Kabushiki Kaisha Kobe Seiko Sho

Sugita Wire Mfg. Co., Ltd.

Takehiko Kato

Toshiaki Yutori

Yasuhiro Hosogi

Masatoshi Sudo

Toyofumi Hasegawa

Sadayoshi Furusawa

Masaaki Katsumata

Heiji Sugita

Takeshi Nakahara

High strength low carbon steel wire rods excellent in the cold drawing property have a composite structure in which an acicular low temperature transformation phase comprising a martensite, bainite and/or the mixed structure thereof that comprises, by weight %,

High strength low carbon steel wire rods and method of producing them

High strength low carbon steel wire rods

Described herein is high strength steels used for bolts containing as alloy elements:

High strength steel bolts

High strength low carbon steels having good ultraworkability which comprises 0.01-0.3 wt % of C, below 1.5 wt % of Si, 0.3-2.5 wt % of Mn and the balance of iron and inevitable impurities. In the steel, a low temperature transformation product phase consisting of acicular martensite, bainite or a mixed structure thereof is uniformly dispersed in a ferrite phase in an amount by volume of 15-40%. Wire articles of these steels and methods for making the steels are also disclosed.

High strength low carbon steels, steel articles thereof and method for

A high strength bolt having a as-formed structure and a method of manufacturing the high strength bolt which method comprises the steps of: heating a steel alloy containing 0.15 to 0.3 wt % C and 1 to 3 wt % Mn to a temperature not lower than Ac.sub.3 transformation point; subjecting the steel alloy to isothermal transformation at 450.degree. to 580.degree. C.; subjecting, after cooling, the steel alloy to cold wire drawing at a reduction rate not larger than 40%; and bolt forming the steel. A cold wire drawing at a reduction rate not larger than 40% may be carried out before the above-mentioned isothermal transformation step.

High strength bolt and method of producing same

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Kobe, Japan

Takehiko Kato