Other

Sanyo Special Steel Co., Ltd.

Toyo Denki Seizo Kabushiki Kaisha

Honda Motor Co., Ltd.

Makoto Iguchi

Kimihiro Muraoka

Takashige Tamamushi

Masayoshi Saga

Yoshinobu Ohtsubo

Motohiro Nishikawa

Hiroshi Nishimori

Toshio Higuchi

Yoshimi Usui

Ryoji Hayashi

Disclosed is a production process of a steel product for induction hardening and a steel product for carburizing, having improved grain size properties and machinability. This production process comprises the steps of: providing an ingot or bloom comprising a steel comprising, by weight, carbon (C): 0.10 to 0.45% or 0.25 to 0.70%, silicon (Si): 0.03 to 1.0%, manganese (Mn): 0.2 to 2.0%, titanium (Ti): 0.05 to 0.2%, aluminum (Al): 0.005 to 0.05%, and nitrogen (N): not more than 0.01% with the balance consisting of iron (Fe) and unavoidable impurities; and subjecting the steel ingot or bloom to a series of hot working steps including the step of rolling the steel ingot or bloom into a semi-finished steel product, the step of rolling the semi-finished steel product into a steel bar or wire rod, and the step of forging the steel bar or wire rod into a product. In the above series of hot working steps, the steel is given a thermal history in which said steel is at least once heated to 1,250&#xb0; C. or above, is cooled to room temperature, and is then reheated to a temperature range of 800 to 1,100&#xb0; C.

Process for producing steel products having improved grain size properties and machinability

Disclosed is a process for producing a retainer for a constant velocity joint for automobiles or the like, which has improved flexural strength properties without sacrificing the machinability, using a steel corresponding to SCr 415 (JIS) or SCM 415 (JIS). This production process comprises the steps of: providing a steel comprising by weight carbon (C): 0.10 to 0.25%, silicon (Si): 0.03 to 0.15%, manganese (Mn): 0.20 to 0.60%, sulfur (S): 0.003 to 0.030%, chromium (Cr): 1.00 to 1.50%, titanium (Ti): 0.05 to 0.20%, boron (B): 0.0005 to 0.0050%, and nitrogen (N): not more than 0.01% with the balance consisting of iron (Fe) and inevitable impurities; hot forging the steel at a heating temperature of 1000 to 1100&deg; C. to prepare a forged product having a Rockwell hardness of not more than 88 HRB; machining and optionally piercing the forged product; carburizing and quenching and tempering the machined steel to attain an effective case depth of 0.4 to 0.9 mm, the effective case depth being defined as the distance from the surface of the steel to the position of the steel in its depth direction where the Vickers hardness is HV 550.

Process for producing retainer for constant velocity joint possessing improved machinability and flexural strength

Disclosed is a process for producing an inner race for a constant velocity joint comprising the steps of: providing a steel comprising by weight carbon 0.10 to 0.25%, silicon 0.03 to 0.15%, manganese 0.20 to 0.60%, sulfur 0.003 to 0.030%, chromium 1.00 to 1.50%, titanium 0.05 to 0.20%, boron 0.0005 to 0.0050%, and nitrogen not more than 0.01% with the balance consisting of iron and impurities; hot rolling or hot forging the steel, to prepare a rolled/forged product; cold forging and machining the rolled/forged product; and carburizing, quenching, and tempering the machined rolled/forged product so that the treated steel satisfies an effective case depth of 0.4 to 0.9 mm, a thickness of abnormal-carburizing layer of not more than 15 &mgr;m, and an austenite grain size number as specified in JIS G 0551 of not less than 7.

Process for producing inner race for constant velocity joint having improved workability and strength

Disclosed is a process for producing a shaft having improved strength without sacrificing machinability and cold workability. The process for producing a high strength shaft comprises the steps of: rolling or forging an alloy at a heating temperature of Ac,to 105&deg; C. with a reduction in area of not less than 30%, the alloy comprising by weight carbon: 0.47 to 0.55%, silicon: 0.03 to 0.15%, manganese: 0.20 to 0.50%, molybdenum: 0.08 to 0.30%, sulfur: 0.005 to 0.035%, boron: 0.0005 to 0.005%, titanium: 0.05 to 0.20%, nitrogen: not more than 0.01%, aluminum: 0.005 to 0.05%, and manganese&plus;molybdenum: 0.45 to 0.70% with the balance consisting of iron and unavoidable impurities, thereby producing a steel product having a hardness after rolling or forging of 85 to 97 HRB; and induction hardening the steel product to obtain a shaft, as shown in FIG.,, having a hardening depth ratio (distance from the surface to a position of 500 HV/radius of component) of not less than 0.25 and an austenitic grain size number as specified in JIS G 0551 of not less than 7.

Process for producing high strength shaft

The process for producing a constant velocity joint having improved cold workability, rolling fatigue life, and torsional strength comprises the steps of: rolling or forging an alloy at a heating temperature of Ac.sub.3 to 1000.degree. C. with a reduction in area of not less than 30%, said alloy comprising by weight carbon: 0.52 to 0.60%, silicon: 0.03 to 0.15%, manganese: 0.10 to 0.40%, chromium: 0.05 to 0.30%, molybdenum: 0.10 to 0.30%, sulfur: 0.003 to 0.020%, boron: 0.0005 to 0.005%, titanium: 0.02 to 0.05%, nitrogen: not more than 0.01%, aluminum: 0.005 to 0.05%, and manganese+chromium+molybdenum: 0.35 to 0.80% with the balance consisting of iron and unavoidable impurities; spheroidizing the rolled or forged alloy in such a manner that, after heating to Ac.sub.1 to 770.degree. C., slow cooling is performed from 730.degree. C. to 700.degree. C. at a rate of not more than 15.degree. C./hr, thereby producing a steel product having a hardness of 68 to 78 HRB after spheroidizing; and induction hardening the steel product to obtain a constant velocity joint having a surface hardness of not less than 60 HRC.

Product and process for producing constant velocity joint having

In a gate insulated static induction thyristor with a split gate type shorted cathode structure, a first gate of the split gate structure is used as a cathode short-circuit gate and the cathode region is formed in the second gate. A MOS structure is formed on the second gate as a control gate electrode isolated therefrom. Since the channel integration density is high, the area efficiency increases. The MOS gate structure suppresses the minority carrier (hole) storage effect to permit high-speed swtching of the thyristor, and the shorted cathode structure provides for increased maximum controllable current/voltage durability. The split gate structure can be used in combination with planar, buried, recessed and double gate structures.

Insulated gate static induction thyristor with a split gate type shorted

In a gate insulated static induction thyristor with a split gate type shorted cathode structure, a first gate region of the split gate structure is used as a cathode short-circuit gate and the cathode region is formed between the first and second gate regions. A MOS structure is formed on the second gate region as a insulated gate control gate region electrode isolated therefrom. The MOS gate structure suppresses the minority carrier (hole) storage effect to permit high-speed switching of the thyristor, and the shorted cathode structure provides for increased maximum controllable current/voltage durability. The split gate structure can be used in combination with planar, buried, recessed and double gate structures.

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Himeji, Japan

Makoto Iguchi