Welding electrode coating of any type (rutile, cellulose, basic, or other) has a porous structure, which makes it very good at absorbing moisture from the ambient medium. Therefore, if electrodes are stored in sealed packaging or without packaging at all, the amount of moisture in the coating gradually increases, which leads to deteriorated mechanical properties and subsequent failure thereof.
Welding with the use of such electrodes is challenging, because the uncoated rod constantly sticks to the metal, and primary ignition becomes difficult which may cause unsteady arc burning. In order to avoid these adverse effects, the electrodes should be pre-dried at the averaged temperature of 100 degrees Celsius for 1.5–2 hours.
Electrode Calcination Process
Calcination is a process of heat treatment of electrodes that is performed at temperatures considerably higher than the drying temperature. Electrodes undergo primary calcination at production site. If an electrode becomes damp during storage, drying is normally required first and followed by calcination.
GlobeCore Electrode Drying and Calcination Technology
GlobeCore has implemented a versatile electrode calcination and drying technology, which is implemented in an SSC drying oven with a total charge of 130 cubic decimeters.
In terms of design, the SSC welding electrode drying unit constitutes a compact oven wherein drying is facilitated by precise heating and subsequent cooling. The housing of the welding electrode drying oven is made of plate steel and thermally insulated which allows to sustain heat inside. The heating elements are installed on both sides of the drying oven, and the convection system ensures uniform distribution of hot air throughout the oven.
The drying temperature is set by the operator based on the temperature recommended for the specific electrode coating and is maintained automatically thereafter.
Optimized Drying and Calcination Performance
The welding electrode drying oven design allows speeding up the drying process by spreading the electrodes on the surface of drip trays with each placed in its own cell for drying. In addition to heating, the SSC oven can also operate in blowing mode, which improves the drying process.
Drying and calcination using the GlobeCore technology allows you to achieve the required operational performance of electrodes, to avoid sticking of electrodes, to ensure steady arc burning, to obtain the uniform and high-quality weld formation, to ensure high-quality primary and secondary ignition, and to restore the electrodes that have been impaired due to improper storage.
In order to reduce the likelihood of environmental exposure of electrodes, GlobeCore recommends storing them in vacuum bags, and placing the bags in one large package.