Observation on Molton Slag of Welding

Abstract

It is a very valuable subject to study how at ease we can weld or operate with a specific welding electrode, and there may be many different opinions as to the factors of "USABILITY" of welding electrode, if we so call it.
We have tried to clarify such factors of "usability" of welding electrode, though with difficulties, and according to our investigations it is considered that "fluidity of slag" (fluid condition of slag), amongall, has very close relations with the usability of welding electrode.
One of our investigations about the usability, therefore, has been directed to the molten slag of welding.
For this purpose we took a 50-frames-per second 16 mm colour film, to closely observe the fluid condition of welding molten slag. The several electrodes with typical types of coating, i.e. iluminite, high cellulose, rutile, low hydrogen, high iron oxide and iron powder, and some other electrodes on the market were presented for filming.
In these photographs, the characteristics of each molten slag in its fluidification and solification called our great interest. Especially, rutile and low hydrogen type electrodes showed the extremes in fluidity.
Furthermore, using the low hydrogen type electrode which are not so good in usability, the aspect of molten slag was found as remarkably distinguished from the others.
We thus could reach a conclusion that the fluid conditions of molten slag was connected with physi-cal properties, such as viscosity, surface tension and specific gravity at various temperatures, and also with the solidificable and the fluidable temperature.
The ESAB OK-53P double coated electrode is known as being able to effect the complete "back wave welding" without back sealing run on the Vee Groove joint. This complete back wave welding could also be well understood by observing the specific feature of the aspects of the molten slag in our movie.