Study on Molten Zone in Twin-Roll Casting of Magnesium Alloy Strip

2013 ◽  
Vol 395-396 ◽  
pp. 209-213
Author(s):  
Zhi Pu Pei ◽  
Hong Yang Zhao ◽  
Xiao Dong Hu ◽  
Dong Ying Ju

Thermal flow finite element simulation was carried out to deeply understand the solidification and deformation phenomena of magnesium alloy in molten zone during twin-roll casting process. The results show that temperature near the nip of the rolls is about 680K based on current conditions, and there are two vortexes in the molten pool during casting, a peak formed at solidus. Due to the metal flows in molten pool and relative rotates of the rolls, temperature field of molten zone is different from normal casting, which will cause the solidification structure changes. An experiment by using a vertical type twin-roll caster was also conducted, and the amount of deformation bands at the joint line is larger than that at the two sides. Substructures can be found due to dynamic recrystallization during casting process.

2015 ◽  
Vol 833 ◽  
pp. 15-18 ◽  
Author(s):  
Zhi Pu Pei ◽  
Dong Ying Ju ◽  
Hong Yang Zhao ◽  
Xiao Dong Hu

A quantitative understanding of the twin-roll casting process is required to get high quality as-cast magnesium alloy strips. In this paper, a thermal flow-solidification simulation was carried out to study the behavior of casting zone and its effects on defects generation deeply. Results show that a lower pouring temperature is not suitable for producing defect-free magnesium alloy strips. With increasing of the casting speed, the tendency of cracks formation will getting smaller because of the more uniform temperature distribution. A low pool level leads to a small metal-roll contact area, and a sharp temperature distribution will generates under this situation, which is not good for strips quality.


2009 ◽  
Vol 209 (5) ◽  
pp. 2321-2328 ◽  
Author(s):  
Jian Zeng ◽  
Roger Koitzsch ◽  
Herbert Pfeifer ◽  
Bernd Friedrich

2011 ◽  
Vol 690 ◽  
pp. 129-132 ◽  
Author(s):  
Iman Bayandorian ◽  
Yan Huang ◽  
Geoff M. Scamans ◽  
Zhong Yun Fan

Melt conditioning by intensive shear was used prior to twin roll casting of an AZ91 magnesium alloy strip to promote heterogeneous nucleation and produce a refined and uniform microstructure without severe macro-segregation. The as-cast strip was then processed by homogenization, hot rolling and annealing and the microstructural behaviour during the downstream processing was examined and compared with the strip of the same alloy produced without melt conditioning. The melt conditioned strip after downstream processing displayed significantly improved mechanical properties with an average tensile elongation of ~16%, compared with ~10% for the strip produced without melt conditioning and the reported values of ~1.5-6.2% in the literature.


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