ThermitSchweißen

Thermit welding is a fusion welding process that utilizes the highly exothermic reaction between a metal oxide and aluminum powder. When ignited, this thermite reaction produces molten metal at extremely high temperatures, typically over 2500 degrees Celsius, and aluminum oxide slag. The molten metal, usually iron, then fills the gap between the parts to be joined, creating a strong, permanent weld.

The process involves preparing the surfaces to be welded, often by cleaning and preheating. A mold, typically made of sand or refractory material, is then placed around the joint to contain the molten metal and shape the weld bead. A preheating flame, usually oxy-acetylene, is used to bring the base metal to a sufficient temperature to ensure fusion. Once the preheating is complete, the thermite mixture, contained in a crucible, is ignited. The reaction proceeds rapidly, and the molten metal flows into the mold, fusing with the base metal. After the weld cools and solidifies, the mold is removed, and excess material is chipped or ground away.

Thermit welding is particularly well-suited for joining heavy sections of steel, such as railway tracks, large machine parts, and structural components. Its advantages include the ability to produce strong, high-quality welds in situ, without the need for complex machinery. It is also relatively cost-effective for large-scale applications. However, the process requires careful control of the reaction and mold design to ensure a sound weld. Environmental considerations regarding fumes and slag disposal are also important.