scholarly journals Susceptibility to Localized Corrosion of ASTM F745 and UNS S32750 Stainless Steels Influence of pH and Cytotoxicity Evaluation

Author(s):  
Ricardo W. Gregorutti ◽  
Jorge E. Grau ◽  
Daniel Castrogiovanni ◽  
Julieta Parisi ◽  
Miguel Reigosa ◽  
...  

Background: Body fluids are highly corrosive as they contain chlorides and hydroxides ions, as well as salts, bacteria, proteins and dissolved oxygen. The pH of the body is usually around 7.4, although this value can vary in a range of 4 to 9 after surgery or because of haematomas, inflammations and infections. ASTM F745 (type 316L) stainless steel has been used for load bearing partial and total joint replacements and post trauma reconstructive surgeries. However, long exposure to the aggressive effect of chloride ion present in the human body, may increase the susceptibility to suffer localized corrosion. Although UNS S32750 has greater corrosion resistance to chloride ion, its magnetic characteristics inhibit its use in implantable devices. Nevertheless, this stainless steel could be used in temporary implants and orthodontic appliances such as brackets, wire arches and bands, due to its high resistance to corrosion, the greater mechanical resistance and the high capacity of plastic forming. Objectives: The objective was to evaluate the susceptibility to localized corrosion in simulated body fluid, in the pH range of 4 to 9. Another objective was to evaluate the cytotoxicity of Cr and Ni present in the chemical composition of both stainless steels. Cytocompatibility was also analysed by seeding cells on the surfaces of both stainless steels. Methods: Cyclic polariation test was performed to evaluate the susceptibility to localized corrosion in 0.9 wt% NaCl aqueous solution, at pH between 4 and 9, maintained at 37°C. For cytotoxicity evaluation, neutral red, MTT and collagen assays were performed using UMR-106 cell line. Cytocompatibility was analysed by seeding UMR-106 cells on the surfaces of both stainless steels. Results: F745-SS was more susceptible to suffer localized corrosion than UNS S32750. Although it showed a tendency to develop transpassive reactions at low pH, galvanostatic tests did not reveal the onset of localized corrosion. The results from the cytotoxicity assays indicated that no adverse effects were observed. UMR-106 osteoblastic cells showed high viability, however, a slight reduction in the collagen production was observed. The cytocompatibility was also satisfactory, since the cells seeded on the surfaces had adequate proliferation. Conclusion: F745-SS is more susceptible to suffer localized corrosion than UNS S32750 in the pH range between 4 and 9. UNS S32750 showed an extensive passive region, however, transpassive reactions were observed at lower pH. On the other hand, no cytotoxic effects were promoted by both stainless steels, although a slight reduction in collagen production was observed. Cells seeded on F745-SS and UNS S32750 surfaces had an acceptable proliferation, without evidence of changes in their morphology.

2008 ◽  
Vol 569 ◽  
pp. 197-200 ◽  
Author(s):  
Wei Zhang ◽  
De Ning Zou ◽  
Hong Hong Yao ◽  
Jun Yang

Copper is a well-known alloying element which is used to improve the resistance to general corrosion of stainless steels. Our previous experiments show that the increase of copper content can acquire the excellent antibacterial properties and can also increase the tendency to cold formability of the ferritic stainless steels. However, the effect of alloying Cu on the resistance to localized corrosion has not been clarified sufficiently. In order to understand the effect of copper on pitting corrosion resistance of the ferritic antibacterial stainless steel, the electrochemical experiments were carried out and the anodic polarization curves were performed in 3.5% NaCl solution for two kinds of steels. The results reveal that the ε-Cu phase in ferrite matrix diminishes pitting corrosion resistance of the antibacterial stainless steel in the chlorides medium. It is connected with the poor passive behavior of the ε-Cu phase inclusions.


CORROSION ◽  
1959 ◽  
Vol 15 (1) ◽  
pp. 48-54 ◽  
Author(s):  
N. D. GREENE ◽  
M. G. FONTANA

Abstract By means of a unique artificial pit specimen, pit growth on 18 percent chromium-8 percent nickel stainless steel has been measured and characterized. The effects of solution composition, agitation, atmosphere, corrosion current interruption, chloride ion concentration, and inhibitor additions have been investigated. Pit interaction during pit growth has also been determined. The autocatalytic nature of pitting has been verified, and evidence of ion screening at pit sites has been experimentally observed for the first time. 3.2.2


2017 ◽  
Vol 741 ◽  
pp. 42-49
Author(s):  
Toshiyuki Sunaba ◽  
Susumu Hirano ◽  
Tadao Ishihara

The effects of chloride ion concentration on SCC susceptibility of 15Cr and 13Cr martensitic stainless steels were investigated at 180°C by SSRT. Transgranular SCC occurred in the environment containing CO2 and chloride ion. The increasing chloride ion concentration was significantly affected SCC susceptibility of 15Cr SS. In addition, the contribution of hydrogen to SCC was examined at high temperature by SSRT with electrochemically polarization. The cathodically charged specimens showed hydrogen embrittlement. The fracture surface was similar to that of high temperature SCC. On the other hand, the SCC was accelerated by anodic polarization and not by cathodic polarization. The SCC behavior of martensitic stainless steel at high temperature is affect by evolved hydrogen atom. It is concluded that hydrogen plays a key role in the crack propagation.


Alloy Digest ◽  
1994 ◽  
Vol 43 (8) ◽  

Abstract SUMITOMO DP8 is a duplex stainless steel. Duplex stainless steels are designed to be economical and reliable for material applications in the production of oil and gas to resist the environments there of carbon dioxide, hydrogen sulfide and chlorides. This family of alloys is also resistant to chloride-ion stress-corrosion cracking. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as heat treating and joining. Filing Code: SS-571. Producer or source: Sumitomo Metal Industries Ltd.


2011 ◽  
Vol 347-353 ◽  
pp. 3591-3596 ◽  
Author(s):  
Laura L. Machuca ◽  
Stuart I. Bailey ◽  
Rolf Gubner

A range of stainless steels has been investigated for resistance to microbiologically influenced corrosion in seawater. The corrosion potential was monitored for stainless steel coupons exposed to sterilized seawater and to microbiologically active seawater, which showed the effect of the growth of microorganisms. Cyclic potentiodynamic polarization scans confirmed that 13%Cr stainless steel is very susceptible to localized corrosion under these conditions. 316L stainless steel was also quite susceptible to localized corrosion, whereas 2205 duplex stainless displayed good resistance to localized corrosion. Naturally occurring microorganisms in the seawater were shown to exacerbate the localized corrosion.


2010 ◽  
Vol 654-656 ◽  
pp. 2511-2514 ◽  
Author(s):  
Brytan Zbigniew ◽  
Mirołsaw Bonek ◽  
Leszek Adam Dobrzański ◽  
Daniele Ugues ◽  
Marco Actis Grande

The laser surface remelting (LSR) process was successfully applied to restore localized corrosion resistance in sensitized stainless steel and also as a useful method to improve passivity of some martensitic stainless steels. The LSR process can be successfully applied to repair cracks and defects at the surface of highly thermo-mechanically loaded parts of stainless steel. The purpose of presented study was to evaluate the microstructure and properties of laser remelted surface of stainless steels. The wrought austenitic stainless steel and sintered in vacuum 316L type were studied. The laser treatment was performed with the use of high power diode laser (HPDL) and the influence of beam power of 0.7-2.1kW on the properties of the surface layer was evaluated. The geometrical characteristics and x-ray analysis of weld bead were studied as well as microhardness, surface roughness and corrosion resistance were measured. The increase of laser beam power of LSR resulted in the increase of hardness of sintered stainless steel due to the reduction of porosity and formation of fine dendritic and cellular-dendritic microstructure. The corrosion resistance of remelted surface increased for sintered materials, when remelted at 2.1kW. The wrought stainless steel revealed impairment of pitting corrosion when remelted at lower beam power rate.


2004 ◽  
Vol 467-470 ◽  
pp. 813-818 ◽  
Author(s):  
D.N. Wasnik ◽  
Vivekanand Kain ◽  
I. Samajdar ◽  
Bert Verlinden ◽  
P.K. De

Thermo-mechanical processing of type 304 and type 316L stainless steels done by (a) cold rolling to a reduction in thickness of 20 to 80 percent and (b) solution annealing to obtain a medium size of grains led to a considerable improvement in resistance to both sensitization and intergranular corrosion. The nature of the resultant grain boundaries was examined in a scanning electron microscope using orientation imaging microscopy in electron back scattered diffraction mode. Fraction of random and special grain boundaries were established for each set of thermo-mechanical processing. After appropriate sensitization treatments, the degrees of sensitization of these stainless steels were evaluated by double loop electrochemical potentiokinetic reactivation tests. Standard ASTM tests were used to evaluate susceptibility to intergranular corrosion (IGC) and intergranular stress corrosion cracking (IGSCC). These studies showed that a particular combination of thermomechanical processing led to formation of over 75 percent random grain boundaries in the steels and this imparted resistance to sensitization and to IGC and IGSCC. This opens a new concept in grain boundary (GB) engineering of a high fraction of random GB increasing the resistance to localized corrosion like IGC and IGSCC. Textural studies were carried out with the help of X-ray and MTM-FHM software. It showed significant change of texture in type 304 stainless steel, while no change in the texture of type 316L stainless steel after cold rolling and annealing.


2013 ◽  
Vol 794 ◽  
pp. 583-591 ◽  
Author(s):  
B. Sunil Kumar ◽  
Vivekanand Kain

In the present study macro electrochemical (anodic polarization) and micro electrochemical (scanning electrochemical microscopy (SECM) area scan measurements at passive potential) techniques have been used to study the influence of sigma phase and/or the resultant chromium depletion regions on localized corrosion behavior of aged type 2205 duplex stainless steel (DSS) in neutral chloride ion solution. DSS type 2205 was subjected to aging at 750 °C for 30 min, 10 h and 48 h. The formation and growth of the sigma phase with heat treatments was assessed by optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction. The influence of formation of sub-microscopic and bulky sigma phase on intergranular corrosion (IGC) and pitting corrosion was investigated by various electrochemical techniques including electrochemical potentiokinetic reactivation (EPR), potentiodynamic polarization and SECM. Apart from EPR tests, ASTM A 262 Practice B test was carried out to evaluate the presence of chromium depletion regions with heat treatments. The results showed that with increasing aging duration, the degree of sensitization and IGC rates initially increased and then decreased with heat treatment. The pitting potentials decreased continuously with increase in aging duration up to 10 h as assessed by potentiodynamic polarization tests. The SECM area scan measurements showed more metastable pitting corrosion events for 30 min and 10 h aged specimens compared to the 48 h aged specimen at passive potential in 0.1M neutral chloride ion solution.


Author(s):  
L.E. Murr ◽  
J.S. Dunning ◽  
S. Shankar

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.


Alloy Digest ◽  
2012 ◽  
Vol 61 (4) ◽  

Abstract Stoody AP stainless steel wires are all-position wires. The nickel in this product will achieve a good balance of austenite and ferrite in lean duplex stainless steels. This datasheet provides information on composition and tensile properties as well as fracture toughness. It also includes information on forming and joining. Filing Code: SS-1118. Producer or source: Stoody Company.


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