Тип публикации: статья из журнала
Год издания: 2023
Идентификатор DOI: 10.1007/s00170-023-11103-y
Ключевые слова: metal treatment, continuous pressing, conform, aluminum alloy, friction, calculation
Аннотация: The kinematics of the plastic fow of the metal processed by pressure along the contact surface of the tool is largely determined by the direction of the friction forces acting in the boundary layer. It is possible to forcibly create conditions under which these forces will not hinder but promote the improvement of the metal formingПоказать полностьюprocess. Since the main friction process occurs in the near-contact layer “deformable metal-tool,” the maximum possible value of the friction stress (τ) cannot exceed the intensity of shear stresses acting on this boundary. In calculations related to the fow of metal along the contact surface of the tool, the friction coefcient is usually assumed to be no more than 0.58. According to a number of researchers, when using the Siebel law, this value can reach more than 1.0 and is called the “friction index.” This is due to the fact that the maximum value of resistance to deformation in the near-contact layer can signifcantly exceed the value averaged over the deformation zone. However, the determination of the true resistance to deformation in a thin near-contact metal layer is very difcult, so this value in the calculations can be corrected by the friction index (μ) obtained by experiment. As a result of this work, by solving the equation of the balance of forces required for a stable process of metal extrusion into a die hole, based on the actual length of the contact arc between the workpiece and the container, the calculated value of the friction index was obtained (μ = 1.56). This confrms the position that the maximum value of friction stresses can signifcantly exceed the yield strength of the workpiece material averaged over the volume of the deformation zone under pure shear in the process of continuous pressing by the conform method.
Журнал: The International Journal of Advanced Manufacturing Technology
Номера страниц: 1-11
ISSN журнала: 02683768
Издатель: Springer-Verlag London Ltd