公开(公告)号：US11964338B2

公开(公告)日：2024-04-23

申请号：US16080780

申请日：2017-02-28

Applicant: OSAKA UNIVERSITY

Inventor： Hidetoshi Fujii ,  Rintaro Ueji ,  Yoshiaki Morisada

IPC: B23K20/12 ,  B23K20/227 ,  B23K20/233 ,  B23K103/02 ,  B23K103/10

CPC classification number: B23K20/1235 ,  B23K20/1225 ,  B23K20/123 ,  B23K20/125 ,  B23K20/227 ,  B23K20/2336 ,  B23K2103/02 ,  B23K2103/10

Abstract: A low-temperature joining method effectively suppresses reductions in the mechanical properties of a junction of various types of high-tensile steel or aluminum, and of a heat-affected zone; and produces a joint structure. A method for joining two metal materials by forming a joint interface in which the two metal materials face each other at a joint portion and plunge a rotation tool caused to rotate at a prescribed speed into the joint, the method for low-temperature joining of metal materials characterized in that the peripheral velocity of the outermost periphery of the rotation tool is set to 51 mm/s or less, whereby the recrystallization temperature inherent to the metal materials is reduced by introducing a large strain to the joint, and recrystallized grains are generated at the joint interface by setting the joining temperature to less than the recrystallization temperature inherent to the metal materials.

公开(公告)号：US11872651B2

公开(公告)日：2024-01-16

申请号：US17775421

申请日：2020-10-28

Applicant: OSAKA UNIVERSITY

Inventor： Hidetoshi Fujii ,  Yoshiaki Morisada ,  Yasuhiro Aoki ,  Masayoshi Kamai

IPC: B23K20/00 ,  B23K20/16 ,  B23K20/12 ,  B23K20/227 ,  B23K103/20

CPC classification number: B23K20/16 ,  B23K20/1205 ,  B23K20/2275 ,  B23K2103/20

Abstract: A dissimilar material solid phase bonding method is disclosed wherein one member and another member having different compositions are brought into contact with one another by way of an insert material to form an interface (1) to be bonded, at which the one member and the insert material are in contact with one another, and an interface (2) to be bonded, at which the other member and the insert material are in contact with one another; the temperature of the interface (1) to be bonded and the interface (2) to be bonded is raised by means of frictional heat and/or by electrical heating; a bonding pressure (1) is applied substantially perpendicular to the interface (1) to be bonded; a bonding pressure (2) is applied substantially perpendicular to the interface (2) to be bonded; and the bonding pressure (1) and the bonding pressure (2) are set to different values.

公开(公告)号：US11745287B2

公开(公告)日：2023-09-05

申请号：US16981001

申请日：2019-02-22

Applicant: OSAKA UNIVERSITY

Inventor： Hidetoshi Fujii ,  Yoshiaki Morisada ,  Huihong Liu ,  Yasuhiro Aoki ,  Masayoshi Kamai

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

CPC classification number: B23K20/023 ,  B23K2103/04

Abstract: To provide a solid phase welding method and a solid phase welding apparatus which are possible to accurately control the welding temperature, to lower the welding temperature and to achieve a solid phase welding of the metallic materials. The present invention provides a solid phase welding method for metallic materials comprising, a first step of forming an interface to be welded by abutting end portions of one material to be welded and the other material to be welded and applying a pressure in a direction substantially perpendicular to the interface to be welded, a second step of raising a temperature of the vicinity of the interface to be welded to a welding temperature by an external heating means, wherein the pressure is set to equal to or more than the yield strength of the one material to be welded and/or the other material to be welded at the welding temperature.

公开(公告)号：US11534854B2

公开(公告)日：2022-12-27

申请号：US15734338

申请日：2019-05-28

Applicant: OSAKA UNIVERSITY

Inventor： Hidetoshi Fujii ,  Yoshiaki Morisada ,  Yasuhiro Aoki ,  Akihiko Ikuta

IPC: B23K20/00 ,  B23K20/12 ,  B23K103/14 ,  B23K103/02

Abstract: Provided are a long-life and inexpensive friction stir welding tool that is not dependent on the mode of friction stir welding or the type of material to be welded, and a friction stir welding method using the friction stir welding tool. The friction stir welding tool comprises a body portion having a shoulder portion, and a probe portion disposed on a bottom surface of the body portion, and is characterized in that the probe portion is spherical-crown shaped. Preferably, the shoulder portion is flat or convex, and preferably the hardness of the shoulder portion is greater than the hardness of the probe portion.

公开(公告)号：US20220162723A1

公开(公告)日：2022-05-26

申请号：US17441569

申请日：2020-03-02

Applicant: OSAKA UNIVERSITY

Inventor： Hidetoshi Fujii ,  Yoshiaki Morisada ,  Yasuhiro Aoki

IPC: C21D10/00 ,  B23K20/12 ,  C22C38/16 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00

Abstract: Provided are an effective and simple surface-modifying method for prolonging the life of a steel structure made of a steel material having a high sulfur (S) content, and a steel structure having a life prolonged by the surface-modifying method. A surface-modifying method for forming a friction stir region on the surface of a steel material by friction stir processing, wherein a sulfur (S) content of the steel material is 200 ppm or more.

公开(公告)号：US20220145435A1

公开(公告)日：2022-05-12

申请号：US17435875

申请日：2020-02-20

Applicant: OSAKA UNIVERSITY

Inventor： Hidetoshi Fujii ,  Kohsaku Ushioda ,  Tomoya Nagira ,  Yoshiaki Morisada

IPC: C22C38/20 ,  B23K20/12 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00

Abstract: The present invention provides a weathering steel for solid-state welding that forms an excellent weld when subjected to solid-state welding and has tensile properties equivalent or superior to those of high tensile strength steel, said steel having weathering properties superior to those of conventional weathering steel for welding, wherein the reliability of the weld is equivalent or superior to that of the parent material; and a weathering steel material for solid-state welding. Further, there is provided a solid-state welded structure that includes the weathering steel for solid-state welding according to the present invention, and a solid-state welding method for said weathering steel for solid-state welding. The weathering steel for solid-state welding having a steel composition comprises, in % by mass, C: 0.10 to 0.60% and P: more than 0.035 to 1.000%, with the remainder consisting of Fe and unavoidable impurities.

公开(公告)号：US11110542B2

公开(公告)日：2021-09-07

申请号：US16494916

申请日：2018-03-09

Applicant: OSAKA UNIVERSITY

Inventor： Hidetoshi Fujii ,  Yoshiaki Morisada ,  Yasuhiro Aoki

IPC: B23K20/00 ,  B23K20/12 ,  B23K101/20 ,  B23K103/04

Abstract: The present invention provides a friction welding method capable of reducing the welding temperature and a friction welding method capable of obtaining a welded portion free of defects regardless the type of material. A frictional welding method in which one member is brought into contact with the other member and slides while a load is applied substantially perpendicularly to the interface to be welded, the frictional welding method comprising: a first step in which frictional welding is carried out by setting a pressure calculated from the area and the load of the interface to be welded to be equal to or higher than the yield stress and the tensile strength of one member and/or the other member at a desired welding temperature; and a second step in which frictional welding is carried out by lowering the load, wherein the first step and the second step are continuously carried out.

公开(公告)号：US20210205918A1

公开(公告)日：2021-07-08

申请号：US16080780

申请日：2017-02-28

Applicant: OSAKA UNIVERSITY

Inventor： Hidetoshi Fujii ,  Rintaro Ueji ,  Yoshiaki Morisada

IPC: B23K20/12 ,  B23K20/227 ,  B23K20/233

Abstract: A low-temperature joining method effectively suppresses reductions in the mechanical properties of a junction of various types of high-tensile steel or aluminum, and of a heat-affected zone; and produces a joint structure. A method for joining two metal materials by forming a joint interface in which the two metal materials face each other at a joint portion and plunge a rotation tool caused to rotate at a prescribed speed into the joint, the method for low-temperature joining of metal materials characterized in that the peripheral velocity of the outermost periphery of the rotation tool is set to 51 mm/s or less, whereby the recrystallization temperature inherent to the metal materials is reduced by introducing a large strain to the joint, and recrystallized grains are generated at the joint interface by setting the joining temperature to less than the recrystallization temperature inherent to the metal materials.

公开(公告)号：US09617613B2

公开(公告)日：2017-04-11

申请号：US14384876

申请日：2013-03-12

Applicant: OSAKA UNIVERSITY

Inventor： Hidetoshi Fujii ,  Yoshiaki Morisada

IPC: B23K20/12 ,  C21D8/00 ,  C21D9/50 ,  C21D7/04 ,  C21D9/46

CPC classification number: C21D8/005 ,  B23K20/122 ,  C21D7/04 ,  C21D9/46 ,  C21D9/50 ,  C21D2211/001 ,  C21D2211/008

Abstract: A base material of a ferrous material is heated to an AC1 point, which is a temperature to cause austenite appearance, or higher, and austenite appears in the base material 1a and 1b (S101). An amount of a strain assuming that an Mf point, which is a temperature where the base material becomes martensite completely, is decreased to be less than room temperature is introduced into the base material (S102). The all ferrous material becoming martensite on the occasion of cooling the ferrous material to room temperature is prevented. The base material is cooled to room temperature at a cooling rate where a line extrapolated a cooling curve of the base material intersects with a region where martensite is produced on the CCT diagram (S103). Austenite remains in the manufactured ferrous material at room temperature.