What is the function of the flux coating in MMAW electrodes?
• It helps to strike and maintain the arc. • It generates gases which displace the oxygen and nitrogen of the atmosphere and provide a gaseous shield around the arc to protect the molten droplets during their passage across the arc as well as the molten weld puddle. It produces slag which further protects the molten droplets in the arc and the molten weld puddle from atmospheric attack and also provides an insulating blanket over the weld bead. • It helps to deoxidize and refine the weld metal. • It helps to modify the chemistry by providing alloying elements for the weld metal, either by reducing metallic oxides or by means of powdered ferro-alloys and metals. Thereby the mechanical properties of the weld metal are also suitably modified. • It helps to control the weld bead profile and to obtain smooth weld surface with even ripples. • It helps us to reduce weld spatter. • It insulates the electrode so that it can operate at sufficiently high current without getting overheated. • It m