Showing papers on "Powder metallurgy published in 1973"

Magnetization reversal process in chemically precipitated and ordinary prepared BaFe12O19

Abstract: BaFe12O19 particles were prepared by chemical precipitation and ordinary powder metallurgy methods. These particles were oriented in paraffin wax and the angular variation of coercive force was measured. By using the modified equation of Buessem et al., its variation was analyzed. It was found that reverse‐domain nucleation greatly influences the intrinsic coercive force of BaFe12O19 particles; even stress‐free chemically precipitated single‐domain particles were influenced. Annealing the ball milled powder raised the coercive force drastically. This is due to the reduction of defect‐nucleation centers. It should be noted that by the chemical precipitation method a coercive force of 6000 Oe was obtained, which is one of the highest reported up to this time for isotropic BaFe12O19.

Process and apparatus for densifying powder metal compact to form a gear having a hub portion,and preferred powder metal compact shape for use therewith

Abstract: A process and apparatus are described for densifying a hot powder metal compact in incremental stages with a single stroke of a forming or forging press. Flow of metal during densification and deformation of the hot compact are controlled to prevent undesired flow of material between a hub portion and a main body portion of the final product to be produced. A preferred shape of powder metal compact is described for use with the process and apparatus disclosed herein.

Powder metallurgy composite

Abstract: A bi-metallic powder metal compact is formed by filling a die cavity with at least two different kinds of metal powder separated by divider means which are then withdrawn from the die cavity so that the powders in the cavity may be compacted in the usual manner. One or a plurality of mated bottom punches fill the cavity until a shoe, which is fed from an external source, carrying the separated different kinds of powder is correctly positioned above the cavity. The punches are then withdrawn to the same or different depths as desired, and the shoe is then removed so that the powders may be compressed in the cavity by a top punch and by said bottom punches.

Elimination of carbide segregation to prior particle boundaries

Abstract: Carbide segregation to the prior boundaries of particles used in powder metallurgy to generate an article is eliminated through the use of a nickel-base alloy powder which coordinates carbon with the amount of Mo and W which can form detrimental amounts of undesirable carbides and with Cb, Ta, Hf and Zr which are strong formers of a desirable MC-type carbide.

Powder metal honeycomb

Abstract: A labyrinth seal, for turbine engines, disposed between the rotary blades and the shroud, composed of a powder metal honeycomb in which the cavities thereof are also filled with a powder metal material. The density of the composite and of each of its component parts may be varied to satisfy various operating requirements.

Powder metallurgy production of high performance alloys

Abstract: 1. THE PROCESS OF MAKING A COHERENT GREEN COMPACT WHICH HODS ITS SHAPED DURING SINTERING FROM PRE-ALLOYED COMMINUTED POWDER OF A HIGH PERFORMANCE METAL ALLOY WHICH CANNOT BE PRESSURE COMPACTED UNDER PRESSURES UP TO 70 TONS PER SQUARE INCH UNLESS ITS AVERAGE PARTICLE SIZE IS NOT GREATER THAN ABOUT 5 MICRONS, COMPRISING PROCESSING THE ALLOY POWDER TO AN AVERAGE PARTICLE SIZE BETWEEN ABOUT 9 AND ABOUT 30 MICRONS, MIXING THE ALLOY POWDER WITH A DRY, FINELY DIVIDED ORGANIC BINDER IN AMOUNTS NOT GREATER THAN ABOUT 5% BY WEIGHT OF THE ALLOY POWDER SO AS TO OBTAIN A UNIFORM DISPERSION OF BINDER IN THE ALLOY POWDER, THEN ADDING A SOLVENT FOR THE BINDER IN AMOUNT SUFFICIENT TO FORM A PLASTIC MIXTURE WITH THE ALLOY POWDER AND BINDER, THEN CONSOLIDATING THE PLASTIC MIXTURE TO A BULK DENSITY INTERMEDIATE THAT OF THE POWDER AND THAT OF THE CAST ALLOY, THEN DRYING THE CONSOLIDATED MIXTURE TO EVAPORATE THE SOLVENT, THEN CRUSHING THE CONSOLIDATED MIXTURE TO DISCRETE AGGLOMERATES OF PRE-ALLOYED POWDER PARTICLES TO PROVIDES A SUBSTANTIAL FRACTION OF -100 MESH PARTICLES AT LEAST ABOUT HALF OF THE -100 MESH FRACTION OF WHICH ARE-325 MESH, THEN FILLING A DIE OF THE DESIRED SHAPED WITH THOSE AGGLOMERATES, THEN COMPACTING THE AGGLOMERATES IN THE DIE UNDER PRESSURE TO AT LEAST ABOUT 50% OF THE CAST DENSITY OF THE ALLOY SO AS TO PRODUCE A COHERENT GREEN COMPACT, AND THEN REMOVING THE COMPACT FROM THE DIE.

Method for powder metal production

Abstract: A method for producing pre-alloyed metallic powder which utilizes a pair of electrodes and a reservoir to accomplish its objectives. An arc is struck between a consumable electrode and a second electrode to produce molten metal which is collected, held and homogenized in a reservoir and subsequently atomized.

Process of producing by powder metallurgy techniques a ferritic hot forging of low flow stress

Abstract: Ferritic age-hardenable alloy steels containing correlated percentages of nickel, copper, molybdenum, carbon, etc. in powder form are characterized by low flow stress, thus rendering them particularly suitable for P/M hot forging.

Production of powder alloy products

Abstract: METHOD OF PRODUCING DISPERSION STRENGTHENED SUPERALLOYS HAVING IMPROVED HIGH STRESS-REPTURE PROPERTIES AT ELEVATED TEMPERATURES WHEREIN A POWDER METALLURGY PRODUCT PROCESSED SO AS TO ELIMINATE FINE GRAINS, IS HOT WORKED TO PRODUCE A METALLURGICAL STRUCTURE CHARACTERIZED BY COARSE, ELONGATED GRAINS.

Method of making a through-hardened scale-free forged powdered metal article without heat treatment after forging

Abstract: A method of making forged powdered iron base metal articles of high Rc hardness without need for further machining, surface treatment nor heat treatment after quenching comprising forming a pre-alloyed metal powder, compressing said powder into a briquette, sintering said briquette into a preform, heating said preform to a temperature above its austenizing temperature, forging said preform while above its austenizing temperature into a forged article, permitting the article to cool to approximately its austenizing temperature, and promptly quenching said forged article in a quenching batch.

The fabrication of high-speed tool steel by ultrafine powder metallurgy*

Abstract: Various powder-metallurgy techniques have been developed during recent years to avoid segregation effects associated with the conventional methods of casting and forming high-speed steels. These techniques have generally involved the consolidation of hot working or hot pressing of 50–500μm prealloyed powders into dense billets or rods. The work described has demonstrated that much finer, 0·5–5μm, powders of M2 and M50 steels may be cold pressed and sintered to produce bodies with densities of 99% theoretical containing uniformly distributed 1–2μm particles of carbides. It is anticipated that the method will have application for the manufacture of complex-shaped parts with very small material losses and little machining. An account is given of the preparation of the fine powders by ball-milling and their subsequent compaction, sintering, and microstructure. The control of carbon and oxygen levels by carbon addition to the powders is described.

Method for producing high density steel powders

Abstract: A process for producing high density steel powders for Powder metallurgy is disclosed, wherein the molten stream of low carbon steel or low carbon alloy steel is atomized by high pressure water jet or inert gas jet to be powders, and after drying, the powders are heated in such inert gas as nitrogen or argon, whereby the reduction, decarburization and softening of the powders are simultaneously carried out.

Control method and apparatus for the production of powder metal

Abstract: Control of the process for producing pre-alloyed metallic powder by controlling the melting rate of at least one consumable electrode formed from an ingot of the metal to be ultimately atomized, to produce a controllable continuous flow of metal for atomization into powder. After striking an arc for melting the electrode which is located in a chamber containing a protective atmosphere, the power input to the electrode is selectively adjusted during continual melting to control the melting rate to equal the optimum rate of atomization. The liquid metal droplets from the electrode are collected in a preheated holding reservoir to provide a homogeneous stream of metal which is delivered to a disintegrator. This produces an atomized liquid metal which solidifies into a powdered form and is collected.

Method of producing iron-chromium-aluminum alloys with improved high temperature properties

Abstract: A powder metallurgy product comprising iron and chromium, and/or aluminum and characterized by elongated grains that are stable at elevated temperatures.

Method of making cross-rolled powder metal discs

Abstract: A method of making metal stock utilizing powder metal technology and rolling mill practices The method described comprises filling a container having a contoured interior surface with metal powder, sealing, evacuating and heating the container and cross-rolling the containerized powder in a rolling mill to produce a predictable size and configuration of compacted metal product having properties similar to conventionally rolled or forged stock

Process for heating and sintering ferrous powder metal compacts with radio frequency magnetic field

Abstract: A relatively high frequency (in the radio frequency range) magnetic field is used for reducing electrical resistivity of ferrous powder metal compacts prior to subjecting the compacts to a relatively lower frequency magnetic field which rapidly raises the temperature level of the material of each compact to a sintering temperature.

Wear resistant powder metal magnetic pole piece made from oxide coated fe-al-si powders

Abstract: A POWDER METALLURGY PRODUCED WEAR RESISTANT MAGNETIC POLE PIECE FOR USE AS A PICKUP HEAD WITH MAGNETIC PLAYBACK TAPES IS PROVIDED MADE FOR A MAGNETICALLY SOFT FERROUS ALLOY CONTAINING EFFECTIVE AMOUNTS OF SULICON AND ALUMINUM. A POWDER OF THE ALLOY IS OXIDIZED TO PROVIDE A THIN OXIDE ON THE PARTICLE THEREOF. THE POWDER IS THEN HOT PRESSED IN VACUUM AT AN ELEVATED TEMPERATURE INTOS DENSE SINERED BODY. THE PRESENCE OF OXIDE OF OXIDE IN THE GRAIN BOUNDRIES CONFERS WEAR RESISTANT PROPERTIES TO THE ALLOY AN OXYGEN CONTENT OF ABOUT 3400 TO 4400 P.P.M. IS PREFERRED.

Silver electrical contact materials containing La{hd 1{118 x{b Sr{hd x{b CrO{HD 3

Abstract: The material consists of a mixture of silver and 1.0 to 20 weight per cent of lanthanum, strontium chromite of the formula La1-xSrxCrO3, where the values of x lie between 0 and 1.0. The addition of 2.5 to 20 weight per cent of cadmium oxide further improves the electrical contact material by providing anti-weld properties to the contact interface. The electrical contacts are formed from the contact material by powder metallurgy techniques.

Ternary boride product and process

Abstract: A hard, tough, strong ceramic body is formed by hot pressing a mixture of a powdered metal and a powdered metal diboride. The metal employed is zirconium, titanium or hafnium and the diboride is the diboride of a different member of the same group of zirconium, titanium or hafnium to form a ternary composition. During hot pressing at temperatures above about 2,000°F., a substantial proportion of acicular ternary monoboride is formed.

Titanium Powder Metallurgy By Decomposition Sintering of the Hydride

Abstract: An approach in titanium powder metallurgy called “decomposition sintering” of the hydride is described in connection with some of its unique characteristics. Hydriding and dehydriding of titanium are a function solely of ambient temperature and hydrogen pressure. Thus, raw titanium was readily hydrided and powdered, and the powders were readily converted to massive metal in a single operation comprised of ram pressing in vacuum at elevated temperature, i.e., decomposition to metal during the sintering process. The important aspect of ductility was retained by sufficient dehydriding, and by other impurity control as needed for titanium.

Process for production of metal powders having high green strength

Abstract: Metal particles of high green strength are made by the process of thermally agglomerating a mass of finely atomized particulates of said metal into a self-supporting cake, then milling said cake into a body of agglomerate particles having average particle size substantially greater than said atomized particles. Water or gas atomization can be used, and the metals can be ferrous or nonferrous. The product is useful in powder metallurgy.

Powder metallurgy process for producing stainless steel stock

Abstract: A powder metallurgy process for producing stainless steel stock. The process utilizes readily available, inexpensive, oxygen- and carbon-bearing raw materials and yields stainless steel stock of high purity with a low level of interstitials. After determining the degree of homogeneity desired, the process consists of providing an alloy composition from a particle mass comprising iron, chromium- and/or nickel-bearing powders containing oxygen and carbon, purifying the particle mass in an uncompacted condition in order to obtain a coherent porous compact with a desired purity level and then hot working the compact to produce a homogeneous and densified product. The properties of the product produced by this process are comparable to properties of a wrought product of similar chemical composition.

Powder metallurgy friction lining on steel base - is sintered to base without prior compaction

Abstract: Sintered friction metal discs with inner and other toothed rims are made by firstly roughening of the downwards facing surface of the steel base, the filling of the requisite friction powder quantity into a die, placing of the steel piece over die, sintering of friction material to steel base, removal from die after cooling, compacting of coating to final dimension or post sintering treatment and coining. The method results in good edge contours of the sintering and good adhesion of the friction liniing to the steel base. It is used for brake and clutch components, etc.

Cemented carbide intermediate therefor and process for producing the same

Abstract: In a process for producing a cemented carbide by powder metallurgy, oxidizable intermediate products are treated with a carboxylic acid or anhydride thereof having a molecular weight less than 200 to prevent oxidation. The intermediate products thus obtained are also described in detail.

Properties of aluminium-tin alloys produced by powder metallurgy

Abstract: Aluminium-tin powder-metallurgy alloys containing 20–40% Sn and 0–3% Cu were prepared by compaction and extrusion of prealloyed atomized powder. The powder-metallurgy (PM) material had a fine distribution of the tin phase and was stronger, with greater fatigue strength than an Al-20% Sn-1 % Cu cast alloy but was harder and less ductile. Heat-treatment reduced the hardness of the PM alloys to values comparable with those of the cast material, whereas the strength, although also reduced, remained superior to that of the cast product.

Metallic sintering powder or alloy

Abstract: Metallic sintered alloys, especially sintered steel alloys, are prepared from a composition of metal powder and the alloying components and/or from an alloying powder and admixtures of carbides such as chromium-carbides by pressure and sintering. If desired, a following cold or warm working step may be used to improve the densification. The starting powder composition contains 0.5-50 percent by weight of carbides consisting completely or substantially of complex chromiumcarbides and/or complex manganese-carbides and/or mixed carbides compose these elements.