Q. Which functions used for coating?

• Improves arc stability by providing certain chemical which have this ability, by ionizing the path of arc.
• Provides a protective gaseous atmosphere to prevent O2, H2 and N2 pick-up by the molten metal.
• Provides a protective slag over hot metal.
• Provides flux, which helps to remove oxides and other impurities from the molten weld metal.
• Reduces spatter of weld metal- when coating burns off slower than core.
• Acts as deoxidizers.
• Adds alloying elements.
• Increases deposition efficiency.
• Slows down the cooling rate of weld (due to protective layer of slag) to prevent hardening.
• Coatings are normally insulators of electricity and so permit the use pf electrodes in narrow grooves etc.