Showing papers by "Arnold R. Marder published in 1995"
Journal Article•
TL;DR: In this paper, a study was conducted on the arc and melting efficiency of the plasma arc, gas tungsten, gas metal arc, and submerged arc welding processes using A36 steel base metal, and the results were extended to develop a quantitative method for estimating weld metal dilution.
Abstract: A study was conducted on the arc and melting efficiency of the plasma arc, gas tungsten arc, gas metal arc, and submerged arc welding processes The results of this work are extended to develop a quantitative method for estimating weld metal dilution in a companion paper Arc efficiency was determined as a function of current for each process using A36 steel base metal Melting efficiency was evaluated with variations in arc power and travel speed during deposition of austenitic stainless steel filler metal onto A36 steel substrates The arc efficiency did not vary significantly within a given process over the range of currents investigated The consumable electrode processes exhibited the highest arc efficiency (084), followed by the gas tungsten arc (067) and plasma arc (047) processes Resistive heating of the consumable GMAW electrode was calculated to account for a significant difference in arc efficiency between the gas metal arc and gas tungsten arc processes A semi-empirical relation was developed for the melting efficiency as a function of net arc power and travel speed, which described the experimental data well An interaction was observed between the arc and melting efficiency A low arc efficiency factor limits the power delivered to the substrate which, in turn, limits the maximum travel speed for a given set of conditions High melting efficiency is favored by high arc powers and travel speeds As a result, a low arc efficiency can limit the maximum obtainable melting efficiency
242 citations
TL;DR: In this paper, the undercooling required for eutectic nucleation was measured using differential scanning calorimetry for Al-Zn alloys containing 2-8 wt% Al.
Abstract: The undercooling required for eutectic nucleation was measured using differential scanning calorimetry for Al-Zn alloys containing 2–8 wt% Al. While an average undercooling of only 0.25°C was required for the nucleation of Zn by proeutectic Al, an undercooling of 4.0°C was necessary for the nucleation of Al by primary Zn. The non-reciprocal nucleation characteristics of this system results in the formation of Zn halos around proeutectic Al dendrites and a difference in the eutectic structure when comparing hypo- to hypereutectic alloys in terms of interlamellar spacing, second phase volume fraction, and eutectic morphology.
47 citations
TL;DR: In this article, a criterion for selecting weld overlay coatings for erosion mitigation in circulated fluidized beds (CFBs) was developed, and 11 weld overlay alloys were deposited on 1018 steel substrates using the plasma arc welding process and erosion tested at 400°C.
38 citations
TL;DR: In this paper, a series of erosion tests were performed to determine the erosivity of several different circulating fluidized bed materials, including boiler tube steel, and they measured the shape of the particles using a quantitative image analysis system and it was found that particle shape changed with the size fraction of the bed particles.
13 citations
TL;DR: In this paper, six epoxy-based coating systems were tested for their resistance to degradation in the form of "cold-wall" blistering on type 1010 steel (UNS G10100) substrates.
Abstract: Six epoxy-based coating systems were tested for their resistance to degradation in the form of “cold-wall” blistering. The coatings were applied to type 1010 steel (UNS G10100) substrates ...
13 citations
TL;DR: In this paper, a simulation procedure for reproducing high-temperature cracks found in coalfired boiler tubes was developed based on an intergranular corrosion/thermal stress interactive initiation mechanism and an environmentally assisted fatigue crack propagation mechanism.
6 citations
01 Jan 1995
TL;DR: In this article, a criterion for selecting weld overlay coatings for erosion mitigation in circulated fluidized beds (CFBs) was developed, and 11 weld overlay alloys were deposited on 1018 steel substrates using the plasma arc welding process and erosion tested at 400 “C".
Abstract: Research was conducted to develop a criterion for selecting weld overlay coatings for erosion mitigation in circulated fluidized beds (CFBs). Initially, 11 weld overlay alloys were deposited on 1018 steel substrates using the plasma arc welding process and erosion tested at 400 “C. Erosion resistance was evaluated by determining the steady state erosion rate, and the microstructure of each coating was characterized before erosion testing. The steady state erosion rates for several weld overlay coatings (Ultimet, Inconel-625 and 316L SS) were considerably lower than the other coatings evaluated (Armacor-M, B-60, TS-2, Stellite-6, Hastelloy-22, high Cr iron and 420 SS). No correlations were found between the room temperature hardness of the weld overlay coatings and their erosion resistance at elevated temperature. Microhardness tests were performed on the eroded samples below the erosion surface in order to determine the size of the plastically deformed zone, and it was found that some coatings deformed plastically as a result of erosion while others did not. Possible erosion mechanisms for these groups of coatings were analyzed.