A Thermal Hydrodynamic Lubrication Theory for Hydrostatic Extrusion of Low Strength Materials

1976 ◽  
Vol 98 (2) ◽  
pp. 335-342 ◽  
Author(s):  
R. W. Snidle ◽  
B. Parsons ◽  
D. Dowson
Keyword(s):  
Plastic Deformation ◽  
Theoretical Analysis ◽  
Thermal Effects ◽  
Hydrodynamic Lubrication ◽  
Extrusion Process ◽  
Lubrication Theory ◽  
Lubricant Film ◽  
Hydrostatic Extrusion ◽  
Solid Friction ◽  
Hydrodynamic Lubrication Theory

The paper presents a theoretical analysis of hydrodynamic lubrication in the hydrostatic extrusion process which includes a consideration of thermal effects in the lubricant film arising from the work of plastic deformation. A Newtonian lubricant with an exponential pressure-temperature-viscosity relationship has been assumed and allowance has been made for the effects of redundant deformation of the worked material. The results of the theory are compared with those from previous isothermal and solid friction theories.

An Elasto-Plasto-Hydrodynamic Lubrication Analysis of the Hydrostatic Extrusion Process

1973 ◽  
Vol 95 (2) ◽  
pp. 113-122 ◽  
Author(s):  
R. W. Snidle ◽  
D. Dowson ◽  
B. Parsons
Keyword(s):  
Plastic Deformation ◽  
Thermal Effects ◽  
Preliminary Analysis ◽  
Hydrodynamic Lubrication ◽  
Numerical Procedure ◽  
Extrusion Process ◽  
Lubricant Film ◽  
Hydrostatic Extrusion ◽  
Small Influence ◽  
Theoretical Results

The authors describe a numerical procedure for the solution of the problem of hydro-dynamic lubrication in the hydrostatic extrusion process. The lubricant is assumed to be a Newtonian fluid and in this preliminary analysis it is assumed that the yield strength of the worked material remains constant. Elastic deformation of the billet as it enters and leaves the die is considered but this effect is found to have only a small influence upon the thickness of the lubricant film which is generated. Thermal effects arising from plastic deformation of the billet and viscous dissipation in the lubricant film are also considered. Theoretical results are presented showing the influence of die angle and reduction ratio upon values of film thickness and extrusion pressure for two materials.

An Isothermal Hydrodynamic Lubrication Theory for Hydrostatic Extrusion and Drawing Processes With Conical Dies

1971 ◽  
Vol 93 (1) ◽  
pp. 69-74 ◽  
Author(s):  
W. R. D. Wilson ◽  
J. A. Walowit
Keyword(s):  
Experimental Data ◽  
Hydrodynamic Lubrication ◽  
Lubrication Theory ◽  
Back Pressure ◽  
Hydrostatic Extrusion ◽  
Drawing Process ◽  
Uniform Deformation ◽  
Hydrodynamic Lubrication Theory ◽  
Lubrication Conditions ◽  
Good Agreement

A hydrodynamic lubrication theory is developed for a generalized hydrostatic extrusion and drawing process with augmentation and back pressure. The die is assumed to be conical and uniform deformation and isothermal lubrication conditions are assumed to exist. The theory is in good agreement with experimental data previously published by other workers.

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