A method for obtaining a lead-free or low lead content brass billet subjects a mixture of lead-free or low lead content brass chips and graphite powder to extrusion, either direct or inverted. The method obtains lead-free or low lead content brass billets.

A method for obtaining a lead-free or low lead content brass billet subjects a mixture of lead-free or low lead content brass chips and graphite powder to extrusion, either direct or inverted. The method obtains lead-free or low lead content brass billets.

A green compact according to the present invention is a green compact, which is obtained by compaction-molding raw material powder containing metal powder as a main raw material, the green compact including an oxide film formed between particles of the raw material powder forming the green compact, the oxide film binding the particles of the raw material powder to each other, in which the metal powder to toe used includes metal powder showing a circularity R at a cumulative frequency of 80% of 0.75 or more, the circularity R being expressed by Equation (1), where S represents a two-dimensional projected area of the metal powder and L represents a two-dimensional projected circumferential length of the metal powder.

[00001]$\begin{array}{cc}R=4.Math.\pi \times \frac{S}{L^2}& \left(1\right)\end{array}$

A method for manufacturing metal powder is provided. The method includes preparing first metal powder, agglomerating the first metal powder to manufacture second metal powder in which the first metal powder is agglomerated, coating the second metal powder with an organic binder, and agglomerating and coarsening the second metal powder coated with the organic binder to manufacture third metal powder having higher flowability than the second metal powder coated with the organic binder.

A magnetic core has a structure in which Fe-based soft magnetic alloy particles are connected via a grain boundary. The Fe-based soft magnetic alloy particles contain Al, Cr and Si. An oxide layer containing at least Fe, Al, Cr and Si is formed at the grain boundary that connects the neighboring Fe-based soft magnetic alloy particles. The oxide layer contains an amount of Al larger than that in Fe-based soft magnetic alloy particles, and includes a first region in which the ratio of Al is higher than the ratio of each of Fe, Cr and Si to the sum of Fe, Cr, Al and Si, and a second region in which the ratio of Fe is higher than the ratio of each of Al, Cr and Si to the sum of Fe, Cr, Al and Si. The first region is on the Fe-based soft magnetic alloy particle side.

Disclosed herein are embodiments of hardfacing/hardbanding materials, alloys, or powder compositions that can have low chromium content or be chromium free. In some embodiments, the alloys can contain transition metal borides and borocarbides with a particular metallic component weight percentage. The disclosed alloys can have high hardness and ASTM G65 performance, making them advantageous for hardfacing/hardbanding applications.

A process for producing nickel particles comprises the steps of: melting a nickel source to produce a melt; and powderizing molten nickel contained in the melt by an atomization method comprising atomizing a gas or an aqueous medium onto the melt, thereby producing nickel particles having purity of 90% or more. In the production process, it is also possible to melt a metal that is more likely to be oxidized than nickel together with the nickel source and then remove an oxide of the metal which is produced as the result of the melting.

A metal powder for powder metallurgy according to the invention contains Co as a principal component, Cr in a proportion of 25 to 32 mass %, Ni in a proportion of 5 to 15 mass %, Fe in a proportion of 0.5 to 2 mass %, W in a proportion of 4 to 10 mass %, Si in a proportion of 0.3 mass % to 1.5 mass %, and C in a proportion of 0.05 mass % to 0.8 mass %, wherein when one element selected from the group consisting of Ti, V, Y, Zr, Nb, Hf, and Ta is defined as a first element, and one element selected from the group and having a higher group number in the periodic table than that of the first element or having the same group number as that of the first element and a higher period number than that of the first element is defined as a second element, the first element is contained in a proportion of 0.01 to 0.5 mass %, and the second element is contained in a proportion of 0.01 to 0.5 mass %.

A metal powder for powder metallurgy according to the invention contains Co as a principal component, Cr in a proportion of 25 to 32 mass %, Ni in a proportion of 5 to 15 mass %, Fe in a proportion of 0.5 to 2 mass %, W in a proportion of 4 to 10 mass %, Si in a proportion of 0.3 mass % to 1.5 mass %, and C in a proportion of 0.05 mass % to 0.8 mass %, wherein when one element selected from the group consisting of Ti, V, Y, Zr, Nb, Hf, and Ta is defined as a first element, and one element selected from the group and having a higher group number in the periodic table than that of the first element or having the same group number as that of the first element and a higher period number than that of the first element is defined as a second element, the first element is contained in a proportion of 0.01 to 0.5 mass %, and the second element is contained in a proportion of 0.01 to 0.5 mass %.

A sintered bearing includes, on an inner peripheral surface, a cylindrical portion and a one-side increased-diameter portion, which are provided so as to be continuous in the axial direction. An end portion of one side in the axial direction of the cylindrical portion and an end portion of another side in the axial direction of the increased-diameter portion coincide, and the cylindrical portion and the increased-diameter portion are molded by performing sizing on a sintered compact having a tubular shape, which is introduced into a die.