Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
  • B22F1/10—Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
  • B22F1/10—Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
  • B22F1/103—Metallic powder containing lubricating or binding agents; Metallic powder containing organic material containing an organic binding agent comprising a mixture of, or obtained by reaction of, two or more components other than a solvent or a lubricating agent
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
  • B22F3/02—Compacting only
  • B22F2003/023—Lubricant mixed with the metal powder
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
  • B22F2998/10—Processes characterised by the sequence of their steps

Definitions

• internal and external serrations, bores and blind holes with profile or even openings with countersink or shoulder can be made in a single molding step.
• the parameters of the manufacturing process are determined by the required component properties; They are tailored to the chemical composition, density and dimensional accuracy of the component.
• a cost comparison with competitive technologies such as stamping, cold forming, precision casting, precision forging and plastic injection molding is heavily influenced by the required material, geometry and quantity.
• sugarcane waxes and blends made therefrom with other waxes and wax-like products are excellent lubricants for metal powder compositions that achieve excellent results in the sintered metallurgy / PM process.
• Compaction at temperatures above room temperature has distinct advantages, resulting in a product with higher density and higher strength than the compaction performed at lower temperatures.
• An object of the present invention is to produce compacts using the sugarcane wax-based specific lubricant in the metal powders having high flexural strength, compressive strength and high bulk density, and that the sintered products have a high sintered density and a low ejection force.
• the compact is subject to considerable stress as it is expelled from the compacting tool.
• the molded part / article must be held together during compaction between compaction and sintering so that it does not crack or crack, or otherwise be damaged. Therefore, a high bending strength and compressive strength is very important. This is particularly important for thin-walled and filigree molded parts / products.
• This natural, renewable, CO2 neutral and sustainable lubricant is obtained from the sugarcane plant and has a C chain length distribution of preferably C 10 -C 40.
• end groups occur in addition to aliphatic hydrocarbons acid and alcohol end groups. The acid end groups are partially esterified.
• the sugar cane wax can be ground, sprayed or wind-screened to any desired fineness with finenesses from 1 ⁇ m to 1,000 ⁇ m.
• the best results in our experiments were achieved with finenesses of 100% smaller than 80 ⁇ m, 100% smaller than 50 ⁇ m and 100% smaller than 30 ⁇ m.
• metal powder includes iron-based powders consisting essentially of iron powders and not more than about 1.0% by weight, preferably not more than about 0.5% by weight. contain normal impurities.
• highly condensable metallurgical grade iron powders are ANCORSTEEL 1000 series of pure iron powders, e.g. 1000, 1000B and 1000C available from Hoeganaes Corporation, Riverton, New Jersey and similar powders available from Höganäs AB, Sweden.
• ANCORSTEEL 1000 iron powder has a typical screen profile, with about 22% by weight of the particles under a No.
• the ANCORSTEEL 1000 powder has an apparent density of about 2.85-3.00 g / cm 3, typically 2.94 g / cm 3.
• Other iron powders which can be used in the invention are normally sponge iron powders, such as Hoeganaes ANCOR MH-100 powder.
• the iron-based powders may also contain iron, preferably substantially pure iron, which has been pre-alloyed, diffusion-bonded or mixed with one or more alloying elements.
• alloying elements that can be bonded to the iron particles include, but are not limited to, molybdenum, manganese, magnesium, chromium, silicon, copper, nickel, gold, vanadium, columbium (niobium), graphite, phosphorus, aluminum Binary alloys of copper and tin or phosphorus, ferroalloys of manganese, chromium, boron, phosphorus or silicon, low-melting tertiary or quaternary eutectics of carbon and two or three selected from iron, vanadium, manganese, chromium and molybdenum, carbides of tungsten or silicon , Silicon nitride, alumina and sulfides of manganese or molybdenum and combinations thereof.
• the alloying elements are generally combined with iron powder, preferably substantially pure iron powder in an amount of up to 7 wt.%, Preferably 0.25 to 5 wt.%, More preferably 0.25 to 4 wt certain special uses, the alloying elements may be present in an amount of from 7% to 15% by weight of the iron powder and alloying element.
• the iron-based powders may therefore contain iron particles which are in a mixture with alloying elements which are in the form of alloy powder.
• alloy powder refers to any particulate element or compound, as previously mentioned, which has been physically mixed with the iron particles, whether or not the element or compound alloys with the iron powder.
• binders examples include those described in U.S. Pat U.S. Patent Nos. 4,483,905 and 4,676,831, both to Engström , and in U.S. Patent No. 4,834,800 to Semel are disclosed.
• the iron-based powder may further be in the form of iron which has been pre-alloyed with one or more of the alloying elements.
• the pre-alloyed powders can be made by making a melt of iron and the desired alloying elements and then atomizing the melt, the atomised droplets forming the powder when solidified. The amount of alloying element or elements that are introduced depends on properties that are desired in the finished metal part. Pre-alloyed iron powders employing such alloying elements are available from Hoeganaes Corporation as part of the ANCORSTEEL series of powders.
• a preferred iron-based powder is prepared from a molybdenum (Mo) prealloyed iron.
• the powder is prepared by atomizing a melt of substantially pure iron containing between 0.1 to 3% by weight of Mo.
• An example of such a powder is Hoeganaes ANCORSTEEL 85HP steel powder containing 0.70-0.90 wt% Mo, less than about 0.4 wt% in total of other materials such as manganese, chromium, silicon, copper, nickel, molybdenum or aluminum contains, and less than 0.03 wt.% of carbon.
• Hoeganaes ANCORSTEEL 4600V steel powder containing 0.4 to 0.7 wt% molybdenum, 1.0 to 3.0 wt% nickel, and 0.05 to 0.35 wt% manganese and contains less than 0.03% by weight of carbon.
• This steel powder composition is a mixture of two different prealloyed iron-based powders, one being a master alloy of 0.4 to 3.0 wt% molybdenum iron, the other being a carbon precursor of iron and at least 25 wt% of a transition element component wherein said constituent comprises at least one element selected from the group consisting of chromium, manganese, vanadium and columbium. This mixture is present in proportions that provide at least 0.05% by weight of the transition element ingredient to the steel powder composition.
• Such a powder is commercially available as Hoeganaes ANCORSTEEL 41 AB steel powder containing about 0.85 weight percent molybdenum, about 1 weight percent nickel, about 0.9 weight percent manganese, about 0.75 weight percent chromium and about Contains 0.5 wt.% Carbon.
• iron-based powders useful in the practice of the invention are ferromagnetic powders.
• An example is a composition of a substantially pure iron powder mixed with powders of iron pre-alloyed with small amounts of phosphorus.
• thermoplastic material to provide a substantially uniform coating of the thermoplastic material
• each particle has a substantially uniform surrounding coating around the iron core particle.
• Sufficient thermoplastic material is applied to provide a coating of from 0.05% to 15% by weight of the iron particles.
• the thermoplastic material is in an amount of 0.2% by weight, preferably 0.4 to 2% by weight, and more preferably 0.5 to 1.0% by weight coated particles present.
• thermoplastic resins such as polyethersulfones, polyetherimides, polycarbonates or polyphenyl ethers having a weight average molecular weight in the range of 5,000 to 50,000.
• Other polymer-coated iron-based powders include those containing an inner coating of iron phosphate, as in U.S. Patent Nos. 4,270,674 and 4,920,270 U.S. Patent No. 5,063,011 to Rutz et al , described.
• the particles of pure iron, prealloyed iron, diffusion-bonded iron or iron coated with thermoplastics may have a particle size of from 1 .mu.m to 1000 .mu.m. In general, the particles have a weight average particle size in the range of 10 ⁇ m to 500 ⁇ m. Preferred is a particle size of 50 microns to 150 microns.
• the metal powder composition may contain one or more additives selected from the group consisting of binders, processing aids, and hard phases.
• the binders may be added to the powder composition according to the method described in U.S. Pat U.S. Patent 4,834,800 and mixed into the metal powder compositions in amounts of about 0.005 to 3 wt.%, preferably about 0.05 to 1.5 wt.%, and more preferably about 0.1 to 1 wt.%, based on the weight of the iron and the alloy powders ,
• the processing aids used in the metal powder composition may consist of talc, forsterite, manganese sulfide, sulfur, molybdenum disulfide, boron nitride, tellurium, selenium, barium difluoride and calcium difluoride, used either separately or in combination.
• the hard phases used in the metal powder composition may be selected from carbides of tungsten, vanadium, titanium, niobium, chromium, molybdenum, tantalum and zirconium, nitrides of aluminum, titanium, vanadium, molybdenum and chromium, Al 2 O 3 , B 4 C and made of different ceramic materials.
• the metal powder and the lubricant particles are mixed to form a substantially homogeneous powder composition.
• the lubricant is added to the metal powder composition in the form of solid particles.
• the average particle size of the lubricants may vary, but is preferably in the range of 1-1000 microns.
• the particle size is too large, it becomes difficult for the lubricant to leave the pore structure of the metal powder composition during compaction, and the lubricant can then lead to large pores after sintering, resulting in a compact having deteriorated strength properties.
• the compacted body In the cold compacting according to the invention, it is preferable to heat the compacted body to a temperature above the melting point peak of the sugarcane wax-based lubricant for a sufficient period of time prior to step c) so that substantially the same temperature is achieved throughout the body.
• the compacted body which is not yet sintered at this time, is given a high bending strength, which simplifies handling and processing of the compacted body between compaction and sintering without cracking or otherwise damaging it.
• the increased flexural strengths and compressive strengths can not be obtained by using examples of commercially available lubricants for cold compaction, whereby the sugarcane wax-based lubricant according to the present invention can be considered as being particularly preferable.
• the metal powder composition is ideally preheated before it is fed to the preheated compaction tool.
• preheating of the metal powder composition it is important that the sugarcane wax-based lubricant does not soften or melt. This would complicate the handling of the powder composition and make filling in the compaction tool difficult.
• the reproducibility of the weight components throughout the body of the product or the exact adherence of the formulation throughout the body of the product would be more difficult. It could lead to density fluctuations. And so you would have bigger problems to come to a compacted body with an exactly uniform density.
• step b) of the process the metal powder composition is preheated to a temperature of 5-30 ° C below the melting point of the lubricant on sugar cane wax.
• Table 1 shows lubricant indicating melting point peak, measured bulk density (GD) and ejection force (Ej.F) in cold compaction of ASC 100.29 (manufactured by Hoeganaes AB) mixed with 0.5 wt% graphite, 2 wt% Cu -200 and 0.6% by weight of lubricant.
• the compression pressure was 600 MPa.
• Table 1 Lubricant for Cold Compaction ⁇ / b> GD grams / cm2 EjF N / mm2 DSC Peak Raw sugarcane wax DEUREX® X 50 7.22 21.5 90 Sugarcane wax DEUREX® X 52 bleached 7.18 18.7 82 * EBS wax 7.18 17.7 144 * not subject of the invention
• EBS wax is an ethylene-bis-stearamide wax.
• the bulk density was measured according to ISO 3927 1985 and the discharge force was measured according to the DEUREX method.
• the melting point peaks for the lubricants are reported as peak values of the melting curve measured by differential scanning calorimeter (DSC) method on a Model 912S DSC instrument, available from TA Instruments, New Castle, DE 197 201 USA.
• Table 2 shows a comparison of the sugarcane wax base lubricant X 50 and EBS wax relating to heating the compacted body prior to sintering, wherein the compacted body is heated to a temperature above the melting point peak of the lubricant for a sufficient period of time to substantially cool the compacted body to achieve the same temperature throughout the compacted body.
• the increased flexural strength provides a compacted green body that can be handled and processed prior to sintering. This option is particularly desired in many areas.
• Table 3 below shows lubricant indicating the melting point peak of the compaction pressure (Comp. Press.), The measured bulk density (GD), the ejection energy (Ej.En) in the cold compaction of ASC 100.29 (sold by Höganäs AB) mixed with 0.45 % By weight of lubricant and 0.15% by weight of methacrylate binder.
• Table 3 Lubricants in Bonded Metal Compositions in Cold Compression ⁇ / b> lubricant Compression pressure MPs GD g / cm Ej.En.
• Table 4 shows lubricants indicating melting point peak, powder temperature, mold temperature, and bulk density (GD) and ejection force (Ej.F).
• the compression pressure was 600 MPa. ⁇ b> Table 4 Lubricants during hot compression ⁇ / b> lubricant Mp. powder temperature recounttemp. GD g / cm Ej.FN / mm2 DEUREX® X50 90 80 80 7.27 20.3 DEUREX® X50 90 80 85 7.29 20.8 * EBS wax 144 120 120 7.22 17.0 (*) EBS wax (such as DEUREX A 20) is not part of the invention
• the materials blended with the lubricants according to the invention exhibit comparable bulk densities (GD) and ejection forces (Ej.F) at lower energy input.
• EBS wax can be admixed to the sugarcane wax up to a concentration of 80% without losing the positive properties of the lubricant according to the invention.
• Oleic amide can be added to the sugarcane wax up to a concentration of 80% without losing the positive properties of the lubricant according to the invention.
• Erucic acid amide can be admixed to the sugarcane wax up to a concentration of 80% without losing the positive properties of the lubricant according to the invention.
• Behenic acid amide can be admixed to the sugarcane wax up to a concentration of 80%, without losing the positive properties of the lubricant according to the invention.
• Arachidonic acid amide can be admixed to the sugarcane wax up to a concentration of 80%, without losing the positive properties of the lubricant according to the invention.
• Montan waxes can be admixed to the sugarcane wax up to a concentration of 80%, without losing the positive properties of the lubricant according to the invention.

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• Powder Metallurgy (AREA)

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Citations (14)

• 2015
  • 2015-11-03 EP EP15003147.4A patent/EP3165302A1/fr not_active Withdrawn

Patent Citations (15)

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