Nippon Steel & Sumikin Stainless Steel Corporation

Hiroshi Urashima

Toshio Tanoue

Hiroshige Inoue

Yoshiharu Inoue

Shinichi Teraoka

Shunji Sakamoto

Shinji Tsuge

Yuusuke Oikawa

Ryo Matsuhashi

An automotive member or oil filler pipe includes: a member of ferritic stainless steel containing, in mass %, at most 0.015% of C, at most 0.015% of N, 10.5 to 18.0% of Cr, 0.01 to 0.80% of Si, 0.01 to 0.80% of Mn, at most 0.050% of P, at most 0.010% of S, 0.010 to 0.100% of Al, more than 0.3 to 1.5% of Mo, and one or both of 0.03 to 0.30% of Ti and Nb; and a metal fitting of an aluminized stainless steel sheet, which is attached to the member to define therebetween a gap structure to be exposed to a chloride environment, and has an Al-plating weight per unit area ranging from 20 to 150 g/min the gap structure. Surfaces of the metal fitting and member not facing the gap are coated with a cation electrodeposition coating film having a thickness of 5 to 35 &#x3bc;m.

Inexpensive automobile component and oil feed pipe having excellent salt corrosion resistance

An automotive member or a feed oil pipe includes: a member made of a ferritic stainless steel containing predetermined components containing 10.5% to 18.0% of Cr in mass %; a metal fitting made of an aluminized stainless steel sheet, the metal fitting being attached to the member; and a gap structure defined between the member and the metal fitting, the gap structure being exposed to a chloride environment, where the metal fitting has an Al-plating weight per unit area of 20 g/mor more and 150 g/mor less on a surface corresponding to a gap of the gap structure, and surfaces of the metal fitting and the non-aluminized member other than the gap are coated with a cation electrodeposition coating film having a thickness of 5 &#x3bc;m to 35 &#x3bc;m.

Inexpensive automotive member and feed oil pipe, exhibiting excellent salt corrosion resistance

The present invention provides a lean duplex stainless steel able to suppress the drop in corrosion resistance and toughness of a weld heat affected zone comprising, by mass %, C: 0.06% or less, Si: 0.1 to 1.5%, Mn: 2.0 to 4.0%, P: 0.05% or less, S: 0.005% or less, Cr: 19.0 to 23.0%, Ni: 1.0 to 4.0%, Mo: 1.0% or less, Cu: 0.1 to 3.0%, V: 0.05 to 0.5%, Al: 0.003 to 0.050%, O: 0.007% or less, N: 0.10 to 0.25%, and Ti: 0.05% or less, having a balance of Fe and unavoidable impurities. An Md30 value is 80 or less, an Ni-bal is &#x2212;7.1 to 4, an austenite phase area percentage is 40 to 70%, and a 2&#xd7;Ni+Cu is 3.5 or more: Md30=551&#x2212;462&#xd7;(C+N)&#x2212;9.2&#xd7;Si&#x2212;8.1&#xd7;Mn&#x2212;29&#xd7;(Ni+Cu)&#x2212;13.7&#xd7;Cr&#x2212;18.5&#xd7;Mo&#x2212;68&#xd7;Nb; Ni-bal=(Ni+0.5Mn+0.5Cu+30C+30N)&#x2212;1.1(Cr+1.5Si+Mo+W)+8.2 and N(%)&#x2266;0.37+0.03&#xd7;(Ni-bal).

Lean duplex stainless steel excellent in corrosion resistance and toughness of weld heat affected zone

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Tokyo, Japan

Hiroshi Urashima