An oil-impregnated sintered bearing comprises a bearing hole. In the bearing, sliding surfaces supporting an outer circumferential surface of a shaft and an oil supply surface whose diameter is larger than that of the sliding surfaces are formed on an inner circumferential surface of the bearing hole into which the shaft is inserted. The sliding surfaces and the oil supply surfaces are adjacent to each other in the axial direction of the bearing hole. A height gap “d1” between the sliding surfaces and the oil supply surface is not less than 0.01% and not more than 15% of an inner diameter of the sliding surfaces. A surface opening percentage of the sliding surfaces is not higher than 10%. A surface opening percentage of the oil supply surface is higher than 10%. An average circle-equivalent diameter of opening parts of pores on the sliding surfaces is not larger than 20 μm.

Spherical shaped ejection particles are ejected against a surface of a sintered body including hard particles and a binder metal phase bonding the hard particles together, with a compressed gas at an ejection pressure of from 0.2 MPa to 0.6 MPa or at an ejection velocity of from 80 m/s to 200 m/s and the spherical ejection particles having a hardness not less than the hardness of the binder metal phase and that is a hardness of 1000 HV or less and being particles having an average particle diameter from 20 μm to 149 μm. Thus, plastic deformation resulting from such impact and the instantaneous temperature rise and cooling occurring at the impact sites micronizes the structure of the binder metal phase, causes a change to a dense structure, and imparts compressive residual stress thereto. This results in strengthening, and enables prevention of brittle fracture in the sintered body.

A method for manufacturing at least one portion of a part using successive deposition of layers, involving the steps of: a) depositing a first layer of a molten metal on a substrate such that a first metal strip is formed on the substrate; b) depositing a second layer of a molten metal on the first strip such that a second metal strip is formed on the first strip; and c) repeating steps a) and then b) for each new metal layer to be deposited on a preceding strip until the at least one portion of the part has been formed. The method may further include step d) compressing the formed bead after performing n instances of step c), n being greater than or equal to 1. The step of compressing the formed bead may be performed before the complete cooling of said bead.

Provided is a sizing apparatus including: a die set including a die plate that holds a die provided with a through hole to which a workpiece is to be supplied, and upper and lower punches that are to be inserted into the through hole to press the workpiece; a press main body that includes punch driving mechanisms that actuate the punches and in which the die set is configured to be attached to and detached from a predetermined position; and a turntable that is rotated on the die plate and supplies a workpiece to the die and discharges a workpiece from the die. The die set includes the turntable, and a supporting base on which the turntable is placed. The supporting base includes an axis positioning portion that is provided coaxially with a central axis of the turntable and positions the central axis at a predetermined position of the supporting base.

According to a method for the surface compaction and calibration of a sintered component, the sintered component runs along an axis through a plurality of die sections of a die, the inner diameter of which decreases in pressing direction and wherein the individual die sections are arranged such that a following die section of the plurality of die sections directly adjoins the corresponding die section which precedes it in pressing direction, and after the surface compaction at the last die section with decreasing inner diameter there is a relaxation of the sintered component in a relief section directly adjoining the last die section, which relief section has a greater diameter than the immediately preceding last die section of the die section with a decreasing inner diameter. The sintered component is calibrated in the relief section, whereby the inner contour of the relief section corresponds with the intended contour with the nominal dimensions of the sintered component.

The Cu-based sintered sliding material has a composition including, by mass %, 7% to 35% of Ni, 1% to 10% of Sn, 0.9% to 3% of P, and 0.5% to 5% of C, with a remainder of Cu and inevitable impurities, wherein the Cu-based sintered sliding material includes a sintered body including: alloy grains that contain Sn and C and contain a CuNi-based alloy as a main component; grain boundary phases that contain Ni and P as main components and are dispersedly distributed in grain boundaries of the alloy grains; and free graphite that intervenes at the grain boundaries of the alloy grains, the Cu-based sintered sliding material has a structure in which pores are dispersedly formed in the grain boundaries of the alloy grains, and an amount of C in a metal matrix including the alloy grains and the grain boundary phases is, by mass %, 0.02% to 0.20%.

The Cu-based sintered sliding material has a composition including, by mass %, 7% to 35% of Ni, 1% to 10% of Sn, 0.9% to 3% of P, and 0.5% to 5% of C, with a remainder of Cu and inevitable impurities, wherein the Cu-based sintered sliding material includes a sintered body including: alloy grains that contain Sn and C and contain a CuNi-based alloy as a main component; grain boundary phases that contain Ni and P as main components and are dispersedly distributed in grain boundaries of the alloy grains; and free graphite that intervenes at the grain boundaries of the alloy grains, the Cu-based sintered sliding material has a structure in which pores are dispersedly formed in the grain boundaries of the alloy grains, and an amount of C in a metal matrix including the alloy grains and the grain boundary phases is, by mass %, 0.02% to 0.20%.

A sintered bearing is made of a sintered compact containing nickel silver (CuNiZn) as a base. In the sintered bearing, P is not added in the sintered compact. Alternatively, a content of P in the sintered compact is less than 0.05 mass % in terms of mass ratio to a total mass. Consequently, crystal grains constituting the sintered compact can be micronized. In particular, in the sintered bearing, an average crystal particle diameter of the crystal grains constituting the sintered compact is 20 m or less. Consequently, the mechanical strength and the vibration resisting properties can be improved, and the rotation shaft can be prevented from being damaged.

A sintered bearing is made of a sintered compact containing nickel silver (CuNiZn) as a base. In the sintered bearing, P is not added in the sintered compact. Alternatively, a content of P in the sintered compact is less than 0.05 mass % in terms of mass ratio to a total mass. Consequently, crystal grains constituting the sintered compact can be micronized. In particular, in the sintered bearing, an average crystal particle diameter of the crystal grains constituting the sintered compact is 20 m or less. Consequently, the mechanical strength and the vibration resisting properties can be improved, and the rotation shaft can be prevented from being damaged.

It has been found that metal parts having rough surfaces can be manufactured by (1) compacting a metal powder under high pressure in a mold to make a green part, wherein at least one face of the mold is roughened by electrical discharge machining to have an R.sub.a of 10 to 200 micro-inches, as measured with a profilometer having a stylus tip, (2) heating the green metal part to a temperature of at least 1500 F. to sinter the green metal part to produce the metal part having at least one rough surface, wherein the rough surface has an R.sub.a which is within the range of 10 to 200 micro-inches, as measured with a profilometer having a chisel tip, and (3) optionally, buffing, classifying, deburring and/or washing the metal part. This method can be beneficially used in manufacturing clutch plates, pressure plates, and cam shaft sprockets.