Title:
HIGH-STRENGTH ELECTRICAL-RESISTANCE-WELDED STEEL PIPE AND MANUFACTURING METHOD THEREFOR
Document Type and Number:
WIPO Patent Application WO/2011/118841
Kind Code:
A1
Abstract:
The disclosed high-strength electrical-resistance-welded steel pipe is suitable for use as an automobile shock-absorbing member. Said steel pipe contains, by mass, between 0.05% and 0.20% carbon, between 0.5% and 2.0% silicon, between 1.0% and 3.0% manganese, at most 0.1% phosphorus, at most 0.01% sulfur, between 0.01% and 0.1% aluminum, and at most 0.005% nitrogen, with the remainder comprising iron and unavoidable impurities. Said steel pipe has a two-phase structure comprising a ferrite phase and a martensite phase, with the volume fraction of the martensite phase between 20% and 60%. The disclosed steel pipe has a tensile strength (TS) of at least 1,180 MPa, an axial elongation (El) of at least 10%, and a yield ratio of less than 90%. After a coating baking process in which the steel pipe is prestressed by 2% and then heat-treated at 170°C for 10 minutes, the amount of strength increase (BH amount) is at least 100 MPa and the yield ratio increases to at least 90%.
Inventors:
ARATANI, Masatoshi (JFE STEEL CORPORATION 2-3, Uchisaiwai-cho 2-chome, Chiyoda-k, Tokyo 11, 〒1000011, JP)
荒谷 昌利 (〒11 東京都千代田区内幸町二丁目２番３号JFEスチール株式会社知的財産部内 Tokyo, 〒1000011, JP)
KAWABATA, Yoshikazu (JFE STEEL CORPORATION 2-3, Uchisaiwai-cho 2-chome, Chiyoda-k, Tokyo 11, 〒1000011, JP)
河端 良和 (〒11 東京都千代田区内幸町二丁目２番３号JFEスチール株式会社知的財産部内 Tokyo, 〒1000011, JP)
荒谷 昌利 (〒11 東京都千代田区内幸町二丁目２番３号JFEスチール株式会社知的財産部内 Tokyo, 〒1000011, JP)
KAWABATA, Yoshikazu (JFE STEEL CORPORATION 2-3, Uchisaiwai-cho 2-chome, Chiyoda-k, Tokyo 11, 〒1000011, JP)
河端 良和 (〒11 東京都千代田区内幸町二丁目２番３号JFEスチール株式会社知的財産部内 Tokyo, 〒1000011, JP)
Application Number:
JP2011/057928
Publication Date:
September 29, 2011
Filing Date:
March 23, 2011
Export Citation:
Assignee:
JFE STEEL CORPORATION (2-3 Uchisaiwai-cho 2-chome, Chiyoda-ku Tokyo, 11, 〒1000011, JP)
JFEスチール株式会社 (〒11 東京都千代田区内幸町二丁目２番３号 Tokyo, 〒1000011, JP)
ARATANI, Masatoshi (JFE STEEL CORPORATION 2-3, Uchisaiwai-cho 2-chome, Chiyoda-k, Tokyo 11, 〒1000011, JP)
荒谷 昌利 (〒11 東京都千代田区内幸町二丁目２番３号JFEスチール株式会社知的財産部内 Tokyo, 〒1000011, JP)
KAWABATA, Yoshikazu (JFE STEEL CORPORATION 2-3, Uchisaiwai-cho 2-chome, Chiyoda-k, Tokyo 11, 〒1000011, JP)
JFEスチール株式会社 (〒11 東京都千代田区内幸町二丁目２番３号 Tokyo, 〒1000011, JP)
ARATANI, Masatoshi (JFE STEEL CORPORATION 2-3, Uchisaiwai-cho 2-chome, Chiyoda-k, Tokyo 11, 〒1000011, JP)
荒谷 昌利 (〒11 東京都千代田区内幸町二丁目２番３号JFEスチール株式会社知的財産部内 Tokyo, 〒1000011, JP)
KAWABATA, Yoshikazu (JFE STEEL CORPORATION 2-3, Uchisaiwai-cho 2-chome, Chiyoda-k, Tokyo 11, 〒1000011, JP)
International Classes:
C22C38/06; B21C37/08; C21D8/02; C21D9/46; C22C38/58
Attorney, Agent or Firm:
OCHIAI, Kenichiro (7th floor Yanagiya building, 1-10, Nihonbashi 2-chome, Chuo-k, Tokyo 27, 〒1030027, JP)
Claims:
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