Aisin Aw Co., Ltd.

Nippon Steel Corporation

Aisin Corporation

Koji Obayashi

Keita Taguchi

Takaaki Ogiso

Manabu Kubota

Yasutaka Miyake

Keisuke Matsuzaka

Tatsuya Koyama

Kei Miyanishi

Susumu Kato

Shuji Kozawa

Daisuke Kasai

Daisuke Iwata

Kazuaki Okada

Hiroshi Shibata

Tomoyuki Hori

Naoki Yokoyama

Ken Shimizu

Koichi Kato

Tsutomu Sato

Mamoru Takeuchi

Ryuta Sugiyama

Yuji Adachi

Hirokazu Sato

Takeshi Ryujin

Takeshi Naito

Toshiaki Matsumura

Masashi Sakakibara

Provided is a method for executing a quenching method in which an object to be treated that is a quenching target is cooled with a quenching coolant that is a coolant for quenching, in which the object to be treated is moved inside the quenching coolant accumulated in a cooling tank, by a moving device for moving the object to be treated, and at least from when the object to be treated comes into contact with the quenching coolant until a surface of the object to be treated undergoes martensitic transformation, a state in which a relative speed of the object to be treated and the quenching coolant is slower than a moving speed of the object to be treated is maintained.

Quenching method

In this steel component, the concentration of C in a surface layer is 0.85 mass % or more to 1.2 mass % or less, which is higher than the concentration of C in a starting material steel, the surface layer has a volume ratio of a retained-austenite structure higher than 0% and lower than 10%, the remainder of the surface layer is a martensitic structure, the area fraction of grain boundary carbides in the surface layer is lower than 2%, a layer inside the surface layer is higher than the surface layer in a volume ratio of a retained-austenite structure, and in the layer inside the surface layer, the remainder is a martensitic structure.

Steel component, gear component, and producing method for steel component

A steel gearincludes a generally cylindrical outer peripheral ring portion, on an outer peripheral surfaceof which a toothed shapeis formed, and a flange portionprovided to extend radially inward from an inner peripheral surfaceof the outer peripheral ring portion. The outer peripheral ring portionincludes a first projecting portionthat projects toward one side in the axial direction with respect to a coupling position at which the first projecting portionis coupled to the flange portion, and a second projecting portionthat projects toward the other side in the axial direction with respect to a coupling position at which the second projecting portionis coupled to the flange portion. The axial length of the first projecting portionis longer than the axial length of the second projecting portion. The outer peripheral ring portionincludes a carburized layerformed in a surface layer of the toothed shape, and a thermal history layerformed in a region including the carburized layerand at a depth, in the inward direction from the outer peripheral surface, larger than the depth of the carburized layer, the thermal history layerhaving a history of being heated through high-frequency induction heating until becoming austenite. The depth T of the thermal history layerin the inward direction from a tooth bottomof the toothed shapeis larger at the second projecting portionthan at the first projecting portion

Steel gear and manufacturing method for the same

A steel gear includes a substantially cylindrical outer peripheral ring portion having a toothed shape formed on its outer peripheral surface; and a flange portion extended radially inward from an inner peripheral surface of the outer peripheral ring portion. The steel gear has a thermal history layer formed in the outer peripheral ring portion, and the depth of the thermal history layer in the direction inward from the tooth bottom of the toothed shape of the outer peripheral surface is greater in the first protruding portion and the second protruding portion than in the coupling portion with the flange portion, and is substantially the same between the first protruding portion and the second protruding portion. As a result, even if the 'carburization/slow cooling/high-frequency quenching treatment' is used as a manufacturing method of the steel gear, the steel gear has high dimensional accuracy.

A drive plate includes a disk-shaped plate portion; and a tooth-shaped portion formed at an outer peripheral end of the plate portion. The plate portion and the tooth-shaped portion are integrally shaped from a single steel plate material. The plate portion and the tooth-shaped portion include a carburized layer provided over an entire surface layer of the plate portion and the tooth-shaped portion, the carburized layer having a carbon concentration higher than that of a center portion of the plate portion and the tooth-shaped portion in a thickness direction. The carburized layer of the plate portion is higher in hardness than the center portion of the plate portion in the thickness direction. The carburized layer of the tooth-shaped portion has been subjected to a quenching process, and is further higher in hardness than the carburized layer of the plate portion.

Drive plate and manufacturing method for the same

A manufacturing method for a composite steel part including manufacturing a first steel part by preparing an intermediate product in which an extra portion is added, and heating the intermediate product to an austenitizing temperature in a carburizing atmosphere to form a carburized layer, cooling the intermediate product at a rate less than a cooling rate at which martensitic transformation is caused and in which the intermediate product is cooled to a temperature equal to or less than a temperature at which structure transformation due to the cooling is completed, heating the intermediate product to an austenitizing range by high-density energy and thereafter cooled at a rate equal to or more than the cooling rate at which martensitic transformation is caused to form a carburized quenched portion, cutting the extra portion of the intermediate product, and welding the first steel part and the second steel part to each other.

Composite steel part and manufacturing method for the same

A manufacturing method for a composite steel part including preparing an intermediate product in which an extra portion, which has a thickness equal to or more than that of a carburized layer to be formed in a subsequent carburizing step, has been added to a welding expected portion, carburizing the intermediate product by heating to an austenitizing temperature or more in a carburizing atmosphere, then cooling the intermediate product at a cooling rate less than a rate at which martensitic transformation occurs and without completing structural transformation due to the cooling, quenching a portion of the intermediate product after heating to an austenitizing range by high-density energy and thereafter cooling to cause martensitic transformation to form a carburized quenched portion, removing an extra portion of the intermediate product; and then welding a second steel part to the welding expected portion.

A method of manufacturing a gear, and the resulting gear, the method resulting such that the surface layer portions of the tooth portions and a tooth root portion are made to be a carburized layer, the remaining portion of the tooth portions and a portion of a disk portion lying below the carburized layer be a quench-hardened layer, and a region of the disk portion lying deeper than the quench-hardened layer be an unquenched layer. The gear is manufactured using raw material steel having the following chemical composition: C: 0.1% to 0.40% (% by mass), Si: 0.35% to 3.0%, Mn: 0.1% to 3.0%, Cr: less than 0.2%, Mo: 0.1% or less, P: 0.03% or less, S: 0.15% or less, Al: 0.05% or less, N: 0.03% or less, and Fe and unavoidable impurities.

Gears and its process of manufacture

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Toyoake, Japan

Koji Obayashi