Common terms and explanations of metal powder injection molding and metallurgical powder
time：2020-05-07Views：646 Author：Best Seiko
One. Commonly used metal powder injection molding materials in Chinese and English 1. Sintered materials with heavy metal density not less than 16.5g/cm3. Such as: tungsten alloy containing nickel and copper. 2. Cermet Cermet is a sintered material composed of at least one metallic phase and at least one non-metallic phase usually having ceramic properties. 3. Sintered parts Sintered parts made of powder and strengthened by sintering. The parts usually have precise tolerances and are easy to install. 4. Sintered structural parts Sintered structural parts are usually used in mechanically manufactured sintered parts, excluding bearings, filters and friction materials. 5. Oil-retaining bearing The sintered bearing in which the openings are impregnated with lubricating oil. 6. Sintered metal filter Sintered metal filter is usually used for permeable sintered metal parts for solid-liquid or solid-gas separation. 7. Sintered magnetic parts sintered magnetic parts can meet the requirements of magnetic sintered parts. 8. Sintered friction material This sintered friction material is a composite material composed of a metal-based and metallic or non-metallic additive. The additive is used to change the friction and wear characteristics of the material. 9. Sintered electrical contact material Sintered electrical contact material with high electrical conductivity and arc corrosion resistance, such as: tungsten-copper, tungsten-silver, silver-graphite and silver-cadmium oxide composite materials 10. Carbide: hardmetal or tungsten carbide or cemented carbide 2. Names and characteristics of various metal/ceramic powders Related term powder powder usually refers to a collection of discrete particles with a size of 0.1um~1mm. Slurry slurry is a castable viscous dispersion system formed in the liquid. Billet feedstock is used as plasticized powder for injection molding or powder extrusion raw materials. Atomized powder Atomized powder A powder of molten metal or alloy dispersed into droplets and solidified into individual particles. (The dispersion medium is usually a high-speed gas flow or liquid flow.) Carbonyl powder carbonyl powder is a powder obtained by thermally dissociating a metal carbonyl compound. Electrolytic powder electrolytic powder powder prepared by electrolytic deposition method. Reduced powder A powder made by reducing metal compounds by chemical reduction. Sponge powder Sponge powder is a porous reduced powder made by pulverizing a highly porous metal sponge made by a reduction method. Alloy powder alloyed powder is a metal powder made by partial or complete alloying of two or more components. Pre-alloyed powder usually refers to a fully alloyed powder made by atomizing the melt. Composite powder composite powder Each particle is a powder composed of two or more different ingredients. Coated powder is a composite powder formed by coating a layer of different components on the surface of particles. Combined powder blended powder is a powder composed of different batches of powder with the same nominal composition. Binder binder is added to the powder in order to increase the strength of the green compact or prevent the powder from segregating, and can be removed before or during sintering. Dopant (additive) A small amount of substance added to the metal powder in order to prevent or control the recrystallization or grain growth of the sintered body during sintering or during use. (Mainly used for tungsten powder metallurgy) Lubricant lubricant is added to the powder in order to reduce the friction between the particles and the surface of the compact and the mold wall. Plasticizer plasticizer is used as a binder, a thermoplastic material designed to improve powder formability. Granulation Granulation is a process of agglomerating finer particles into coarse powder particles to improve the fluidity of the powder. Mechanical alloying Mechanical alloying uses a high-energy grinder or ball mill to achieve solid alloying. The apparent density of the bulk density is the mass that the powder freely fills per unit volume under specified conditions. Bulk density The mass of powder per unit volume measured under non-specified conditions. Tap density The mass per unit volume measured after tapping the powder in the container under specified conditions. Compressibility The degree of compression of the powder under pressurized conditions, usually uniaxial compression in a closed mold. Formability The ability of compactibility powder to be compressed into a certain shape and to maintain this shape during subsequent processing is a function of powder fluidity, compressibility and green compact strength. Compression ratio The ratio of the volume of the powder before pressurization to the volume of the green compact after demolding. Fill factor The ratio of the height of the powder filling mold to the height of the green compact after demolding. Flowability The qualitative term describing the flow of powder through a defined hole. Hydrogen loss The relative mass loss caused by heating of metal powder or green compact in pure hydrogen under specified conditions. Specific surface area The total surface area per unit mass of powder. Particle size The linear size of individual powder particles measured by sieving or other suitable methods. Particle size distribution The particle size distribution divides the powder sample into several levels according to different particle sizes, and the percentage of each level of powder (by mass, by quantity or by volume). Particle size cut The fraction of powder that falls within the two nominal particle size limits after classification. 3. Forming process term 1. Forming forming process to transform powder into agglomerate with desired shape. 2. Pressing In a mold or other container, under the action of external force, the process of compacting the powder into a prescribed shape and size. 3. Compact compact, green compact is a blank made by cold pressing or injection molding. 4. The blank does not reach the required size and shape of the compact, pre-sintered blank or sintered blank. 5. The skeleton is a porous compact or sintered body for infiltration. 6. Cold pressing The uniaxial pressing of cold pressing powder at room temperature. 7. Warm pressing The uniaxial powder pressing is usually performed at a temperature between the ambient temperature and the temperature at which diffusion may occur, and is intended to enhance densification. 8. Hot pressing The uniaxial pressing of hot pressing powder or green compact at high temperature activates diffusion and creep phenomena. 9. Isostatic pressing isostatic pressing is applied to the surface of the powder (or green compact) or the surface of the soft mold parts containing the powder (or green compact) by pressing with approximately equal pressure in each direction. 10. Cold isostatic pressing (CIP) isostatic pressing at room temperature, the pressure transmission medium is usually liquid. 11. Hot isostatic pressing (HIP) Hot isostatic pressing (HIP) isostatic pressing at high temperature, which can activate diffusion and creep phenomena. The pressure transmission medium is usually a gas. 12. Metal powder injection molding metal injection moulding (MIM) is a molding method in which the plasticized mixture of metal powder and its binder is injected into the model. 13. Powder rolling A method of introducing powder into a pair of rotating rollers to subsolidify it into a cohesive continuous strip. 14. Volume filling method The volume filling method is to measure the powder filled in the female mold by setting the powder filling depth. 15. Weight filling method Weight filling is a method of measuring the powder charged into the female mold by weighing the weight of the powder. 16. (Auxiliary) Vibration-filling method vibration-a s sisted filling A method of filling powder into a vibrating model or female mold. 17. Holding time dwell time The time that the compact is held under constant pressure during forming. 18. Mold set tool set is a complete set of molds for producing specific powder products by pressing or repressing. 19. A female die in which a powder is pressed or a sintered part is pressed to form a cavity. 20. A part used in the lower punch, upper and lower stamper to seal the female die from the lower part and transmit pressure from the bottom to the powder or sintered part. 21. In the upper punch, a part used to seal the female mold from the upper part and transfer pressure from top to bottom to the powder or sintered part. 22. Core rod core rod is used to form the part of the mold that forms the contour surface in the compact or sintered body in the pressing direction. 23. Powder shoe The part of the press forming press used to feed powder into the cavity of the female model in the feed shoe mold frame. 24. Combined die punching: When pressing two or more table blanks, it is used to control a group of die punches with different powder loading and pressing height. 25. Green compact The green compact is pressed or injection-molded but not sintered. 26. Layered lamination forms a layered structure defect in the compact or sintered body or refers to the defect itself. 27. Elastic back effect The phenomenon that the size of spring back green compact increases after demoulding. 4. Terms related to sintering process and parameters 1. Heat treatment of sintering powder or green compact at a temperature lower than the melting point of the main component, the purpose is to improve the strength by metallurgical bonding between particles. 2. Packing material A material in which the compact is embedded in the firing or sintering process for separation and protection. 3. Presintering heat treatment of the compact at a temperature lower than the sintering temperature. 4. Pressure sintering pressure A sintering process that applies uniaxial pressure while sintering. 5. Loose-powder sintering, sintering of gravity sintering powder without pressing. 6. Liquid-phase sintering Liquid-phase sintering A powder or compact having at least two components is sintered in a state where a liquid phase is formed. 7. Over-sintering oversintering sintering temperature is too high and/or sintering time is too long resulting in deterioration of product performance. 8. The undersintering sintering temperature is too low and/or the sintering time is too short, so that the product does not achieve the desired performance of sintering. 9. Infiltration infiltration The process of filling the pores in the unsintered or sintered product with a metal or alloy with a melting point lower than that of the product in the molten state. 10. Dewaxing, dewaxing, burn-off use heat to discharge organic additives (binder or lubricant) in the compact. 11. Mesh belt furnace Mesh belt furnace is generally a sintering furnace with continuous belt conveying parts in the furnace protected by muffle. 12. Walking-beam furnace Walking-beam furnace is a sintering furnace that transfers the parts placed in the sintering tray through the walking-beam system in the furnace. 13. Pusher furnace Pusher furnace puts the parts into the burning boat, and sintering furnace that transfers the parts in the furnace through the propulsion system. 14. Sintering neck formation Neck formation forms sintered connections between particles during sintering. 15. Foaming blistering results in the phenomenon of blistering on the surface of the sintered part due to the vigorous discharge of gas. 16. Phenomenon of sweating sweating liquid phase exudation during heat treatment. 17. Sinter shell When sinter skin is sintered, a surface layer formed on the sintered part has properties different from those inside the product. 18. Relative density The ratio of the density of the porous body to the density of the same component material in the non-porous state, expressed as a percentage. 19. Radial crushing density The radial crushing strength of a sintered cylinder sample measured by applying radial pressure. 20. Porosity The ratio of the volume of all pores in the porosity porous body to the total volume. 21. Diffusion pores diffusion porosity The pores formed by the diffusion of one component substance into another component due to the Kirkendall effect. 22. Pore size distribution Pore size distribution Percentage of pores at various levels in the material calculated by quantity or volume. 23. Apparent hardness The hardness of the sintered material measured under specified conditions, which includes the influence of pores. 24. Solid hardness The hardness of a phase or particle or a certain area of a sintered material measured under specified conditions, which excludes the influence of pores. 25. The bubble-point pressure forces the gas through the liquid-impregnated product to produce the very small pressure required for the first bubble. 26. Fluid permeability The number of liquid or gas passing through a porous body per unit time measured under specified conditions. 5. Common treatment methods after sintering 1. Re-pressing In order to improve the physical and/or mechanical properties, pressure is usually applied to the sintered products. 2. Finishing sizing repressing in order to achieve the required size. 3. Reshaping coining in order to achieve a specific surface topography. 4. Powder forging powder forging Unsintered, pre-sintered or sintered preforms made of powder are thermally densified by forging, accompanied by changes in shape. 5. Impregnation method of filling the open pores of the sintered part with non-metallic substances (such as oil, paraffin or resin). 6. Steam treatment Steam treatment heats sintered iron-based products in superheated steam to form a protective film of iron oxide in the surface layer, thereby improving certain properties.