Jtekt Corporation

Nippon Steel Corporation

Nippon Steel Sumitomo Metal Corporation

Koyo Seiko Company, Ltd.

Takashi Sada

Yutaka Neishi

Kohei Kanetani

Takahisa Suzuki

Tomohiro Yamashita

Tatsuya Koyama

Daisuke Hirakami

Katsuhiko Kizawa

Wataru Yoshida

Towako Matsui

Shingo Yamasaki

Junji Murata

Toshiyuki Saito

Masahiro Suzuki

Kazuyoshi Yamakawa

Tsuyoshi Mikami

Hiroki Matsuyama

Kazuya Suzuki

Keisuke Chiba

Naoki Tani

Tomoya Hattori

Takahiro Shimano

Tetsuya Hironaka

There is provided a carburized bearing that is excellent in rolling contact fatigue life with a change in structure under a hydrogen-generating environment. In the carburized bearing, a chemical composition of a core portion consists of, in mass %, C: 0.25 to 0.45%, Si: 0.10 to 0.50 %, Mn: 0.40 to 0.70 %, P: 0.015% or less, S: 0.005% or less, Cr: 0.80 to 1.50%, Mo: 0.17 to 0.30%, V: 0.24 to 0.40%. Al: 0.005 to 0.100%, N: 0.0300% or less, O: 0.0015% or less, and the balance being Fe and impurities, and satisfies Formula (1) to Formula (4) described in the present specification. A proportion of a total area of CaO—CaS—MgO—AlOcomposite oxides with respect to a total area of oxides in the carburized leaping is 30.0% or more, and a number density of oxides having an equivalent circle diameter of 20.0 μm or more is 15.0 pieces/mmor less.

Carburized bearing

A steel consists of, in mass %, C: 0.25 to 0.45%, Si: 0.10 to 0.50%, Mn: 0.40 to 0.70%, P: 0.015% or less, S: 0.005% or less, Cr: 0.80 to 1.50%, Mo: 0.17 to 0.30%, V: 0.24 to 0.40%, Al: 0.005 to 0.100%, N: 0.0300% or less, O: 0.0015% or less, and the balance being Fe and impurities, and satisfies Formula (1) to Formula (4) described in the present specification, wherein: its microstructure is composed of ferrite and pearlite having a total area fraction of 5.0 to 100.0%, and a hard phase having a total area fraction of 0 to 95.0%; a proportion of a total area of CaO—CaS—MgO—AlOcomposite oxides with respect to a total area of oxides in the steel is 30.0% or more; and a number density of oxides having an equivalent circle diameter of 20.0 μm or more is 15.0 pieces/mmor less.

Steel

A core portion of the carbonitrided bearing component includes a chemical composition consisting of, in mass %, C: 0.15 to 0.45%, Si: 0.50% or less, Mn: 0.20 to 0.60%, P: 0.015% or less, S: 0.005% or less, Cr 0.80 to 1.50%, Mo: 0.17 to 0.30%, V: 0.24 to 0.40%, Al: 0.005 to 0.100%, N: 0.0300% or less, O: 0.0015% or less, and the balance being Fe and impurities, and satisfying Formula (1) to Formula (4) described in the embodiment of the present specification. A concentration of C of its surface is, in mass %, 0.70 to 1.20%, a concentration of N of the surface is, in mass %, 0.15 to 0.60%, a Rockwell C-scale hardness HRC of the surface is 58 to 65, and in the core portion, an area ratio of an area of coarse V-based precipitates to a total area of V-based precipitates is 15.0% or less.

Carbonitrided bearing component

The steel material includes a chemical composition containing, in mass %, C: 0.15 to 0.45%, Si: 0.50% or less, Mn: 0.20 to 0.60%, P: 0.015% or less, S: 0.005% or less, Cr: 0.80 to 1.50%, Mo: 0.17 to 0.30%, V: 0.24 to 0.40%, Al: 0.005 to 0.100%, N: 0.0300% or less, O: 0.0015% or less, and the balance being Fe and impurities, and satisfying Formula (1) to Formula (4) described in Embodiment, wherein, in its microstructure, a total area fraction of ferrite and pearlite is 10.0% or more, and a proportion of a content of V (mass %) in electrolytic extraction residue to the content of V (mass %) in the chemical composition is 10.0% or less.

Steel material to be starting material of carbonitrided bearing component

A rolling sliding member includes a base part and a surface layer. The base part has a composition that includes 0.30 mass % to 0.45 mass % of carbon, 0.15 mass % to 0.45 mass % of silicon, 0.40 to 1.50 mass % of manganese, 0.60 mass % to 2.00 mass % of chromium, 0.10 mass % to 0.35 mass % of molybdenum, 0.20 mass % to 0.40 mass % of vanadium, and 0.005 mass % to 0.100 mass % of aluminum, and a remainder of iron and inevitable impurities. The surface layer is positioned around the base part. The surface layer has a Vickers hardness of 700 to 800 and a retained austenite content of 25 volume % to 50 volume %. The thickness of a grain boundary oxide layer satisfies Formula: thickness of grain boundary oxide layer&#x2264;equivalent diameter of rolling sliding member&#xd7;1.4&#xd7;10.

Rolling sliding member and method of producing the same, and rolling bearing including rolling sliding member

A heat treatment apparatus that thermally treats an annular workpiece formed of a steel material by inductively heating the workpiece includes a treatment tank in which the workpiece is set and thermally treated, a holding portion that holds the workpiece at a predetermined position, an induction heating coil that surrounds the workpiece to inductively heat the workpiece, and a cooling medium that cools surfaces of the workpiece during the induction heating of the workpiece.

Heat treatment apparatus and heat treatment method

The steel material for a carburized bearing part according to the present invention contains, by mass %, C: 0.25 to 0.45%, Si: 0.15 to 0.45%, Mn: 0.40 to 1.50%, P: 0.015% or less, S: 0.005% or less, Cr: 0.60 to 2.00%, Mo: 0.10 to 0.35%, V: 0.20 to 0.40%, Al: 0.005 to 0.100%, Ca: 0.0002 to 0.0010%, N: 0.0300% or less and O: 0.0015% or less, with the balance being Fe and impurities, and satisfies Formulae (1) to (3).1.20&#x3c;0.4Cr+0.4Mo+4.5V&#x3c;2.75&#x2003;&#x2003;(1)A1/A2&#x3e;0.50&#x2003;&#x2003;(2)2.7C+0.4Si+Mn+0.45Ni+0.8Cr+Mo+V&#x3e;2.55&#x2003;&#x2003;(3)Formula (2) shows an area fraction of sulfides containing Ca in an amount of 1 mol % or more among sulfides having an equivalent circular diameter of 1 &#x3bc;m or more.

Steel material for carburized bearing part

Provided is a steel for carbonitrided bearing which excels in hardenability and also excels in toughness, wear resistance, and surface-originated flaking life after quenching and tempering. A steel for carbonitrided bearing of the present embodiment has a chemical composition containing, in mass %, C: 0.22 to 0.45%, Si: not more than 0.50%, Mn: 0.40 to 1.50%, P: not more than 0.015%, S: not more than 0.005%, Cr: 0.30 to 2.0%, Mo: 0.10 to 0.35%, V: 0.20 to 0.40%, Al: 0.005 to 0.10%, N: not more than 0.030%, and O: not more than 0.0015%, with the balance being Fe and impurities, and satisfying Formulae (1) and (2).1.20&#x3c;0.4Cr+0.4Mo+4.5V&#x3c;2.60&#x2003;&#x2003;(1)2.7C+0.4Si+Mn+0.8Cr+Mo+V&#x3e;2.20&#x2003;&#x2003;(2)

Steel for carbonitrided bearing

Provided is a carbonitrided bearing part which has high hardenability and toughness, and is excellent in wear resistance and surface-originated flaking life. A carbonitrided bearing part of the present embodiment has a chemical composition containing, in mass %, C: 0.15 to 0.45%, Si: not more than 0.50%, Mn: 0.40 to 1.50%, P: not more than 0.015%, S: not more than 0.005%, Cr: 0.30 to 2.0%, Mo: 0.10 to 0.35%, V: 0.20 to 0.40%, Al: 0.005 to 0.10%, N: not more than 0.030%, and O: not more than 0.0015%, with the balance being Fe and impurities, and satisfying Formulae (1) and (2). At surface, C concentration is 0.7 to 1.2%, N concentration is 0.15 to 0.6%, and Rockwell hardness HRC is 58 to 65.1.20&#x3c;0.4Cr+0.4Mo+4.5V&#x3c;2.60&#x2003;&#x2003;(1)2.7C+0.4Si+Mn+0.8Cr+Mo+V&#x3e;2.20&#x2003;&#x2003;(2)

Carbonitrided bearing part

A bearing constituent member includes a base material including steel and a carbonitrided layer that is a surface layer on the steel, the steel including 0.3 to 0.45 mass % of carbon, 0.5 mass % or lower of silicon, 0.4 to 1.5 mass % of manganese, 0.3 to 2 mass % of chromium, 0.1 to 0.35 mass % of molybdenum, 0.2 to 0.4 mass % of vanadium, and a remainder of iron and unavoidable impurities. Surface Vickers hardness at a position at a depth of 50 &#x3bc;m from a surface of a rolling sliding surface is 700 to 800, internal hardness is 550 to 690 in terms of Vickers hardness, and an amount of residual austenite in a range from the surface to a depth of 10 &#x3bc;m is at least 30 vol %.

Bearing constituent member, method of manufacturing bearing constituent member, and rolling bearing

A bearing ring formed of quenched and tempered high carbon chromium bearing steel, including an inner layer portion formed of tempered martensite or sorbite and having a Vickers hardness of more than 490 HV and 710 HV or less, and a surface layer portion formed to enclose an entire periphery of the inner layer portion, formed of tempered martensite, and having a higher hardness than the inner layer portion.

Bearing ring and rolling bearing

A split outer ring of a split rolling bearing, which splits in a radial direction, includes a pair of split outer ring members which are each formed into a semi-cylindrical shape and which are formed into a cylindrical shape by being butted against each other at circumferential end portions. A pair of first flat plane portions which extend from both axial end edges of the end portions towards a center in parallel with an axis and a V-shaped recess portion, positioned between the first flat plane portions and is recessed in a circumferential direction relative to the pair of first flat plane portions, are formed at one end portion of the circumferential end portions which are butted against each other, and a pair of second flat plane portions which extend from the both axial end edges in parallel with the axis.

Split outer ring, split rolling bearing using the same ring and construction and method of mounting the same rolling bearing

A bearing structure includes a housing including a first housing portion and a second housing portion forming together with the first housing portion, a cross-sectionally generally-circular support hole, and a rolling bearing including a pair of outer rings mounted within the support hole of the housing in closely-contacted relation thereto, a plurality of rolling elements mounted to be able to roll on inner side surfaces of the pair of outer rings, and a pair of cages holding the rolling elements. The first housing portion and the second housing portion are mounted in an offset relation to each other in a radial direction so that at mating surfaces of circumferential end portions of the pair of outer rings, the outer ring end portions disposed at an upstream side with respect to a direction of rotation of the shaft form radially inwardly-projecting steps, respectively.

Bearing structure and manufacturing method thereof

A tapered roller bearing includes: an oil guide member that opens and closes an annular opening between an outer peripheral surface of a large rib of an inner ring and an outer ring and is mounted on the large rib; and a discharge port that discharges, along the outer peripheral surface of the large rib, lubricating oil and is formed through an inner peripheral portion of the oil guide member. The oil guide member includes a closing portion for closing the annular opening. When a fluid pressure of the lubricating oil which flows through pockets of a cage toward an inner peripheral surface of the outer ring is below a predetermined values, the closing portion closes the annular opening and guides the lubricating oil toward the discharge port. When the fluid pressure exceeds the predetermined value, the closing portion opens the annular opening.

Growing community of inventors

Kashiwara, Japan

Takashi Sada