Literature review:
1. Introduction:
In ingot casting the molten metal is poured in the mold to get solidified ingot where liquid metal transformed to solid metal. So the poring temperature of the molten metal is very important parameter. Poring temperature is the initial temperature of the molten metal used for the casting ingots as it is poured. So this poring temperature will obviously be higher than the solidification temperature (i.e., higher the liquidus line) of the metal. And the difference between the solidification temperature and the poring temperature of the metal is called the superheat. If the poring temperature is lower than the liquidus line then the liquid is more prone to get solidified and get low fluidity. So the metal is getting solidify in the mold before flow into all regions of the mold. The fluidity in metal casting can be increased by: 1) increasing the superheat. 2) Choose a eutectic alloy or pure metal. 3) Choose a metal with a higher heat of fusion.
According to R. Vlakanta .[4] Solidification is phase transformation process that is accompanied by release of thermal energy. In solidification, the essential and common features of systems are undergoing solid-liquid(s/l) phase change and a moving boundary exists which is separated the two phases of differing thermophysical properties and at this boundary the thermal energy is liberated. So the latent heat is extracted in solidification process during phase transformation. Generally the latent and sensible heats of the system are removed by conduction, convection and radiation. For a example the super heat in the melt and latent heat of fusion liberated at the s/l interface are transferred across the solidified metal, the metal-mold interface, and the mold...
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...cation so that minimize the scrap losses.
Table2. Solidification and cooling shrinkage of various metals.
Metal alloy Solidification Shrinkage (volume %) Cooling Shrinkage
(volume %) Solidus Temperature
(˚C)
Al
Al -4.5Cu
Al-12Si
Au
Bi
Cu
Fe (pure)
Steel
Ductile cast iron
Gray cast iron (2%C)
Gray cast iron (5%C)
White cast iron (5%C)
Ga
Ge
Mg
Ni
Pb
Sn
Sb
zn 7.1
6.3
3.8
5.1
-3.3(expansion)
5.1
3.5
2.5 to 3.0
-4.5 to+2.7
4.0
-2.5
5.0
-3.2
-5.1
4.2
5.1
2.7
2.3
0.6
4.7 5.1
5.3
4.8
5.2
1.0
6.4
6.0 to 7.5
4.2 to 6.0
3.0
3.0
3.0
3.0
0.0
1.6
5.4
7.0
2.8
1.5
2.0
4.0 660
570
580
1063
271
1083
1535
1500
1148
1155
1148
1148
30
937
649
1453
327
232
631
420
5.Dr.Eman J.Abed, the influence of different casting method on solidification time and mechanical properties of AL-Sn castings, international journal of Engineering & Technology IJET-IJENS,vol:11 No:06.
Aluminum is a lightweight, silvery metal. The atomic weight of aluminum is 26.9815; the element melts at 660° C (1220° F), boils at 2467° C (4473° F), and has a specific gravity of 2.7. Aluminum is a strongly electropositive metal and extremely reactive. In contact with air, aluminum rapidly becomes covered with a tough, transparent layer of aluminum oxide that resists further corrosive action. For this reason, materials made of aluminum do not tarnish or rust. The metal reduces many other metallic compounds to their base metals. For example, when thermite (a mixture of powdered iron oxide and aluminum) is heated, the aluminum rapidly removes the oxygen from the iron; the heat of the reaction is sufficient to melt the iron. This phenomenon is used in the thermite process for welding iron .
Bronzes are made by making two molds (one larger than the other), pouring melted bronze in...
-Developed and implemented strip casting overseas to eliminate a step in the steel making process
Since all metals have different densities and makeups I think that the heat capacity will greatly vary. The makeup of iron is very different than aluminum so the heat capacity will be quite different. Also, a lot of metals are not completely pure and that will also have some effect on the heat capacity.
"Chemical Elements.com - Aluminum (Al)." Chemical Elements.com - Aluminum (Al). N.p., n.d. Web. 19 Mar. 2014. .
The inefficiencies and the problems involved in making steels in the traditional form of ingots are alleviated by the continuous-casting process, which produces higher quality steels at reduced costs. Conceived in the 1860s, continuous or strand casting was first developed for casting nonferrous metal strips. The process now is used widely for steel production, with major productivity improvements and cost reductions.
After quenching, the heated steel will cool down. Due to the different rate of cooling, the different types of microstructure will be formed. The formation of pearlite, bainite and martensite determine the physical properties such as hardness, strength and ductility.
The center of the Earth is composed of a solid metallic core surrounded by a molten layer of liquid metal. This paper will discuss the reasons to believe the theory that the Earth has a molten core, and the important discoveries that have led to this generally accepted theory. It is very reasonable to agree with this theory when paying credence to the logical evidence that answers questions about the Earth’s core. This evidence includes information about the elemental make up of the Earth, the reason for the Earth’s magnetic field, and some of the possibilities of the Earth’s formation.
Aluminum is one of a number of soft metals that scientists call "poor" metals. It can be shaped and twisted into any form. It can be rolled into thick plates for armored tanks or into thin foil for chewing gum wrappers. It may be drawn into a wire or made into cans. Aluminum is a generally popular metal because it does not rust and it resists wear from weather and chemicals. (Bowman, 391) Aluminum is an element. Its atomic number is thirteen and its atomic weight is usually twenty-seven. Pure aluminum melts at 660.2ºC and boils at 2500ºC. Its density is 2.7 grams per cube centimeter. Aluminum is never found uncombined in nature. (Bowman, 391) Aluminum is a very useful metal that is light, easy to shape and can be strong. This makes aluminum one of the most used metals in the world, right behind iron and steel. (Geary, 185) In its pure state, aluminum is quite weak compared to the other metals. However, its strength can be greatly increased by adding small amounts of alloying elements, heat-treating, or cold working. Only a small percentage of aluminum is used in its pure form. It is made into such items as electrical conductors, jewelry, and decorative trim for alliances and cars. A combination of the three techniques has produced aluminum alloys that, pound for pound, are stronger than structural steel. Some common metals used in alloys for aluminum are copper, magnesium and zinc.(Walker, 31) The added elements give the aluminum strength and other properties. (Newmark, 41) Aluminum is one of the lightest metals. It weighs about 168.5 pounds per cubic foot, about a third as much as steel which weighs 487 pounds per cubic foot. (Neely, 214) As a result, aluminum has replaced steel for many uses. For example, some ...
Introduction: A phase change is a result from the kinetic energy (heat) either decreasing or increasing to change the state of matter (i.e. water, liquid, or gas.) Thus saying, freezing is the phase change from a liquid to a solid which results from less kinetic energy/heat. Also, melting is the phase change from a solid to a liquid which results from adding kinetic energy/heat. So, the freezing and melting point of something is the temperature at which these phase changes occur. Therefore, a phase change will occur when a vial of 10 mL of water is placed into a cup of crushed ice mixed with four spoonfuls with 5 mL of sodium chloride for 30 minutes. If 10 mL of water is placed in an ice bath, it will then freeze at 5 degrees Celsius because the kinetic energy will leave quicker with the ice involved. The purpose of this lab is to observe what temperature the water must be to undergo a phase change.
Melting takes place when a solid gets enough energy to melt. When it gets enough energy it is called the melting point. An example of melting would be snow turning into water. The reverse of the melting process is called freezing. Liquid water freezes and becomes solid ice when the molecules lose a lot of energy. When a solid goes to a gas and skips the liquid, sublimation occurs. The best example of sublimation would be dry ice. Deposition is when a gas goes directly to a solid without going through the liquid phase. An example of deposition is when water vaper turns to tiny crystals.
Casting is used to produce an average of 40%(by weight) of stock for machine parts,bt in some areas of machine building, such as appliance tool manufacture, the percentage of castings is 80 percent. Appliance building consumes about 70 percent of all cast stock, the metallurgical industry devour 20 percent, and 10 percent is used in hygienic engineering. Cast parts are used in metal working lathes, combustion engines, compressors, pumps, electronic motors, condensation and hydraulic turbines, rolling mills,
Continuous casting process starts by molten steel flows from a ladle through a tundish into the molder.
A mould is formed into the geometric shape of desired part. Molten metal is then poured into the mould; the mould holds this material in shape as it solidifies.
Metals possess many unique fundamental properties that make them an ideal material for use in a diverse range of applications. Many common place things know today are made from metals; bridges, utensils, vehicles of all modes of transport, contain some form of metal or metallic compound. Properties such as high tensile strength, high fracture toughness, malleability and availability are just some of the many advantages associated with metals. Metals, accompanied by their many compounds and alloys, similar properties, high and low corrosion levels, and affects, whether negative or positive, are a grand force to be reckoned with.