Kabushiki Kaisha Kobe Seiko Sho

Shinko Kosen Kogyo Kabushiki

Yasunobu Kawaguchi

Takenori Nakayama

Shigeaki Miyauchi

Heijiro Kawakami

Kozo Katsube

Mamoru Murahashi

Yoshinori Yamamoto

Masataka Shimotsusa

Kan Momozaki

Norio Ohkouchi

Susumu Takada

Yoshiro Yamada

Yukio Yamaoka

Hiroyuki Takahashi

Tadayoshi Fujiwara

Yasuhiro Oki

Kazuichi Hamada

Takashi Taniguchi

Disclosed is a spring steel for a high corrosion resistant and high strength, which exhibits an excellent drawability without softening heat treatment after hot rolling, and which has a strength of 1900 MPa or more by quenching and tempering and an excellent corrosion resistance. The spring steel contains elements of C, Si, Mn and Cr, and elements of Ni and/or Mo in suitable amounts, the balance being essentially Fe and inevitable impurities, wherein the elements satisfy the following requirement:

Spring steel of high strength and high corrosion resistance

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 coil of tapered wire for forming coil springs, formed by winding substantially in concentric loops a quench-hardened and tempered tapered wire having a successive arrangement of tapered wire segments each consisting of a thick section, two thin sections and two tapered sections connecting the thin sections to the opposite ends of the thick section, respectively. The tapered wire is subjected to a preforming action immediately before being wound in loops on a winding drum, to form plastic bends in the thick sections and plastic bends of a radius of curvature greater than that of the plastic bends in the thick sections so that the tapered wire is wound in substantially uniform, concentric circular loops on a winding drum. When the tapered wire is unwound from the coil and is subjected to a straightening process of a fixed straightening arrangement of a series of straightener rollers before being coiled in tapered wire coil springs on a coil spring forming mill, the thick sections undergo a straightening action greater than that acts on the thin sections, so that which the tapered wire unwound from the coil of tapered wire is straightened in a substantially straight tapered wire and thereby the tapered wire is coiled in tapered wire coil springs having a correct size and a uniform shape.

Coil of tapered wire

A tapered rod producing process by which a tapered rod having a profile very near to an aimed profile can be produced with high accuracy. According to the process, during working of a wire diameter gradually decreasing portion of a tapered rod in which the diameter of a stock gradually decreases in a feeding direction of the stock, the drawing length of the stock from starting to ending of acceleration of variable speed feeding mechanism is made greater than predetermined length of the wire diameter gradually decreasing portion, and during working of a wire diameter gradually increasing portion in which the diameter of the stock gradually increases, the drawing length of the stock from starting to completion of deceleration of the variable speed feeding mechanism is made smaller than an a desired length of the wire diameter gradually increasing portion of the tapered rod.

Production of a taper rod

Growing community of inventors

Kobe, Japan

Yasunobu Kawaguchi