Term
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Definition
| *What is it called when stable ceramic powders are combined with binders and gelling agents to produce the mold material? |
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Term
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Definition
| *What is small metal supports that can be positioned between the core and the surface of the molded cavity? |
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Term
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Definition
| In the method of making a reentrant angle or inset section by using a three-piece flask, a part is produced by using a third segment of flask called a cheek. Pg 314 |
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Term
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Definition
| *What is the ability to retain a given shape when packed into a mold? |
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Term
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Definition
| Room temperature curing is the dominant characteristic of the _________. Pg 313 |
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Term
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Definition
| *What is the ability to permit the metal to shrink after it solidifies and ultimately to free the casting by disintegration of the surrounding mold? |
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Term
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Definition
| *What is determined by sifting loose sand into a steel cylinder, leveling off the column, stricking it 3 times with a standard weight then measuring the final height? |
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Term
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Definition
| -A measure of these properties. Also referred to as Green Compressive Strength. |
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Term
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Definition
| When large quantities are to be produced , or when the casting is large it may be desirable to have the cope and drag halves of split patterns attached to separate match plates to produce mating ___________. |
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Term
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Definition
| pg 311 – Casting processes are unique in their ability to incorporate internal cavities or reentrant sections with relative ease. To produce these features it is often necessary to use _______as part of the mold. They add cost, but much expands the capabilities of the process and good design practice can often facilitate and simplify their use. |
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Term
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Definition
| pg 312 – Cores are often the most fragile part of a mold assembly. This is the oldest process, where it uses a vegetable or synthetic oil binder, and water with cereal or clay to develop green strength |
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Term
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Definition
| pg 313-314 – Since the core material must be removed from the finished casting, the cores must be connected to the outer surfaces of the mold cavity. Recesses at these connection points, known as ________ |
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Term
| Counter-Gravity Investment Casting |
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Definition
| – pg 319 – turns the pouring process upside down. In one variation of the process, a ceramic shell mold is place in a mold chamber with the sprue end down. The open end of the chamber is set against a seal, and the open end of the sprue is lowered into the molten pool. A vacuum is then induced within the chamber. Vacuum draws metal through the central sprue and into the mold. Also known as the Hitchiner technique |
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Term
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Definition
| *Problems can be fixed by using this process of heating the mold to a temperature of 300F or higher and baking until most of the moisture is driven off. |
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Term
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Definition
| *What process is made with sand, a small amount of clay and quite a bit of water is first packed around a pattern? |
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Term
| Evaporative Pattern Casting |
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Definition
| *The full-mold and lost-foam process that can be used for castings of any size and can employ both ferrous and nonferrous metals? |
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Term
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Definition
| -In a full mold and lost foam process, the pattern is made of _______, and remains in the mold during the pouring of the metal. The molten metal melts and burns it away |
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Term
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Definition
| -graphite can be combined with cement, starch, and water are compacted around the pattern. It is broken to remove the metal cast. |
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Term
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Definition
| -Molding usually begins with a pattern and a ____. They may be either straight-walled containers with guide pins or removable jackets, and they are generally constructed of lightweight aluminum or magnesium. |
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Term
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Definition
| -If a one piece pattern is simple in shape and contains a flat surface, it can be placed directly on a ___________ |
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Term
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Definition
| -green sand or some type of chemically bonded sand is compacted around the pattern and gating system, taking care not to crush or distort it. |
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Term
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Definition
| -The molten metal enters the mold cavity through one or more openings called ______ |
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Term
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Definition
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Term
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Definition
| *What process is most used for casting ferrous and nonferrous metals and accounts for 90% of all casting made in the USA? |
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Term
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Definition
| *This is the often preferred method of mold making when only a few castings are to be made from any given design |
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Term
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Definition
| The _____ of the compacted sand can provided a quick indication of mold strength and give additional insight into the strength and permeability characteristics. Page 302 |
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Term
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Definition
| sand containing a liquid thermostetting binder and catalyst is packed into a core box that has been heated to around 230 C. When the sand contacts the hot surface, the catalyst is heated and the initial stages of curing occur. When the core is removed, the pattern retains the core shape. Page 313 |
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Term
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Definition
| or cracks can form in casting made from metals or alloys with large amounts of solidification shrinkage. Page 303 |
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Term
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Definition
| is a very old process and has been preformed by dentists and jewelers for years; uses a type of binder and molding aggregate and the following steps: production of a master pattern, production of a master die, production of wax patterns, assemble wax patterns onto a common wax sprue, coat the cluster with thin layer of investment material, produce the final investment around the coated cluster, allow the investment to fully harden, melt/dissolve wax pattern from the mold, preheat mold for pouring, pour molten metal, remove casting from the mold. Page 317-318 |
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Term
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Definition
| a flask is placed over that pattern, filled with sand, and the pattern, flask, and sand are then lifted and dropped several times, producing optimum packing around the pattern. Page 304 |
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Term
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Definition
| -When the product has a geometry such that a one-piece or split pattern could not be removed from the molding sand, a ________ can sometimes be developed. Separate pieces are held to a primary pattern segment by beveled grooves or pins. |
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Term
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Definition
| the pattern is made of expanded plystrene and remains in the mold during the pouring of the metal. The polystyrene assembly is first dipped into a water-based ceramic that wets the surface and forms a thin refractory coating (rigid enough to prevent mold collapse during pouring but thin to permit the escape of the molten gaseous pattern material) |
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Term
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Definition
| small parts of a mold placed in an oven where the wax melts and runs out, and any residue vaporizes. When the molds are placed in the oven, the molten wax is absorbed into the porous investment. The wax "disappears", hence the name "lost-wax process". |
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Term
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Definition
| -The cope and drag segments of a split pattern are permanently fastened to opposite sides of a wood or metal ______. Its positioned between the upper and lower segments of the flask. |
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Term
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Definition
| -A device that kneeds, rolls, and stirs the sand. |
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Term
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Definition
| offers high dimensional accuracy, good hot strength, and high resistance to mold-related casting defects and are cured by room-temperature chemical reactions. The system is based on organic resin binders, curing agents, and various additives and modifiers. |
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Term
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Definition
| -also called solid patterns and are the simplest and often least expensive patters to make. It is essentially a duplicate of the part to be cast, modified only by various allowances and by possible addition of core prints. |
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Term
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Definition
| the first step in making sand casting is the design and construction of a _____. This is a duplicate of the part to be cast, modified in accordance with the requirements of the casting process, the metal being cast, and the particular molding technique that is being used. There are many different types. |
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Term
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Definition
| It can be the result of high pouring temperatures (excess fluidity), high metal pressure, or the use of high permeability sands with coarse, uniform particles.303- When motel metal penetrates between the sand grains, causing the mold material to become embedded in the surface of the casting. |
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Term
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Definition
300, 301 – The ability to permit gas to escape through it.
A measure of how easily gases can pass through the narrow voids between the sand grains. |
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Term
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Definition
mold material is plaster of paris
315 |
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Term
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Definition
| 300– The ability to withstand high temperatures |
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Term
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Definition
| 279- a system of channels throughout a mold used in the sand casting process. |
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Term
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Definition
| 303 – Castings having large, flat surfaces are more prone to ______ since a considerable amount of expansion must occur in a single, fixed direction. |
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Term
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Definition
| 304 –uses the centrifugal force of a rotating impeller to throw sand against the pattern. Can be used to produce large molds with uniform compaction throughout |
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Term
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Definition
| -operations designed to separate the molds and sand from the flasks, separate the casting from the molding sand, and separate or remove the cores from the casting. |
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Term
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Definition
| (pg 316)- A popular ceramic molding technique where a reusable pattern is placed inside a slightly tapered flask, and a slurry like mixture of refractory aggregate, hydrolyzed ethyl silicate, alcohol, and a gelling agent is poured on top. This is then ignited with a torch, which is then followed by a baking operation. |
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Term
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Definition
| (pg 308)- A six step molding process, which offers better surface finish than can be obtained with ordinary sand molding, better dimensional accuracy, and a higher production rate with reduced labor requirements (in many cases can be completely mechanize) |
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Term
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Definition
| (pg 306)- A compromise between the green-sand process and the dry sand molds. _______ dry only the sand that is adjacent to the mold cavity. Water is usually removed to a depth of about 13 mm |
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Term
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Definition
| (pg 305)- an inexpensive metal band that is positioned around the mold to hold the sand in place |
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Term
| Sodium Silicate (CO2) Molding |
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Definition
| (pg 307)- type of molding that receives its strength from the addition of 3 to 4% sodium silicate, a liquid inorganic binder also known as water glas. The addition of CO2 gas makes the soft compound harden in seconds. |
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Term
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Definition
| ______ use an air-operated squeeze head, a flexible diaphragm, or small individually activated squeeze heads to compact the sand.(pg 304)- The act of compacting. |
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Term
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Definition
| -(pg 298)- These are used when moderate quantities of a casting are desired. The pattern is divided into two segments along a single parting plane, which corresponds to the parting plane of the mold. |
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Term
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Definition
(pg 310 and 320)- also used in metal molding. A sprue is the vertical portion of the gating system that the material travels down from the pouring cup. Used in a couple of different molding techniques.
(297) – In sand casting, a sprue is an opening which molten metal is poured through |
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Term
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Definition
| – (306) – In ________, sections containing a cope impression on the bottom and a drag impression on the top are piled vertically on top of one another |
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Term
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Definition
| (301) – permeability and strength tests are performed on these specimens |
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Term
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Definition
| (310) – A sand based molding method known as both V-process and Vacuum molding when a vacuum performs the role of the sand binder. |
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Term
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Definition
| (310) – A sand based molding method known as both V-process and Vacuum molding when a vacuum performs the role of the sand binder. |
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Term
| Vertically Parted Flaskless Molding |
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Definition
| (305) – machine where the cope and drag patterns are incorporated into the opposing sides of a vertical mold |
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Term
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Definition
| A liquid inorganic binder that is also know as _____. Sodium Silicate |
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Term
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Definition
| (337) – are the preferred method of melting in many foundries because of (1) their rapid melting rates, (2) their ability to hold the molten metal for any desired period of time, and (3) the greater ease of incorporating pollution control equipment. |
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Term
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Definition
| -In this the inertial forces of rotation or spinning are used to distribute the molten metal into the mold cavities or cavity |
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Term
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Definition
| uses centrifugal action to force the metal from a central pouring reservoir, through runners, into separate mold cavities that are offset from the axis of rotation. |
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Term
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Definition
| -Are usually employed for the die casting of materials that are not suitable for the hot-chamber design. metal is melted in a separate furnace, then transported to the die casting machine. |
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Term
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Definition
| -Usually employed in the solidification of basic shapes that become the feedstock for deformation processes such as rolling are forging |
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Term
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Definition
| -A refractory-lined, vertical steel shell into which alternating layers of coke, iron, limestone or other flux, and all possible alloy additions are charged and melted under forced-air draft. |
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Term
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Definition
| -In this process, molten metal is forced into metal molds under pressure of several thousand pounds per square inch and held under this pressure during solidification. |
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Term
| Direct Fuel-Fired Furnace |
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Definition
| -Also know as reverberatory furnaces, are similar to small open-hearth furnaces but are less sophisticated |
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Term
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Definition
| -The metal is contained and solidified in an electromagnetic field designed to counteract the gravitational forces and hydrostatic pressure of the metal column. |
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Term
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Definition
| *When the rate of temperature change on a dye is the dominant feature leading to cracking. |
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Term
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Definition
| *An attractive means of altering properties while retaining the shape of the product? |
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Term
| Heated-Manifold Direct-Injection Die Casting |
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Definition
| Molten Zinc is forced through a heated manifold and then through heated mininozzles directly into the die cavity, thereby eliminating the need for sprues, gates, and runners. p. 330 |
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Term
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Definition
| *This offers fast cycling times and the added advantage that the molten metal is injected from the same chamber in which it is melted |
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Term
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Definition
| *Porosity that is at or connected to free surfaces can be filled with resinous material such as polyester by a process known as_________? |
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Term
| Indirect Fuel-Fired Furnaces |
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Definition
| Although limited in size and melting rate they are often used to melt bathes of nonferrous materials. Also called crucible furnaces where the outer surface is heated by external flame. Pg 337 |
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Term
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Definition
| Consists of two types of induction furnaces, the high frequency/coreless and the low frequency/channel type. Involves using electric current passing through water cooled coil surrounding a crucible. Pg 338 |
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Term
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Definition
| *These include prethreaded bosses, electrical heating elements, threaded studs, and high-strength bearing surfaces that are positioned in the die before the lower-melting-temperature metal is injected |
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Term
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Definition
| - Includes all techniques(non & destructive) that was presented in chapter 11 and can be applied to cast metal products. Ex x-ray radiography, liquid penetrant inspection and magnetic particle inspection are extremely common Pg 140 |
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Term
| Low-Pressure Permanent Mold Casting |
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Definition
| - A low pressure gas (3-15 psi) acts on the surface of a molten metal bath. In response, molten metal rises up a refractory tube and enters the metal mold or gating system from the bottom. By controlling the pressure, the mold can be filled in a controlled, nonturbulent manner, which further minimizes gas porosity and dross formation (327). |
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Term
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Definition
| - In this process a reusable mold is machined from gray cast iron, steel, bronze, graphite, or other material. After preheating a mold coating is applied to the preheated mold, sand or metal cores are positioned, the mold is clamped shut, and molten metal is poured in and flows through the feeding system into the mold cavity by simple gravity flow. After solidification the mold is opened and the product is removed |
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Term
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Definition
| p.330 - a method of die casting in which oxygen is introduced to the mold prior to each die casting shot. The oxygen and molten metal react to form fine, dispersed oxide particles virtually eliminating gas porosity. Used on aluminum, zinc, and lead alloys to create products with higher strengths. |
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Term
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Definition
| *This is a device used for pouring or transferring molten metal into casting molds. |
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Term
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Definition
| *This is removable and exchangeable pieces used to increase the complexity of mold cavities in permanent mold casting |
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Term
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Definition
| - p. 337 - a.k.a. "Direct Fuel-Fired Furnaces"; similar to open-hearth furnaces, this process uses radiant and convective heating by passing the fuel-fired flame directly over the pool of molten metal. These furnaces can hold more material than crucible furnaces and temperature as well as composition are easily controlled. |
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Term
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Definition
| p. 334 - unlike centrifugal casting, this method can be used to make a lot of cast parts at once by spinning the molds around a central reservoir which acts as a riser into which the molten metal is poured |
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Term
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Definition
| p. 332 - a die casting method similar to squeeze casting applicable for most alloy compositions where a wide freezing range results in the coexistence of liquid and solid states. This semisolid material is easy to manipulate and work with. |
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Term
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Definition
| -Hollow castings can be produced by a variant of permanent mold casting known as_______. Hot metal is poured into the metal mold and is allowed to cool until the shell of the desired thickness has formed. The mold is inverted and the remaining liquid is poured out. |
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Term
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Definition
| *This is when molten metal is introduced into a metal mold die cavity through large gate areas and at slower metal velocities to avoid turbulence and held at high pressure during solidification. |
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Term
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Definition
| ( page 323 ) – is when surface cracking occurs in a die and it is in response to the large number of cycles of heating and cooling the die goes through |
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Term
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Definition
| ( page 333 ) – a special class of semisolids which can be handled mechanically like a solid but flows like a liquid when agitated or squeezed |
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Term
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Definition
| ( page 333 ) – the inertial forces of rotation or spinning are used to distribute the molten metal into the mold cavity or cavities; a dry-sand, graphite, or metal mold rotates about either a horizontal or vertical axis at speeds of 300 to 3000 rpm |
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Term
| Vacuum Permanent Mold Casting |
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Definition
| *This is a variation of permanent mold casting where a vacuum is used to draw material into the mold cavity |
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Term
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Definition
| *This is the allowing the trapped air in a mold to escape through slight cracks or by very small holes that permit the escape of trapped air |
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Term
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Definition
| p. 346 - when cooling metals, if the cooling rate exceeds 10^60 C/sec, the material can solidify without becoming crystalline. The "glassy metals" usually exhibit unique properties such as high strength, high corrosion resistance, and reduced energy requirements for magnetization. |
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Term
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Definition
| *This is associated with flow characteristics, it is a measure of a powder's ability to fill available space with out the application of external pressure. |
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Term
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Definition
| *When a liquid is fragmented into droplets which then solidify into particles |
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Term
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Definition
| *This worsens flow characteristics and compressibility, and increases green strength |
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Term
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Definition
| *This is the process of homogenizing powder combinations |
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Term
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Definition
| (page 316): a process in which most volatiles are consumed and a three-dimensional network of microscopic cracks (mircocrazing) form in the ceramic, during casting. |
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Term
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Definition
| *This is a process used in isostatic pressing, when a powder is put into a flexible isolating medium that can resist the subsequent temperatures and pressures during pressing. |
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Term
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Definition
| *This is a pressing operation that is usually preformed to restore or improve dimensional precision |
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Term
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Definition
| *This is one of the most critical steps in P/M processing; losses powder is compressed and densified into a shape known as a green compact |
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Term
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Definition
| (pg 347) – combination of metals and nonmetals in a single product. |
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Term
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Definition
| *This is the effectiveness of applied pressure in raising the density of the powder. |
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Term
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Definition
| (pg 346) – a measure of the ease by which powder can be fed and distributed into a die. |
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Term
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Definition
| (pg 347) – describes the strength of the pressed powder immediately after compacting. |
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Term
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Definition
| (pg 353) - combines powder compaction and sintering into a single operation that involves gas-pressure squeezing at elevated temperature. |
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Term
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Definition
| 356 – refers to the forcing of oil or other liquid, such as polymeric resin, into the porous network. It and infiltration are secondary processes that utilize the interconnected porosity of permeability of low-density P/M products. |
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Term
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Definition
| 356 – Process where molten metal or alloy with a melting point lower that the P/M constituent flows into the interconnected pores of the product under pressure or by capillary action. P/M products may be subject to metal infiltration when the presence of pores is undesirable. |
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Term
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Definition
| 350 – When extremely complex shapes are desired, the powder is generally encapsulated in a flexible mold and immersed in a pressurized gas or liquid, a process known as isostatic (inform pressure) compaction. |
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Term
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Definition
| 352 468 – Process where the product is composed of more than one material, and the lower-melting-point materials melt and flow into the voids between the remaining particles. |
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Term
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Definition
|
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Term
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Definition
| -a rather recent extension of conventional powder metallurgy that offers the shape forming capability of plastics, the precision of die casting, and the materials flexibility of powder metallurgy. |
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Term
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Definition
|
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Term
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Definition
| -Massive metal deformation takes place in the second pressing, the operation is known as _____ |
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Term
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Definition
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Term
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Definition
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Term
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Definition
| The ability to permit gases to escape through a material (ch14, 300) |
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Term
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Definition
| The ability to absorb fluids, high amounts of porosity are undesirable in load bearing components (352) |
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Term
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Definition
| The process by which fine powdered materials are blended, pressed into a desired shape (compacted), and then heated (sintered) in a controlled atmosphere to bond the contacting surfaces of the particles and establish desired properties, aka P/M (344) |
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Term
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Definition
| Powders of aluminum alloys, copper alloys, stainless steel, nickel-based alloys, titanium alloys, cobalt-based alloys, and various low-alloy steels. |
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Term
| Pressure-Assisted Sintering |
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Definition
| Technique developed to produce full-density powder products without the expense of canning and decanning. |
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Term
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Definition
| where all 3 stages of sintering occurs in an oxygen free state. 353 |
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Term
| Rapidly Solidified Powder |
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Definition
| -Increasing the cooling rate of the liquid material can result in the formation of an unlrafine or micrcrystaline grain size. ??? |
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Term
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Definition
| a second pressing operation that occurs after the first to counter for warping and part distortion in the cooling process. |
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Term
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Definition
| is the process in which two or more separate pieces are joined by brazing while the are also being sintered 353. |
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Term
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Definition
| (hot isostatic pressing) combines powder compactions and sintering into a single operation that involves gas pressure squeezing at elevated temperature. 353 |
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Term
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Definition
| *What is when a pressed-powder compacts are heated in a controlled atmosphere environment to a temperature below the melting point but high enough to permit solid-state diffusion |
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Term
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Definition
|
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Term
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Definition
| *Involves squeezing all or selected regions of forgings, ductile castings, or powder metallurgy products, to achieve a prescribed thickness or enhanced dimensional precision |
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Term
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Definition
| aka insitu compaction or Osprey process – another means in producing a high-density shape from fine particles. Consider an atomizer in which jets of inert or harmless gas propel molten droplets down into a collecting container. Pg 355 |
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Term
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Definition
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Term
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Definition
| Preheating the powder prior to pressing, the metal is softened and responds better to applied pressures. Better compaction results in improved properties, both as-compacted and after final processing. Pg 351 |
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