公开(公告)号：US20200378420A1

公开(公告)日：2020-12-03

申请号：US16636788

申请日：2018-08-20

Applicant: NIPPON STEEL CORPORATION

Inventor： Kazuki MATSUDA ,  Shinji KODAMA ,  Kotaro WATANABE ,  Masatoshi TOKUNAGA

IPC: F16B5/08

Abstract: A lap fillet arc welded joint includes: a first steel sheet and a second steel sheet which are overlapped each other, the first steel sheet and the second steel sheet each having a tensile strength of 950 MPa or more; and a weld metal which extends along a corner formed by an upper surface of the first steel sheet and an end surface of the second steel sheet. When: a toe angle of the weld metal is defined as β; the total number of concave portions present on the surface of the weld metal included a range of 0.4 mm or less from a fusion boundary is defined as NA; and the number of concave portions in contact with ferrite grains having a maximum grain size of 10 μm or more is defined as NB, the weld metal satisfies the following conditional expressions (1) and (2) at the same time. 0°

公开(公告)号：US20250033137A1

公开(公告)日：2025-01-30

申请号：US18837140

申请日：2023-03-20

Applicant: NIPPON STEEL CORPORATION

Inventor： Masanori YASUYAMA ,  Yasuaki NAITO ,  Takashi IMAMURA ,  Masatoshi TOKUNAGA ,  Naoaki SHIMADA

IPC: B23K20/02 ,  B23K103/04 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04

Abstract: A method for manufacturing a projection weld joint according to the present disclosure includes: pressing a projection portion of a steel member having the projection portion on a plane onto a surface of a hot-stamping steel sheet, wherein the hot-stamping steel sheet has an Al-based plating layer on the surface and has a tensile strength of 1.5 GPa or more; applying first energization to the hot-stamping steel sheet, the projection portion, and the steel member to make the projection portion serve as a projection weld; quenching the projection weld; and applying second energization to the quenched projection weld to temper edges of the projection weld while keeping a central part of the projection weld quenched.

公开(公告)号：US20250144737A1

公开(公告)日：2025-05-08

申请号：US18835943

申请日：2022-12-23

Applicant: NIPPON STEEL CORPORATION ,  TOYODA IRON WORKS CO., LTD.

Inventor： Masanori YASUYAMA ,  Masafumi AZUMA ,  Gen MURAYAMA ,  Takashi IMAMURA ,  Masatoshi TOKUNAGA ,  Koichi OI ,  Yoshinori OYAMA ,  Osamu KAWAGUCHI

IPC: B23K11/14 ,  B23K11/16 ,  B23K11/24 ,  C22C38/02 ,  C22C38/04

Abstract: A method for manufacturing a projection weld joint according to an aspect of the present invention includes: a first energizing step of energizing a steel sheet and a steel member so as to form a plurality of joint portions by projection welding a steel member to a first surface of a steel sheet that is a non-coated steel sheet or a zinc-type-coated steel sheet, in which the steel sheet has a tensile strength of 1.5 GPa or more, and the steel sheet has a Ceq of 0.30 mass % or more, and the manufacturing method further includes: a cooling step of quenching each of the plurality of joint portions; and a second energizing step of further energizing the steel sheet and the steel member so as to temper an end region in each of the plurality of joint portions.