US 12,434,326 B2
Method for friction stir welding or processing high strength steel
Bryan Macek, Rochester Hills, MI (US)
Assigned to FCA US LLC, Auburn Hills, MI (US)
Filed by FCA US LLC, Auburn Hills, MI (US)
Filed on Sep. 26, 2023, as Appl. No. 18/474,290.
Prior Publication US 2025/0100069 A1, Mar. 27, 2025
Int. Cl. B23K 20/00 (2006.01); B23K 20/12 (2006.01); B23K 20/24 (2006.01); B23K 20/26 (2006.01); B23K 103/04 (2006.01)
CPC B23K 20/1235 (2013.01) [B23K 20/24 (2013.01); B23K 20/26 (2013.01); B23K 2103/04 (2018.08)] 4 Claims
OG exemplary drawing
 
1. A method of processing high-strength steel comprising:
providing a first piece of high-strength steel having a tensile strength between 590 MPa and 2000 MPa;
friction stir processing the first piece of high-strength steel by;
pre-heating a preheating zone area in advance of a friction stir welding tool; and
moving the friction stir welding tool between 500 mm and 3000 mm per minute to attain a mixed zone having a mixed zone temperature at the mixed zone between a eutectoid temperature of the high-strength steel of 727 C and a forge welding temperature of the high-strength steel of 1500 C from a combination of the friction from the friction welding tool and the step of pre-heating, wherein the step of pre-heating provides more than half of a heat at the mixed zone and moving the friction stir welding tool provides less than half of the heat at the mixed zone.