scholarly journals Temperature and time effect of thermal aging treatment on microstructure and corrosion resistance of UNS S31803 duplex stainless steel

2021 ◽  
Vol 10 (8) ◽  
pp. e24910817369
Author(s):  
Isabela Dainezi ◽  
Spyridion Haritos Borges ◽  
Luciola Lucena de Sousa ◽  
Neide Aparecida Mariano
Keyword(s):  
Thermal Analysis ◽  
Corrosion Resistance ◽  
Stainless Steels ◽  
Sigma Phase ◽  
Aging Treatment ◽  
Time Effect ◽  
Thermal Treatments ◽  
Nacl Solution ◽  
Solution Treated ◽  
Cyclic Potentiodynamic Polarization

Duplex stainless steels correspond to a class of steel in which the microstructure is composed basically by the phases ferrite and austenite. Given the metastable character of ferrite, associated phase transformations can occur during thermal treatments, which can lead to a reduction in corrosion resistance. Therefore, the aim of this work was to evaluate the influence of the solution-treated at 1100°C for 30min and aging at 500 and 600°C for 1, 3 and 12h, on the microstructure and corrosion resistance of DSS UNS S31803. The steels were characterized by SEM, EDS, XRD, hardness, microhardness and thermal analysis. The steels aged at 500°C for 1h presented the phase alpha line dispersed in the ferrite, and the steels aged at 600°C for 12h presented the phases alpha line, sigma and chi. In the assays of double cycle potentiodynamic reactivation in solution of 0.5M H2SO4 and 0.01M KSNC, it was observed that no sensitization occurred. Furthermore, in the tests of cyclic potentiodynamic polarization, in 3.5% NaCl solution, it was verified that the precipitation of the alpha line phase did not alter corrosion resistance; nevertheless, the sigma phase reduced corrosion resistance.

Influence of Various Heat Treatment on Corrosion Resistance of As-Extruded Mg-9Li-3Al-2.5Sr Alloys

2014 ◽  
Vol 788 ◽  
pp. 41-44 ◽  
Author(s):  
Yuan Qing Yu ◽  
Xiao Dong Peng ◽  
Hong Yu Yi ◽  
Jun Wei Liu
Keyword(s):  
Corrosion Resistance ◽  
Intermetallic Compounds ◽  
Unit Volume ◽  
Aging Treatment ◽  
Corrosion Current ◽  
Immersion Test ◽  
Corrosion Process ◽  
Nacl Solution ◽  
Boundary Area ◽  
Solution Treated

The corrosion behavior of Mg-9Li-3Al-2.5Sr alloy, solution treated at 400°C for 3h with various aging temperature (Ta; Ta=75,100,125,150,175°C), was investigated in 3.5% NaCl solution by immersion test and polarization curve measurement. Experimental results suggest that the alloy aged at150°Cfor 6h exhibits the highest corrosion resistance while the alloy treated at 75°C for 6h presents lowermost corrosion resistance. The corrosion resistance of the alloy is related to the grain size and the distribution of Al4Sr compound. The segregation of intermetallic compounds can accelerate the corrosion process. It was found that duo to the proper solid-solution and aging treatment, intermetallic compounds were distributed evenly along the grain boundaries, which can reduce the corrosion rate and corrosion current. In addition,with the growth of grain, the decrease of the grain boundary area per unit volume lead to improvement of corrosion resistance of the alloys.

Sigma Phase Precipitation of Duplex Stainless Steel and its Effect on Corrosion Resistance

2009 ◽  
Vol 620-622 ◽  
pp. 391-394 ◽  
Author(s):  
Ying Han ◽  
De Ning Zou ◽  
Wei Zhang ◽  
Rui Huang
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Duplex Stainless Steel ◽  
Aging Time ◽  
Corrosion Behavior ◽  
Stainless Steels ◽  
Sigma Phase ◽  
Precipitation Amount ◽  
Aging Treatment ◽  
Phase Precipitation

The present study concerns the influence of aging parameters on the microstructure and corrosion behavior of duplex stainless steel S31803 and S32750. It has been found that the microstructural evolutions were extremely sensitive to sigma phase precipitation during aging treatment, and sigma phase was enhanced with the increase of aging time from 2 min to 120min at its precipitation peak temperature 850 °C for S31803 and 920°C for S32750 steels respectively. The precipitation of sigma phase in S32750 is ahead of that in S31803 steel, within 10min, the sigma phase precipitation rate of S32750 is much faster than that of S31803 steel. The precipitation amount of sigma phases in S32750 steel is noticeable higher than that in S31803 steel during any aging treatment. The corrosion resistance is directly influenced by the abundant sigma phases, especially for the S32750. This result is helpful for practical aging treatment establishment of the S31803 and S32750 duplex stainless steels.

scholarly journals Effect of Sigma Phase on Corrosion Resistance of Duplex Stainless Steels

1996 ◽  
Vol 45 (2) ◽  
pp. 83-89 ◽  
Author(s):  
Shuji Hashizume ◽  
Kaoru Sato ◽  
Masaharu Honda ◽  
Katsumi Masamura ◽  
Jun-ichi Sakai ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Stainless Steels ◽  
Sigma Phase ◽  
Duplex Stainless Steels

scholarly journals Comparison of Corrosion Resistance in Physiological Saline Solution of Two Austenitic Stainless Steels – 316LV and REX734

2017 ◽  
Vol 11 (2) ◽  
pp. 91-95 ◽  
Author(s):  
Eliza Romańczuk ◽  
Zbigniew Oksiuta
Keyword(s):  
Corrosion Resistance ◽  
Stainless Steels ◽  
Saline Solution ◽  
Austenitic Stainless Steels ◽  
Physiological Saline ◽  
Nacl Solution ◽  
Corrosion Properties ◽  
Physiological Saline Solution ◽  
Superior Corrosion Resistance ◽  
Lower Nickel

AbstractIn this work two austenitic stainless steels, REX734 and 316LV were tested in terms of their microstructure and corrosion properties. The REX734 is a newer generation stainless steel, with modified chemical composition, in comparison to the 316LV grade. Potentiodynamic study of corrosion resistance was conducted in physiological saline solution (0.9% NaCl solution). In spite of the similarities of microstructure, grain size and phase structure in both materials, the corrosion tests revealed that the REX734, with lower nickel and higher nitrogen content, had better corrosion resistance than 316LV. Repassivation potential in the REX734 was almost six times higher than for the 316LV steel. Superior corrosion resistance of the REX734 steel was also confirmed by surface observations of both materials, since bigger and more densely distributed pits were detected in 316LV alloy.

Effect of heat treatment on microstructure and corrosion resistance of extruded ZK80 Mg alloy

2019 ◽  
Vol 9 (9) ◽  
pp. 1092-1099
Author(s):  
Fenghong Cao ◽  
Chang Chen ◽  
Zhenyu Wang
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Aging Time ◽  
Room Temperature ◽  
Aging Treatment ◽  
Corrosion Process ◽  
Corrosion Mechanism ◽  
Nacl Solution ◽  
Corrosion Properties

The corrosion characteristics and corrosion mechanism of the extruded ZK80 alloy with different states soaking in 3.5% NaCl solution at room temperature were analyzed via OM, SEM, EDS, XRD and static weightlessness method and other experimental analysis methods. The results show that when the aging temperature is constant, and the corrosion rate decreases with the lengthen of aging time, while when the corrosion time is constant, the corrosion rate increases with the increase in aging time. Appropriate aging treatment not only refines the grain of the alloy, but also precipitates the Mg–Zn phase which can effectively prevent the corrosion process and improve the anti-corrosion properties of the alloy. The main corrosion characteristics of the alloy are filamentary corrosion and pitting corrosion.

scholarly journals Effect of Sr and Ti Addition on the Corrosion Behaviour of Al-7Si-0.3Mg Alloy

2017 ◽  
Vol 17 (2) ◽  
pp. 125-130 ◽  
Author(s):  
M. Uludağ ◽  
M. Kocabaş ◽  
D. Dışpınar ◽  
R. Çetin ◽  
N. Cansever
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Potentiodynamic Polarization ◽  
Corrosion Test ◽  
Corrosion Behaviour ◽  
Tensile Tests ◽  
Nacl Solution ◽  
Cyclic Potentiodynamic Polarization ◽  
Ti Addition

AbstractIn the present study, the corrosion behaviour of A356 (Al-7Si-0.3Mg) alloy in 3.5% NaCl solution has been evaluated using cyclic/potentiodynamic polarization tests. The alloy was provided in the unmodified form and it was then modified with AlTi5B1 for grain refinement and with AlSr15 for Si modifications. These modifications yield to better mechanical properties. Tensile tests were performed. In addition, bifilm index and SDAS values were calculated and microstructure of the samples was investigated. As a result of the corrosion test, the Ecorr values for all conditions were determined approximately equal, and the samples were pitted rapidly. The degassing of the melt decreased the bifilm index (i.e. higher melt quality) and thereby the corrosion resistance was increased. The lowest corrosion rate was founded at degassing and as-received condition (3.9x10-3mm/year). However, additive elements do not show the effect which degassing process shows.

scholarly journals Austenitic-ferritic stainless steel containing niobium

2013 ◽  
Vol 66 (4) ◽  
pp. 467-471
Author(s):  
André Itman Filho ◽  
Wandercleiton da Silva Cardoso ◽  
Leonardo Cabral Gontijo ◽  
Rosana Vilarim da Silva ◽  
Luiz Carlos Casteletti
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Charge Transfer ◽  
Ferritic Stainless Steel ◽  
Stainless Steels ◽  
Sigma Phase ◽  
Charge Transfer Resistance ◽  
Chemical Compositions ◽  
Transfer Resistance ◽  
Ferritic Stainless Steels

The austenitic-ferritic stainless steels present a better combination of mechanical properties and stress corrosion resistance than the ferritic or austenitic ones. The microstructures of these steels depend on the chemical compositions and heat treatments. In these steels, solidification starts at about 1450ºC with the formation of ferrite, austenite at about 1300ºC and sigma phase in the range of 600 to 950ºC.The latter undertakes the corrosion resistance and the toughness of these steels. According to literature, niobium has a great influence in the transformation phase of austenitic-ferritic stainless steels. This study evaluated the effect of niobium in the microstructure, microhardness and charge transfer resistance of one austenitic-ferritic stainless steel. The samples were annealed at 1050ºC and aged at 850ºC to promote formation of the sigma phase. The corrosion testes were carried out in artificial saliva solution. The addition of 0.5% Nb in the steel led to the formation of the Laves phase.This phase, associated with the sigma phase, increases the hardness of the steel, although with a reduction in the values of the charge transfer resistance.

Effect of Solution Annealing Time on the Microstructure and Corrosion Resistance of Duplex Stainless Steel

2018 ◽  
Vol 930 ◽  
pp. 374-379 ◽  
Author(s):  
Stephania Capellari de Rezende ◽  
Maria Eurenice Rocha Cronemberger ◽  
Rodrigo Silva ◽  
Carlos A. Della Rovere ◽  
Sebastião Elias Kuri ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Annealing Time ◽  
Annealing Treatment ◽  
Intermetallic Phases ◽  
Air Cooling ◽  
Thermal Treatments ◽  
Solution Annealing ◽  
Electrochemical Tests ◽  
Cyclic Potentiodynamic Polarization ◽  
Saf 2205

The formation of intermetallic phases during thermal treatments is a decisive point for the performance of duplex stainless steels, which may prevent the obtaining or provoke degradation of their properties. This paper presents an investigation on the corrosion resistance of duplex SAF 2205 steel as received and after solution annealing treatment. The objective was to evaluate the correlation between the solution annealing time, the resulting microstructural changes and the corrosion resistance of the steel through electrochemical tests of cyclic potentiodynamic polarization and double-cycle potentiokinetic reactivation (DL-EPR). The heat treatments were performed at 1100° C for 30, 120 and 240 min with subsequent air cooling. The results of the DL-EPR showed that although there was no presence of intermetallic phases even with the absence of intermetallic phases, the solution annealing time influenced the degree of chromium depletion of the samples, so that with the increase of time, there was an increase in the degree of chrome depletion.

scholarly journals The Difference of Corrosion Behavior in Initial Period for the Hot-Rolled and Cold-Rolled 2205 Duplex Stainless Steel

2018 ◽  
Author(s):  
Tao Gao ◽  
Jian Wang ◽  
Qi Sun ◽  
Peide Han
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Duplex Stainless Steel ◽  
Sigma Phase ◽  
Aging Treatment ◽  
Rolled Material ◽  
2205 Duplex Stainless Steel ◽  
Cold Rolled ◽  
The Difference ◽  
Hot Rolled

The precipitate phases often play an important influence on the corrosion resistance of 2205 Duplex stainless steel (DSS). In the presented paper, the microstructure and corrosion resistance in the hot-rolled and cold-rolled 2205 DSS aging for different time at 850 °C was investigated by XRD, SEM and potentiodynamic polarization. It has been found that the Chi(χ) phase and Sigm(σ) phase were precipitated in turn after aging treatment of hot-rolled and cold-rolled materials, but the precipitate amount in cold-rolled material is much more than that of hot-rolled samples. The corrosion resistance of the solution-annealed cold-rolled material is similar to the hot-rolled material, but the corrosion resistance of cold-rolled material with precipitate is weaker than that of hot-rolled material after aging treatment. Pitting initiates preferentially in the Cr-depleted region from σ phase in aged hot-rolled 2205, and severe selective corrosion occurs on sigma/ferrite interfaces aged for a long aged lime. However, the initiation of pitting corrosion may take place at the phase boundary, defect and martensite in the aged cold-rolled 2205. The σ phase is further selectively dissolved by electrochemical method to investigate the difference of microstructure and corrosion behavior in hot-rolled and cold-rolled 2205 duplex stainless steel.

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