Komatsu Corporation

Kabushiki Kaisha Komatsu Seisakusho

Osaka University

Takemori Takayama

Yoshikiyo Tanaka

Tetsuo Ohnishi

Kazuo Okamura

Chikara Nakao

Kan'ichi Sato

Naoji Hamasaka

Keiichi Maeda

Chigo Okayama

Masayuki Ohishi

Takeyo Terao

Hiroshi Ono

Katsuyoshi Saito

Yoshitaka Ohyama

Masato Miyake

Tetsuo Onishi

Masanari Furumoto

Noriko Morioka

Koji Yamamoto

Yusuke Hiratsuka

Yoritoshi Minamino

Shigeo Otsuka

Hirotaka Kato

Yuichi Hori

Koji Yamada

A steel with high hardness and excellent toughness contains, in mass %, 0.55-1.10% C, 0.10-2.00% Si, 0.10-2.00% Mn, 0.030% or less P, 0.030% or less S, 1.10-2.50% Cr, and 0.010-0.10% Al, with the balance consisting of Fe and unavoidable impurities. The structure of the steel after quenching is a dual phase structure of martensitic structure and spheroidized carbide. Spheroidized cementite particles with an aspect ratio of 1.5 or less constitute at least 90% of all cementite particles. The proportion of the number of spheroidized cementite particles on the prior austenite grain boundaries to a total number of cementite particles is 20% or less.

Steel with high hardness and excellent toughness

An iron-based sintered sliding material includes: a sintered structure which contains 10-50 wt. % copper and 1-15 wt. % carbon and has been formed by sintering a powder mixture obtained by mixing at least one of an Fe&#x2014;Cu alloy powder containing copper in an amount which is the solid solubility or larger and is 5-50 wt. %, excluding 50 wt. %, and an Fe&#x2014;Cu&#x2014;C alloy powder containing copper in an amount which is the solid solubility or larger and is 5-50 wt. %, excluding 50 wt. %, and containing carbon in an amount of 0-5 wt. %, excluding 0 wt. %, with a graphite powder and at least one of a copper powder and a copper alloy powder; and graphite particles dispersed in the sintered sliding material in an amount of 1-14 wt. % or 3-50 vol. %.

Sintered material, ferrous sintered sliding material, producing method of the same, sliding member, producing method of the same and coupling device

A ferrous abrasion resistant sliding material and sliding member having improved seizing resistance, abrasion resistance and heat crack resistance are provided. The ferrous abrasion resistant sliding material has a parent phase taking the form of at least either one of a ferrite phase or a martensite phase, wherein the parent phase contains Al of 1.5 to 20 wt %, and at least either carbide, which may be selected from one or more types, of cementite, CrC-type carbide, FeMC-type carbide and MC-type carbide, or graphite is dispersed therein.

Ferrous abrasion resistant sliding materials and sliding members

A contact material which provides improved wear resistance as well as reduced adhesion utilizing the features of an intermetallic compound having an ordered phase, with the intention of (i) improving the seizure resistance and/or wear resistance of an implement bearing which slides under low-speed, high-surface-pressure conditions and is susceptible to lubricant starvation; (ii) preventing abnormal noises; and (iii) achieving prolonged greasing intervals. The contact material contains 10% by volume or more a metallic alloy phase having such a composition range that causes an order-disorder transition. The metallic alloy phase is a Fe base alloy phase containing one or more elements selected from the group consisting of Al, Si, Co and Ni.

Contact material, composite sintered contact component and method of producing same

A ferrous sintered multilayer roll-formed bushing having a ferrous sintered sliding material layer which is sinter-bonded to a back metal steel, wherein the ferrous sintered sliding material layer is produced in such a manner that a Fe&#x2014;C&#x2014;Cu&#x2014;Sn based sintered sliding material mixed powder containing at least carbon of 0.40 to 15 wt %, Cu of 13 to 40 wt % and Sn of 0.5 to 10 wt % is preliminarily sinter-bonded to said back metal steel and then finally sinter-bonded by a liquid-phase sintering at high temperatures higher than 1000&#xb0; C. after bending into a roll.

Ferrous sintered multilayer roll-formed bushing, producing method of the same and connecting device

A ferrous seal sliding part excellent in heat crack resistance, seizing resistance and abrasion resistance is provided. The ferrous seal sliding part having a seal sliding surface, wherein the seal sliding surface has a martensite parent phase which forms a solid solution with carbon of 0.15 to 0.6 wt % and contains a first dispersion material of at least either cementite of 5 to 70% by volume or MC-type carbide of 0.1 to 10% by volume and a second dispersion material of at least either graphite of 1 to 15% by volume or Cu alloy phase of 1 to 20% by volume dispersed therein, with a total content of the first dispersion material and the second dispersion material being 5 to 70% by volume.

Ferrous seal sliding parts and producing method thereof

A ferrous seal sliding part excellent in heat crack resistance, seizure resistance and abrasion resistance is provided. The ferrous seal sliding part has a seal sliding surface, wherein the seal sliding surface has a quench hardened layer having a structure in which a martensite parent phase forms a solid solution with carbon of 0.15 to 0.6 wt % and contains cementite dispersed therein in a content of 3 to 50% by volume.

A sintered sliding member comprises a back metal () and a ferrous sintered sliding body () which is sintering-bonded to the back metal (). The ferrous sintered sliding body () has martensite phase having a solid soluble carbon concentration of 0.15 to 0.5 wt % and contains carbide in a content of 5 to 50% by volume. The sintered sliding member is excellent in abrasion resistance, seizing resistance and heat crack resistance.

Sintered sliding member and connecting device

A ferrous abrasion resistant sliding material capable of improving seizing resistance, abrasion resistance and heat crack resistance is provided. The ferrous abrasion resistant sliding material has a martensite parent phase which forms a solid solution with carbon of 0.15 to 0.5 wt %, and the martensite parent phase contains one or more types of each special carbide of Cr, Mo, W and V dispersed therein in a total content of 10 to 50% by volume.

Ferrous abrasion resistant sliding material

There is provided an inexpensive rolling element used under high interface pressure such as induction hardened gears, the rolling element being improved in the seizure resistance of its tooth flanks and having a temper hardness of HRC 50 or more at 300&#xb0; C. To this end, the rolling element is made from a steel material containing at least 0.45 to 1.5 wt % C and one or more alloy elements selected from 0.1 to 0.5 wt % V and 0.3 to 1.5 wt % Cr, and has a rolling contact surface layer having a structure tempered at low temperature in which 2 to 18% by volume cementite disperses in a martensite parent phase formed by induction heating and cooling and containing 0.25 to 0.8 wt % carbon solid-dissolving therein.

Case hardened gear and method of producing the same

Various inexpensive rolling elements for use under high interface pressure such as induction hardened gears are provided, which have improved seizure resistance at tooth flanks and a temper hardness of HRC 50 or more at 300 &#xb0; C. To this end, a rolling element is made from a steel material which contains at least 0.5 to 1.5 wt % carbon and 0.2 to 2.0 wt % one or more alloy elements selected from V, Ti, Zr, Nb, Ta and Hf; and in which 0.4 to 4.0% by volume one or more compounds selected from the carbides, nitrides and carbonitrides of the above alloy elements and having an average particle diameter of 0.2 to 5 &#x3bc;m are dispersed. In such a rolling element, the soluble carbon concentration of a martensite parent phase of a rolling contact surface layer is adjusted to 0.3 to 0.8 wt %, the martensite parent phase having been subjected to induction hardening and low temperature tempering, and one or more of the above carbides, nitrides and carbonitrides are dispersed in an amount of 0.4 to 4.0% by volume within the martensite parent phase.

Rolling element and method of producing the same

To provide a thermal spray membrane contact material, contact member and contact part and an apparatus to which they are applied, showing excellent seizure resistance and wear resistance even under high surface pressure/low speed sliding, high speed/high temperature sliding, or high surface pressure/high speed sliding. In a bucket connecting apparatus connecting an arm and a bucket by a work implement connecting pin, the above-mentioned work implement connecting pin comprises a base material made of steel having an axis function and a contact surface formed of a thermal spray membrane contact material film-formed on the base material, said contact surface being placed at least on a supported surface site of the work implement connecting pin relative to a bracket and on a slipping contact surface with a work implement bushing, further, said thermal spray membrane contact material being composed of a Mo metal phase, or 10 vol % or more of a Mo metal phase and a metal phase and/or alloy phase containing one or more elements selected from the group consisting of Fe, Ni, Co, Cr, Cu and Zn.

Thermal spray membrane contact material, contact member and contact part, and apparatuses to which they are applied

A rolling member excellent in pitting strength, spalling strength and bending strength of dedendum has a first quench hardened layerwhich is formed on a surface layer of the rolling member and has a parent phase taking the form of martensite phase which forms a solid solution with carbon of 0.35 to 0.8 wt %, and a second quench hardened layerwhich is formed at a deeper layer under the first quench hardened layer and has a parent phase containing at least either one of martensite phase or bainite phase which forms a solid solution with carbon of 0.07 to 0.3 wt % and contains cementite dispersed therein in a content of 2 to 20% by volume.

Rolling member and producing method thereof

Quenched layers are formed without irregularities on the inner circumferential surface of a track bushing having a small inside diameter or on the inner circumferential surfaces of two or more track bushings which are subjected to quenching in an overlapped condition. To introduce a cooling medium for cooling the inner circumferential surface of the track bushing, a guide tube having an outside diameter smaller than the inside diameter of the track bushing is disposed on the side of the inner circumferential surface and the cooling medium introduced by the guide tube is diverted by a diverting member having a spherical or similar curved surface, such that the cooling medium is allowed to flow in a direction substantially parallel with an axial direction of the track bushingwithin a space defined by the outer circumferential surface of the guide tube and the inner circumferential surface of the track bushing, thereby performing laminar flow cooling.

Growing community of inventors

Hirakata, Japan

Takemori Takayama