Friction stir welding method for stirring pin and shaft shoulder during differential speed rotation

Abstract

The invention discloses a friction stir welding method for a stirring pin and a shaft shoulder during differential speed rotation, relates to the friction stir welding method and solves the problems of high downward pressure and high forward resistance and various problems caused by overcoming high speed rotation of the stirring pin and high speed rotation of the shaft shoulder in the same direction or non-rotation of the shaft shoulder existing in conventional friction stir welding. The method comprises the following steps of: inserting the stirring pin of a stirring head into a part to be welded at a rotation speed of between 3,000 and 30,000 rpm, wherein the rotation speed of the shaft shoulder of the stirring head is less than that of the stirring pin and the rotation direction of thestirring head is reverse to that of the stirring pin; the rotation speed of the shaft shoulder is 10 to 1,000 rpm; the insertion speed of the stirring head is 1 to 5 millimeter / minute; the depth of the stirring pin inserted into a workpiece is 0 to 0.5mm less than the thickness of the workpiece; and the depth of the shaft shoulder inserted into the workpiece is 0 to 0.5mm; and moving the stirringhead along the horizontal direction of a butting surface of a first welded workpiece and a second welded workpiece at a speed of between 100 and 5,000 millimeter / minute. The heat required by the welding does not depend on the friction between the shaft shoulder and the welded material, so high downward pressure is not needed to ensure the friction of the shaft shoulder part to produce heat and the downward pressure is reduced.

Description

technical field [0001] The invention relates to a friction stir welding method, which belongs to the technical field of welding. Background technique [0002] Friction stir welding is a new type of solid-phase joining technology, which overcomes the problems of welding defects such as cracks and pores in the fusion welding method, and enables some materials that were difficult to weld in the past to achieve high-quality welding, and has become aluminum, magnesium and other materials in one fell swoop. The preferred welding method for its alloys. However, conventional friction stir welding has the following disadvantages: (1) More than 80% of the frictional heat generation comes from the friction between the shoulder and the material to be welded, and a large downforce is required to generate sufficient heat during the welding process; (2) The temperature of the material to be welded near the stirring head is low, and the torque required for the rotation of the stirring head...

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Problems solved by technology

[0004] The purpose of the present invention is to solve the problems of large downforce, large torque, large forward resistance, strict clamping requirements, large equipment and high energy consumption in conventional friction stir welding, and also to overcome the high-speed rotation of the stirring needle and the shaft Shoulders rotate at high speed in the same direction or not, resulting in weld overheating, serious flash, and holes. A friction stir welding method in which the stirring needle and the shoulder rotate at a differential speed is proposed.

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