Design of complex shape, as a rule, receive the combination of individual elements (components, assemblies) with detachable or permanent joints. Welding – the process of obtaining permanent link through the establishment of atomic bonds between the welded parts at their local or general heating, or plastic deformation, or the joint action of both. Permanent joints made using welding, welded joints are called. By welding connecting parts mainly made of metal. However, welded connections are used for parts made of non-metals – plastics and ceramics, or combinations thereof, for this type of welding is required other than the welding of metal welding oborudvanie. To get the weld does not require any special elements (rivets, plates, etc.). The connection is due to the formation of bonds between the atoms of the joined parts. For the weld metal is characterized by the appearance of the metallic bond, due to the interaction of electrons and ions are socialized lattice.
When welding of ceramics with metals or each increase in the proportion of covalent or ionic components of communication. To obtain a welded joint is not enough to touch the surfaces of connected components, it is necessary to use welding oborudvanie. Interatomic bonds are established only when the atoms joined parts get some extra energy necessary to overcome existing between the energy barrier. This energy called the activation energy. When welding, it is introduced into the joint area from outside by heating (thermal activation) or plastic deformation (mechanical activation). Convergence and the introduction of welded parts activation energy in the welding zone – the necessary conditions for the formation of one-piece welded joints. The essence of the welding pressure is to share the plastic deformation of the material on the edges of the welded parts. Due to plastic deformation is facilitated by the establishment of atomic bonds connected parts. To speed up the process of applying pressure welding with heating. In some cases, heated to fusion weldable metal surface or intermediate support pads, the pressure can be carried out in continuous or intermittent modes.