HIGH-STRENGTH BOLT EXCELLENT IN DELAYED FRACTURE RESISTANCE CHARACTERISTICS AND ITS STEEL PRODUCT

Title:

HIGH-STRENGTH BOLT EXCELLENT IN DELAYED FRACTURE RESISTANCE CHARACTERISTICS AND ITS STEEL PRODUCT

Document Type and Number:

WIPO Patent Application WO/2002/077467

Kind Code:

A1

Abstract:

A high-strength bolt having a bolt tensile strength of at least 1200 N/mm?2¿ and being excellent in delayed fracture resistance characteristics and its steel product. A high-strength bolt having its head and shank formed of a steel product, wherein the steel product is so regulated in quality that the relation between a bolt tensile strength TS (N/mm?2¿) and a tempering temperature T (°C) satisfies the following expression (1), the relation between the bolt tensile strength TS and a carbon equivalent C¿eq? (%) calculated from its chemical components satisfies the following expression (2), and a bolt tensile strength by hardening and tempering ranges from 1200 N/mm?2¿ to 1600 N/mm?2¿. TS $m(F) 1.1T + 850 .....(1) TS $m(F) 550C¿eq? +1000 ....(2) where, C¿eq? = C + (Mn/6) + (Si/24) + (Ni/40) + (Cr/5) + (Mo/4) + (V/14).

Inventors:

UNO NOBUYOSHI (JP)
KANISAWA HIDEO (JP)

Application Number:

PCT/JP2002/002796

Publication Date:

October 03, 2002

Filing Date:

March 22, 2002

Export Citation:

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Assignee:

NIPPON STEEL CORP (JP)
UNO NOBUYOSHI (JP)
KANISAWA HIDEO (JP)

International Classes:

C21D9/00; C22C38/00; C22C38/06; C22C38/22; C22C38/24; C22C38/28; C22C38/44; C22C38/46; F16B33/02; F16B35/00; C21D1/18; (IPC1-7): F16B35/00; C22C38/00; C22C38/24; C22C38/28; C21D9/00

Foreign References:

JP2001062639A	2001-03-13
JPS6452045A	1989-02-28
JPH03229009A	1991-10-11
JPH02267243A	1990-11-01
JPH036352A	1991-01-11
JPS61130456A	1986-06-18
JPH0429607A	1992-01-31

Other References: