Bimetal forming mechanics with special reference to indentation, extrusion and upsetting

Yew-Shing Kaiser Ouyang, Purdue University

Abstract

The main aim of the bimetal forming process is to produce net-shape bimetal products of desired clad thickness and uniformity, and simultaneously to secure pressure welding of metallurgical quality at each bimetal interface. Currently this is achieved in restrictive ways, e.g. by rolling or the direct extrusion of a carefully prepared close fitting bimetal billets. The procedures involved are not very efficient and this is due, in some measure, to the limited understanding of certain basic bimetal forming mechanics and the underdevelopment of bimetal forming theory. The majority of analytical schemes cited in the literature use upper bound theory (u.b.t.) and the investigations published to date deal almost entirely with steady state problems that have been solved by manipulating kinematically admissible velocity fields (k.a.v.f.). This thesis pertains to analytical and phenomenological studies concerning the interactions of bimetal components under basic forming configurations, i.e. indentation, extrusion and upsetting. The objectives are to facilitate bimetal process modelling, innovation and product defect avoidance. Special interest is placed on unsteady state problems. Upper-bound solutions based on approximate slip-line fields and slab methods are obtained. Bimetal preforms made of plasticine of various colors and hardnesses are used as model materials and plasticine modelling techniques is thereby enhanced.

Degree

Ph.D.

Advisors

Barash, Purdue University.

Subject Area

Industrial engineering|Metallurgy

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