Mathematical model and theoretical research of flow shear constitutive relation during rheo-rolling of semisolid alloy

Abstract

The mathematical model of flow shear constitutive relation during rheo-rolling process has been established. The distribution of velocity and shear stress in rolling cavity was investigated, and the effects of process parameters on shear stress of Sn-15Pb alloy during rheo-rolling process were studied. In rolling cavity, the nearer the roll is, the bigger the velocity and shear stress are. The shear stress increases with the increment of the roll speed and the roll radius during rheo-rolling process, but deceases with the increment of the thickness of the strip. When the solid fraction of Sn-15Pb alloy increases from 0.3 to 0.5, the shear stress increases slowly, but when the solid fraction increases from 0.5 to 0.6, the shear stress rapidly.

Keywords

semisolid / rheo-rolling / flow shear / mathematical model

References

[1] Flemings M C. Behavior of Metal Alloys in the Semi-solid State[J]. Metall. Trans. A, 1991, 22: 957-981.

[2] Kang C G, Jung H K. Semisolid Forming Process-numerical Simulation and Experimental Study[J]. Metall. Mater. Trans. B, 2001, 32: 363-372.

[3] Guo H M, Yang X J, Hu B, et al. Rheo-diecasting Process for Semisolid Aluminum Alloys[J]. J. Wuhan Univ. Technol.-Mater. Sci. Ed., 2007, 22(4): 590-595.

[4] Song R B, Kang Y L, Zhao A M. Semi-solid Rolling Process of Steel Strips [J]. J. Mater. Process. Technol., 2008, 198: 291-299.

[5] Ji S, Fan Z, Bevis M J. Semi-solid Processing of Engineering Alloys by a Twin-screw Rheomoulding Process [J]. Mater. Sci. Eng. A, 2001, 299: 210-217.

[6] Guan R G, Chen L Q, Li J P, et al. Dynamical Solidification Behaviors and Metal Flow during Continuous Semisolid Extrusion Process of AZ31 Alloy [J]. J. Mater. Process. Technol., 2009, 25: 395-400.

[7] Haga T, Tkahshi K, Ikawaand M, et al. Twin Roll Casting of Aluminum Alloy Strips [J]. J. Mater. Process. Technol., 2004, 153: 42-47.

[8] Song R B, Kang Y L, Sun J L, et al. Mechanical Characteristics of Rolled Products of Semi-solid Steels [J]. Acta Metal. Sin., 2002, 38(2): 153-156.

[9] Huang H Q, Cao F R, Guan R G, et al. Mathematical Model and Theoretical Research of Unit Rolling Pressure Distribution in Rectangular Groove during Rheo-rolling of Semisolid Alloy [J]. Acta Metall. Sin., 2011, 47(3): 291-297.

[10] Yang M B, Pan F S, Peng X D, et al. Macroscopic and Microscopic Coupling Mathematical Model for Solidification Process of Twin-roll Thin Strip [J]. J. Chongqing Univ. (Nat. Sci.), 2005, 28(5): 39-44.

[11] Tang X L, Shang S Z, Lu G M, et al. Research on the Constitutive Equation of 6061 Aluminum Alloys in the Hot Compressive Deformation [J]. Spec. Cast. Nonferr. Alloys, 2010, 30(12): 1113-1116.

[12] Chen X Y, Mao W M, Zhong X Y. Rheological Mechanics Model of Shear Rate Thickening the Behmior of Semisolid Slurries [J]. Acta Metall. Sin., 1998, 34(2): 179-183.

[13] Zhang Z X, Dong Z N. Mechanics of Viscous Fluids [M], 2011 Beijing: Tsinghua University Press. 15-30.

[14] Luo S J, Cheng Y S, Shan W W. Rheology of Semi-solid Metal [M], 2011 Beijing: National Defence Industry Press.

[15] Laxmanan V, Flemings M C. Deformation of Semisolid Sn-15%Pb Alloy [J]. Metall. Trans., 1980, 11(12): 1927-1937.