Electric current assisted friction column/tapered plug welding method and tool thereof

Abstract

The invention discloses an electric current assisted friction column / tapered plug welding method which comprises the following steps: according to the technological requirements of friction plug welding, a cylindrical or frustum-shaped stopper rod is adopted to prefabricate a taphole in the to-be-welded area of a workpiece; a tool is utilized to clamp the stopper rod and the workpiece, and the taphole and the stopper rod are enabled to be coaxial; a welding machine and an auxiliary power supply are started, axial force is applied while rotating the stopper rod to form a conductive loop among the auxiliary power supply, the stopper rod, the workpiece and a conductive block, the end material of the stopper rod rapidly reaches the thermoplasticity state under the action of friction heat and resistance heat, and at the same time, a plastic material moves around to fill an interval under the action of thermal mechanical coupling, and the interval is filled as the welding process is carried out; and after upsetting is finished, the welding machine and the auxiliary power supply are turned off, so that electric current assisted friction column / tapered plug welding is finished. With adoption of the electric current assisted friction column / tapered plug welding method, requirements for friction heat can be lowered, so that requirements for the power system of welding equipment are lowered, plug weld texture and mechanical properties can be improved, and a welding process window can be widened.

Description

technical field [0001] The invention belongs to the technical field of solid-phase friction welding, and in particular relates to a novel friction column / cone plug welding method using a composite heat source of electric current and solid-phase friction. Background technique [0002] Friction column / plug welding is a new type of solid-phase joining technology based on the welding process of continuous drive friction welding and stud welding. It was invented and patented by the British Welding Institute in 1992. The basic principle is: prefabricate a plug hole to be welded on the base metal, keep the consumable plug rod material with a diameter smaller than the plug hole concentric with the plug hole, and rotate at a high speed, while exerting a certain axial pressure on the plug rod and The bottom of the plug hole moves, and when the rotating stopper rod comes into contact with the bottom of the plug hole, the heat generation process of frictional shearing begins. Under the...

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Problems solved by technology

[0005] There are some problems in the application process of traditional friction column / cone plug welding: (1) high requirements on welding equipment, high welding speed and large axial pressure are required, resulting in a narrow range of welding process adjustment; (2) At the beginning of welding, due to the excessive load, the welding torque rises rapidly, which may easily cause the welding machine to be stuck due to overload; (3) the flow of plastic material at the fillet transition at the bottom of the plug weld is not sufficient, and due to insufficient frictional heat source, it is easy to cause unwelded (4) Due to the short duration of the welding process and the fast welding cooling rate, a coarse structure may be formed inside the entire plug weld, resulting in an increase in hardness and a decrease in plasticity, which has an adverse effect on the mechanical properties and plastic deformation of the plug weld

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