Patent ID: 6622904
Filing Date: 2003-09-23
Classification: B23K

Abstract:
A friction stir welding method comprising the steps of:butting an end portion of a first plate against an end portion of a second plate, which second plate has a raised portion projecting beyond one surface of said second plate, said raised portion being projected in the thickness direction of said plate from one surface of the butted end portion of said first plate; and performing friction stir welding using a rotary tool including a small-diameter portion at the leading end of a large-diameter portion, by inserting said small-diameter portion into the butted region at said first plate and said second plate; wherein a part of said large-diameter portion is inserted into said raised portion; said rotary tool is rotated clockwise and moved relatively along said butted region, as seen from said large-diameter portion side; said second plate is positioned rightwards from the axial center of said rotary tool, as seen in said direction of movement; said raised portion is positioned leftwards from the axial center of said rotary tool; and no raised portion is placed in a region of the friction stir welding where higher pressure of the fluidized metal, during the friction stir welding, occurs, said region where higher pressure of fluidized metal occurs being defined by the direction of rotation and of movement of the rotary tool.