1. Mirko Gojić, Croatia
In the case of continuous casting of metal ribbons with the melt-spinning process on the industrial scale, larger quantity of melt could lead to a slow excessive warming of the chilling wheel, which would further lead to solidification of a ribbon at non-uniform conditions and increased wearing of the wheel. Primary goal of our work was to determine to what extent the release of heat during contact of the melt/ribbon on the circumferential surface of the chilling wheel affect its surface temperature rise, and inversely how much elevated temperature of the chill wheel surface affects on metal ribbon cooling rate and its solidification velocity. On the basis of developed mathematical model, a computer program was made and used for analyses of heat transfer in the melt-spinning process. The calculations show that contact resistance between metal melt and chilling wheel has a great influence on melt/ribbon cooling and chill wheel heating rate, and must not be neglected in numerical calculations, even if its value is very low. In the case of continuous casting, significant long term surface temperature increase may take place, if the wheel is not internally cooled. But inner cooling is effective only if wheel casing thickness is properly chosen. New method for determining contact resistance through variable heat transfer coefficient is introduced which takes into account physical properties of the casting material, process parameters and contact time/length between metal melt/ribbon and substrate and enables cooling rate prediction before the experiment execution. In the case of continuous casting, heat balance of the melt-spinning process is calculated and influence of the chill wheel cooling mode on cooling rate of metallic ribbon is analyzed. In the frame of the practical part of our investigation work the ribbons from the aluminium and copper, and following copper base shape memory alloys: CuAl12Ni4, CuAl13Ni4, CuAl14Ni4 and CuAl15Ni4 were produced.
Ključne reči :
Tematska oblast:
SIMPOZIJUM A: Nauka materije, kondenzovane materije
Datum:
21.05.2013.
Br. otvaranja:
194
Contemporary Materials - 2013 - Savremeni materijali
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