US 12,220,765 B2
Butt welded joint of steel material and method for manufacturing same
Hiroyuki Okuhira, Moriya (JP); Rikiya Ishikawa, Itabashi-ku (JP); and Takuya Tadano, Taito-ku (JP)
Assigned to SMC CORPORATION, Chiyoda-ku (JP)
Appl. No. 17/252,915
Filed by SMC CORPORATION, Chiyoda-ku (JP)
PCT Filed Jun. 6, 2019, PCT No. PCT/JP2019/022446
§ 371(c)(1), (2) Date Dec. 16, 2020,
PCT Pub. No. WO2020/003950, PCT Pub. Date Jan. 2, 2020.
Claims priority of application No. 2018-122414 (JP), filed on Jun. 27, 2018.
Prior Publication US 2021/0260699 A1, Aug. 26, 2021
Int. Cl. B23K 26/282 (2014.01); B23K 26/32 (2014.01); B23K 101/04 (2006.01); B23K 103/04 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/44 (2006.01)
CPC B23K 26/282 (2015.10) [B23K 26/32 (2013.01); B23K 2101/04 (2018.08); B23K 2103/04 (2018.08); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/44 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A butt-welded joint of steel materials, base materials of the butt-welded joint being a pair of the steel materials, in a state in which end portions of the pair of the base materials are abutted against each other, the butt-welded joint comprising a welded portion formed in a circumferential direction along the end portions to extend from surfaces of the base materials to an inner portion of the base materials and straddle the end portions, wherein
the base materials have a carbon concentration of 0.1 mass % or greater and 0.35 mass % or less,
the welded portion includes a melted and solidified portion, a remelted and solidified portion, and a reheated solidified portion, the melted and solidified portion being a portion resulting from melting and solidification of the end portions of a pair of base materials made of the steel materials, the melting being caused as a result of first heating from the surfaces, the remelted and solidified portion being a portion resulting from remelting and resolidification of the melted and solidified portion, the remelting being caused as a result of reheating of the melted and solidified portion from a surface thereof, the reheated solidified portion being a portion formed in an inner region relative to the remelted and solidified portion and having a structure resulting from a change in a structure of the melted and solidified portion, the change being due to the reheating, the change involving no melting, and
a width W0 of the melted and solidified portion, a depth do from a surface of the welded portion to a deepest portion of the melted and solidified portion, a width W1 of the remelted and solidified portion, and a depth d1 from the surface of the welded portion to a deepest portion of the remelted and solidified portion have the following relationships:
0.46W0≤W1, and
0.14d0≤d≤0.73d0, and
in the welded portion formed in the circumferential direction along the end portions of the abutted base materials, a starting portion of the welded portion and a terminal portion thereof are formed to overlap each other at the same location in the circumferential direction, and at the location where the starting portion and the terminal portion overlap each other, a depth h, from the surface of the welded portion, of a recess formed in the remelted and solidified portion and a depth d1 of the remelted and solidified portion have the following relationship:
0.32d1>h.