Electrical Signatures for Chemical Action at the Work Surface in an Oxyfuel Flame

2018 ◽  
Author(s):  
Christopher R. Martin ◽  
Joseph Kinney ◽  
Andrew Matzik ◽  
Jessica Molina
Keyword(s):  
Surface Temperature ◽  
Steel Surface ◽  
Ion Currents ◽  
Chemical Action ◽  
Dc Voltage ◽  
Work Surface

An oxyfuel cutting torch was biased with a positive DC voltage relative to steel and copper work pieces, and ion currents were seen to flow due to ions generated chemically in the flame and at the work surface. A repeatable 150% rise in these currents occurs over steel at a surface temperature around 1050°C. Equally strong intermittent spikes appear over clean and corroded steel samples alike. They are are easily removed by a median value filter, and are believed to be due to small reacting particulates. Tests in which salt was deliberately deposited on the steel surface produces a signal similar in shape, but exaggerated in magnitude to those currents supposed to be from other surface impurities.

scholarly journals Study on the effect of Weber Number to heat transfer of multiple droplets on hot stainless steel surface

2018 ◽  
Vol 154 ◽  
pp. 01114 ◽  
Author(s):  
Aria Riswanda ◽  
Indro Pranoto ◽  
Deendarlianto ◽  
Indarto ◽  
Teguh Wibowo
Keyword(s):  
Stainless Steel ◽  
Surface Temperature ◽  
Weber Number ◽  
Steel Surface ◽  
Cooling System ◽  
Spray Cooling ◽  
Stainless Steel Surface ◽  
Temperature Decrease ◽  
Evaporation Time ◽  
Decrease Rate

Multiple droplets are drops of water that continuously dropped onto a surface. Spray cooling is an application of the use of droplet on a cooling system. Spray cooling is usually used in a cooling system of electronic devices, and material quenching. In this study, correlations between Weber number and surface temperature decrease rate during multiple droplets impingement are investigated and analyzed. Visualization process is used to help determine the evaporation time of droplets impingement by using high speed camera. Induction stove is used to maintain a stainless steel surface temperature at 120°C, 140°C, and 160°C. The Weber number was varied at 15, and 52.5 to simulate low and medium Weber number. The result of this study shows that increase in Weber number does not increase the temperature decrease rate noticeably. Whereas the Weber number decrease the time required for surface temperature to reach its lowest surface temperature. It was also found that for low and medium Weber number, Weber number affect the evaporation time of multiple droplets after impingement.

The Analysis of Thermoelectric Signals in Metallic Sliding

1989 ◽  
Vol 111 (1) ◽  
pp. 114-120 ◽  
Author(s):  
Jui-Hsieh Shen ◽  
C. M. Ettles ◽  
H. A. Scarton
Keyword(s):  
Power Spectrum ◽  
Surface Temperature ◽  
Surface Topography ◽  
Temperature Rise ◽  
Signal Analysis ◽  
Steel Surface ◽  
Power Spectra ◽  
Average Temperature ◽  
Voltage Signal ◽  
Temperature Signal

The thermoelectric signal from an Alumel pin sliding over a steel surface was recorded and analyzed. The load, speed and surface topography were varied and correlations were attempted of the voltage signal against several parameters. The average temperature of the whole contact was found to agree fairly consistently with the surface temperature rise models of Blok and Archard. Of the available methods of signal analysis, the power spectrum of the voltage signal was found to give the best understanding of the micro-mechanisms of sliding, particularly when compared against the power spectra of profilometer signals. The largest component of the temperature signal was found to be caused by wavelength components equal to the extent of the contact. The correlation distance β* of the test surfaces was much less than the contact extent and contributed negligibly to the voltage signal rise.

Splat Solidification of Tin Droplets

1996 ◽  
Author(s):  
R. Bhola ◽  
S. Chandra
Keyword(s):  
Experimental Study ◽  
Stainless Steel ◽  
Simple Model ◽  
Surface Temperature ◽  
Steel Surface ◽  
Liquid Droplet ◽  
Contact Angles ◽  
Stainless Steel Surface ◽  
Splat Solidification ◽  
The Impact

Abstract An experimental study was done of the impact and solidification of tin droplets falling on a stainless steel surface. The surface temperature was varied from 25°C to 240°C. Measurements were made of droplet diameters and contact angles during droplet spread. At a surface temperature of 240°C there was no solidification, and a simple model of liquid droplet impact successfully predicted the extent of droplet spread. Droplets impacting on surfaces at 25°C and 150°C solidified before spreading was complete.

On the collision of a droplet with a solid surface

1991 ◽  
Vol 432 (1884) ◽  
pp. 13-41 ◽  
Keyword(s):  
Stainless Steel ◽  
Surface Temperature ◽  
Liquid Film ◽  
Steel Surface ◽  
Ambient Pressure ◽  
Early Period ◽  
Metallic Surface ◽  
Stainless Steel Surface ◽  
Droplet Shape ◽  
The Impact

The collision dynamics of a liquid droplet on a solid metallic surface were studied using a flash photographic method. The intent was to provide clear images of the droplet structure during the deformation process. The ambient pressure (0.101 MPa), surface material (polished stainless steel), initial droplet diameter (about 1.5 mm), liquid (n-heptane) and impact Weber number (43) were fixed. The primary parameter was the surface temperature, which ranged from 24°C to above the Leidenfrost temperature of the liquid. Experiments were also performed on a droplet impacting a surface on which there existed a liquid film created by deposition of a prior droplet. The evolution of wetted area and spreading rate, both of a droplet on a stainless steel surface and of a droplet spreading over a thin liquid film, were found to be independent of surface temperature during the early period of impact. This result was attributed to negligible surface tension and viscous effects, and in consequence the measurements made during the early period of the impact process were in good agreement with previously published analyses which neglected these effects. A single bubble was observed to form within the droplet during impact at low temperatures. As surface temperature was increased the population of bubbles within the droplet also increased because of progressive activation of nucleation sites on the stainless steel surface. At surface temperatures near to the boiling point of heptane, a spoke-like cellular structure in the liquid was created during the spreading process by coalescence of a ring of bubbles that had formed within the droplet. At higher temperatures, but below the Leidenfrost point, numerous bubbles appeared within the droplet, yet the overall droplet shape, particularly in the early stages of impact (< 0.8 ms), was unaffected by the presence of these bubbles. The maximum value of the diameter of liquid which spreads on the surface is shown to agree with predictions from a simplified model.

Polishing and Lapping Temperatures

1997 ◽  
Vol 119 (1) ◽  
pp. 163-170 ◽  
Author(s):  
Vispi H. Bulsara ◽  
Yoomin Ahn ◽  
Srinivasan Chandrasekar ◽  
Thomas N. Farris
Keyword(s):  
Heat Flux ◽  
Surface Temperature ◽  
Temperature Rise ◽  
Abrasive Particle ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Average Temperature ◽  
Work Surface ◽  
Mechanistic Analysis ◽  
Finishing Process

Polishing is a finishing process in which a smooth work surface is produced by rubbing it against a polishing block with an abrasive slurry interspersed between them. A model has been developed to estimate the temperature rise of the work surface in polishing. In this model, the forces acting on an abrasive particle are derived from a mechanistic analysis of abrasive-workpiece contacts. The heat generated at a contact is taken as the product of the friction force and the relative sliding velocity between the abrasive and the work surface. For calculating the heat flux transferred into the workpiece, each of the abrasive-workpiece contacts is modeled as a hardness indentation of the work material by a conical indenter. The moving heat source analyses of Jaeger and Blok are then applied to estimate the fraction of the heat flux flowing into the workpiece, and the maximum and average temperature rise of the work surface. Calculations of the work surface temperature rise are made for the polishing of steel, soda-lime glass, and ceramics. These show that the work surface temperature rise in polishing is quite small, typically much less than 200°C, and substantially less than in grinding. The low values calculated for the work surface temperature rise are shown to be consistent with many observations pertaining to the mechanical state of polished surfaces. The effect of polishing process variables on the work surface temperature rise is analyzed.

EELS characterization of “Smut” layer films on steel surface prepared for chrome plating by anodic etching

1995 ◽  
Vol 53 ◽  
pp. 538-539
Author(s):  
E Y. Wang ◽  
J. T. Cherian ◽  
A. Madsen ◽  
R. M. Fisher
Keyword(s):  
Steel Surface ◽  
Surface Preparation ◽  
Treatment Method ◽  
Chrome Plating ◽  
Transmission Electron ◽  
Alloy Steels ◽  
Pre Treatment ◽  
Hard Chrome ◽  
Electron Energy Loss

Many steel parts are electro-plated with chromium to protect them against corrosion and to improve their wear-resistance. Good adhesion of the chrome plate to the steel surface, which is essential for long term durability of the part, is extremely dependent on surface preparation prior to plating. Recently, McDonnell Douglas developed a new pre-treatment method for chrome plating in which the steel is anodically etched in a sulfuric acid and hydrofluoric acid solution. On carbon steel surfaces, this anodic pre-treatment produces a dark, loosely adhering material that is commonly called the “smut” layer. On stainless steels and nickel alloys, the surface is only darkened by the anodic pre-treatment and little residue is produced. Anodic pre-treatment prior to hard chrome plating results in much better adherence to both carbon and alloy steels.We have characterized the anodic pre-treated steel surface and the resulting “smut” layer using various techniques including electron spectroscopy for chemical analysis (ESCA) on bulk samples and transmission electron microscopy (TEM) and electron energy-loss spectroscopy (EELS) on stripped films.

Chemical Action in a Magnetic Field

1881 ◽  
Vol 12 (293supp) ◽  
pp. 4675-4676
Author(s):  
Ira Remsen
Keyword(s):  
Magnetic Field ◽  
Chemical Action
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