scholarly journals Electrochemical Impedance Analysis on Cryogenically Treated Dissimilar Metal Welding of 316L Stainless Steel and Monel 400 Alloy Using GTAW

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1088 ◽  
Author(s):  
Cherish Mani ◽  
R Karthikeyan ◽  
Sathish Kannan
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Welded Joints ◽  
Electrochemical Impedance ◽  
Cryogenic Treatment ◽  
Impedance Analysis ◽  
Oil Refining ◽  
Deep Cryogenic Treatment ◽  
Dissimilar Metal ◽  
Monel 400

An attempt was made to study the corrosion behavior of austenitic stainless-steel SS 316L/Monel 400 alloy dissimilar metal welded joints using gas tungsten arc welding. This combination of welded joints is used in re-heaters and heat exchangers in gas processing and oil refining industries. The welded specimens were subjected to post-weld treatments, such as annealing and deep cryogenic treatment. The welded specimens were sectioned into five different parts: SS 316L base, SS 316L HAZ, weld, Monel HAZ, and Monel base. The polarization method and electrochemical impedance analysis were used to analyze the corrosion resistance in a NaCl solution. A polarization graph, Nyquist plot, and Bode plot were constructed for all regions, separately, for the heat-treated and cryo-treated specimens, to analyze the variation in corrosion resistance in different regions, and then the results were compared. To validate the results of electrochemical impedance analysis, scanning electron microscope (SEM) and energy dispersive spectroscope (EDS) analyses were also performed. The results indicated that the cryo-treated specimens have better corrosion resistance when compared to the annealed ones. Weld region on both specimens exhibited better corrosion resistance when compared to other zones.

scholarly journals Corrosion Resistance of AISI 316L Stainless Steel Biomaterial after Plasma Immersion Ion Implantation of Nitrogen

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6790
Author(s):  
Viera Zatkalíková ◽  
Juraj Halanda ◽  
Dušan Vaňa ◽  
Milan Uhríčik ◽  
Lenka Markovičová ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Ion Implantation ◽  
316L Stainless Steel ◽  
Electrochemical Impedance ◽  
Austenitic Stainless Steels ◽  
Aisi 316L ◽  
Corrosion Properties ◽  
Aisi 316L Stainless Steel ◽  
Plasma Immersion Ion Implantation

Plasma immersion ion implantation (PIII) of nitrogen is low-temperature surface technology which enables the improvement of tribological properties without a deterioration of the corrosion behavior of austenitic stainless steels. In this paper the corrosion properties of PIII-treated AISI 316L stainless steel surfaces are evaluated by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PP) and exposure immersion tests (all carried out in the 0.9 wt. % NaCl solution at 37 ± 0.5 °C) and compared with a non-treated surface. Results of the three performed independent corrosion tests consistently confirmed a significant increase in the corrosion resistance after two doses of PIII nitriding.

scholarly journals Deep Cryogenic Treatment of Metallic Materials

2020 ◽  
Author(s):  
Patricia Jovičević-Klug ◽  
Bojan Podgornik
Keyword(s):  
Crystal Structure ◽  
Heat Treatment ◽  
Corrosion Resistance ◽  
Cryogenic Treatment ◽  
Metallic Materials ◽  
Size Change ◽  
Ferrous Alloys ◽  
Deep Cryogenic Treatment ◽  
Ferrous Metals ◽  
Proper Material

Deep cryogenic treatment (DCT) is a type of cryogenic treatment, where a metallic material is subjected to temperatures below -150°C, normally to temperatures of liquid nitrogen (-196 °C). When a material is exposed to DCT as a part of heat treatment, changes in microstructure are induced due to new grain formation, changes in grain size, change in the solubility of atoms, movement of dislocations, alteration of crystal structure, and finally new phase formation. The metallic material's performance and later performance of manufactured components and tools from this specific material are dependent on the selection of proper design, proper material, accuracy with which the tool is made and application of proper heat treatment, including any eventual DCT. Metallic materials are ferrous and non-ferrous metals. In the last years ferrous metals (different grades of steel) and non-ferrous alloys (aluminum, magnesium, titanium, nickel etc.) have been increasingly treated with DCT to alter their properties. DCT treatment has shown to reduce density of defects in crystal structure, increase wear resistance of material, increase hardness, improve toughness, and reduce tensile strength and corrosion resistance. However, some researchers also reported results showing no change in properties (toughness, hardness, corrosion resistance, etc.) or even deterioration when subjected to DCT treatment. This leads to a lack of consistency and reliability of the treatment process, which is needed for successful application in industry. This review provides a synopsis of DCT usage and resulting effects on treated materials used in automotive industry.

Investigation of mechanical and corrosion behavior of laser hybrid weld joint of 2205 duplex stainless steel

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Chuanbo Zheng ◽  
Cheng Zhang ◽  
Xiao Yong Wang ◽  
Jie Gu
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Duplex Stainless Steel ◽  
Base Metal ◽  
Corrosion Behavior ◽  
Welded Joints ◽  
Two Phase ◽  
Content Type ◽  
2205 Duplex Stainless Steel ◽  
Laser Hybrid

Purpose Duplex stainless steel is composed of equal amounts of austenite and ferrite, which has excellent corrosion resistance and strength. However, after the metal was welded, the ratio of austenite and ferrite in the joint is unbalanced, and secondary phase precipitates are produced, which is also an important cause of pitting corrosion in the joint. Design/methodology/approach This paper aims to study the mechanical and corrosion behavior of welded joints, by adjusting the welding parameters of laser hybrid welding, dual heat sources are used to weld 2205 duplex stainless steel. The two-phase content of different parts of the welded joint is measured to study the influence of the ratio of the two-phase on the mechanical and corrosion properties of the joint. Findings The ratio of austenite and ferrite in different welded joints has an obvious difference, and from top to bottom, the austenite content decreased gradually, and the ferrite content increased gradually. The harmful phases are precipitated in the middle and lower part of the joint. The strength of welded joints is slightly lower than that of base metal. At the same time, the fracture analysis shows that some ferrite phases are affected by the precipitate in the grain and produce quasi-cleavage fracture. The corrosion results show that the corrosion resistance of the welded joints is lower than that of the base metal, and the concentration of chloride ions affects the corrosion resistance. Originality/value In this paper, the authors use the influence of different welding processes on the two-phase ratio of the joint to further study the influence of the microstructure on the corrosion resistance and mechanical properties of the weld.

scholarly journals Effects of NiSO4 Concentration on the Coloring Performance and Corrosion Resistance of the Colored Film on 304 Stainless Steel

Coatings ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 598
Author(s):  
Wenwei Li ◽  
Jun-e Qu ◽  
Zhiyong Cao ◽  
Hairen Wang
Keyword(s):  
Stainless Steel ◽  
Wear Resistance ◽  
Corrosion Resistance ◽  
Electrochemical Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Negative Impact ◽  
304 Stainless Steel ◽  
Nacl Solution ◽  
Time Curve ◽  
Steel Surfaces

The colored films were successfully prepared on the 304 stainless steel surfaces in coloring solutions with different NiSO4 contents. The purpose of this study was to investigate the effects of NiSO4 in the coloring solution on the coloring performance of 304 stainless steel and corrosion resistance of the obtained colored film in NaCl solution. The coloring rate was determined from coloring potential-time curve, and the protection properties of the color films in a 3.5% NaCl solution were characterized by potentiodynamic polarization scan, electrochemical impedance spectroscopy, and wear resistance test. The results showed that adding NiSO4 could accelerate the coloring process but brought about a negative impact on the surface’s corrosion resistance.

scholarly journals Microstructure and Corrosion Resistance to H2S in the Welded Joints of X80 Pipeline Steel

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1325 ◽  
Author(s):  
Jian-Bao Wang ◽  
Guang-Chun Xiao ◽  
Wei Zhao ◽  
Bing-Rong Zhang ◽  
Wei-Feng Rao
Keyword(s):  
Corrosion Resistance ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
Electrochemical Impedance ◽  
Pipeline Steel ◽  
Electrochemical Corrosion ◽  
Open Circuit ◽  
Coarse Grained ◽  
Granular Bainite ◽  
X80 Pipeline Steel

The microstructure and corrosion resistance in H2S environments for various zones of X80 pipeline steel submerged arc welded joints were studied. The main microstructures in the base metal (BM), welded metal (WM), coarse-grained heat-affected zone (CGHAZ), and fine-grained heat-affected zone (FGHAZ) were mainly polygonal ferrite and granular bainite; acicular ferrite with fine grains; granular bainite, ferrite, and martensite/austenite constituents, respectively. The corrosion behavior differences resulted from the microstructure gradients. The results of the micro-morphologies of the corrosion product films and the electrochemical corrosion characteristics in H2S environments, including open circuit potential and electrochemical impedance spectroscopy, showed that the order of corrosion resistance was FGHAZ > BM > WM > CGHAZ.

scholarly journals Properties of a Plasma-Nitrided Coating and a CrNx Coating on the Stainless Steel Bipolar Plate of PEMFC

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 183 ◽  
Author(s):  
Meiling Xu ◽  
Shumei Kang ◽  
Jinlin Lu ◽  
Xinyong Yan ◽  
Tingting Chen ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
316L Stainless Steel ◽  
High Efficiency ◽  
Electrochemical Impedance ◽  
Bipolar Plate ◽  
Working Environment ◽  
Stainless Steel Surface ◽  
Bipolar Plates ◽  
Better Than

PEMFC are considered to be the most promising for automotive energy because of their good working effect, low temperature, high efficiency, and zero pollution. Stainless steel as a PEMFC bipolar plate has unparalleled advantages in strength, cost, and processability, but it is easy to corrode in a PEMFC working environment. In order to improve the corrosion resistance, the surface modification of 316L stainless steel is a feasible solution for PEMFC bipolar plates. In the present study, the plasma-nitrided coating and CrNx coating were prepared by the plasma-enhanced balanced magnetron sputtering technology on the 316L stainless steel surface. The microstructures, phase compositions, and corrosion resistance behavior of the coatings were investigated. The corrosion behavior of the prepared plasma-nitrided coating and CrNx coating was investigated by potentiodynamic polarization, potentiostatic polarization, and electrochemical impedance spectroscopy (EIS) in both cathodic and anodic environments. The experimental results show that corrosion resistance of the CrNx coating was better than the plasma-nitrided coating. It was indicated that the technology process of nitriding first and then depositing Cr was better than nitriding only.

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