ISSN:
1662-9779
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Physics
Notes:
A technique to achieve the globular weld structure using stirring the localized semisolidzone during butt-joining of zinc AG40A (Zamak-3) die cast alloy is reported. Since the semisolidtemperature range of this alloy is very narrow, the accurate controlling of weld pool temperaturemust be considered. By presented process, globular microstructure of the weld zone can beachieved. Moreover the near weld zone would have the globular structure due to semisolid holding.A gas heating system was designed to heat up the nitrogen gas to desired temperature accurately. Aheating element was embedded in a castable ceramic block while a stream of gas could pass closelyaround the hot element length. Hot nitrogen gas flow through a precise ceramic nozzle was used tocreate a localized semisolid pool. At this stage a fine stirrer was introduced into the weld seam inorder to mix the two sides into a single uniform joint. Local mechanical properties of differentzones show a good strength in the weld metal zone and heat affected zone by results of the shearpunch tests and hardness tests. Air entrapment in the pool decreases by controlling the speed ofsubstrate movement and stirrer rotation under the nozzle. The strengths of each zone show relativecorrespondence to the variation of the hardness values
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/24/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.141-143.225.pdf
