Electronic Resource
s.l. ; Stafa-Zurich, Switzerland
Solid state phenomena
Vol. 116-117 (Oct. 2006), p. 766-770
ISSN:
1662-9779
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Physics
Notes:
An important step in the processing of semi-solid metals is the inductive re-heating of thefeedstock material. The heating should lead to an uniform billet temperature in order to obtain goodforming results. The billet is supposed to be heated to the target temperature as fast as possible and atthe same time it must be guaranteed, that the outer area of the billet does not melt prematurely.Conventionally the open-loop trajectories consist of simple power over time diagrams and aregenerated by extensive experiments. By using an open-loop control scheme it is possible to chose adesired trajectory for the middle axis temperature of the billet which respects the given constraint onthe heating process. By taking advantage of the flatness property of the system, an open looptrajectory for the coil current can be calculated which ensures the desired behavior of the axistemperature. The shape of the trajectory is determined by the shape of the desired trajectory and thetemperature dependent material properties, which have to be known with the needed accuracy. Thelosses of the converter and induction coil are estimated online so that the induced power is known.The trajectory ensures that the billet is heated to a temperature just below the solidus temperaturewithout overheating of the billet’s surface and with a very homogeneous temperature distribution.The Experiments have been conducted using A356 aluminum alloy
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/22/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.116-117.766.pdf
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