| الوصف: |
The energy- and material-saving one-sided welding process is limited by the liquid metal leakage from the pool and the undercuts formation, which leads to the welded joints impact strength a decrease. Therefore, the one-sided high-speed welding development, which ensures the welded joints impact toughness increase, is the important scientific and technical problem. The effective way to increase the welded joints impact toughness is to increase the welding and crystallization speed, which is limited by the undercuts formation, the nature of which has not been fully established. Based on the welding current magnetic field during one-sided welding, a study it was established that with increasing welding speed, the induction in the arc front does not depend on the welding speed, the arc behind it decreases, and in the fusion zone, where undercuts are formed, it increases. It has been established that the magnetic field induction in the fusion zone during welding speed,increasing due to the heat amount in the side edges a decrease, electrical resistance a decrease and the current flowing through the pool edges an increase. Induction determines the magnetic pressure on the metal in the fusion zone. As the welding speed increases, the downward magnetic pressure increases, under the influence of which liquid metal flows from the pool edges, which leads to the undercuts formation. The undercut formation electromagnetic theory has been developed, according to which, with increasing welding speed, the active spots cooling increases, the arc is concentrated and the heat input into the pool side edges, the electrical resistance of which decreases, is reduced. As a result, the current, flowing through the pool side edges the magnitude, increases, the magnetic field induction and, in a quadratic dependence, the magnetic pressure, under the influence of which the liquid metal flows from the pool edges increases,which leads to the undercuts formation. The undercuts formation electromagnetic theory is confirmed by the fact that ... |