Toyota Jidosha Kabushiki Kaisha

Nippon Steel Corporation

Fuminori Matsuda

Yasuo Takahashi

Takao Nomura

Hatsuhiko Oikawa

Masahito Ito

Tohru Saito

Yutaka Okuda

Goro Watanabe

Hiroshi Sarai

Miyuki Koujiya

Katsutoshi Ueno

Seiya Nakao

Satoru Kitou

Susumu Yamada

Hiroshi Mihara

Kesato Kuroiwa

Kazuo Narita

The present invention relates to a resistance welding method suitable for use in spot welding between a steel-base metal sheet, which has been plated for rust prevention purposes, and an aluminum-base metal sheet and aims to permit a current to flow at a high density across the plated steel sheet and the aluminum-clad steel sheet, thereby realizing high-quality welding. An aluminum-clad steel sheet comprised of a steel layer having projections and an aluminum layer is interposed between the plated steel sheet and the aluminum-base metal sheet to be welded to each other. An electrode is energized by a predetermined weld current from an alternating power supply. The current path is limited to the area of the projections, and metallic melt formed by melting of the plating is accommodated between the projections, preventing the current-carrying area from being increased. Consequently, the temperature of the interface of the plated steel sheet and the aluminum-clad steel sheet can be efficiently raised, resulting in the formation of a proper nugget on both sides of the aluminum-clad steel sheet.

Method and material for resistance welding steel-base metal sheet to

A method of producing a metal mold is disclosed. A heat resistant sheet is forcedly brought into close contact with a product configuration surface of a matrix such as a wooden pattern, a resin model, or the like by making use of negative pressure. The matrix is brought into contact with a melt of a low melting-point alloy while that state of close contact is being maintained and the melt is allowed to cool as it is, thereby casting one part of the mold which makes up a pair. The matrix is then removed, and by using the one part of the mold thus cast as a new matrix, this new matrix is brought into contact with the melt of a low melting-point alloy via the heat resistant rubber sheet and is allowed to cool as it is, thereby casting a counterpart of the mold that makes up the pair.

Method of producing a metal mold

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Toyota, Japan

Fuminori Matsuda