Induction heating is used to heat radially symmetric metallic tubes for a wide variety of applications.
As a rule, the efficacy of tube heating is inversely proportional to the conductivity of the material.
Possible applications include black annealing and bright annealing of stainless steel tubes; low-stress annealing; heating before coating and for drying of tube bends, and heating for production of tube bends; heating for extrusion; heating before hot or cold forming.
SMS Elotherm’s portfolio includes high-frequency induction welding machines for longitudinally welded tubesas well as heating machines for seamless tubes, in particular tubes made of various steel alloys, stainless steels or non-ferrous metals. One of the greatest advantages for customers is the overall expertise of SMS Elotherm for coordinated and stable processes.
Along with black annealing under a normal oxygen atmosphere, bright annealing also benefits from the precise power input of induction technology.
Induction heating enables high heating rates along with precisely controlled results in recrystallisation annealing under a protective atmosphere. Induction bright annealing of stainless steel tubes, for example, takes place in the temperature range from 1050 to 1300°C. As a result, the weld is corrosion-resistant and thetubeis metallurgically prepared for further drawing and rolling operations. The tubesurface remains bright with this process.
EloTube ensures precise preheating with high throughput rates for coating equipment in tubeplants. Automatically controlled frequency changes conform to all variable process requirements. The tube heating machine is suitable for paint and plastic coatings using hose extrusion or winding methods.
SMS Elotherm has continuously refined the heating process to achieve extremely high energy efficiency. The heat is generated directly in the workpiece, which reduces the tube heating time.
Induction heating machines can be readjusted immediately after a product change, for example with a different diameter or wall thickness. Thanks to advanced converter technologies, induction machines from SMS Elotherm consume less electricity than other comparable machines.
With the induction heating of tubes, the heating depth and length (with tube end heating), as well as the heating duration and thus the temperature of the heated tube, can be well integrated into a variety of processes.