Estimation of Frictional Coefficient between Punch and Billet at Back-Stroke in Backward Can Extrusion Test of Steel

A backward can extrusion test provides severe tribological conditions because high pressure, high temperature, and large surface expansion ratio affect the lubricant. During the forward stroke these conditions intensify with increasing cup depth of the extruded workpiece; additionally, the back-stro...

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Bibliographic Details
Published inKey engineering materials Vol. 767; pp. 248 - 255
Main Authors Asai, Kazuhito, Goto, Keisuke, Hayashi, Nobukazu, Kitamura, Kazuhiko
Format Journal Article
LanguageEnglish
Published Zurich Trans Tech Publications Ltd 01.04.2018
Subjects
Coefficient of friction
Extrusion billets
Finite element method
High temperature
Lubricants
Numerical analysis
Tribology
Workpieces
Backward Cans Extrusion
Cold Forging
Friction Coefficient
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Summary:A backward can extrusion test provides severe tribological conditions because high pressure, high temperature, and large surface expansion ratio affect the lubricant. During the forward stroke these conditions intensify with increasing cup depth of the extruded workpiece; additionally, the back-stroke force during retraction of the punch rises to a significant level under a poor-lubricated condition. This study estimates the coefficient of friction μp between punch and workpiece during the back-stroke by combining experiments using conventional soap-phosphate coated steel and numerical analysis by FEM. The values of μp were estimated to be 0.09 and 0.03 in case of small and large workpiece depth, respectively. Friction decreased with elevating temperature.
Bibliography:Selected, peer reviewed papers from the 8th International Conference on Tribology in Manufacturing Processes & Joining by Plastic Deformation, June 24-26, 2018, Elsinore, Denmark
ISSN:1013-9826
1662-9795
1662-9795
DOI:10.4028/www.scientific.net/KEM.767.248