Method of friction stir welding

A method of friction stir welding a first member and a second member to form a friction stir weld joint therebetween, the method comprising:

• providing a stir tool configured to rotate about and move along a stir tool axis and comprising a pin with a pin axial end surface and a pin tapered surface that extends radially outwardly at a pin angle from the pin axial end surface, the pin angle being measured from the stir tool axis;
• providing the first member, the first member comprising first member faying surface,
• providing the second member, the second member comprising a second member top surface and a second member faying surface extending therefrom;
• forming a joint interface between the first member and the second member by abutting at least a portion of the first member faying surface with at least a portion of the second member faying surface, the joint interface being disposed at a joint interface angle measured from a line normal to the second member top surface;
• rotating the pin of the stir tool;
• and
• contacting the rotating pin of the stir tool with the second member faying surface,
• wherein the pin angle of the stir tool and the joint interface angle are approximately equal and the stir tool plasticizes the first member and the second member proximate to the joint interface thereby forming the friction weld joint.

A method of friction stir welding a first member and a second member to form a friction stir weld joint therebetween, the method comprising:

• providing a stir tool configured to rotate about a stir tool axis and comprising a pin;
• providing the first member comprising a first member faying surface;
• providing the second member comprising a second member faying surface;
• forming a joint interface between the first and second members by positioning the first and second members such that at least a portion of the first member faying surface abuts at least a portion of the second member faying surface;
• rotating the pin of the stir tool;
• moving the rotating pin of the stir tool across the joint interface;
• and
• removing heat from the first member,
• wherein the stir tool plasticizes and joins the first member and the second member proximate to the joint interface.