Seam welding
Seam welding is a continuous resistance welding process using rotating electrode wheels to produce leak-tight joints. It is widely used in the production of cans and containers.
Physical-Chemical Mechanism of Action
Roller seam welding uses rotating roller electrodes that continuously glide over the material to be welded. The electrodes generate heat through electrical energy and simultaneously press the material together, leading to melting. This process can be carried out under atmospheric pressure or in a closed system with an evaporating medium (vacuum or gas welding).
Metallurgical Relevance & Risks in Welding
Roller seam welding is especially suited for joining thin sheets and steels, as it enables dense and hydrogen-free joints. However, too rapid cooling can lead to glass-hard martensite, causing cracks and brittleness. A welding process that is too long or a temperature that is too high can lead to the formation of excess material and loss of properties such as strength.
Workshop Practice & Instructions
For roller seam welding, it is crucial to use the correct electrode materials and diameters. The welding speed should be set to produce a uniform joint. In the case of gas welding, the pressure ratio and temperature of the evaporating medium must be precisely controlled. A typical thermal image for roller seam welding shows a strong, narrow weld core with a small enlargement of the metal structure.