Friction stir welding method

A weld body, characterized in that

• a first member and a second member are carried out in a ring shape according to a friction stir welding;
• the friction stir welding is carried out from a side of one face of said first member;
• and
• by continuing to said portion in which the friction stir welding has been carried out, in a radial direction outer side of said ring shape members, the weld body has a portion which is welded according to a second friction stir welding;
• and
• an end portion of said portion which is subjected to welding according to the second friction stir welding is positioned to an end face of a radial direction outer side or a radial direction inner side of said first member or said second member.

A machine tool comprises:

• a table for enable to rotate a face for fixing a pair of members in a vertical face or in a horizontal face;
• and
• a main shaft opposed to said horizontal face or said vertical face and having an axis center along to a horizontal direction or a vertical direction and further enable to rotate under a state in which a friction stir welding use rotary tool is installed to a tip end thereof;
• the machine tool, characterized in that
• as to a direction of said table, in a rotation direction of said table, a side of a small diameter portion of an axis center of said rotary tool is positioned in a rear portion from a side of a large diameter portion of said rotary tool, and said axis center of said rotary tool is enable to incline.

A machine tool comprises:

• a table for enable to rotate a face for fixing a pair of members;
• and
• a main shaft in which an axis center is inclined against a horizontal face or a vertical face of said table and being enable to rotate under a state in which a friction stir welding use rotary toll is installed to a tip end thereof;
• the machine tool, characterized in that
• as to an inclination of said main shaft, in a rotation direction of said table, a side of a small diameter portion of an axis center of said rotary tool is positioned in a rear portion from a large diameter portion of said rotary tool, and said axis center of said rotary tool is enable to incline.