Magnitogorsk State Technical University (Magnitogorsk, Russia):

Baryshnikov M. P., Cand. Eng., Ass. Prof., Chair of Mechanical and Metallurgical Process Engineering

Ufa State Aviation Technical University (Ufa, Russia):

Medvedev E. B., Cand. Eng., Ass. Prof., Chair of Nanotechnologies
E-mail (common): arcosmag@mail.ru

Change of the thickness of an outer layer of a bimetal rod end produced by direct cold extrusion of cross-layered bimetal ingots has been investigated. Such rods are applied to produce bimetal sparkplug center electrodes for combustion engines. The change of the outer layer thickness of a round bimetal rod end was studied at the initial (non-steady) stage of direct cold extrusion depending on the change of the sizes of an initial round bimetal rod (thickness of a bottom layer of a billet). The deformation process at the initial stage is studied due to the fact that initial cross-layered billets used for manufacturing of bimetal billets usually have a small relative thickness of the bottom layer, which often results in final formation of designed dimensions of rods and relative service properties of rods at the initial stage. The investigation results allow stating that the character of change of an outer layer thickness of a round bimetal rod end at the initial stage of direct extrusion depending on the thickness of a bottom layer of an initial bimetal billet can be approximately described by a parabolic relation. It is demonstrated that an external layer with a thickness smaller than that of the lower cross layer of the initial billet at certain values of the thickness of the bottom cross layer of the initial billet. This can be considered the peculiarity of the process under consideration.

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