Agency of Industrial Science and Technology Ministry of International

National Institute of Advanced Industrial Science and Technology

Komatsuseiki Kosakusho Co., Ltd.

Agency of Industrial Science and Technology

Ministry of International Trade & Industry

Masahito Katoh

Kenichi Hibino

Tomomi Shiratori

Yasunori Torisaka

Yoshinori Nakawawa

Kiyoshi Ichikawa

A method for bonding stainless steel members includes: contacting a first stainless steel member with a second stainless steel member that has a strain exceeding 50% reduction; and heating the first and second stainless steel members to a re-crystallization initiation temperature or higher, after the contacting.

Method for bonding stainless steel members and stainless steel

A method of manufacturing metallic materials with extremely fine crystal grains comprises the steps of: taking molten metallic material that was melted by heating in a melting chamber and introducing it into an agitation chamber from said melting chamber, and in this agitation chamber, agitating it for 60 seconds or less by means of a screw-shaped stirring rod that is driven to rotate at 500 rpm or greater, and extruding the metallic material in the state of solid-liquid coexistence from an extrusion nozzle on the outlet side, and quench-solidifying the metallic material in the state of solid-liquid coexistence extruded from said nozzle immediately while it still has fine crystal grains as it is continuously formed into the desired shape. In this method, the speed of rotation of the screw-shaped stirring rod may be 800 to 1000 rpm. Also, the time in which the metallic material resides in the state of solid-liquid coexistence may be 5 to 60 seconds.

Method of manufacturing metallic materials with extremely fine crystal

An elastically deformable die includes two or more die members formed of materials exhibiting different degrees of elastic deformation under the same stress which are combined and arranged such that the elastic deformation thereof under the pressure received from a workpiece during a forming operation causes the surface of the die in contact with the workpiece to be formed to a prescribed configuration. In die forming the composite die is brought in contact with a surface of the workpiece, the die is elastically deformed at the surface of contact by the pressure received from the workpiece during the forming process, and the workpiece is formed to the prescribed configuration by this deformation.

Elastically deformable die and method of die forming using the die

A method of die forming using an elastically deformable die is characterized by using a die provided in advance with a prescribed pattern of thickness variation, allowing the die to be elastically deformed by the pressure it receives from the material being formed during the forming operation, and forming the material to the configuration resulting from the deformation.

Method of die forming using elastically deformable die

A high-strength low-ductility material is formed by a method which comprises treating a bulk or powder of the material thereby converting coarse grains thereof into hyperfine grains capable of manifesting superplasticity when the strain rate is higher than 5.times.10.sup.-3 s.sup.-1, enclosing the treated material with a metallic insulating member, heating the material to a temperature for manifestation of superplasticity, and forging the material by the use of a die in a state heated to a temperature beyond which the die yields to heat.

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Tsukuba, Japan

Masahito Katoh