scholarly journals Sensor Development for Corrosion Monitoring of Stainless Steels in H2SO4 Solutions

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1449
Author(s):  
Miha Hren ◽  
Tadeja Kosec ◽  
Mari Lindgren ◽  
Elina Huttunen-Saarivirta ◽  
Andraž Legat
Keyword(s):  
Stainless Steel ◽  
Stainless Steels ◽  
Electrode Materials ◽  
Electrochemical Techniques ◽  
Industrial Process ◽  
Process Conditions ◽  
Corrosion Monitoring ◽  
Electrochemical Tests ◽  
Hydrometallurgical Processing ◽  
Lower Corrosion Rate

Equipment made of different stainless steels is often used in the hydrometallurgical processing industry. In this study, an electrical resistance sensor was developed for monitoring corrosion in acidic solutions at high temperature. Two types of stainless steel were used as the electrode materials, namely grade 316L stainless steel (EN 1.4404) and grade 2507 duplex stainless steel (EN 1.4410). The materials and sensors were exposed to a 10% H2SO4 solution containing 5000 mg/L of NaCl at various temperatures. Results from the sensors were verified using electrochemical techniques and postexposure examination. Results showed that the microstructure played an important role in the interpretation of corrosion rates, highlighting the importance of using an appropriate stainless steel for the production of sensors. Electrochemical tests and postexposure examination both showed that the grade 2507 had a significantly lower corrosion rate compared to the grade 316L. Under industrial‑process conditions, the results for the grade 2507 sensor were promising with respect to sensor durability and performance, despite the extremely harsh operating environment.

scholarly journals Defect Reduction in Ferritic Stainless Steels through Modelling Plastic Deformation and Metallurgical Evolution

2021 ◽  
Vol 3 (1) ◽  
pp. 22
Author(s):  
Silvia Mancini ◽  
Luigi Langellotto ◽  
Andrea Di Schino
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Microstructural Evolution ◽  
Stainless Steels ◽  
Hot Rolling ◽  
Hot Deformation ◽  
Rolling Process ◽  
Process Conditions ◽  
Ferritic Stainless Steels ◽  
Damage Models

Steel products made of ferritic steel can show some defects, such as jagged edges, following the hot rolling process. Aiming to identify the origin of this type of defect in order to help their reduction, an in-depth study has been carried out considering the hot rolling conditions of flat bars made of EN 1.4512 steel. A wide number of references to austenitic stainless steel can be found in literature: almost all the semi-empirical models describing the microstructural evolution during hot deformation refer to austenitic stainless steel. In this work, a comprehensive model for recrystallization and grain growth of the ferritic stainless steel grade EN 1.4512 is proposed, enriching the literature and works regarding ferritic stainless steels. Thermomechanical and metallurgical models have been implemented. The microstructural evolution and the damage of the material were calculated through the coupling of metallurgical and damage models. In the thermomechanical simulations of the roughing passes, three granulometry levels (PFGS) and three heating furnace temperatures were considered. The ferritic grain evolution metallurgical model was obtained by introducing apposite equations. The results highlight that the defect could be produced by process conditions that spark abnormal heating and consequently uncontrolled growth of the grains. The work-hardened grains undergo elongation during hot deformation without recrystallizing. Those grains “squeeze” the surrounding recrystallized grains towards the edges. Thus, on the edges occurs a series of cracks that macroscopically manifest themselves as jagged edges.

Biofilm-producing abilities of Salmonella strains isolated from Turkey

Biologia ◽  
2013 ◽  
Vol 68 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Basar Karaca ◽  
Nefise Akcelik ◽  
Mustafa Akcelik
Keyword(s):  
Stainless Steel ◽  
Uv Light ◽  
Industrial Process ◽  
Process Conditions ◽  
Food Industries ◽  
Microtiter Plates ◽  
Nacl Concentration ◽  
The Media ◽  
Forming Characteristics ◽  
Steel Surfaces

AbstractIn the present study the biofilm-forming characteristics of 99 serotyped (DMC strains) and 41 genus level-identified (IS strains) Salmonella strains originating from Turkey were investigated. The strains were selected based on their ability to show the biofilm morphotype on Congo red agar plates. In addition, all strains were evaluated with regard to properties related to forming pellicle structures, physical differences of pellicles, any changes in the media associated with the formation of pellicles, and the presence of cellulose within the formed biofilm matrix as determined using 366 nm UV light. The Salmonella Typhimurium DMC4 strain was the best producer of biofilm grown on polystyrene microtiter plates (optical density at 595 nm: 3.418). In subsequent experiments industrial process conditions were used to investigate different morphotyped Salmonella strains’ biofilm-forming capability on stainless steel, a commonly preferred surface for the food industries, and on polystyrene surfaces. The effect of other important industrial conditions, such as temperature (5, 20, 37°C), pH (4.5, 5.5, 6.5, 7.4) and NaCl concentration (0.5, 1.5, 5.5, 10.5%) on the production of biofilm of the different morphotyped Salmonella strains (DMC4; red, dry and rough morphotyped S. Typhimurium, DMC12; brown, dry and rough morphotyped S. Infantis, DMC13; pink, dry and rough morphotyped S. subsp. Roughform) were also assessed. On the other hand, pH values exhibited variable effects on biofilm-forming features for different Salmonella strains on both polystyrene and stainless steel surfaces.

Corrosion Behaviour of Nitronic Steel in Acidic Environment

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Himanshu Sharma ◽  
Anurag Bhardwaj ◽  
Daljeet Singh ◽  
Divyansh Mittal ◽  
Rajiv Kumar ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Stainless Steels ◽  
Corrosion Behaviour ◽  
Steel Corrosion ◽  
Optical Microscope ◽  
Acidic Environment ◽  
Acidic Solutions ◽  
Corrosion Studies ◽  
Structural Applications ◽  
Lower Corrosion Rate

Nitronic steel exhibits an austenitic matrix with carbide precipitates along the grain boundaries. The nitronic steel also shows excellent ductility (nearly 2 times of the other stainless steel) which enhances their structural applications. In the view of the performance of nitrogen alloyed steel, the corrosion behaviour of the as-received nitronic steels wasstudied and compared its corrosion behaviour with the conventional stainless steels being used in chemical and hydropower industries. The corrosion study of the nitronic steel and conventional stainless steels was performed in different aqueous solutions (H2SO4 and NaCl). The results obtained from corrosion studies suggest the lower corrosion rate of nitronic steel as compared to the conventional stainless steels. The corroded surfaces were analyzed using an optical microscope and scanning electron microscope for the elemental analysis of corrosion products. Keywords: Nitronic steel; Corrosion; Stainless steel; Acidic solutions

Monitoring and Testing of Weld Corrosion

2006 ◽  
pp. 203-216
Keyword(s):  
Stainless Steels ◽  
Crevice Corrosion ◽  
Electrochemical Techniques ◽  
Test Methods ◽  
Corrosion Cracking ◽  
Microbiologically Influenced Corrosion ◽  
Corrosion Monitoring ◽  
Service Monitoring ◽  
Testing Techniques ◽  
Weld Corrosion

Abstract This chapter addresses in-service monitoring and corrosion testing of weldments. Three categories of corrosion monitoring are discussed: direct testing of coupons, electrochemical techniques, and nondestructive testing techniques. The majority of the test methods for evaluating corrosion of weldments are used to assess intergranular corrosion of stainless steels and high-nickel alloys. Other applicable tests evaluate pitting and crevice corrosion, stress-corrosion cracking, and microbiologically influenced corrosion. Each of these test methods is reviewed in this chapter.

Potential for Application of Special Stainless Steels for Chemical Process Equipments

2013 ◽  
Vol 794 ◽  
pp. 691-696
Author(s):  
K. Elaya Perumal
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Case Studies ◽  
Stainless Steels ◽  
Chemical Process ◽  
Elevated Temperatures ◽  
Austenitic Stainless Steels ◽  
Process Conditions ◽  
Petrochemical Plant ◽  
Uniform Corrosion

The most predominant material of construction (MOC) for process equipments in chemical process industries (CPI) is plain carbon steel only. This is because of its lowest cost, easy availability, adequate thermal and mechanical properties, ease of fabrication etc. The only limitation is its low corrosion resistance. When corrosion resistance becomes the deciding factor, for overall resistance to general uniform corrosion, the common austenitic stainless steel Type 304(L) SS, 18/8(L) SS, is used. This has limitation with respect to uniform corrosion in reducing acids and to pitting corrosion, crevice corrosion and stress corrosion cracking in chloride containing media. In such situations, Type 316(L) SS, 18/8/2.5Mo/(L), shows somewhat better performance. These are called Standard Austenitic Stainless Steels. Even 316(L) SS shows unsatisfactory corrosion behavior in strong reducing acids, in concentrated chloride solutions at elevated temperatures and in fluids flowing with high velocities. In such cases, if the process conditions cannot be made milder with respect to corrosion phenomena, then there is a strong potential for upgrading the MOCs to Special Stainless Steels. These special stainless steels are either high nickel high molybdenum (~25 % Ni and ~6 % Mo) Super Austenitic Stainless Steels or low nickel (4 to 7 %) Duplex Stainless Steels. With respect to cost, the former are highly expensive than 316(L) SS because of widely varying amounts of nickel and of the presence of high molybdenum and the latter are marginally comparable with 316L SS. It is a common experience in industry that the usage of such special stainless steels is felt necessary only after facing severe corrosion problems in equipments made of standard stainless steels. The purpose of this paper is to present a few case studies of severe corrosion problems analyzed by the author resulting in recommendation of special stainless steel as the corrosion preventive step. The following case studies would be presented. Fertilizer Industry, Ammonia plant, Synthesis Gas Coolers Petrochemical Plant, Proprietary Amine manufacturing Reactor in the presence of Orthophosphoric Acid Petrochemical Plant, Proprietary Amine manufacturing process, Ammonia recovery column. Petrochemical Plant, Reboiler Tubes processing concentrated acetic acid.

The Application of Electrochemical Techniques to the Study of Corrosion of Automotive Trim Materials

CORROSION ◽  
1969 ◽  
Vol 25 (2) ◽  
pp. 47-58 ◽  
Author(s):  
M. S. WALKER ◽  
L. C. ROWE
Keyword(s):  
Corrosion Resistance ◽  
Stainless Steels ◽  
Electrochemical Techniques ◽  
Chloride Ion ◽  
Ion Concentration ◽  
Field Exposure ◽  
Electrochemical Tests ◽  
Potentiodynamic Anodic Polarization ◽  
Pit Initiation ◽  
Mechanisms Of Reactions

Abstract De-icing salts are known to have a contributing effect on the corrosion of automotive trim materials. Various accelerated tests have been developed to evaluate the corrosion resistance of trim materials, but each test has its own limitations. Electrochemical techniques are a valuable supplement to these other methods, not only because they are fast and reproducible but also because they help in determining mechanisms of reactions. A potentiodynamic anodic polarization method was used to show the relative corrosion resistance of four different stainless steels and a chromium plated stainless steel used in trim applications, and the order of corrosion resistance compared favorably with that obtained by conventional chemical tests and by field exposure. Furthermore, the test was used to show distinct differences in the pitting susceptibility of stainless steels exposed to different concentrations of chloride ion. The thermographic test is commonly used to evaluate the corrosion resistance of stainless steels. The effect of specific ingredients in the solution on corrosion was determined by both chemical and electrochemical tests. Chemical tests showed that chloride and thiosulfate ions had the greatest effect on pit initiation, probably because the thiosulfate altered the redox potential of the solution. Potentiodynamic polarization measurements indicated that the chloride ion concentration was rate controlling after corrosion had begun, and the thiosulfate ion caused a shift in potential which placed the material in a corroding region.

scholarly journals A Study on DLC Tool Coating for Deep Drawing and Ironing of Stainless Steel

2018 ◽  
Vol 767 ◽  
pp. 181-188 ◽  
Author(s):  
Esmeray Üstünyagiz ◽  
Mohd Hafis Sulaiman ◽  
Peter Christiansen ◽  
Chris Valentin Nielsen ◽  
Niels Bay
Keyword(s):  
Stainless Steel ◽  
Double Layer ◽  
Deep Drawing ◽  
Industrial Process ◽  
Environmentally Friendly ◽  
Process Conditions ◽  
Tool Coating ◽  
Coated Tool ◽  
Tool Coatings ◽  
Bending Under Tension

The trend in metal forming tribology is to develop new tribo-systems including new lubricants, tool materials and tool coatings in order to substitute environmentally hazardous lubricants by environmentally friendly tribo-systems. In preliminary testing the limits of lubrication of new tribo-systems for sheet forming production, it is advantageous to use dedicated simulative tribo-tests. This paper studies the influence of tool coatings on deep drawing operations using the Bending Under Tension (BUT) test and also under more severe tribological conditions by adopting the Strip Reduction Test (SRT) to replicate industrial ironing of deep drawn, stainless steel parts. Non-hazardous tribo-systems in form of a double layer Diamond-like coated tool applied under dry condition or with an environmentally friendly lubricant were investigated via emulating industrial process conditions in laboratory tests. Experiments revealed that the double layer coating worked successfully, i.e. with no sign of galling, when it was used with environmentally friendly lubricants, whereas the results were more prone to galling under dry condition.

scholarly journals Delicate lithium-manganese spinel LiMn2O4 of quasi-spherical morphology, obtained by hydrolysis of complex compounds, as cathode material for high-power current sources

2021 ◽  
pp. 108-118
Author(s):  
Sviatoslav A. Kirillov ◽  
◽  
Anna V. Potapenko ◽  
Tetiana V. Lisnycha ◽  
◽  
...  
Keyword(s):  
Complex Formation ◽  
Electrode Materials ◽  
Specific Capacity ◽  
High Capacity ◽  
Industrial Process ◽  
Complex Compounds ◽  
High Rate ◽  
Electrochemical Tests ◽  
Tap Density ◽  
Hydrolysis Of

Precipitation of hydroxides and carbonates from solutions containing complex compounds is a valuable industrial process enabling one to synthesize electrode materials with high density particles of microspherical morphology and high tap density. As a complex formation agent, ammonia is almost exclusively used in this process. Aiming at the search of other complex formation agents and the detailed studies of complex formation at precipitation, we have first investigated the hydrolysis of solutions containing citric acid. Equilibria in solutions containing citrate complexes of manganese and carbonates are computed. It is found that in Mn(NO3)2 - хC6H8O7∙H2O - уNa2CO3 systems, a neutral Mn(HCitr) complex dominates up to pH=9.5 and precipitation of MnCO3 from carbonate containing solutions begins at рН~6.5. Experiments show that MnCO3 precipitates from these systems in the form of openwork quasi-spherical aggregates formed by nanosized crystals. The synthesis of LiMn2O4 from this precursor does not influence the morphology of the material, and the resulting product consists of aggregates of less than 4 mkm and nanocrystals of ~90 nm. Electrochemical tests evidence that for the best samples, the specific capacity of 103 mAh/g can be achieved at 1 C current. At 20 C current, they deliver ~25 mAh/g capacity. After high-rate tests, in control cycles with 1 C current, the samples demonstrate high capacity retention, returning up to 98% of their initial capacity. This signifies their good prospects for using in high-rate batteries.

scholarly journals The pitting corrosion monitoring of stainless steel in a simulated corrosive condition in marine applications

2018 ◽  
Vol 1 (1) ◽  
pp. Proof
Author(s):  
Thee Chowwanonthapunya
Keyword(s):  
Stainless Steel ◽  
Passive Film ◽  
Pitting Corrosion ◽  
Stainless Steels ◽  
Immersion Time ◽  
Corrosion Monitoring ◽  
Metallurgical Investigation ◽  
Inhibiting Effect ◽  
Acidic Conditions ◽  
Marine Applications

This paper describes the pitting corrosion monitoring of ferritic and austenitic stainless steel under a simulated acidic condition of marine appications. The monitoring deals with the corrosion weight loss and metallurgical investigation. The results indicated that the stainless steel with passive film shows the good corroison resistance to the simulated corrosive environment for the all test periods. In contrast, the stainless steel without passive film cannot provide the inhibiting effect for the whole test periods. After the 24 hr. of testing , both of the stainless steel are locally attacked. Pitting corrosion was observed on the surface of both stainless steels. In small pits, the self-accelerating corrosion can occur. Therefore, the longer immersion time attributes to the higher corrosion rate of both stainless steel in a simulated acidic conditions.

NiAl precipitation in Fe-12w/o Cr-5w/o Ni-4w/o Al

1983 ◽  
Vol 41 ◽  
pp. 202-203
Author(s):  
L.E. Murr ◽  
J.S. Dunning ◽  
S. Shankar
Keyword(s):  
Solid Solution ◽  
Stainless Steel ◽  
Stainless Steels ◽  
Alloy Composition ◽  
Chromium Content ◽  
Scale Up ◽  
Optical Metallography ◽  
Property Evaluation ◽  
310 Stainless Steel ◽  
Microstructural Studies

Aluminum additions to conventional 18Cr-8Ni austenitic stainless steel compositions impart excellent resistance to high sulfur environments. However, problems are typically encountered with aluminum additions above about 1% due to embrittlement caused by aluminum in solid solution and the precipitation of NiAl. Consequently, little use has been made of aluminum alloy additions to stainless steels for use in sulfur or H2S environments in the chemical industry, energy conversion or generation, and mineral processing, for example.A research program at the Albany Research Center has concentrated on the development of a wrought alloy composition with as low a chromium content as possible, with the idea of developing a low-chromium substitute for 310 stainless steel (25Cr-20Ni) which is often used in high-sulfur environments. On the basis of workability and microstructural studies involving optical metallography on 100g button ingots soaked at 700°C and air-cooled, a low-alloy composition Fe-12Cr-5Ni-4Al (in wt %) was selected for scale up and property evaluation.

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