CHANGE THE SETTING OF THE DRYING AGENT IN THE PROCESS OF DRYING WELDING ELECTRODES COATING

Abstract

Drying agent parameters variations in the drying process of the electrodes coating and influence
of initial moisture content of coating on drying process were investigated experimentally. Dependencies
of drying agent temperature vs three main drying periods, relative humidity and dew point were graphed.
Investigations were carried out for humidity of the coating after pressuring 4.45%; 8%; 10,16 %.
We propose mechanism of formation of coating defects which is as follows: upon the process of
removal of capillary almost free moisture is superimposed a process of removal of moisture more firmly
associated with the colloidal particles of silicates.
Such moisture begins to remove at higher temperatures. With increasing temperature of the
drying agent there exists sufficiently high risk of vaporization of the capillary moisture directly in the
capillaries. Water vapor with high pressure does not manage to pass through the capillary thereby
coating can crack or peel off the surface of the whole electrode regions (swell). Increase in temperature
(to increase the intensity of the drying process) in this case besides swelling can lead to the formation of
defects in the form of circular cracks and delamination.