Aisin Aw Co., Ltd.

Daido Tokushuko Kabushiki Kaisha

Nippon Steel Corporation Muroran Works

Nippon Steel Corporation

Kouji Ohbayashi

Takao Taniguchi

Michio Maruki

Kazuaki Okada

Yoshimi Watanabe

Naohisa Momiyama

Yutaka Eto

Taro Matsukawa

Yoshihisa Yamamoto

Fumitomo Yokoyama

Shuji Kozawa

Hideo Kanisawa

Toshiyuki Morita

Shigeharu Ikeda

Kazumichi Tsukuda

Kengo Nomura

Koki Mizuno

Minoru Hidaka

Hideji Kato

Kohki Mizuno

Kazunari Suzuki

Hironori Fukushima

Masaki Kuwabara

Takatoshi Suzuki

Masataka Shimazaki

Masayoshi Imakire

The present invention relates to a mechanical part, which is obtained by: processing a steel into a shape of a part, the steel having an alloy composition containing, by weight percent, C: 0.10 to 0.30%, Si: 0.50 to 3.00%, Mn: 0.30 to 3.00%, P: 0.030% or less, S: 0.030% or less, Cu: 0.01 to 1.00%, Ni: 0.01 to 3.00%, Cr: 0.20 to 1.00%, Al: 0.20% or less, N: 0.05% or less, and the remainder of Fe and inevitable impurities, and the alloy composition satisfying the following condition:[Si %]+[Ni %]+[Cu %]&#x2212;[Cr %]&#x3e;0.50,in which [Si %], [Ni %], [Cu %] and [Cr %] represent the concentration of Si, the concentration of Ni, the concentration of Cu and the concentration of Cr in the alloy composition, respectively; subjecting the steel to a carburizing treatment in a vacuum, followed by gradually cooling the steel; and subsequently subjecting the steel to a high-frequency hardening to thereby harden a surface of the steel.

Carburized and high-frequency hardened part having high strength

A steel component formed by carburizing and then induction-hardening of a steel consisting essentially of, by mass, C: minimum 0.08% and less than 0.3%; Si: maximum 2.0%; Mn: from 0.2% to 3.0%; P: maximum 0.03%; S: from 0.005% to 0.05%; Ni: maximum 1.5%; Cr: maximum 3.0%; Mo: maximum 1.0%; O: maximum 0.0025%; and N: from 0.005% to 0.03%; and further including either or both of, by mass, Al: from 0.005% to 0.05%, and Ti: from 0.005% to 0.05%; and still further including either or both of, by mass, V: maximum 0.3%, and Nb: maximum 0.3%; and a balance including Fe and unavoidable impurities. The hardness of the surface layer is at least 55 HRC and the hardness of the core portion is from 20 to 50 HRC. The core portion does not include a martensite structure.

Carburized and induction-hardened component

The present invention provides a method for induction hardening of a steel member having an outer ring portion and, more specifically, for induction hardening of an outer circumferential surface of the outer ring portion. The method uses two pressing members, each of which includes a flat basal surface and a projecting portion projecting therefrom. Each of the projecting portions has a cross-section in the shape of a perfect circle. Also, the projecting portions have, on the outer circumferences thereof, respective pressing surfaces. While gaps are maintained between axial end faces of the outer ring portion and the basal surfaces of the pressing members, the pressing members are pressed against the outer ring portion so that the pressing surfaces each abut against the inner circumference side of the outer ring portion. While a biasing force is applied to the pressing members, the induction hardening process is applied to the outer circumferential surface. During the induction hardening process, the pressing members are moved toward each other until the basal surfaces abut against respective axial end faces of the outer ring portion.

Induction hardening method and jig used in induction hardening process

A method of manufacturing a sheave member for a belt-type continuously variable transmission includes a forming step wherein an intermediate product having a sheave surface is formed by forging a steel material; a carburization step wherein the intermediate product is heated in a carburization gas; a gradual cooling step wherein the cooling speed is equal to or less than 20&#xb0; C./sec, at least until the temperature of the intermediate product has passed through the transformation point; a high-frequency electrical heating step wherein a selected portion(s) of the intermediate product is heated; a water quenching step wherein the selected portion is quenched by contact with water; and a finishing step wherein a grinding process is applied to the intermediate product to attain the final shape. In the cooling step, preferably, the intermediate product is contacted with a cooling gas at a pressure lower than atmospheric pressure.

Sheave member for belt-type continuously variable transmission and method of manufacturing the same

A planetary carrier supports pinion gears of a planetary gear set via pinion shafts. Each hole in which a pinion shaft is mounted has a shallow hardened wall surface that is hardened by very-high-frequency induction heating and quenching. Therefore, the durability of the pinion shaft-supporting holes of a cold-forged piece or a pressed piece can be improved without thermal strain.

Planetary carrier and method of manufacture

A cutting tip has a cutting face and a flank face. A compression face for plastically deforming a workpiece is provided between the cutting face and the flank face. The cutting tip allows work-hardening to be easily performed by plastic deformation of the cut-finished surface during cutting, without adding a separate process step.

Cutting tip, cutting method, and cutting-processed element

In a steel member surface treatment method, only a surface layer portion of the steel member is heated to its melting point or higher to form a melt, by high density energy-beam irradiation. Subsequently, the melted portion is rapidly cooled to a martensitic transformation region, to form a martensitic structure. The temperature increasing rate in irradiation of the surface layer of the steel member is preferably 7500&deg; C./second or greater. Thereby, thermal strain and quenching failure are reduced even if the steel member is a thin plate component and a high production efficiency can be achieved.

Steel member surface treatment method

A surface hardening method, in which a surface layer on a thin steel plate member is stably melted and solidified to provide a high surface resistance against wear includes irradiation with a high density energy beam to melt a process surface portion of the steel member followed by rapid cooling. The melted surface portion includes a fully melted layer and an adjacent imperfectly or partially melted layer. At least the cooling to solidify the molten steel is performed in a short time period less than an austenitic transformation completion time at temperatures below melting, e.g., one-twentieth of the normal austenitic transformation time, and preferably both heating to melt the surface layer and cooling to solidify and harden the surface layer are performed in a time period less than the normal austenitic transformation completion time period. The high density energy beam can be divided to irradiate plural regions to melt the surfaces of the plural regions at the same time. The thermal capacity (or thickness) of the entire steel member can be designed to be as small as four times the thermal capacity of the process portion (or depth of melted portion) and still allow self cooling of the steel member to produce surface hardening. Additionally the melted-hardened surface has improved smoothness such as exhibited by a roughness which is only sixty percent or less of the roughness of non-processed surfaces.

Surface processing method for a steel member and surface processed steel

A bainite forming process for treating a steel material reduces the time required for a complete thermal treatment as well as the cycle time for the thermal treatment device without necessitating any special means for handling the steel material. The steel material is heated to a temperature higher than the austenitic transformation point, and temporarily quenched to an intermediate point temperature higher than the martensitic transformation point. Then, the temperature of the steel material is again raised towards the range corresponding to bainitic transformation to form a bainitic structure. The reheating is discontinued before the temperature corresponding to the austenitic transformation point is reached, and the steel material is then quenched. In the heating steps, only the portion to be treated by the bainite forming process is locally irradiated with a high-density energy beam.

Temperature-raising bainite forming process

A lockup clutch for torque converter which prevents engaging and disengaging shock when a transmission torque suddenly changes, includes a lockup clutch assembly, a lockup clutch piston operating the lockup clutch assembly, and a damper device disposed between the lockup clutch piston and an output member for absorbing changes of transmission torque occurring in association with the operation of the lockup clutch assembly. The lockup clutch piston is made of steel and has a thermally treated portion placed at a surface in contact with springs of the damper device wherein the thermally treated portion is hardened by rapid local melting with high density energy radiation such as electron beam followed by rapid cooling.

Lockup clutch for a torque converter and method of thermally treating a

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Kouji Ohbayashi