 2205 DSS.

Lots of other work has been done to study the corrosion behavior and mechanical properties of the HT-HAZ [11–13]. However, these studies were only focused on one zone in a weld joint and few investigations have involved on the mechanical properties and corrosion behavior of the LT-HAZ. Moreover, the evolution of microstructure, mechanical properties and corrosion behavior in different zones from WMZ to base metal (BM) in a 2205 DDS joint is never investigated systematically.

In this paper, the microstructure, microhardness and corrosion behavior in different zones of the back surface in a 2205 DSS weld joint were studied systematically. The back surface is chosen to study here because it is the work surface in practice. Five adjacent zones were divided from the center of weld metal to the base metal. The optical microstructures of each zone were observed. To rg/10.1016/j.jmapro.2015.03.009 2015 The Society of Manufacturing Engineers. Published by Elsevier Ltd. All rights reserved.on of microstructure and corrosion beh ss steel GTA-welding joint

Geng, Junsheng Sun ∗, Lingyu Guo, Hongquan Wa for Liquid–Solid Structural Evolution and Processing of Materials (Ministry of Educatio e i n f o uary 2015 vised form 12 March 2015 arch 2015 tainless steel t gas arc welding joint e s avior a b s t r a c t

The microstructure, microhardness a metal of a 2205 duplex stainless stee welding with filler wire, were inves ondary austenite appeared in weld m grains were formed near the fusion lin ent austenite content. It also revealed elements (Cr, Mo, Ni and N) and preci from weld metal to fusion line, while surement indicated the zone contain weld metal zone. Moreover, the surfa measurements. © 2015 The Society of Manuior in 2205 duplex andong University, Jinan 250061, PR China rrosion behavior in five zones from the weld metal to base t, which was welded by double-pass tungsten inert gas arc d systematically. Results indicated that a great deal of secdue to the reheat of second pass welding and coarse ferrite ile other zones had the similar microstructures with a differicrohardness was determined by the partitioning of alloying s such as chromium nitride. Austenite was harder than ferrite versed from fusion line to base metal. Electrochemical measion line was the easiest to suffer pitting attack, followed by rphologies were in good agreement with the electrochemical ring Engineers. Published by Elsevier Ltd. All rights reserved.

S. Geng et al. / Journal of Manufacturing Processes 19 (2015) 32–37 33

Table 1

Chemical composition (wt.%) of the base and filler metals.

Component C Si Mn P S Cr Ni Mo Nb Cu Co N Fe

Base metal 0.018 0.54 1.57 0.022 0.001 22.44 5.71 3.19 0.008 0.18 0.07 0.175 Bal.

Filler wire 0.024 0.72 0.80 0.016 0.019 22.22 9.36 3.01 – 0.06 – 0.154 Bal. evaluate the corrosion behavior of the weld joint, the potentiodynamic polarization measurements of each zone were performed according to ASTM standard G-61 [14]. Besides, the surface characteristics of each zone were analyzed before and after the potentiodynamic polarization measurements. Finally, the microhardness of the center o of a weld j study, we a and corrosi the weakes work, such ding gas etc specified zo 2. Materia