The Laser Cleaning Process for the Removal of Surface Corrosion Developed over One Year on Stainless Steel SS304

2020 ◽  
Vol 4 (2) ◽  
Author(s):  
R. Linggamm ◽  
M. M. Quazi ◽  
M. H. Aiman ◽  
J. Farzad ◽  
M. Nasir Bashir
Keyword(s):  
Stainless Steel ◽  
Laser Cleaning ◽  
Cleaning Process ◽  
Surface Corrosion ◽  
One Year

scholarly journals Real-Time Monitoring of Laser Cleaning for Hot-Rolled Stainless Steel by Laser-Induced Breakdown Spectroscopy

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 790
Author(s):  
Xing Li ◽  
Yingchun Guan
Keyword(s):  
Stainless Steel ◽  
Emission Line ◽  
Real Time ◽  
Oxide Layer ◽  
Laser Cleaning ◽  
Laser Induced Breakdown Spectroscopy ◽  
Cleaning Process ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown ◽  
Hot Rolled

Laser cleaning is a competitive alternative to ablate and remove the hard oxide layer on hot-rolled stainless steel. To meet the practical demand, laser-induced breakdown spectroscopy (LIBS) was applied for real-time monitoring of the cleaning process in this study. Furthermore, the as-received and laser cleaned surfaces were characterized by an optical micrograph, an X-ray diffractometer, and a laser scanning confocal microscope. The results showed the relative intensity ratio (RIR) of the FeI emission line at 520.9 nm and the CrI emission line at 589.2 could be a quantitative index to monitor the cleaning process. When the oxide layer was not fully cleaned, the LIBS signals of the substrate were not excited, and the ratio was almost invariant as the power of the laser increased. However, it sharply increased once the oxide layer was effectively cleaned, the cleaned surface was bright, and the surface roughness was smaller in this case. Subsequently, as the surface was over-cleaned with the further increase of laser power, the RIR value remained large. The optimal laser cleaning parameters obtained by the monitoring were determined to avoid re-oxidation and reduce the roughness of the cleaned surface.

Evaluation of Mandibular Arch Width Changes following Fixed Retention in Post Orthodontic Patients - a Randomized Clinical Trial

2020 ◽  
Author(s):  
Nasreen Iqbal Nagani
Keyword(s):  
Stainless Steel ◽  
Steel Wire ◽  
P Value ◽  
Chi Square ◽  
Mandibular Arch ◽  
Arch Width ◽  
Orthodontic Patients ◽  
Mean Differences ◽  
One Year ◽  
The Stability

Background: Retention is an integral phase in which teeth are maintained in their newly adapted position for which retainers are inserted. Retainers are generally of two types: removable and fixed. Fixed retainers are indicated in the mandibular arch for an indefinite period specifically in the non-extraction cases. Changes in intercanine and intermolar widths are valuable parameters to evaluate the stability. The objectives of this study were to assess and compare the mandibular intercanine and intermolar width changes following orthodontic treatment after insertion of two types of fixed lingual retainers for one year. Methods: Total 54 subjects were recruited in which two types of fixed lingual retainers were inserted in the mandibular arch randomly. Intercanine and intermolar arch widths were measured by digital caliper of 0.01 mm accuracy. Data was analyzed by using Statistical Package of Social Sciences (SPSS V-21). Chi-square and independent t tests were used to compare baseline characteristics. Intercanine and intermolar widths were assessed and compared using independent t test, p-value ≤ 0.05 is considered as statistically significant. Results: Intercanine width increased from baseline to T4 in both retainers. When mean differences of intercanine width were compared between two retainers significant differences were observed at T1, T2, T3 and T4 with significant p-values (< 0.05) and increased intercanine width with multistranded stainless steel wire (MSW) retainers. Conclusion: Mandibular intercanine width increases significantly in post retention phase with multistranded stainless steel retainers. Thus, fiber reinforced composite retainers are more effective in preserving the arch width changes.

scholarly journals Direct-Contact Cytotoxicity Evaluation of CoCrFeNi-Based Multi-Principal Element Alloys

2018 ◽  
Vol 9 (4) ◽  
pp. 59 ◽  
Author(s):  
Ryan Newell ◽  
Zi Wang ◽  
Isabel Arias ◽  
Abhishek Mehta ◽  
Yongho Sohn ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Direct Contact ◽  
Orthopedic Implants ◽  
Cell Number ◽  
In Vitro Cytotoxicity ◽  
Principal Element ◽  
Surface Corrosion ◽  
Alamarblue Assay ◽  
Control Samples

Transition metal multi-principal element alloys (MPEAs) are novel alloys that may offer enhanced surface and mechanical properties compared with commercial metallic alloys. However, their biocompatibility has not been investigated. In this study, three CoCrFeNi-based MPEAs were fabricated, and the in vitro cytotoxicity was evaluated in direct contact with fibroblasts for 168 h. The cell viability and cell number were assessed at 24, 96, and 168 h using LIVE/DEAD assay and alamarBlue assay, respectively. All MPEA sample wells had a high percentage of viable cells at each time point. The two quaternary MPEAs demonstrated a similar cell response to stainless steel control with the alamarBlue assay, while the quinary MPEA with Mn had a lower cell number after 168 h. Fibroblasts cultured with the MPEA samples demonstrated a consistent elongated morphology, while those cultured with the Ni control samples demonstrated changes in cell morphology after 24 h. No significant surface corrosion was observed on the MPEAs or stainless steel samples following the cell culture, while the Ni control samples had extensive corrosion. The cell growth and viability results demonstrate the cytocompatibility of the MPEAs. The biocompatibility of MPEAs should be investigated further to determine if MPEAs may be utilized in orthopedic implants and other biomedical applications.

Development of Laser Cleaning for Metallic Equipment

2018 ◽  
Author(s):  
L. Carvalho ◽  
W. Pacquentin ◽  
M. Tabarant ◽  
J. Lambert ◽  
A. Semerok ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Laser Scanning ◽  
Surface Defects ◽  
Complex Geometry ◽  
Laser Cleaning ◽  
304L Stainless Steel ◽  
Primary Coolant ◽  
Aisi 304L ◽  
Weight Percentage ◽  
Aisi 304L Stainless Steel

Laser cleaning study was performed on prepared samples using a nanosecond pulsed ytterbium fiber laser. To prepare samples, AISI 304L stainless steel samples were oxidized and implemented with non-radioactive contaminants in a controlled manner. In order to validate the cleaning process for metallic equipment polluted in nuclear installations, two types of contamination with europium (Eu) and with cobalt (Co) were studied. Eu was used as a simulator-product resulting from uranium fission, while Co — as an activation-product of nickel, which is a composing element of a primary coolant system of a reactor. The oxide layers have suffered laser scanning which was followed by the furnace treatment to obtain thicknesses in the range of 100 nm to 1 μm depending on the oxidation parameters [1] with a mean weight percentage of 1% of Eu and 1 % of Co in the volume of the oxide layer. Glow Discharge Optical Emission (GD-OES) and Mass Spectrometry (GD-MS) analyses have been performed to assess the efficiency of the cleaning treatment and to follow the distribution of residual contamination with a detection limit of 0.1mg/kg of Eu and Co. Decontamination rates up to 95.5 % were obtained. One of the identified reasons for this limitation is that the radionuclides are trapped in surface defects like micro cracks [2, 3]. Therefore, cleaning treatments have been applied on surface defects with controlled geometry and a micrometric aperture obtained by laser engraving and juxtaposition of polished sheets of AISI 304L stainless steel. The goal of this study is surface decontamination without either welding or inducing penetration of contamination into the cracks. GD-MS analysis and Scanning Electron Microscopy (SEM) were performed to analyze the efficiency of the treatment and the diffusion of contaminants in this complex geometry.

scholarly journals Efficiency and safety of using a peritoneal dialysis catheter weighted with a stainless steel ballast : the Limousin experience

2019 ◽  
Vol 2 (4) ◽  
pp. 193-200
Author(s):  
Bénédicte Larivière-Durgueil ◽  
Rémi Boudet ◽  
Marie Essig ◽  
Stéphane Bouvier ◽  
Ali Abdeh ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Peritoneal Dialysis ◽  
Infectious Complications ◽  
Control Group ◽  
Peritoneal Dialysis Catheter ◽  
Causal Factors ◽  
Catheter Migration ◽  
Mechanical Complications ◽  
Increased Risk ◽  
One Year

Objective: To assess the recurrence of PD catheter migration after the introduction of a walnut ballast. Materials and Methods: Retrospective study from 1999 to 2014 of PD patients followed in Limousin. Were compared two groups: ballast group (patients who benefited from the establishment of stainless steel ballast at the intraperitoneal catheter extremity) with 26 patients and control group with 204 patients. The primary endpoint was the occurrence of an episode catheter’s migration after ballast’s establishment. Secondary objectives were (i) to determine the causal factors leading to the catheter weighting, (ii) to ensure the safety of the procedure on the following criteria: infectious complications, mechanicals complications, epurations criteria, and catheter’s survival. Results: More than one year after the implementation of the ballast, no recurrent migration was observed in 86.6% of cases. It wasn’t found an increased risk of infections (OR = 0.5, 95% CI [0.22, 1.13]) or mechanical complications (OR = 1.77- 95% CI [0.77, 4.05]) between the two groups. The adequation criteria were similar: KT / V total : 2.37 in the control group and 2.28 in the ballast group (p = 0.63). The survival of the ballast catheter was comparable among the two groups (p = 0.983). Three causal factors that led to the ballast were identified: automated peritoneal dialysis (APD) (OR = 0.38, 95% CI [0.16, 0.9]), the failure from the first use of the catheter (OR = 19.48, CI 95 % [7.67, 49.48]) and the incarceration of the omentum (OR = 15.84, 95% CI [5.81, 43.21]). Conclusion: The ballast used in these study appears to prevent recurrence of migration, without any impact in terms of infectious or mechanical complications, or on the dialysis criteria or on catheter’s survival. However this catheter does currently not have an EC authorization

Surface Characterization of Incoloy 825 Ni-Based Alloy/2507 Super Duplex Stainless Steel Dissimilar Friction Stir Welds

CORROSION ◽  
10.5006/2755 ◽  
2018 ◽  
Vol 74 (11) ◽  
pp. 1259-1271 ◽  
Author(s):  
Jalal Kangazian ◽  
Morteza Shamanian ◽  
Ali Ashrafi
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Surface Characterization ◽  
Electrochemical Impedance ◽  
Friction Stir Weld ◽  
General Corrosion ◽  
Super Duplex Stainless Steel ◽  
Friction Stir ◽  
Surface Corrosion ◽  
Incoloy 825

Surface features of a dissimilar friction stir weld between Incoloy 825 Ni-based alloy and SAF 2507 super duplex stainless steel were investigated using scanning electron microscopy, microhardness test, cyclic potentiodynamic polarization, and electrochemical impedance spectroscopy. The surface of the weldment showed lower general corrosion resistance in comparison to the base metals. Areas under the weld shoulder exhibited weak pitting resistance because of the deformed structure and/or chromium nitride precipitates. Incoloy 825 located under the shoulder also displayed the highest susceptibility to pit growth because of the austenite matrix containing titanium nitride phases. Overall, the obtained results demonstrated that the friction stir welding method could significantly deteriorate the surface corrosion behavior of the processed regions.

scholarly journals Effect of Heat Treatment on the Microstructure and Corrosion Resistance of Stainless/Carbon Steel Bimetal Plate

2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Hao Li ◽  
Liyuan Zhang ◽  
Boyang Zhang ◽  
Qingdong Zhang
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Carbon Steel ◽  
Carbon Content ◽  
Carbon Diffusion ◽  
Annealing Process ◽  
Stainless Steel Surface ◽  
Surface Corrosion ◽  
Annealing Conditions

In order to research the effect of heat treatment on the microstructure and corrosion resistance of stainless/carbon steel bimetal plate, the annealing process at 700°C with different times was carried out for stainless/carbon steel bimetal plate. Because the carbon content of carbon steel was higher than that of stainless steel, the carbon would diffuse from carbon steel to stainless steel in the bimetal plate during the annealing process. The carbon diffusion would cause the thickness of the decarburized layer in carbon steel and the carbon content of stainless steel to increase. The carbon diffusion would be ongoing with the annealing process until the carbon content of stainless steel reached 0.08%. The higher carbon content could help in the formation of more chromium-depleted regions in the stainless steel surface, causing the stainless steel in the bimetal plate to have a poorer surface corrosion resistance than that of stainless steel under the same annealing conditions.

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