Self-sustaining friction stir welding stirring head with irrotational lower shaft shoulder and welding method of stirring head

Abstract

The invention relates to a stirring head, in particular to a self-sustaining friction stir welding stirring head with an irrotational lower shaft shoulder. The invention solves the problems that welding heat input is increased as a lower shaft shoulder of an existing self-sustaining friction stir welding stirring head rotates to generate heat, weld formation is difficult, and the mechanical property of a welding joint is low. An upper end surface of a stirring needle is fixed on a lower end surface of an upper shaft shoulder. The upper shaft shoulder and the stirring needle are arranged coaxially, and are characterized in that the lower stirring head is composed of a support base, a radial positioning bearing and the lower shaft shoulder, a circular groove is machined at the center of the upper end face of the support base, the radial positioning bearing is mounted in the circular groove, the lower shaft shoulder is fixedly mounted on the upper end face of the support base, and central holes are processed on the lower shaft shoulder along the longitudinal direction. In the welding process, the lower part of the stirring needle runs through the central holes and is installed on the support base through the radial positioning bearing. The diameter D2 of the lower shaft shoulder is not less than that D1 of the upper shaft shoulder. The stirring head of the invention is used for friction stir welding.

Description

technical field [0001] The invention relates to a stirring head for friction stir welding. Background technique [0002] The self-sustaining friction stir welding method is a new type of environmentally friendly solid phase connection technology derived from conventional friction stir welding. It can not only effectively avoid welding defects such as cracks and pores caused by traditional fusion welding methods, but also solve conventional friction stir welding. Welding needs a backing plate, and there may be problems such as root defects in the weld, so the self-sustaining friction stir welding method has been rapidly developed and widely used. In the above method, the stirring head is composed of a stirring pin and upper and lower shoulders. The lower shoulder acts as a backing plate for conventional friction stir welding. During welding, the lower shoulder is driven by the stirring pin to rotate and generate heat. The lower shaft The load on the shoulder is all applied t...

AI Technical Summary

Problems solved by technology

[0004] In order to solve the problem that the lower shoulder of the existing self-sustaining friction stir welding stirrer rotates to produce heat, the welding heat input increases, the welding seam is difficult to form and the mechanical properties of the welded joint are low, and a lower shoulder is proposed. Rotating self-contained stirring head

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