Hitachi Powdered Metals Co., Ltd.

Denso Corporation

Nissan Motor Company Limited

Honda Giken Kogyo Kabushiki Kaisha

Hitachi Koki Co., Ltd.

Jfe Steel Corporation

Tadayuki Tsutsui

Takashi Suzuki

Jyun-ichi Yamada

Yutaka Mabuchi

Jun Sakai

Takashi Murata

Shigeru Unami

Yukiko Ozaki

Kei Ishii

Hideo Shikata

Akira Fujiki

Akira Fujiwara

Yoshihiro Tanimura

Yukihiro Maekawa

Bo Hu

Tsutomu Saka

Yuuichi Aoki

Sumihisa Kotani

Kouji Yamada

Tomoaki Arakawa

Yuji Yamanishi

Osamu Murai

Yuuji Yamanishi

Ryoji Sato

Jyun-Ichi Yamada

Disclosed is a sintered gear composed of a sintered alloy having a metal matrix and pores. The tooth surface () of the tooth and the bottom land () have a densified layer () in which the porosity is reduced to 10% or less from the sintered alloy. The densified layer at the tooth surface is formed with a thickness of 300 to 1,000 microns, and the densified layer at the bottom land is formed with a thickness of 10 to 300 microns. The boundary surface of the densified layer is continuous from the tooth surface side to the bottom land side so as not to have a substantial level difference.

Sintered gear

A sintered sprocket for a silent chain is obtained from a material with few addition elements by a simple densifying method. The sintered sprocket is made of an ferrous material having an ovarall composition containing Cu at 1 to 2%, C at 0.5 to 0.8%, Mn as an inevitable impurity at 0.10% or less, and balance of Fe and other inevitable impurities by mass and has a density of 7.1 Mg/mor higher, 65 HRA or higher as a hardness in the gear teeth, and a martensite, sorbite, bainite, or their mixed structure as a cross-sectional microscopic structure in at least the gear teeth and the peripheral area of the gear teeth.

Sintered sprocket for silent chain and production method therefor

An inexpensive mechanical fuse having a high fatigue limit ratio and high rupture reliability, and superior in forming performance, and a method of manufacturing the same are presented. The mechanical fuse is composed of Fe-based sintered alloy, and comprises an inner rimfixed to one power transmission shaft, an outer rimfixed to the other power transmission shaft, and plural armsfor linking the inner rimand outer rim, which are formed integrally. The armsinclude rupture portionswhich are ruptured when exposed to an overload torque. By treating in steam, an iron oxide phase is formed in the surface layer and pore inner wall. The iron oxide phase is effective to form round pores and lower the notch sensitivity. As a result, the fatigue strength and fatigue limit ratio are enhanced.

Mechanical fuse and method of manufacturing the same

A mechanical fuse has further improved and stabilized fatigue limit ratio, and can obtain high reliability under a using condition in which cyclic loading is applied. The mechanical fuse includes a Fe-based sintered alloy that has at least one element of P at 0.15 to 1.5 mass %, Si at 0.4 to 2.0 mass %, and Mn at 1.0 to 4.0 mass %, and the remainder consisting of Fe and inevitable impurities. An iron oxide layer is formed on a pore inner wall and the pores have roundness of 0.004 or more. A method of production therefore is also provided.

Mechanical fuse and production method for the same

A sintered sprocket has a high overall density and excellent contact pressure resistance. The sprocket is produced from a sintered alloy selected from the following alloys ((1) to (3)), is densified to have a relative density of 95% or higher in the surface layer of the gear teeth by forming by rolling, having a surface hardness of 700 HV or higher, and is useful for a crankshaft, a cam shaft, a balancer shaft, or a water pump shaft of an internal combustion engine:

Machinability is drastically improved while maintaining some degree of hardness in an Fe-based sintered alloy. A good machinability Fe-based sintered alloy has an overall composition of, in percent by weight, at least one element selected from the group consisting of P in an amount of 0.1 to 1.0% and Si in an amount of 2.0 to 3.0%, B in an amount of 0.003 to 0.31%, 0 in an amount of 0.007 to 0.69%, C in an amount of 0.1 to 2.0%, and the balance consisting of Fe and unavoidable impurities, has a matrix hardness ranging from Hv 150 to 250, and has free graphite dispersed therein.

Good machinability Fe-based sintered alloy and process of manufacture therefor

There is disclosed a method for manufacturing an Fe-based sintered alloy which is superb in machinability. This process comprises the steps of coating a paste-like coating agent including a compound of boron to a surface of a compact of Fe-based or Fe, Cu-based sintered alloy powder including carbon or a pre-sintered compact obtained by heating the compact at a diffusion temperature or less of carbon, and sintering a resultant compact or a pre-sintered compact at a diffusion temperature or more of carbon. An Fe-based sintered alloy manufactured through this process and a bearing cap made of such an Fe-based sintered alloy are also disclosed. In the invention, a film including a compound of boron and pyrolytic resin can be used instead of the paste-like coating agent.

Fe-based sintered alloy manufacturing process, Fe-based sintered alloy

Disclosed is a sintered iron alloy, a method of manufacturing the same, a powdered mixture used for manufacturing the same and a method of modifying the surface of the iron alloy. The sintered iron alloy is produced by compacting a powdered mixture comprising: boron or boron compound which is selected from the group consisting of boron oxide, boron sulfide, boron halide, boron hydride, boric acid, borate and tetrafluoroborate; 0.1 to 2.0% by weight of graphite; and iron, and sintering it. Alternatively, the iron alloy is produced by impregnating a modifier containing boron or boron compound, into a green compact, a presintered compact or sintered body which contains iron and carbon, and heating it.

Manufacturing process of sintered iron alloy improved in machinability,

The present invention relates to a method for producing, without quench-hardening process, a ferrous sintered alloy having satisfactory strength which is equal to that of the conventional ferrous sintered quenched material, and the method comprises the steps of: preparing a powder mixture by adding, in weight ratios, 1 to 2% of copper powder, 1 to 3% of Ni powder, and graphite to a ferrous alloy powder consisting of 3 to 5% of Ni, 0.4 to 0.7% of Mo, and the remainder Fe, the quantity of said graphite being determined such that the C-content after sintering is 0.2 to 0.7%; compacting said powder mixture in a tool to form a green compact; sintering said green compact in a non-oxidizing atmosphere at a temperature in the range of 1130.degree. to 1230.degree. C.; and cooling the sintered product in the sintering furnace at a rate of 5.degree. C./min. to 20.degree. C./min.

Method for producing ferrous sintered alloy having quenched structure

A method of manufacturing a sintered machine part, by which the machine part can be manufactured to be sufficiently strong, wear and abrasion resistive, and durable against the fatigue caused by recursive impacts, without the heat treatments. In the method, a machine part composed of 0.1 to 0.8% of carbon by weight, 2 to 6% of nickel by weight, 0.6 to 1.6% of molybdenum by weight, 1 to 3% of copper by weight and balance iron is manufactured by mixing partially diffused alloy powder composed of 2 to 6% of nickel by weight, 0.4 to 0.6% of molybdenum by weight, 1 to 3% of copper by weight and balance iron with graphite powder amounting to 0.1 to 0.8% by weight and molybdenum simple powder having 2 to 7 .mu.m mean particle size amounting to 0.2 to 1% by weight, and then by compacting the mixed powder and sintering the compact.

Sintered machine part and method

Growing community of inventors

Matsudo, Japan

Tadayuki Tsutsui