Large-specification electric upsetting method for gradient change of electrode resistivity and anvil electrode

Abstract

The invention discloses a large-specification electric upsetting method for gradient change of electrode resistivity. The method comprises the following steps: under the action of electric upsetting, gradually and radially increasing a rod blank to form a garlic bulb; when the garlic bulb is increased to the size that the center of the garlic bulb is about to generate an axial sinking trend in the radial direction, taking an annular belt area where the edge of the garlic bulb is in contact with the anvil electrode as an annular inhibition area on the anvil electrode; increasing the resistivity of the annular suppression region to locally reduce the current density; and in the radial increasing process of the garlic bulb, reducing the current density of the blanks continuously reaching the annular inhibition area, wherein the temperature is reduced, the fluidity of the annular parts, corresponding to the annular inhibition region, of the garlic bulbs is inhibited, and the tendency that the annular parts, corresponding to the annular inhibition region, of the garlic bulb drive the centers of the garlic bulb to axially flow is inhibited; and finally, the sinking trend of the center of the garlic bulb is inhibited. The problem that end face recession cannot be improved by changing electric upsetting loading parameters is solved, and the grain refinement degree of garlic bulbs is increased while the end face recession is improved.

Description

technical field [0001] The invention belongs to the field of metal plastic forming in material processing engineering. Background technique [0002] The electric upsetting process satisfies the needs of local accurate aggregation of long rod parts with super large and variable cross-sections. The electrothermal upsetting process couples the three physical fields of electrothermal force, passes current between the anvil electrode and the clamping electrode, heats through the contact resistance and its own resistance, and applies a certain upsetting force on the right end of the billet, and the billet at the cold end is sent to It enters the heating area between the anvil electrode and the clamping electrode, so that the blank gradually undergoes plastic deformation to complete local aggregation. Since the plastic deformation area is strictly restricted in the heating area, a workpiece with a large amount of deformation can be quickly realized. [0003] When electric upsetti...

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Problems solved by technology

[0004] Aiming at the deficiencies of the above-mentioned technologies, the present invention provides a large-scale electrical upsetting method with a gradient change in electrode resistivity, which solves the problem that the end surface depression cannot be improved by changing the loading parameters of the electrical upsetting

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