Ntn Corporation

Miyu Sato

Chikara Ohki

Masahiro Yamada

Noriaki Miwa

Hiroshi Yuki

Ayaka Yamahara

A rolling member is formed of quenched steel having a contact surface. The rolling member includes a superficial part in a region up to a depth of 20 μm from the contact surface. Steel contains greater than or equal to 0.70 mass % and less than or equal to 1.10 mass % of carbon, greater than or equal to 0.15 mass % and less than or equal to 0.35 mass % of silicon, greater than or equal to 0.30 mass % and less than or equal to 0.60 mass % of manganese, greater than or equal to 1.30 mass % and less than or equal to 1.60 mass % of chromium, greater than or equal to 0.01 mass % and less than or equal to 0.50 mass % of molybdenum, and greater than or equal to 0.01 mass % and less than or equal to 0.50 mass % of vanadium, and the remainder of iron and inevitable impurities.

Rolling member and rolling bearing

A mechanical component according to one aspect of the present invention is made of a titanium alloy and has a surface. The mechanical component includes a plurality of primary α crystal grains and a plurality of secondary α crystal grains. At the surface of the mechanical component the primary α crystal grains have an area ratio of 10% or more and 30% or less. At the surface of the mechanical component the secondary α crystal grains have a major diameter of 75 μm or less and a minor diameter of 10 μm or less. At the surface of the mechanical component 1% by mass or more of oxygen is included.

Mechanical component and method for manufacturing mechanical component

In one aspect of the present invention, a method for manufacturing a bearing component includes: a preparation step of preparing a ring-shaped member of steel having a radially inner surface, a radially outer surface, and a thickness which is a distance between the radially inner surface and the radially outer surface; and a heat treatment step of performing a heat treatment to locally heat one of the radially inner surface and the radially outer surface to a heat treatment temperature and subsequently cool the one of the radially inner surface and the radially outer surface, the method satisfying S&#x2265;930/(0.3477 W&#x2212;1.594 W&#x2212;0.804), where S represents an average temperature increasing rate (unit: &#xb0; C./sec) applied when the surface is heated and W represents the thickness (unit: mm).

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Kuwana, Japan

Miyu Sato