Ferritic stainless steel for heat exchanger

• US 5,512,239 A
• Filed: 04/18/1995
• Issued: 04/30/1996
• Est. Priority Date: 04/22/1994
• Status: Expired due to Term

• Current Assignee: IHI Aerospace Company Limited (IHI Corporation), Nippon Yakin Kogyo Company Limited, Tokyo Radiator Manufacturing Company Limited
• Original Assignee: Nippon Yakin Kogyo Company Limited, Nissan Motor Co., Ltd., Tokyo Radiator Manufacturing Company Limited
• Inventors: Fujiwara, Yoshito, Kimura, Mituo, Takamura, Tohsaku, Iio, Masatoshi, Kobayashi, Yutaka
• Primary Examiner(s): Yee, Deborah
• Application Number:
  US08/423,377
• Time in Patent Office: 378 Days
• Field of Search: 420/68, 420/69, 148/325
• US Class Current: 420/68
• CPC Class Codes: C22C 38/26 with niobium or tantalum
• CPC Class Codes: C22C 38/28 with titanium or zirconium
• CPC Class Codes: F28F 21/082 from steel or ferrous alloys

Abstract

A ferritic stainless steel comprises C: not more than 0.025 wt %, Si: not more than 0.10 wt %, Mn: not more than 1.0 wt %, Cr: 17.0-25.0 wt %, Ni: not more than 0.50 wt %, Mo: 0.50-2.00 wt %, Al: not more than 0.025 wt %, N: not more than 0.025 wt %, at least one of Nb: 10(C wt %+N wt %)-1.0 wt % and Ti: 10(C wt %+N wt %)-1.0 wt %, and the balance being substantially Fe and inevitable impurities and is effectively used in various heat exchangers.

Claims

1. A ferritic stainless steel for heat exchangers consisting essentially of:

not more than 0.015 wt % of C;

not more than 0.05 wt % of Si;

not more than 1.0 wt % of Mn;

18.0-20.0 wt % of Cr;

not more than 0.50 wt % Ni;

0.70-1.00 wt % of Mo;

not more than 0.020 wt % of Al;

not more than 0.015 wt % of N;

at least one of Nb in an amount of 15(C wt %+N wt %)-0.7 wt %, and Ti in an amount of 15(C wt %+N wt %)-0.7 wt %; and

a balance of substantially Fe and inevitable impurities.