HIGH STRENGTH BOLT EXCELLENT IN CHARACTERISTICS OF RESISTANCE TO DELAYED FRACTURE AND RESISTANCE TO RELAXATION

Title:

HIGH STRENGTH BOLT EXCELLENT IN CHARACTERISTICS OF RESISTANCE TO DELAYED FRACTURE AND RESISTANCE TO RELAXATION

Document Type and Number:

WIPO Patent Application WO/2005/083141

Kind Code:

A1

Abstract:

A high strength bolt having a tensile strength of 1200 N/mm² or more and being excellent in characteristics of the resistance to delayed fracture and the resistance to relaxation, which is produced by subjecting a steel for a bolt having a chemical composition, in mass %, wherein 0.5 to 1.0 % of C, 0.55 to 3 % of Si, 0.2 to 2 % of Mn, 0.03 % or less (not containing 0 %) of P, 0.03 % or less (not containing 0 %) of S, and 0.3 % or less (not containing 0 %) of Al are contained, and having a structure wherein the total area proportion of pro-eutectoid ferrite, pro-eutectoid cementite, bainite and martensite is less than 20 % and the balance is pearlite, to wire drawing, subjecting the drawn product to cold heading and squeezing to form an article having a bolt form, and then bluing the article at a temperature range of 100 to 500°C.

Inventors:

TAKASHIMA MITSUO (JP)
TAKADA KENTARO (JP)
IIDA ZENJI (JP)
TSUKIYAMA KATSUHIRO (JP)
EGAWA TAKEHIKO (JP)
NAMIMURA YUICHI (JP)
IBARAKI NOBUHIKO (JP)

Application Number:

PCT/JP2005/003393

Publication Date:

September 09, 2005

Filing Date:

March 01, 2005

Export Citation:

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Assignee:

HONDA MOTOR CO LTD (JP)
SAGA TEKKOHSHO CO LTD (JP)
KOBE STEEL LTD (JP)
TAKASHIMA MITSUO (JP)
TAKADA KENTARO (JP)
IIDA ZENJI (JP)
TSUKIYAMA KATSUHIRO (JP)
EGAWA TAKEHIKO (JP)
NAMIMURA YUICHI (JP)
IBARAKI NOBUHIKO (JP)

International Classes:

C22C38/00; C22C38/06; C22C38/58; F16B35/00; C21D9/00; (IPC1-7): C22C38/00; C22C38/06; C22C38/58; F16B35/00

Foreign References:

JP2000337333A	2000-12-05
JPH11315349A	1999-11-16
JPH0344127B2	1991-07-05
JP2001348618A	2001-12-18

Other References: