Friction stir welding method

Abstract

The invention provides a friction stir welding method of forming a weld portion having an excellent fatigue property in the case of welding a weld material by using a friction stir welding method. The invention provides a friction stir welding method structured such as to insert a tool provided in such a manner that a pin-shaped probe protrudes to an end surface of a columnar member to a weld material in a state of being rotated, and move the tool in a state of being rotated, thereby welding two or more weld materials in accordance with a friction stirring, in which a cavity portion is provided in a part of a weld portion of the weld material, a member is formed in the cavity portion, and the weld material is welded by the friction stirring. In accordance with the invention, since an unwelded portion is not formed near the cavity portion, a notch effect is reduced, and it is possible to form the weld member which is excellent in the fatigue property.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a conceptual view showing a positional relation between a weld material and an embedded member in accordance with one example of a welding method of the present invention;

FIG. 2 is a conceptual view showing a state before welding in accordance with one example of the welding method of the present invention;

FIG. 3 is a conceptual view showing a state under welding in accordance with one example of the welding method of the present invention;

FIG. 4 is a view showing a defect generating condition in a weld portion having a cavity portion and a positional relation between a rotating tool and a weld member;

FIG. 5 is a view showing a cross sectional photograph in the weld portion using the embedded member;

FIG. 6 is a conceptual view in the case of applying a frictional stir welding method using the embedded member to a weld structure;

FIG. 7 is a conceptual view showing a positional relation between a weld material and an embedded member in accordance with one example of a lap welding method of the present invention;

FIG. 8 is a conceptual view showing a state before welding in accordance with one example of the lap welding method of the present invention;

FIG. 9 is a conceptual view showing a state under welding in accordance with one example of the lap welding method of the present invention;

FIG. 10 is a conceptual view showing a positional relation between a weld material and an embedded member in accordance with one example of a butt welding method of the present invention;

FIG. 11 is a conceptual view showing a state before welding in accordance with one example of the butt welding method of the present invention; and

FIG. 12 is a conceptual view showing a state under welding in accordance with one example of the butt welding method of the present invention;

Claims

1. A friction stir welding method of inserting a tool provided in such a manner that a pin-shaped probe protrudes to an end surface of a columnar member to a weld material in a state of being rotated, and move said tool in a state of being rotated, thereby welding two or more weld materials in accordance with a friction stirring, wherein a cavity portion is provided in a part of a weld portion of said weld material, a member is formed in said cavity portion, and said weld material is welded by the friction stirring.

2. A friction stir welding method as claimed in claim 1, wherein the method welds to a joint portion of said weld material in accordance with the friction stirring.

3. A friction stir welding method as claimed in claim 1, wherein the method welds from one of said weld materials in accordance with the friction stirring.

4. A friction stir welding method as claimed in claim 1, wherein said cavity portion has a circular shape.

5. A friction stir welding method as claimed in claim 1, wherein a member having an approximately equal cross sectional shape to that of said cavity portion is embedded in said cavity portion.

6. A friction stir welding method as claimed in claim 1, wherein said cavity portion has a circular arc shape with respect to a direction of the weld portion of said weld material.

7. A weld structure formed in a friction stir welding method of welding two or more weld materials in accordance with a friction stirring, wherein a cavity portion is provided in a part of a weld portion of said weld material, and a member is formed in said cavity portion.

8. A weld structure as claimed in claim 7, wherein a joint portion of said weld material is welded in accordance with a friction stirring.

9. A weld structure as claimed in claim 7, wherein the structure is welded from one of said weld materials in accordance with the friction stirring.

10. A weld structure as claimed in claim 7, wherein said cavity portion has a circular shape.

11. A weld structure welded in accordance with the friction stir welding method as claimed in claim 1.

12. A weld structure as claimed in claim 7, wherein a member having an approximately equal cross sectional shape to that of said cavity portion is embedded in said cavity portion.

13. A friction stir welding method as claimed in claim 1, wherein the member formed in said cavity portion is made of a harder material than said weld material.

14. A friction stir welding method as claimed in claim 4, wherein a radius of said cavity portion is equal to or less than one half of a thickness of said weld material.

15. A weld structure as claimed in claim 7, wherein the member formed in said cavity portion is made of a harder material than said weld material.

16. A weld structure as claimed in claim 10, wherein a radius of said cavity portion is equal to or less than one half of a thickness of said weld material.