Kabushiki Kaisha Kobe Seiko Sho

Kobe Steel, Ltd.

Nhk Spring Co., Ltd.

Suncall Corporation

Shinko Wire Company, Ltd.

Other

Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)

Shinko Kosen Kogyo Kabushiki Kaisha

Nobuhiko Ibaraki

Takaaki Minamida

Sumie Suda

Kenji Ochiai

Nao Yoshihara

Hiroshi Yaguchi

Mamoru Nagao

Noritoshi Takamura

Koichi Makii

Masato Kaiso

Atsushi Inada

Koji Harada

Tadayoshi Fujiwara

Shigetsugu Yoshida

Katsuji Mizutani

Tetsuo Jinbo

Takeshi Kuroda

Takenori Nakayama

Seiichi Koike

Yukio Yamaoka

Kozo Katsube

Mamoru Murahashi

Mitsuo Takashima

Yoshinori Yamamoto

Masataka Shimotsusa

Norio Ohkouchi

Yasuhiro Oki

Naoki Terakado

Masaru Kodama

Masao Yamada

Shinzo Ashida

Satoru Tendo

Noriaki Hiraga

Sakae Wada

Katsuhiro Tsukiyama

Yuichi Namimura

Yoshihiro Mitani

Tamotsu Shohzaki

Satoru Tendoh

Atushi Inada

Shigenobu Nanba

Takashi Iwata

Toshiki Suwa

A steel wire has tempered martensite, comprises, as essential components, by mass, C: 0.53 to 0.68%; Si: 1.2 to 2.5%; Mn: 0.2 to 1.5%; Cr: 1.4 to 2.5%; Al: 0.05% or less; further comprises, as a selective component, Ni: 0.4% or less; V: 0.4% or less; Mo: 0.05 to 0.5%; or Nb: 0.05 to 0.5%; and further comprises remainder essentially consisting of Fe and inevitable impurities, wherein the grain size number of prior austenite is 11.0 or larger, and the proof stress ratio (&#x3c3;/&#x3c3;), namely, a ratio of 0.2% proof stress (&#x3c3;) to tensile strength (&#x3c3;) is 0.85 or lower. Satisfying the above requirements makes it possible to produce a steel wire for high-strength spring excellent both in workability (cold workability), and in sag resistance and fatigue properties.

Steel wire for high strength spring excellent in workability and high strength

Disclosed is a hard-drawn spring which exhibits fatigue strength and sag resistance equal or superior to springs produced using an oil-tempered wire. The hard-drawn spring is produced using a steel wire containing 0.5 to 0.7 mass % of C, 1.0 to 1.95 mass % of Si, 0.5 to 1.5 mass % of Mn and 0.5 to 1.5 mass % of Cr, with the balance being Fe and inevitable impurities. In the steel wire, the number of carbides having circle-equivalent diameters of 0.1 &#x3bc;m or more is 5 particles/100 &#x3bc;mor less.

Spring produced by a process comprising coiling a hard drawn steel wire excellent in fatigue strength and resistance to setting

The spring steel according to the present invention is a spring steel excellent in sag resistance and fatigue property containing: C: 0.5 to 0.8% by mass (hereinafter, referred to as %), Si: 1.2 to 2.5%, Mn: 0.2 to 1.5%, Cr: 1.0 to 4.0%, V: 0.5% or less (including 0%), P: 0.02% or less (excluding 0%), S: 0.02% or less (excluding 0%), Al: 0.05% or less (excluding 0%), and Fe and inevitable impurities as the balance, wherein the Si content and the Cr content satisfy the following formula (1):0.8&#xd7;[Si]+[Cr]&#x2267;2.6&#x2003;&#x2003;(1)(wherein, [Si] and [Cr] respectively represent the Si content (%) and the Cr content (%)). The spring steel is useful in improving both sag resistance and fatigue property.

Spring steel excellent in sag resistance and fatigue property

Steel wire for hard drawn spring excellent in fatigue strength and resistance to settling, and hard drawn spring and method of making thereof

Disclosed is a steel wire rod for hard-drawn springs capable of exhibiting fatigue strength and sag resistance equivalent to or higher than springs made of an oil-tempered wire. The steel wire rod contains carbon in a range from 0.5 to less than 0.7 mass %, silicon in a range from 1.4 to 2.5 mass %, manganese in a range from 0.5 to 1.5 mass %, chromium in a range from 0.05 to 2.0 mass %, and vanadium in a range from 0.05 to 0.40 mass %, and has an area ratio Rp with respect to pearlite which satisfies the mathematical expression (1):(area %)&#x2267;55&#xd7;[]+61&#x2003;&#x2003;(1)where [C] denotes the content (mass %) of carbon.

Steel wire rod for hard drawn spring, drawn wire rod for hard drawn spring and hard drawn spring, and method for producing hard drawn spring

High-strength steel wire excelling in resistance to strain aging embrittlement and longitudinal cracking, and method for production thereof

A wire rod for drawing which is superior in drawability as well as twisting characteristics, and a method for producing the wire rod. The wire rod is characterized in that the raw material thereof is a eutectoid steel or hypereutectoid steel containing 0.1-2.0 mass % Si and 0.2-2.0 mass % Mn and the pearlite structure therein accounts for no less than 80 area % of microstructure and the maximum length of ferrite as the second phase therein is no larger than 10 &mgr;m. The wire rod is produced by drawing with a true strain of 1.5 or above and subjecting the wire rod to patenting at a heating temperature defined by a specific equation.

Wire rod for drawing superior in twisting characteristics and method for production thereof

A high-strength bolt having excellent delayed fracture resistance and stress relaxation resistance in addition to a tensile strength of 1200 N/mm or higher is disclosed. A steel material for the high-strength bolt includes C: 0.50 to 1.0% by mass (hereinafter, referred to simply as &ldquo;%&rdquo;), Si: 0.5% or less (not including 0%), Mn: 0.2 to 1%, P: 0.03% or less (including 0%) and S: 0.03% or less (including 0%). The steel material has pro-eutectoid ferrite, pro-eutectoid cementite, bainite and martensite structures at less than 20% in total and a pearlite structure as the remainder. The high-strength bolt is produced by drawing the steel material severely to obtain a steel wire, forming the steel wire into a bolt shape through a cold heading, and subjecting the shaped steel wire to a blueing treatment at a temperature within a range of 100 to 400&deg; C.

Method for manufacturing high strength bolt excellent in resistance to delayed fracture and to relaxation

Spring steel superior in workability

High-carbon steel wire superior in resistance to longitudinal cracking, steel product for the same, and process for production of the same

A non-heat treated wire or bar steel for springs which is characterized by having in its as-rolled state a tensile strength of 120-150 kgf/mm,and a bending breakage rate no higher than 15% when tested according to JIS Z-2248 under the condition of r/d&equals;2.8 where r (mm) denotes the inside radius of the bending curvature and d (mm) denotes the diameter of the as-rolled stock.

Non-heat treated wire or bar steel for springs

A steel wire is composed mainly of fine pearlite and/or coarse pearlite, where the lamellar cementite in the pearlite is amorphous or amorphous-like. Alternatively, the wire may be composed mainly of bainite, where the cementite in the bainite is amorphous or amorphous-like. To manufacture the steel wire, a starting steel product is subjected repeatedly to patenting and cold drawing, and then subjected to final drawing at a true strain of 2.0 or above while cooling. The steel wire is higher in strength and toughness than wire whose lamellar cementite consists of nano crystals. The steel wire does not suffer any delamination when subjected to torsion.

High strength and high toughness steel wires and method for making the

The present invention provides a spring steel with excellent performance, characterized in that the spring steel is produced by making a spring steel contain an appropriate amount of at least one or more of Ti, Nb, Zr, Ta, and Hf, thereby generating fine inclusions including carbide, nitride, sulfides and/or their complex compounds, to make the inclusions exert the effect of trapping diffusive hydrogen whereby the resistance to hydrogen embrittlement is enhanced, wherein the size and number of the coarse inclusions are regulated, thereby suppressing the decrease of the fatigue life. The spring steel can provide a valve spring or a suspension spring or the like, with enhanced strength and higher stress resistance, together with improved resistance to hydrogen embrittlement and fatigue.

Spring steel with excellent resistance to hydrogen embrittlement and

A high strength steel strand for PC of a wire material having a pearlite structure and containing 0.80 to 1.30% of C, 0.60 to 2.50% of Si and 0.30 to 1.50% of Mn, remainder being Fe and unavoidable impurities, wherein a cementite portion of the wire material comprises a mixed structure of fibrous cementite and granular cementite, the volumetric proportion of the granular cementite to the total cementite is 10 to 40%, the particle diameter of the granular cementite is 40 to 300.ANG., and the strand has a tensile strength of 235 kgf/mm.sup.2 or higher and an elongation of 3.5% or greater.

High strength steel strand for prestressed concrete and method for

Disclosed are a steel wire rod for manufacturing a fine steel wire excellent in drawability, strength and toughness in which the contents of components such as C, Si, Mn, P, S, Al, Cu are specified, the contents of one or more of elements selected from a group consisting of Cr, W, Ni and Mo are also specified, and in which the balance is essentially Fe and inevitable impurities and for which, the composition of non-metallic inclusions of oxides is also specified; a fine steel wire obtained by drawing of the steel wire rod; and a twisted wire cord made by twisting of the fine steel wires. Further, disclosed is a die schedule for manufacturing the above fine steel wire. Thus, there can be provided a steel wire rod with excellent drawability and which does not break during drawing; a fine steel wire excellent in strength and toughness obtained from the steel wire rod; and a twisted wire cord obtained by twisting together lengths of the fine steel wires.

Hot rolled steel wire rod, fine steel wire and twisted steel wire

Growing community of inventors

Kobe, Japan

Nobuhiko Ibaraki