US 12,097,569 B2
Joined structure and method for manufacturing joined structure
Kyohei Maeda, Kanagawa (JP); and Reiichi Suzuki, Kanagawa (JP)
Assigned to Kobe Steel, Ltd., Kobe (JP)
Appl. No. 17/292,141
Filed by Kobe Steel, Ltd., Kobe (JP)
PCT Filed Sep. 19, 2019, PCT No. PCT/JP2019/036843
§ 371(c)(1), (2) Date May 7, 2021,
PCT Pub. No. WO2020/105266, PCT Pub. Date May 28, 2020.
Claims priority of application No. 2018-216804 (JP), filed on Nov. 19, 2018.
Prior Publication US 2021/0394299 A1, Dec. 23, 2021
Int. Cl. B23K 11/34 (2006.01); B23K 11/11 (2006.01); B23K 11/16 (2006.01); C21D 3/04 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); B23K 103/04 (2006.01)
CPC B23K 11/34 (2013.01) [B23K 11/115 (2013.01); B23K 11/163 (2013.01); C21D 3/04 (2013.01); C22C 38/002 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); B23K 2103/04 (2018.08)] 16 Claims
OG exemplary drawing
 
1. A joint structure, comprising:
a first member comprising a high tensile strength steel;
a second member comprising a high tensile strength steel and superposed on the first member;
a surface soft layer formed on at least one of a superposition surface of the first member, on which the second member is superposed, and a superposition surface of the second member, on which the first member is superposed;
a molten-solidified portion formed by melting and solidifying the first member and the second member; and
a heat affected zone formed around the molten-solidified portion,
wherein the surface soft layer has a total thickness of 5 μm or more and 200 μm or less, and the molten-solidified portion has a carbon amount of 0.21 mass % or more, and
a maximum Vickers hardness of the surface soft layer in the heat affected zone is 100 Hv or more and 500 Hv or less.