Friction stir welding apparatus, system and method

• US 8,348,136 B1
• Filed: 02/20/2012
• Issued: 01/08/2013
• Est. Priority Date: 04/06/2010
• Status: Active Grant

• Current Assignee: United Launch Alliance LLC
• Original Assignee: United Launch Alliance LLC
• Inventors: Potter, David M., Hansen, Richard K.
• Primary Examiner(s): STONER, KILEY SHAWN
• Application Number:
  US13/400,339
• Time in Patent Office: 323 Days
• Field of Search: None
• US Class Current: 228/112.1
• CPC Class Codes: B23K 20/122 using a non-consumable tool, e.g. friction stir welding
• CPC Class Codes: B23K 20/126 Workpiece support, i.e. backing or clamping
• CPC Class Codes: B23K 2101/06 Tubes
• CPC Class Codes: B23K 37/0533 external pipe alignment clamps

Abstract

A method of performing friction stir welding is provided herein. More specifically, traditional friction stir welding requires a rotatable head that is forced against a plurality of work pieces to bond the same. The rotational and normal forces generated by the friction stir welding tool are generally reacted by a backing plate, anvil, mandrel or other mechanisms, such hardware are subject to the applied forces and are often supported with additional internal supports. Conversely, a method of performing a friction stir weld is described that omits the need for such a backing member and internal supports as it is performed using a self reacting pin tool.

Claims

1. A method for performing circumferential stir welding without an internal mandrel or internal supports, comprising:

providing a first arcuate outer surface;

providing a second arcuate outer surface;

orienting the first and second arcuate outer surfaces to be stacked vertically with respect to one another;

aligning said first arcuate outer surface and said second arcuate outer surface such that an end of each is abutted to form a seam;

providing a first ring assembly having a first inner ring, a first outer ring disposed radially outward from the first inner ring, and a plurality of first clamp assemblies extending radially inward beyond said first inner ring;

providing a second ring assembly having a second inner ring, a second outer ring disposed radially outward from the second inner ring, and a plurality of second clamp assemblies extending radially inward beyond said second inner ring;

positioning said first ring assembly and said second ring assembly adjacent to said seam, wherein said first ring assembly is spaced from said second ring assembly with said seam therebetween and wherein an inner surface of said first arcuate outer surface and said second arcuate outer surface are unsupported in a normal direction;

providing a stand that supports the first and second outer surfaces and the first and second ring assemblies in a vertical arrangement;

creating a bore in said first arcuate outer surface and said second arcuate outer surface wherein a portion of said bore is intersected by said seam;

placing a pin of a rotating tool within said bore;

forcing said tool onto said first arcuate outer surface and said second arcuate outer surface wherein said force is reacted by at least one of said first ring assembly and said second ring assembly and said force is not reacted with an internal mandrel;

rotating said tool;

translating said tool with respect to said first arcuate outer surface and said second arcuate outer surface to form a weld therebetween;

removing said pin from said seam to reveal a hole; and

plugging the hole.

2. The method of claim 1, further comprising

rotating said tool;

forcing said tool into a first point of seam to operatively contact said first arcuate outer surface and said second arcuate outer surface wherein said force is reacted only by at least one of said first ring assembly and said second ring assembly;

translating said tool with respect to said first arcuate outer surface and said second arcuate outer surface to form a first weld therebetween;

removing said pin from said seam;

forcing said tool into a second point of seam, which is spaced from said first point, to operatively contact said first arcuate outer surface and said second arcuate outer surface wherein said force is reacted only by at least one of said first ring assembly and said second ring assembly;

translating said tool with respect to said first arcuate outer surface and said second arcuate outer surface to form a second weld therebetween; and

removing said pin from said seam.

3. The method of claim 1, further comprising associating the pin with said seam a plurality of times to create tack welds in addition to said first weld and said second weld such that a the circumference of said seam has generally evenly spaced tack welds therearound.

4. The method of claim 2, wherein said first weld and said second weld are approximately 4.0 inches in length.

5. A method, as claimed in claim 1, further including:

changing a positioning of the first or second arcuate surfaces by adjusting corresponding the clamp assemblies of said first and second plurality of clamp assemblies.

6. A method, as claimed in claim 1, wherein:

said translating step further includes rotating the first and second ring assemblies relative to the rotating tool.

7. The method of claim 5, wherein at least one clamp assembly of said plurality first and second clamp assemblies includes a guide for engagement with at least one of said first plate and said second plate by way of an adjustable member associated with said at least one clamp.