Method of treating surfaces or boundary layers by resistance heating

摘要

Known methods of treating surfaces or boundary layers or of reinforcing boundary layers of cylindrical or flat components made of low-melting-point materials, e.g. aluminium, have the disadvantage that, on account of non-continuous heating of the members to be joined, the formation of the joint is adversely affected, and the usable grain size of the metal powder, the possible reinforcement layer thickness and the working speed are limited. The solution according to the invention is intended to provide a method which, in the reinforcing of boundary layers of low-melting-point materials, permits a continuous input of heat, a lower total quantity of heat, the use of larger grain sizes and thus greater layer thicknesses. This is achieved by a pulse-shaped direct current being used, preferably with a current rise. An electrode force FE (4) is superimposed with a certain program on this welding current IS (3) in a synchronized manner. An advantageous combination of welding current IS (3) and electrode force FE (4) leads to boundary-layer reinforcements of greater reliability and with greater layer thickness on components being possible on low-melting-point and other critical metals (Fig. 2). <IMAGE>