Sumitomo Metal Industries, Inc.

Yuuichi Komizo

Masakatsu Ueda

Yasuto Fukada

Hiroyuki Hirata

Masahiko Hamada

The present invention provides (1) diffusion bonding methods for joining metallic materials like carbon steels or stainless steels,interposing a bonding material, such as 10 to 80 .mu.m thick Ni-based alloy with the melting point of 1150.degree. C. or lower,between base materials, heating so that the length heated at 800.degree. C. or above measures from 3 to 20 mm, in case of joining stainless steels a bonded layer, further, being heated between the both melting points, and applying the compressive stress, for example 0.5 to 2 kgf/mm.sup.2, so that a lateral expansion ratio is made within 1.0 to 1.1, and (2) a joined structure having the bonded joint formed thereby.

Method for joining metallic materials by diffusion bonding and joined

The method provides a diffusion-bonding of dual-phase stainless steel material having excellent strength and corrosion. The method includes: cold-working a material to be bonded so as to enhance the proof stress; inserting into the bonding portion an insert material; applying pressure thereto while performing shielding by mixed nitrogen/argon gas; heating the restricted bonding portion; cooling at a restricted rate; so as to form a bonded portion having the ferritic phase percentage of 30-70% by volume.

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Nishinomiya, Japan

Yuuichi Komizo