US 12,305,246 B2
Needle-peening method
Tsuyoshi Shiozaki, Tokyo (JP); and Naoki Yamaguchi, Tokyo (JP)
Assigned to JFE Steel Corporation, Tokyo (JP)
Appl. No. 17/436,272
Filed by JFE Steel Corporation, Tokyo (JP)
PCT Filed Nov. 7, 2019, PCT No. PCT/JP2019/043633
§ 371(c)(1), (2) Date Sep. 3, 2021,
PCT Pub. No. WO2020/183783, PCT Pub. Date Jul. 17, 2020.
Claims priority of application No. 2019-042366 (JP), filed on Mar. 8, 2019.
Prior Publication US 2022/0177988 A1, Jun. 9, 2022
Int. Cl. C21D 7/06 (2006.01)
CPC C21D 7/06 (2013.01) 5 Claims
OG exemplary drawing
 
1. A needle-peening method of peening a weld toe of a welded joint for welding and joining two pieces of sheet metal by using a plurality of peening pins,
the method comprising:
vibrating the plurality of the peening pins in a center axis direction, wherein center axes of each of the plurality of the peening pins is parallel to each other;
rotating the plurality of the peening pins about one rotation axis parallel to the center axes of the plurality of the peening pins while at least one of the plurality of the peening pins is rotated about an offset rotation axis; and
moving the plurality of the peening pins along a welding direction to peen the weld toe, wherein
a radius of curvature of a cross section perpendicular to the welding direction at a distal end part of each of the plurality of the peening pins is equal to or larger than 0.05 mm and smaller than 1.00 mm.