TPT-January-2015

Technology News

Plasma annealing for automotive and heat exchanger tubing

compact design, high energy conversion efficiency and low gas consumption, and gives the operator the ability to target mechanical properties with a great degree of accuracy. Rapid heating and reduced time of recrystallisation results in fine grain size with uniform crystal structure. This in turn improves material formability, and its susceptibility to bending and further drawing. Plasma annealer can cold start production in few minutes and can be stopped immediately. This avoids the lengthy heating-up and cooling-down times and associated energy costs that are symptomatic of a conventional furnace.

their mixtures can be used for purging of plasma machine. Hydrogen, nitrogen and forming gas are the most commonly used gases while helium and argon are used in specific applications. The choice of gas is important as it impacts the surface finish of the processed material. Many applications with demanding surface quality can be found in heat exchanger, aviation, automotive and medical sectors. Plasma treatment can be used also for surface activation. Plasma annealed tube surface remains active and susceptible to coating, whilst still in protective atmosphere. Plasma annealer or plasma cleaner can therefore run immediately in-front of a coating or plating line in order to avoid the use of chemicals for surface preparation. Plasma annealer features

TUBES for the automotive industry and heat exchanger tubing are made of various materials and sizes. Copper, galvanised steel, stainless steel, nickel alloys, aluminium, or composite material are all used in automotive and heat exchanger applications. The sizes also vary with ODs over 1" and over. For such a varied product range one has to adopt a variety of different annealing and surface cleaning techniques. Most of the above product range can be heat treated and degreased also with plasma. Plasma annealing has been gaining increasing interest among tube manufacturers in the automotive and heat exchanger sector. Plasma annealing can be used for production of tubes made from the mentioned materials and sizes. The advantage of using plasma as opposed to a conventional furnace is high rate of power input, which translates to high process speeds. Plasma annealing can be performed in-line with tube welding or drawing substituting multiple lines of a traditional tube furnace. It can also be used for a brazing step in double- wall tube production. Braking system and fuel delivery tubing in a car are typical applications where plasma can be used effectively. Plasma annealing or surface treatment is conducted in a protective atmosphere, which results in superior surface quality of the finished tubes. Ion sputtering on the material surface results in fine dry surface cleaning and surface oxide removal, which have proved beneficial to applications with demanding surface requirements. A range of inert gases or

Plasmait GmbH – Austria Email: info@plasmait.com Website: www.plasmait.com

Plasma annealing is gaining increasing interest among tube manufacturers in the automotive industry

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J anuary 2015