Manual Metal Arc (MMA) Weld Deposition
In this process, an arc is drawn between a coated consumable electrode and the workpiece. The metallic core is melted by the arc and is transferred to the weld pool as molten droplets. The electrode coating also melts to form a gas shield around the arc and the weld pool as well asa slag on the surface of the weld pool, thus protecting the cooling weld-pool from the atmosphere. The slag must be removed after each layer. MMA welding is still a widely used hardfacing process. Due to the low cost of the equipment, the low operating costs of the process, and the ease of transporting the equipment, this flexible process is ideally suited to repair work.
Electrodes are available in these standard diameters:
- 2,6 mm (special order)
- 3,2 mm
- 4,0 mm
- 5,0 mm
- 6,4 mm
Electrodes are supplied in lengths of 350mm (14”) and are boxed in 5.0 kg boxes.
Depending upon the process parameters, the hardness of the welded deposit can vary from the values provided in the table above.