Influence of microstructure and elemental partitioning on pitting corrosion resistance of duplex stainless steel welding joints

Zhang, Zhiqiang; Jing, Hongyang; Xu, Lianyong; Han, Yongdian; Zhao, Lei; Zhang, Jianli

doi:10.1016/j.apsusc.2016.10.047

Cited by 133 publications

(67 citation statements)

References 42 publications

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“…In addition, the element diffusion and redistribution in the substrate at different annealing temperatures is another key factor. The pitting resistance for DSS depends on the weaker phase (weaker means less resistance), that is, the lower PREN value of the two‐phase . Figure illustrates that the lower PREN is in the austenite phase at 1,080°C, hence, the pit preferentially occurs in the austenite (Figure a).…”

Section: Discussionmentioning

confidence: 95%

Effect of annealing temperature on pitting behavior and microstructure evolution of hyper‐duplex stainless steel 2707

Sun

Liu

et al. 2019

Materials & Corrosion

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Hyper‐duplex stainless steel (HDSS) 2707 is a competitive material for application in extremely caustic environments. In this study, different annealing temperatures ranging from 1020°C to 1200°C were examined by electrochemical tests and microstructure analysis. The microstructure characterization indicated that precipitations were detected when the annealing temperature was below 1050°C and a relatively balanced austenite–ferrite phase structure was obtained at 1100°C. Through electrochemical measurements in NaBr solution, it was revealed that with the increase of temperature the pitting resistance of HDSS 2707 first rose then declined, peaking at 1100°C. The highest critical pitting temperature was about 67°C. In addition, the pitting position shifted from austenite phase to austenite–ferrite boundary and finally to ferrite interior with the annealing temperature increasing, which was in agreement with the pitting resistance equivalent values (PREN) of the two phases.

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Section: Discussionmentioning

confidence: 95%

Effect of annealing temperature on pitting behavior and microstructure evolution of hyper‐duplex stainless steel 2707

Sun

Liu

et al. 2019

Materials & Corrosion

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“…While previous studies have largely focused on the root pass HAZ because of loss of corrosion resistance (Refs. 14,18,33,[35][36][37], this paper focuses on metallurgical changes in the root FZ because of the initially unexpected results shown in Fig. 5.…”

Section: Implications Of Resultsmentioning

confidence: 99%

Root Pass Microstructure in Super Duplex Stainless Steel Multipass Welds

2019

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Superduplex stainless steels (SDSS) are Fe-Cr-Ni-N alloys with a dual-phase wrought microstructure consisting of approximately 50-50 vol-% austenite/ferrite. This phase balance provides superior pitting corrosion resistance and twice the yield strength compared to standard austenitic stainless steels (Refs. 1, 2). As a result, SDSS are commonly used in applications that require high strength, toughness, and corrosion resistance where stress corrosion cracking (SCC) is a concern (Refs. 1-4). Welding of duplex stainless steel (DSS) significantly alters the engineered microstruc-ture, and has been reported to cause loss of corrosion resistance (Refs. 5-7) and reduced impact toughness (Refs. 5,8). Detrimental property changes in the weld fusion zone (FZ) and heat-affected zone (HAZ) have been reported to originate from the following: deviation from a proper austenite/ ferrite microstructure phase balance (Ref. 9), composition (Refs. 7, 10), and formation of brittle secondary phases like the sigma () phase (Ref. 11). Base metal and filler composition, heat input (Refs. 4, 12), dilution (Ref. 4), shielding gas (Refs. 12-15), cooling rates (i.e., rate of change of temperature with respect to time) (Refs. 16, 17), interpass temperatures in multipass welding (Ref. 4), and weld process type (Refs. 9, 18) are all important process variables that collectively influence the welded microstructure and the FZ and HAZ material properties (Ref. 3).Maintaining a proper austenite/ferrite phase balance, while avoiding formation of embrittling phases (e.g., ), is necessary to maintain acceptable weld FZ and HAZ toughness and corrosion resistance. Both nickel and nitrogen are austenite stabilizers, and researchers have investigated welding with overalloyed (nickel) filler metals (e.g., ER2594 on duplex 2205) (Refs. 13, 19) and nitrogen-containing shielding gases (Refs. 15,(20)(21)(22). Researchers have demonstrated that nitrogen loss from weld metal during welding reduces austenite content and reduces corrosion resistance (Refs. 23, 24), while intentional additions of nitrogen to argon shielding promotes austenite formation and can increase corrosion resistance (Refs. 20, 24).The thermal history of the FZ and HAZ is also very important for microstructural phase balance. For DSS, the microstructure solidifies as 100% ferrite and then forms austenite in a diffusion-mediated phase transformation with the primary austenite forming between 800˚ and 1200˚C (1472˚ and 2192˚F), although it can form at temperatures up to 1350˚C (2462˚F) for superduplex grades (Refs. 25,26). As welding heat input (arc energy) increases, weld FZ and HAZ cooling rates decrease. Slower cooling rates increase the amount of time for austenite nucleation and growth in the 800˚-1200˚C (1472˚-2192˚F) temperature ABSTRACT Superduplex stainless steels (SDSS) have twice the base strength and pitting corrosion resistance of austenitic stainless steels and are commonly used when stresscorrosion cracking is a concern. During multipass welding of SDSS, a 50-50 austenite-fe...

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“…Moreover, the microstructure was the key factor to determine the properties of weld joint during laser processing [17][18][19][20][21][22][23][24][25][26][27]. The investigations showed that with the increase of δ-ferrite content and grain refinement in the weld joint of stainless steel, the mechanical properties and corrosion resistance could increase [17,18].…”

Section: Introductionmentioning

confidence: 99%

“…In addition, the presence of inclusions in weld joint would also affect the microstructure and performance of weld joint. It was found that the chromium nitride (Cr 2 N) precipitation led to relatively poor resistance to pitting corrosion in gas tungsten arc welding of duplex stainless steel with pure argon shielding gas because the accumulation of elements and changes of metallography were caused by the formation of inclusions [23]. With the increase and accumulation of sulfides in the weld of stainless steel, the corrosion resistance of weld joint was decreased due to the readily corrodible and soluble sulfide inclusions [24,25].…”

Section: Introductionmentioning

confidence: 99%

Influence of carbon dioxide shielding gas on microstructure and corrosion property of welds

Zhou

Xiao

et al. 2019

Materialwissenschaft Werkst

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The microstructures and corrosion properties of weld joints are studied during 10 kW high power fiber laser welding of 304 stainless steel with shielding gases of 100 % argon, 80 % argon containing 20 % carbon dioxide and 100 % carbon dioxide, respectively. As the content of carbon dioxide in argon shielding gas increases from 0 % to 20 % then to 100 % during 10 kW high power fibre laser welding, the interdendritic δ‐ferrite in weld joints changes from lathy, short strip and trivial structures to thick‐long strip with short secondary dendrite arms then to skeletal‐network structure. Oxide inclusions, observed in 100 % carbon dioxide shielded weld, promote the formation of the skeletal‐network structure of δ‐ferrite and the homogenization of chromium and nickel in weld joint. The 100 % argon shielded weld joint has a highest initial corrosion current density, the 80 % argon containing 20 % carbon dioxide shielded weld has a lowest pitting potential, while the 100 % carbon dioxide shielded weld has a highest initial corrosion potential. The microstructures and element distribution play important role in determining the corrosion properties of the weld joints.

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Influence of microstructure and elemental partitioning on pitting corrosion resistance of duplex stainless steel welding joints

Cited by 133 publications

References 42 publications

Effect of annealing temperature on pitting behavior and microstructure evolution of hyper‐duplex stainless steel 2707

Effect of annealing temperature on pitting behavior and microstructure evolution of hyper‐duplex stainless steel 2707

Root Pass Microstructure in Super Duplex Stainless Steel Multipass Welds

Influence of carbon dioxide shielding gas on microstructure and corrosion property of welds

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