Kobe Steel, Ltd.

Kabushiki Kaisha Kobe Seiko Sho

Suncall Corporation

Kabushiki Kaisha Fuji Seisakusho

Kabushiki Kaisha Fujikihan

Shinko Kosen Kogyo Kabushiki

Yoshiro Yamada

Tatsu Fujita

Tetsuo Yamada

Atsuo Mizuta

Tsugio Kaneda

Shinichi Shimazu

Nobuyasu Hatsuoka

Noboru Yamakoshi

Kazuhiro Uzumaki

Masaaki Ishida

Yoshihiro Yamaguchi

Yukio Yamaoka

Keiichiro Teratoko

Yasunobu Kawaguchi

Hiroshi Suzuki

Hiroyuki Takahashi

Tadayoshi Fujiwara

Yasuhiro Oki

Rikuo Ogawa

Heijiro Kawakami

Hironobu Sasada

Shinzo Ashida

Osamu Tsuda

Yukio Wada

Shohei Murakami

Kouro Takatsuka

Yuji Isono

Shoji Akita

Tadamasa Yokoyama

Takashi Taniguchi

Kazuichi Hamada

Hard metal particles having hardness which is lower than the hardness of a nitrided outermost layer of a spring and in the range of Hv 500 to 800 and a diameter of 500 to 900 &mgr;m are protected against the nitrided surface of the spring at a velocity of 40 to 90 m/sec to prevent generation of a microcrack in the surface layer and provide a compression residual stress comparatively deep inside the spring. Against the resultant spring surface, a number of fine metal particles having a mean diameter of all particles of 80 &mgr;m or less, a mean diameter of each particle in the range between 10 &mgr;m inclusive and less than 100 &mgr;m, a spherical or near spherical shape with no square portions, a specific gravity of 7.0 to 9.0, and hardness which falls in the range between Hv 600 and Hv 1100 inclusive and is equal to or less than the hardness of the outermost surface layer of the spring after nitriding, at a velocity of 50 to 190 m/sec., while controlling temperature to be low enough to cause work hardening but not to cause softening due to recovery/recrystallization, to provide a high compression residual stress in a near surface layer without generation of microcracks in the surface layer and thus obtain a valve spring and the like excellent in fatigue strength.

Spring with excellent fatigue endurance property and surface treatment method for producing the spring

Fatigue-resistance is significantly increased by performing shot peening using fine shots. A plurality of particles of hard metal having a diameter ranging from 20 to 100 micrometers are ejected onto a surface of a steel workpiece at an impinging speed greater than 80 m/second. The impinging speed is controlled so that the upper limit of temperature rising of the surface of the workpiece is maintained at a temperature more than 150.degree. C. but less than the temperature at which recovery recrystallization and austentizing of steel occurs.

Surface treatment method for a steel workpiece using high speed shot

Wire rods containing an adequate quantity of C within the range from 0.70 to 1.00%, Si from 0.5 to 3.0%, Mn from 0.30 to 2.0%, Cr from 0.10 to 0.5%, Al from 0.030 to 0.10% and N from 0.004 to 0.015% and unavoidable impurities, and with Fe for all the rest are subjected to re-heat patenting to increase the tensile strength to 135 kgf/mm.sup.2 or higher, then are drawn by adequately selecting the conditions, number of times of drawing in the range from 7 to 16 times, drawings speed from 50 to 550 m/minute, extent of drawing form 70-90, and water cooling immediately after each drawing to manufacture steel wires of high strength and high toughness. The wires are used as PC wires, steel wires for skewed bridge cables, steel stranded wires, spring wires, main cable wires for extra-long suspension bridge large diameter wires for core of aluminum cables steel reinforced (transmission cable), and as galvanized steel wires for such applications.

High strength and high toughness steel bar, rod and wire and the process

A spring steel for vehicles having a composition substantially composed of 0.5-0.7 wt % of C, 1.0-1.8 wt & of Si, 0.1-1.0 wt % of Mn, below 0.7 wt % of Cr, 0.03-0.5 wt % of V and the balance of Fe and normally present impurities, and optionally at least one of Al, Zr, Nb and Ti each contained in an amount of 0.02-0.1 wt %.

Spring steel for vehicles

A method and apparatus for the controlled cooling of a hot rolled steel rod. A hot rolled steel rod issued from a final stand of mill train is rapidly cooled, and then formed into a coil. The coiled rod is transported in a generally horizontal direction with its loops held at an angle of 30.degree. to 60.degree. relative to the direction of transportation and with a pitch of at least 2d/sin .alpha. where d is a diameter of the rod and .alpha. is the above-mentioned angle. A cooling medium, e.g. air, is forcibly applied to the coiled rod upwardly from below the coiled rod to cool the coiled rod uniformly at such a cooling rate as to achieve a phase transformation to obtain a structure consisting essentially of fine pearlite. The apparatus includes a cooling device for the rapid cooling, a laying head for the coil forming, a conveyor for transporting the coiled rod while supporting its loops at the angle and pitch, a coolant supply, and a mechanism for collecting the treated rod.

Method and apparatus for the controlled cooling of hot rolled steel rods

A large gauge high strength steel rod having a diameter of not less than 9 mm, is produced from high carbon steel containing, by weight percent, from 0.65 to 0.90% carbon and from 0.15 to 1.5% chromium capable of being drawn without subsequent heat treatment.

High strength steel rod of large gauge

Method of producing large diameter steel rods

A method and apparatus for cooling a rod of a coil form, immediately after the hot-rolling thereof and within which the rod, whose loops are spaced a given pitch from one another, is laid flat upon a chain conveyor, and more particularly upon rails thereof, and transported therealong by means of endless chains, includes the cooling of the rod with cooling fluid or air which is introduced from below the cooling floors through means of nozzle portions formed within the bodies of the cooling floors. The method and apparatus features the arrangement and construction, including the configuration, of the nozzle portions thus formed, the cooling fluid being projected upwardly at an angle within the range of 10.degree.-70.degree. with respect to the plane of the cooling bed, and horizontally at an angle within the range of 10.degree.-150.degree. with respect to the transporting direction of the rod, towards the rod directly above the rail and chain portions of the conveyor, as well as being projected upwardly at an angle within the range of 15.degree.-75.degree. with respect to the plane of the cooling bed, and horizontally at an angle within the range of 30.degree.-150.degree. with respect to the direction of the transportation of the rod, towards the overlapped, sidewise circumferential portions of the rod. Thus, uniform cooling may be achieved over the entire length of the coiled rod.

Method and apparatus for cooling hot rolled rod

A method for cooling a steel wire which is being drawn in a dry lubricant wire drawing operation wherein the rear portion of the die, including the backrelief portion thereof and the wire which has just been drawn to the desired dimension, are brought into direct contact with a cooling medium so as to effect forced cooling thereof, the wire thereby being cooled before the commencement of strain-aging embrittlement within the wire.

Method of cooling steel wire

Growing community of inventors

Akashi, Japan

Yoshiro Yamada