The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform

Vinod Kumar - One of the best experts on this subject based on the ideXlab platform.

  • optimization of weld bead width in tungsten inert gas welding of austenitic Stainless Steel Alloy
    American journal of mechanical engineering, 2014
    Co-Authors: Vinod Kumar
    Abstract:

    This paper investigates the effects of process parameters on weld bead width of austenitic Stainless Steel SS-310 in tungsten inert gas welding. The four parameters namely welding current, type of gas, gas flow rate and included angle of weld plates during butt joint were varied at three levels. The DOE approach was used to design experimental conditions. Orthogonal array L9 was used for carrying out experimentation. The optimization of weld bead width in tungsten inert gas welding of austenitic Stainless Steel Alloy was done using ANOVA. The minimum value of bead width of SS 310 is 8.27 mm at current value 130A.

Michael P. Brady - One of the best experts on this subject based on the ideXlab platform.

  • Pre-oxidized and nitrided Stainless Steel Alloy foil for proton exchange membrane fuel cell bipolar plates. Part 2: Single-cell fuel cell evaluation of stamped plates
    Journal of Power Sources, 2010
    Co-Authors: Todd J. Toops, Michael P. Brady, Peter F. Tortorelli, Josh A. Pihl, Francisco Estevez, Daniel Connors, Fernando H. Garzon, Tommy Rockward, Don Gervasio, William Mylan
    Abstract:

    Abstract Thermal (gas) nitridation of Stainless Steel Alloys can yield low interfacial contact resistance (ICR), electrically conductive and corrosion-resistant nitride containing surface layers (Cr2N, CrN, TiN, V2N, VN, etc.) of interest for fuel cells, batteries, and sensors. This paper presents results of proton exchange membrane (PEM) single-cell fuel cell studies of stamped and pre-oxidized/nitrided developmental Fe–20Cr–4V weight percent (wt.%) and commercial type 2205 Stainless Steel Alloy foils. The single-cell fuel cell behavior of the stamped and pre-oxidized/nitrided material was compared to as-stamped (no surface treatment) 904L, 2205, and Fe–20Cr–4V Stainless Steel Alloy foils and machined graphite of similar flow field design. The best fuel cell behavior among the Alloys was exhibited by the pre-oxidized/nitrided Fe–20Cr–4V, which exhibited ∼5–20% better peak power output than untreated Fe–20Cr–4V, 2205, and 904L metal stampings. Durability was assessed for pre-oxidized/nitrided Fe–20Cr–4V, 904L metal, and graphite plates by 1000+ h of cyclic single-cell fuel cell testing. All three materials showed good durability with no significant degradation in cell power output. Post-test analysis indicated no metal ion contamination of the membrane electrode assemblies (MEAs) occurred with the pre-oxidized and nitrided Fe–20Cr–4V or graphite plates, and only a minor amount of contamination with the 904L plates.

  • Pre-oxidized and nitrided Stainless Steel Alloy foil for proton exchange membrane fuel cell bipolar plates: Part 1. Corrosion, interfacial contact resistance, and surface structure
    Journal of Power Sources, 2010
    Co-Authors: Michael P. Brady, Peter F. Tortorelli, Heli Wang, John A. Turner, Harry M. Meyer, Karren L. More, Brian D. Mccarthy
    Abstract:

    Abstract Thermal (gas) nitridation of Stainless Steel Alloys can yield low interfacial contact resistance (ICR), electrically conductive and corrosion-resistant nitride containing surface layers (Cr 2 N, CrN, TiN, V 2 N, VN, etc.) of interest for fuel cells, batteries, and sensors. This paper presents results of scale-up studies to determine the feasibility of extending the nitridation approach to thin 0.1 mm Stainless Steel Alloy foils for proton exchange membrane fuel cell (PEMFC) bipolar plates. Developmental Fe–20Cr–4V Alloy and type 2205 Stainless Steel foils were treated by pre-oxidation and nitridation to form low-ICR, corrosion-resistant surfaces. As-treated Fe–20Cr–4V foil exhibited target (low) ICR values, whereas 2205 foil suffered from run-to-run variation in ICR values, ranging up to 2× the target value. Pre-oxidized and nitrided surface structure examination revealed surface-through-layer-thickness V-nitride particles for the treated Fe–20Cr–4V, but near continuous chromia for treated 2205 Stainless Steel, which was linked to the variation in ICR values. Promising corrosion resistance was observed under simulated aggressive PEMFC anode- and cathode-side bipolar plate conditions for both materials, although ICR values were observed to increase. The implications of these findings for stamped bipolar plate foils are discussed.

  • Growth of Cr-Nitrides on commercial Ni–Cr and Fe–Cr base Alloys to protect PEMFC bipolar plates
    International Journal of Hydrogen Energy, 2007
    Co-Authors: Michael P. Brady, Heli Wang, John A. Turner, B. Yang, Mélanie Bordignon, Régine Molins, M. Abd Elhamid, L. Lipp, L.r. Walker
    Abstract:

    Nitridation of Cr-bearing Alloys can yield low interfacial contact resistance (ICR), electrically conductive and corrosion-resistant CrN or Cr2N base surfaces of interest for a range of electrochemical devices, including fuel cells, batteries, and sensors. This paper presents results of exploratory studies of the nitridation of commercially available, high Cr (30–35 wt%) Ni–Cr Alloys and a ferritic high Cr (29 wt%) Stainless Steel for proton exchange membrane fuel cell (PEMFC) bipolar plates. A high degree of corrosion resistance in sulfuric acid solutions designed to simulate bipolar plate conditions and low ICR values were achieved. Oxygen impurities in the nitriding environment were observed to play a significant role in the nitrided surface structures that formed, with detrimental effects for the Ni–Cr base Alloys, but beneficial effects for the Stainless Steel Alloy. Positive results from single-cell fuel cell testing are also presented.

Korukonda L. Murty - One of the best experts on this subject based on the ideXlab platform.

Geunhong Jeon - One of the best experts on this subject based on the ideXlab platform.

  • gas tungsten arc welding assisted hybrid friction stir welding of dissimilar materials al6061 t6 aluminum Alloy and sts304 Stainless Steel
    Materials & Design, 2012
    Co-Authors: Hansur Bang, Heeseon Bang, Geunhong Jeon
    Abstract:

    Abstract The aim of this research is to evaluate the potential for using the gas tungsten arc welding (GTAW) assisted hybrid friction stir welding (HFSW) process to join a Stainless Steel Alloy (STS304) to an aluminum Alloy (Al6061) in order to improve the weld strength. The difference in mechanical and microstructural characteristics of dissimilar joint by friction stir welding (FSW) and HFSW has been investigated and compared. Transverse tensile strength of approximately 93% of the aluminum Alloy (Al6061) base metal tensile strength is obtained with HFSW, which is higher than the tensile strength of FSW welds. This may be due to the enhanced material plastic flow and partial annealing effect in dissimilar materials due to preheating of Stainless Steel surface by GTAW, resulting in significantly increased elongation of welds. The results indicate that HFSW that integrates GTAW preheating to FSW is advantageous in joining dissimilar combinations compared to conventional FSW.

Dev Chidambaram - One of the best experts on this subject based on the ideXlab platform.

  • The effect of Li0 on the corrosion of Stainless Steel Alloy 316L exposed to molten LiCl-Li2O-Li
    Corrosion Science, 2017
    Co-Authors: Augustus Merwin, Dev Chidambaram
    Abstract:

    Abstract A knowledge gap exists in our understanding of corrosion of Alloys in molten LiCl-Li2O-Li. Coupons of Stainless Steel Alloy 316L were exposed to LiCl-Li2O solutions containing up to 1 wt%Li. A protective surface films of LiCrO2 forms in molten solutions containing up to 0.4 wt%Li. The surfaces of samples exposed to melts containing greater than 0.4 wt% Li were observed to be depleted of Cr and mostly devoid of oxides. Results indicate that material interactions with the LiCl-Li2O-Li system are governed by electrochemical oxidation phenomena when the Li concentration is low, while liquid metal effects dominate when the Li concentration is high.

  • Alternate Anodes for the Electrolytic Reduction of UO 2
    Metallurgical and Materials Transactions A, 2014
    Co-Authors: Augustus Merwin, Dev Chidambaram
    Abstract:

    The electrolytic reduction process of UO2 employs a platinum anode and a Stainless Steel cathode in molten LiCl-LiO2 maintained at 973 K (700 °C). The degradation of platinum under the severely oxidizing conditions encountered during the process is an issue of concern. In this study, Inconel 600 and 718, Stainless Steel Alloy 316, tungsten, nickel, molybdenum, and titanium, were investigated though electrochemical polarization techniques, electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy to serve as potential anode materials. Of the various materials investigated, only tungsten exhibited sufficient stability at the required potential in the molten electrolyte. Tungsten anodes were further studied in molten LiCl-LiO2 electrolyte containing 2, 4, and 6 wt pct of Li2O. In LiCl-2 wt pct Li2O tungsten was found to be sufficiently stable to both oxidation and microstructural changes and the stability is attributed to the formation of a lithium-intercalated tungsten oxide surface film. Increase in the concentration of Li2O was found to lead to accelerated corrosion of the anode, in conjunction with the formation of a peroxotungstate oxide film.