Kabushiki Kaisha Kobe Seiko Sho

Ntn Corporation

Kobe Steel, Ltd.

Nippon Koshuha Steel Co., Ltd.

Toyofumi Hasegawa

Sadayoshi Furusawa

Takeshi Nakahara

Kazuhiko Yoshida

Tatsuhiro Goto

Hideo Hata

Akira Wakita

Heijiro Kawakami

Takehiko Kato

Katsumasa Tanaka

Kan Momozaki

Jiro Koarai

Hideo Takeshita

Hitoshi Sato

Toshio Kawasaki

Toshiki Suwa

Masatoshi Nishizawa

Toshihiro Minami

The present invention provides a steel wire rod or bar which exhibits good cold deformability even though it does not undergo spheroidizing annealing after hot rolling. The steel wire rod or bar with good cold deformability is characterized in that its ferrite structure contains no less than 25 nitride and carbide particles in a mixed state or composite state per 25 &mgr;m on average in a sectional area three-fourths of the diameter within the circumference of the rod or bar. Such nitride and carbide precipitates contribute to the reduction of flow stress at temperatures raised by heat generation at the time of cold deforming.

Steel wire rod or bar with good cold deformability and machine parts made thereof

The present invention provides an outer ring for a high strength constant velocity joint which has an excellent torsional strength and torsional fatigue strength and can provide an improved processability, and a process for producing the same. An outer ring used for a high strength constant velocity joint having an involute serration part and a screw part, the outer ring made of a steel containing: C: 0.45 to 0.53%, Si: 0.05 to 0.25%, Mn: 0.7 to 1.0%, Al: 0.01 to 0.05%, Mo: 0.2 to 0.4%, N: 0.003 to 0.012%, the remainder being Fe and inevitable impurities, the inevitable impurities including: Cr: 0.05% or less than 0.05%, P: 0.015% or less than 0.015%, S: 0.01% or less than 0.01%, and O: 0.002% or less than 0.002%, wherein an old austenite crystal grain at the involute serration end is 8 or more in JIS grain size classification; a surface hardness at the end is 720 or more in Hv; and a ratio (CD/R) is 0.35 to 0.60 where CD is an effective hardened layer depth at which a hardness at the end is 450 in Hv and R is a radius of a shaft part.

Outer ring for high strength constant velocity joint and production

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

High strength steel bolts

A material for steel wool is disclosed which essentially consists of 0.05 to 0.20% of C, up to 0.10% of Si, 0.50 to 1.30% of Mn, 0.035 to 0.10% of P, up to 0.04% of S,0.05 to 0.15% of N and the balance Fe. In this material, Al.sub.2 O.sub.3 inclusions with sizes not smaller than 3 microns are suppressed to a level not greater than 20 ppm and when the content of the Al.sub.2 O.sub.3 inclusions (3 microns and over) is in the range of 5 to 20 ppm, Al.sub.2 O.sub.3 inclusions with a size ranging from 3 to 10 microns is contained in an amount not smaller than 30% of the total content of Al.sub.2 O.sub.3 inclusions with sizes not smaller than 3 microns.

Material for steel wool

A method for warm forging a cup-shaped piece is disclosed. In warm forging a blank is heated between 400.degree. and 800.degree. C. and is inserted within a die having a cross sectional area substantially larger than that of the blank. The ends of the blank are clamped between a recess in the die and a recess in an upsetting punch and the upsetting punch compresses the blank until its sides become sufficiently bulged to almost touch, or touch, the sides of the die. The upsetting punch is then removed and a backward extruding punch is press fitted into the bulged blank and the blank is extruded to form a cup. The extrusion punch is lubricated and cooled by lubricant and coolant applicators at a position remote from the die so that the blank is not prematurely cooled by the coolant.

Warm forging method for cup-shaped pieces

Growing community of inventors

Kobe, Japan

Toyofumi Hasegawa