_Preheating – Soldering
As with every thermal process, soldering also often involves unwanted embrittlement of the material structure.
Soldering describes a method for positive material joining of materials, in which a liquid phase is formed by melting a solder. Unlike welding, however, the liquid temperature does not reach that of the parent metals. After solidification of the solder, a positive material joint has formed.
Furnace soldering is therefore very advantageous in order to avoid unwanted changes in the material structure; due to the uniform heating of the parts to be joined, any stresses in the material structure are excluded from the outset
The parts to be joined are heated in a furnace with inserted solder and oxidation of the cleaned pats is specifically prevented by isolation of the air in the furnace or by adding an inert gas. Without using a flux, diverse solders can be made in one operation and the parent materials can be heat treated simultaneously, i.e. during the same operation (!). These furnaces either operate batch-wise like, e.g. the chamber or shaft furnace, or continuously by means of a conveyor belt.