Frangible firearm projectiles, firearm cartridges, and methods for forming the same. The projectiles are formed from metal powder and include an anti-sparking agent. One or more of iron, zinc, bismuth, tin, copper, nickel, tungsten, boron, and/or alloys thereof may form the metal powder. The projectiles may be formed from a compacted mixture of two or more different metal powders. The anti-sparking agent may include a borate, such as boric acid, zinc chloride, and/or petrolatum. The anti-sparking agent may be dispersed within, and/or applied as a coating on, the exterior of the projectile. The compacted mixture may be heat treated for a time sufficient to form a plurality of discrete alloy domains within the compacted mixture. Such domains may be formed by a mechanism that includes vapor-phase diffusion bonding and oxidation of the metal powders and that does form a liquid phase of the metal powder or utilize a polymeric binder.

Provided is a mixed powder for powder metallurgy that contains a readily available compound as a lubricant, does not need to contain a stain-causing metal soap, has excellent ejection properties and compressibility, and can exhibit excellent fluidity without deteriorating the ejection properties or the compressibility even in the case of further containing carbon black. The mixed powder for powder metallurgy comprising an (a) iron-based powder and a (b) lubricant, wherein the (b) lubricant is an ester of disaccharide and fatty acid represented by R—COOH, and the R is an alkyl group having 11 or more carbon atoms or an alkenyl group having 11 or more carbon atoms.

Provided is a method of manufacturing a machine part having a radial crushing strength of 120 MPa or more, including: a compression molding step of compressing raw material powder including, as a main component, metal powder that is capable of forming an oxide coating and has a pure iron powder content ratio of 95 mass % or more, to thereby obtain a green compact (10) having a predetermined shape; and a coating forming step of causing the metal powder to react with an oxidizing gas while heating the green compact (10) at a temperature lower than a sintering temperature of the metal powder in an oxidizing gas atmosphere, to thereby obtain a reinforced green compact (11) in which the oxide coating (5) is formed between particles of the metal powder.

Provided is a method of manufacturing a machine part having a radial crushing strength of 120 MPa or more, including: a compression molding step of compressing raw material powder including, as a main component, metal powder that is capable of forming an oxide coating and has a pure iron powder content ratio of 95 mass % or more, to thereby obtain a green compact (10) having a predetermined shape; and a coating forming step of causing the metal powder to react with an oxidizing gas while heating the green compact (10) at a temperature lower than a sintering temperature of the metal powder in an oxidizing gas atmosphere, to thereby obtain a reinforced green compact (11) in which the oxide coating (5) is formed between particles of the metal powder.

Provided is a steel strip joining method that can appropriately evaluate risk of a fracture in a joined part and prevent a fracture more reliably. An iron-based mixed powder for powder metallurgy comprises: an iron-based alloy powder; and an alloying powder, wherein the iron-based alloy powder contains Mo: 0.2 mass % or more and 1.5 mass % or less, the alloying powder contains a graphite powder and a copper powder, a ratio of a mass of the graphite powder to a total mass of the iron-based alloy powder and the alloying powder is 0.10 mass % to 1.0 mass %, a ratio of a mass of the copper powder to the total mass of the iron-based alloy powder and the alloying powder is 0.5 mass % to 3.0 mass %, and the copper powder has an average particle size of 25 μm or less, and a specific surface area of 0.30 m.sup.2/g or more.

A heat-resistant sintered sliding member according to the present invention has a structure in which a lubrication phase is dispersed in a matrix, in which an entire composition of the sliding member is composed of a composition containing, by mass %, Cr: 18% to 35%, Mo: 0.3% to 15%, Ni: 0% to 30%, Si: 0.5% to 6%, S: 0.2% to 4.0%, P: 0% to 1.2%, B: 0% to 0.8%, and a Fe balance containing inevitable impurities, in which the matrix is a Fe—Cr—Mo—Si-based matrix or a Fe—Cr—Mo—Ni—Si-based matrix, the lubrication phase contains chromium sulfide, and a porosity of an entire sliding member is 2.0% or less.

Disclosed herein is a method and apparatus for forming pellets in a non-ambient environment such as a strong magnetic field. The apparatus includes a die body, a die bottom, a short push pin, a long push pin, a press tube, and an extended push pin. A powder is loaded into the die body, which is then positioned in the non-ambient environment, and the powder allowed to equilibrate. A pellet is then formed by pressing on the extended push pin while the powder is in the non-ambient environment.

A method for manufacturing a poppet valve or mushroom valve includes providing a mixture of metal powder and a binder, filling and pressing said mixture in a mold, to obtain a green product, removing the binder from the green product, and thermally sintering the green product to a poppet valve blank, by hot isostatic pressing. A poppet valve is also provided that is manufactured with this method.

A method for manufacturing a poppet valve or mushroom valve includes providing a mixture of metal powder and a binder, filling and pressing said mixture in a mold, to obtain a green product, removing the binder from the green product, and thermally sintering the green product to a poppet valve blank, by hot isostatic pressing. A poppet valve is also provided that is manufactured with this method.

A method for manufacturing a metal object having a solid lubricating surface layer includes: providing a metal blank having a surface; providing a plurality of microparticles and solid lubricating powder, and mixing them together, wherein the microparticles have a hardness greater than that of the surface; and projecting the microparticles and the solid lubricating powder onto the surface, wherein the microparticles cause plastic flow on the surface to form a compressive stress layer, and the solid lubricating powder adheres to the compressive stress layer to form a solid lubricating surface layer.