Effects of Antibacterial Treatment Temperature on the Properties of Copper-Bearing Antibacterial Duplex Stainless Steels

2012 ◽  
Vol 486 ◽  
pp. 289-296 ◽  
Author(s):  
Hong Liang Xiang ◽  
Jin Chun Fan ◽  
Dong Liu ◽  
Pei Pei Guo
Keyword(s):  
Passive Film ◽  
Stainless Steels ◽  
Antibacterial Effect ◽  
Volume Fraction ◽  
Antibacterial Properties ◽  
Treatment Temperature ◽  
Antibacterial Treatment ◽  
Duplex Stainless Steels ◽  
The Matrix ◽  
The Stability

Antibacterial copper-rich phases such as ε-Cu were precipitated in copper-bearing antibacterial duplex stainless steels after antibacterial treatment. In this paper, the effects of antibacterial treatment on the corrosion resistance properties of copper-bearing antibacterial duplex stainless steels were investigated by electrochemical methods. The film-cover method was used to antibacterial tests.The results showed that as the antibacterial treatment temperature increased in the rang of 540~580 , the copper-rich precipitates grew faster and evolved from granular into rod-like. With the proportion of rod-like copper-rich phases in matrix increased, the resistant to pitting corrosion decreased and the positions of copper-rich phase precipitated were apt to become pitting nucleation source.The presence of ε-Cu and other copper-rich phases in passive film reduced the overall potential and passive film resistance, decreasing the stability of passive film. Antibacterial test showed that with the treatment temperature increased, the volume fraction and the uniformity of the distribution of copper-rich precipitates in the matrix first increased, then decreased, resulting in the changes in antibacterial properties of the steels, and 560 obtained the best antibacterial effect.

The Fatigue Properties of Duplex Stainless Steels: Role of Microstructure

2008 ◽  
Vol 378-379 ◽  
pp. 101-114 ◽  
Author(s):  
Jean Bernard Vogt
Keyword(s):  
Fatigue Resistance ◽  
Stainless Steels ◽  
Load Transfer ◽  
Volume Fraction ◽  
Low Cycle Fatigue ◽  
Fatigue Behaviour ◽  
Cyclic Softening ◽  
Duplex Stainless Steels ◽  
Fatigue Properties

The paper analyzes the role of microstructure on the low cycle fatigue behaviour of duplex stainless steels. The alloys are investigated in their as received condition and after ageing at 475°C. The fatigue resistance and the cyclic accommodation of these DSS are strongly controlled by the volume fraction of α and γ "phases which is related to the chemical composition in particular nitrogen. It is shown that DSS with a high fraction of austenite present a good combination of fatigue resistance and cyclic softening especially in the aged condition. The mutual interaction between ferrite and austenite referred to load transfer is beneficial for increasing the fatigue resistance. Alloying with nitrogen appears to be a promising way to master an optimised microstructure leading to high mechanical resistant DSS.

scholarly journals Investigation of the Localized Corrosion and Passive Behavior of Type 304 Stainless Steels with 0.2–1.8 wt % B

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2097 ◽  
Author(s):  
Heon-Young Ha ◽  
Jae Jang ◽  
Tae-Ho Lee ◽  
Chihyoung Won ◽  
Chang-Hoon Lee ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Pitting Corrosion ◽  
Stainless Steels ◽  
Volume Fraction ◽  
Localized Corrosion ◽  
Ingot Metallurgy ◽  
Passive Behavior ◽  
Pitting Corrosion Resistance ◽  
The Matrix ◽  
Type 304

The pitting corrosion resistance and passive behavior of type 304 borated stainless steels (Febalance–18Cr–12Ni–1.5Mn–(0.19, 0.78, and 1.76 wt %)B) manufactured through conventional ingot metallurgy were investigated. The alloys were composed of an austenitic matrix and Cr2B phase, and the volume fraction of Cr2B increased from 1.68 to 22.66 vol % as the B content increased from 0.19 to 1.76 wt %. Potentiodynamic polarization tests measured in aqueous NaCl solutions revealed that the pitting corrosion resistance was reduced as the B content increased and the pits were initiated at the matrix adjacent to the Cr2B phase. It was found that the reduced resistance to pitting corrosion by B addition was due to the formation of more defective and thinner passive film and increased pit initiation sites in the matrix.

scholarly journals Effects of Si and Sn Contents and Heat-Treatment Temperature on the Corrosion Behavior of AISI 439 Ferrite Stainless Steel

2022 ◽  
Vol 60 (1) ◽  
pp. 26-34
Author(s):  
Chan Yang Kim ◽  
Do hyung Kim ◽  
Won sub Chung
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Passive Film ◽  
Heat Treatment Temperature ◽  
Inhibitory Effect ◽  
Heat Treatment Condition ◽  
Treatment Temperature ◽  
Fe Oxide ◽  
The Stability

This study was conducted to evaluate the corrosion resistance and optimize the heat-treatment process of AISI 439 ferrite stainless steel silicon and tin alloys with reduced chromium. The microstructure of the specimens and deposition under each condition were analyzed. The production of oxide films was compared based on the thickness of the film and the change in the contents of each element. In addition, electrochemical analyses of each heat-treatment condition was used to quantitatively compare corrosion resistance and passive film stability based on the relative chromium, silicon, and tin contents. It was found that the addition of silicon and tin compensated for the decrease in corrosion resistance induced by the chromium reduction. The addition of the two elements inhibited iron (Fe) oxide production in the surface oxide film, thereby improving the corrosion resistance of the material and improving the stability of the passive film. Moreover, the SiO2 and SnO2 layers inhibited the production of Fe oxide and contributed to the stability of the film along with Cr2O3, the main component of the passive film. However, when the heat treatment temperature increased above a specific temperature, the oxide inhibitory effect of the two elements was relatively offset. Nevertheless, further research to optimize the content of the three elements will help develop materials with superior mechanical properties and corrosion resistance.

Effect of Secondary Phases Precipitation on Corrosion Resistance of Duplex Stainless Steels

2016 ◽  
Vol 879 ◽  
pp. 1495-1500 ◽  
Author(s):  
Luca Pezzato ◽  
Mattia Lago ◽  
Katya Brunelli ◽  
Marco Breda ◽  
Enrico Piva ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Stainless Steels ◽  
Room Temperature ◽  
Volume Fraction ◽  
Secondary Phase ◽  
Duplex Stainless Steels ◽  
Secondary Phases ◽  
Critical Range ◽  
Pitting Corrosion Resistance ◽  
Equivalent Number

Duplex Stainless steels (DSS) are biphasic austeno-ferritic steels in which the best combination of mechanical and corrosion resistance properties is achieved for almost equal volume fraction of the phases. These steels are classified according to their pitting corrosion resistance, assessed by the PREN index (Pitting Resistance Equivalent Number) which, although qualitatively, is widely employed as comparison. The present work is aimed to study the pitting resistance of four DSS grades (SAF 2101, 2304, 2205 and 2507) in the as-received condition and after isothermal aging in the critical range 750°C-900°C, to highlight the effect of secondary phases precipitation on the corrosion behavior. The materials were potentiodynamically tested in artificial seawater (pH7) at room temperature and the corresponding Critical Pitting Temperatures (CPT) were determined according to ASTM G150. Secondary phase precipitation mainly affected the lean duplex grades whereas the high-alloyed DSS were more stable even if large precipitation occurred.

Phases Quantification in Duplex Stainless Steels Weldments

2014 ◽  
Vol 698 ◽  
pp. 209-214
Author(s):  
M. Breda ◽  
S.A. Ontiveros Vidal ◽  
Jacopo Basoni ◽  
Irene Calliari
Keyword(s):  
Corrosion Resistance ◽  
Stainless Steels ◽  
Material Properties ◽  
Volume Fraction ◽  
Secondary Compounds ◽  
Duplex Stainless Steels ◽  
Ferrite Phase ◽  
Steel Plates ◽  
Phase Ratio ◽  
Extreme Care

Duplex Stainless Steels (DSS) are very attractive steels and their application is presently of increasing interest, especially as structural materials in aggressive environments. DSS are austeno-ferritic biphasic steels, having an austenite-to-ferrite phase ratio of about one, giving the best combination of mechanical and corrosion-resistance properties. However, these steels must be handled with extreme care, especially if thermal cycles are involved, owing to the formation of dangerous secondary compounds that highly worsen their excellent properties.The production of big pipes requires manufacturing welding operations on steel plates or sheets and the final products must satisfy specific requirements in terms of material properties. DSS approximately contain equal volume fraction of the phases that, in practice, cover a slightly wider range within 40/60 and 60/40. Therefore, since DSS properties depend on phase ratio, ferrite quantification on an industrial scale represents a topic of great interest, which must be as reliable as possible and, at the same time, quickly executable.The present paper gives a comparison of different methods currently employed for ferrite determination in DSS weldments, in order to understand the limits derived from the specific employed technique.

scholarly journals Effect of Al on Microstructure and Properties of Hot-Rolled 2205 Dual Stainless Steel

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Qian Meng ◽  
Peiqing La ◽  
Liang Yao ◽  
Peng Zhang ◽  
Yupeng Wei ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steels ◽  
Volume Fraction ◽  
Elongation Rate ◽  
Al Content ◽  
Oxidation Rates ◽  
Corrosion Rates ◽  
The Matrix ◽  
Hot Rolled ◽  
Oxidation And Corrosion

The microstructure, mechanical properties, oxidation, and corrosion resistance of 2205 stainless steels without and with Al in a range of 0.5 to 2.5 wt.% were investigated in this paper. The results showed that the matrix phase transformed from austenite to ferrite. The volume fraction of the ferrite in the steels decreased at first and then increased and was the lowest in the steel with 0.5 wt.% Al. Most of the Al was dissolved in the ferrite and austenite phases in the steels. The ultimate tensile strength and elongation rate of the steels increased at first and then decreased with the increasing Al content, with the highest values in the steel with 0.5 wt.% Al. The yield strength of the steels slightly increased from 544 to 607 MPa due to the addition of Al. The oxidation rates of the steels with Al were much lower than that of the steel without Al, and the rate of the steel with 1.5 wt.% Al was the lowest, approximately 10 times lower than that of the steel without Al. The corrosion rates of the steels with 0.5 and 1.0 wt.% Al were slightly higher than that of the alloy without Al. In general, the steel with 1 wt.% Al had optimal properties.

Recrystallization during Annealing of a Cold Rolled Lean Duplex Stainless Steel

2012 ◽  
Vol 715-716 ◽  
pp. 550-550 ◽  
Author(s):  
Clara Herrera ◽  
Dirk Ponge ◽  
Dierk Raabe
Keyword(s):  
Stainless Steel ◽  
Cold Rolling ◽  
Duplex Stainless Steel ◽  
Stainless Steels ◽  
Volume Fraction ◽  
Annealing Treatment ◽  
Grain Morphology ◽  
Duplex Stainless Steels ◽  
Lean Duplex Stainless Steel ◽  
Bamboo Structure

Duplex stainless steels (DSSs) are based on the Fe-Cr-Ni system and formed by ferrite (30-70%) and austenite. They have high tensile strength, good toughness and weldability and excellent corrosion resistance including stress-corrosion cracking and resistance to localized corrosion. The increase of the raw materials of the last years, there has been a motivation to develop new stainless steels with lower contents of nickel and molybdenum. Lean duplex stainless steels (LDSSs) are almost Mo free and nickel content lower than 4%. The lean duplex grades are expected to substitute not only 304/316 grades but also other duplex stainless steel grades. LDSSs are used for structural applications and for the less corrosion conditions such as liquor tanks and suction rolls. The aim of the present work was to study the kinetics of recovery and recrystallization of the lean duplex stainless steel 1.4362 during annealing treatment. The material was subjected to hot rolling and cold rolling of 70%, annealing treatment for different times at temperatures from 1000 to 1100°C and subsequently water quenched. Optical microscopy and electron back scattering diffraction (EBSD) were employed to study the evolution of the microstructure during the annealing treatment. After cold rolling austenite exhibited more strain hardening than ferrite. Consequently, the driving force of the austenite for recrystallization is higher. During annealing, recovery took place in ferrite, while the austenite remained nearly unrecovered until beginning of recrystallization. The layered grain morphology produced during cold rolling remained after the annealing treatment. The volume fraction of the phases did not show significant changes with the annealing time. Nevertheless, the volume fraction of austenite decline with an increasing of annealing temperature. After 60 seconds at 1100°C, annealing primary recrystallization had progressed in both phases, which show a bamboo-structure where the grain boundaries ran perpendicular to the phase boundaries. Grain growth progressed for longer annealing times. After 600 seconds, the bamboo-structure started to change for a more globular grain structure, pearl-structure. It continued and became more pronounced at longer annealing times. At lower temperatures, the recrystallization behavior is similar; however, the structure was refined. Recovery is favored by the high stacking fault energy of ferrite and the layered grain morphology. The lean duplex stainless steel 1.4362 shows a similar recrystallization kinetics compare with standard duplex stainless steels.

scholarly journals Quantitative Description of Duplex Stainless Steels Microstructure Using Selective Etching

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1750
Author(s):  
Aleksandr Sergeevich Fedorov ◽  
Andrey Igorevich Zhitenev ◽  
Darya Andreevna Strekalovskaya ◽  
Aleksandr Aleksandrovich Kur ◽  
Alexey Aleksandrovich Alkhimenko
Keyword(s):  
Stainless Steels ◽  
Volume Fraction ◽  
Quantitative Description ◽  
Integrated Approach ◽  
Selective Etching ◽  
Duplex Stainless Steels ◽  
Parameters Estimation ◽  
Metallographic Analysis ◽  
Secondary Phases ◽  
Metallic Inclusions

The properties of duplex stainless steels (DSSs) depend on the ferrite–austenite ratio, on the content of secondary phases and on the contamination with non-metallic inclusions. To assess the quality of DSSs, it is necessary to use an integrated approach which includes controlling for the volume fraction, the morphology and the distribution of all phases and non-metallic inclusions. Samples of several grades of DSSs were obtained using various heat treatments, such as solution annealing and quenching from 1050 to 1250 °C to obtain different amounts of ferrite and to provoke annealing at 850 °C to precipitate σ-phase. As a result, a metallographic technique of phase analysis in DSSs based on selective etching and subsequent structure parameters estimation according to ASTM E1245 was developed. We demonstrated that the developed method of quantitative analysis based on selective etching and metallographic analysis according to ASTM E1245 allows us to obtaining much more accurate results, compared to the point count method described in ASTM E562 and to the XRD method.

Effect of Nitrogen Content on the Hot Ductility during Hot Deformation of Stainless Steels

2009 ◽  
Vol 620-622 ◽  
pp. 161-164 ◽  
Author(s):  
Jie Liu ◽  
Guang Wei Fan ◽  
Pei De Han ◽  
Jian Sheng Liu ◽  
Ji Qiang Gao ◽  
...  
Keyword(s):  
Nitrogen Content ◽  
Stainless Steels ◽  
Hot Deformation ◽  
Volume Fraction ◽  
Duplex Stainless Steels ◽  
Hot Ductility ◽  
Strain Rates ◽  
High Nitrogen Content ◽  
High Nitrogen ◽  
Deformation Degree

Effects of nitrogen content on hot ductility of duplex stainless steels have been investigated. With the increase of nitrogen content in the duplex stainless steels, mechanical strength increased, while hot ductility and elongation decreased. With the same strain rates and deformation degree, the high nitrogen content led to the high optimum hot ductility temperature for the high nitrogen DSS alloy. These results indicated the importance of control over the shape and volume fraction of phases in duplex stainless steels to achieve the optimum hot ductility.

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