High Strength PM Research Articles

A new approach to improve machinability of high strength PM parts

Through development work at Quebec Metal Powders Ltd, boron nitride has opened a new avenue to improve the machinability of PM components. As a result of this work, a new machinable powder grade, ATOMET 29M, has been introduced to the PM industry. A series of machinability tests confirmed significant reductions in drilling thrust force as well as improvements in tool life, when compared to conventional powder grades. Moreover, the beneficial effect of boron nitride was retained even at high carbon content, thus extending the feasibility of performing efficient machining operations on high strength PM materials.

Recent advances in production of steel powders for high strength PM parts

Kawasaki has recently developed three series of low alloy steel powders: 1) A new type of Ni-Cu-Mo alloy steel powder; 2) A low oxygen alloy steel powder by vacuum annealing; 3) A composite type alloy steel powder. This paper describes recent advances in alloy steel powders, in particular their production methods and the properties of these low alloy steel powders. Furthermore, a new composite type alloy steel powder for ultra high strength parts will also be presented.

New Aluminium Powders

Currently available compaction-ready aluminium powders enable sintered preforms to be readily produced by the powder metallurgy route. Aluminium bearing materials with good sliding properties can be produced by sintering-in abrasion-resistant particles or by using alloy powders with homogeneously distributed lead additions. Reactively ground and mechanically alloyed granulates with dispersoid particles of oxides, carbides, and inter-metallic compounds provide high-temperature PM materials with improved properties. New techniques for powder production provide aluminium alloy powders with extraordinary metallurgical effects within the particles and controlled properties. The consolidation of rapidly solidified aluminium alloy powders into high-strength PM semiproducts has considerably enlarged the potential of aluminium powder metallurgy. The aims of numerous worldwide development projects in powder metallurgy are to improve conventional aluminium alloys and develop new alloys which cannot be produced by the . traditional melting route. PM/0253

Wear Mechanism and Cutting Performance of Conventional and High-Strength PM High-Speed Steels

Abstract One of the reasons for employing PM techniques in the manufacture of high-speed steels is to avoid the carbide clusters that limit the strength of ordinary high-speed steels. The combination of proper PM techniques, upgrading the steel to an optimum chemical composition, and correct heat treatment results in superior strength and toughness characteristics. The effects of a superior cutting edge strength on the tool wear and the tool performance of some broaches and milling tools are discussed. The life of broaches may be greatly improved while, in the case of milling tools, the machining rate may also be raised. Case studies from actual production are used as illustrations. For high-quality industrial tools, the best way of saving scarce and expensive alloy metals may not be to lower the alloy content of the tool, but to make sure that the tool is capable of machining more components. The crucial factor is the alloy expenditure per machined component. PM/0189