中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
Vol. 11 No. 1 February 2001 |
(1. Department of Mechanical Engineering, Tsinghua University,
Beijing 100084, P.R.China;
2. Foundry Institute, University of Science and Technology Beijing,
Beijing 100083, P.R.China;
3. Department of Material Science and Engineering, Hebei University of Science and Technology,
Shijiazhuang 050054, P.R.China)
Abstract:The major unsteady phenomena in semisolid continuous casting process are the breakage and breakout. The essential reasons for them are the passageway blocking or the solidified shell too thin to endure the withdrawal force because of the remained shell formed at the beginning and its developing afterwards. Through theoretically analyzing the crack filling and the remained shell developing, stability conditions were presented. The essential one of them is that the stress acted on the semisolid slurry must be larger than the yield stress of it. The condition without breakage is to build a balance between the increase of the remained shell resulted in solidifying and the decrease of it resulted in flowing of the semisolid slurry. The condition without breakout is to ensure the solidified thickness larger than the safe thickness. The corresponding mathematical formulas of these conditions were set up and the verification experiments show that these conditions are reliable in applications.
Key words: semisolid metal; continuous casting; stability condition; breakage; breakout