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28 August 2012

metal science ,cast iron


1. SAND PROCESSINGAsir is the most commonly used is a mountain of sand, beach sand, river sand, clay and silica sand. Mixing is the most important step. In the processing of sand. Clay, water and additives as binder (bentonite) is required to print the sand. Precise measurement of the amount of mixing of these materials is very important to the levels as follows: 30% clay, 50% sand, 15% water, the binder / bentonite 5%.

2. PATTERN MAKINGpatterns are polalogam. Metal patterns used in order to maintain the accuracy of object size castings, especially in mass production, so the pattern should be durable and high memilikiproduktivitas.
3. PRINT MAKINGMolds used are made with tangan.bahan mold used consists of a mixture of clay, sand and water. Usually the mold sand is mixed with a binder (bentonite) in advance in order to more easily glue or compressed, bentonite can also be added if the product is made small with a difficult shape. Sand mold is usually done in the following order:A. Mold board laid flat on the floor scattered with sand flat.2. Pattern and order prints to drag placed on molding board cetakan.Rangka
     should be large enough so that the thickness of 30-50 mm sand. Determined the location of the channel down
     first.3. Advance that has been sifted sand is sprinkled to cover the surface pattern in order
    print. Advance is made thick layer of sand 30 mm.4. Print sand dumped on it and compacted with a pestle. In this pulverization
    must be done carefully so that the pattern is not driven directly by the collider.
    Further sand fell through the upper edge of the mold frame and carded
    mold removed along with the pattern of the mold board.5. Mold and placed on a board behind the print, and other patterns with half-
    same order prints for cup mounted on top, then sprinkled the separator material
    on the surface of separation and the surface pattern.6. Rod down the channel and additive pattern set, then sand and sand face print
  included in the framework of the mold is solidified. The next cup is separated from the drag and
  placed horizontally on the printed board. Diverter and down the channel created by
  using a spatula, and Patterns for diverter lines previously installed yan
  contact with the main pattern, so no need to be made with a spatula.

4. RAW MATERIALSRaw materials are usually used are:A. Former home of a centrifugal pump.2. Products that failed to print3. Pengecoaran the remainder of the channel down while pouring castings,4. All types of scrap metal are eligible gray cast iron,

5. Melting processThe production process objects cast conducted by first merging the raw iron (pig Iron) in the furnace, where the molten material plus old scrap iron or steel before casted.In principle, there are 4 types of furnace that we can use, namely:A. Kitchen Cupola2. The air kitchen or kitchen fire3. Kitchen Play4. Kitchen Electricity
6. TO PRINT casting processThe resulting molten iron is poured into a ladle cupola that had been coatedrefractory bricks. In the process of inoculation is carried out, namely the addition of silicon toin liquid iron. The addition of ferro silicon or graphite-forming substances in the0:05 to 0:25% of small amounts of it will form graphite type A.The purpose of inoculation is:A. Form the nucleus of the freezing order and controlled directional solidification.2. Deployment of graphite evenly.3. Improve the mechanical properties.Methods commonly used for the inoculation is toinoculant insert into the ladle before molten iron is poured from the cupola to thein the ladle. Before the molten iron is poured into the mold, the molten iron is moved-ladle into the casting ladle. But before using this ladle mustfirst coated with a refractory brick that is dried with gas burner orresidual oil burner for half to one hour

7. PROCESS COOLING

The cooling process is done after the liquid iron is poured into the mold. The cooling process itself lasts for 2-3 hours, the cooling process carried out for 1 day, with the aim to get a good castings. So the day after the demolition of the liquid iron is poured into the mold.
8. DISASSEMBLY PROCESSDemolition process that has been in chill castings is done by lifting the castings from the mold, with one way is to leverage the iron.
9. CastingsElimination of the channel down and the addition of castings made after castingremoved from the mold. There are two ways to channel melepaslan down andaddition, by means of mechanical and manual. In practice,channels are usually off by itself when doneremoval of loose sand or if not, normally released byhammered or blasted each other. The former is further down the channel willused in the subsequent smelting
10. CLEANINGAfter the demolition, sand casting objects embedded in the surface cleaned by brushing with a wire brush
11. MACHININGAfter a thorough cleaning, then do the pulleys in the clear machining.yaitu digrinda manner in order to flatten the surface of the workpiece, such as leveling the former areas of separation and the rest of the channel.
12. EXAMINATIONThe next process after the machining process is the process of checking the quality of the product. Examination of pulleys products consist of:A. Examination form
    In this case is studied irregularity, sand inclusions, cracks
    etc. contained in the product surface.2. Examination of defects in
    In this investigation examined the existence of defects such as air cavity, the cavity
    shrinkage, cracks and so forth that exist in the product without breaking it.
    As a result of the examination of a variety of product defects, form, place the
    researched, state and other products should be recorded appropriately.
    Further to the products that pass inspection, the quality should dicatat24

   exactly the same path for feedback in the planning techniques
   whereas for a product that is defective pulleys mild (not severe) for example
   presence of voids / pinholes on the surface of the product, it still can be solved
   by way of filling.
13. ADDITIONThe procedure starts with filling defects patched with putty and then followed by a smoothing putty by sanding and painting. As for the type of severe defects such as uneven pulleys or depreciation is too large it can not be repaired and returned usually melted down for the next casting.

14. GOODS SOIn this process include the end of kseluruhan process that has been done above. For further product requires only one additional process, namely pulleys should be in the paint. Painting process here aims to avoid that product does not rust






TYPES OF IRON POURSo much material of various kinds as a raw material of various products as desired, and the more consideration in selecting and determining the type of materials to be used, each type of material available materials have many advantages also has the disadvantage of not less.A. White cast iron (White Cast Iron)White cast iron (white cast iron) contain low levels of silicon, which at the time of solidification of iron carbida bond formed in the graphite matrix. In the non-alloyed cast iron shaped pearlite structure.White cast iron (white cast iron) has a hardness number between 400 to 600 HB 270 N/mm2 appeal to the voltage and still can be improved by lowering the carbon content of 2.75 to 2.9% to 450 N/mm2. Machining process for white cast iron can only be done by grinding (grinding).White cast iron (white cast iron) is used in the manufacture of machine parts grinding, crushing completeness, component kitchen heaters (furnaces) and others. White cast iron is not listed on the british standard. white cast iron (white cast iron) can be given a heat treatment (heat treatment) to reduce the number of violence through the process of softening (anealing), by heating at a temperature of 8500c to describe the free-carbon is formed due to rapid cooling after casting (foundry). This process is done only in an emergency. While controlling the properties of white cast iron is still in control of the cooling method with the "ironchill "as well as the elemental composition of molten material that has been mentioned.2. Grey cast iron (Grey Cast Iron)Gray cast iron (gray cast iron) containing flake-shaped graphite elements that have properties capable machine (machinability) and entered the ranks of British Standards, which distinguishes the type of gray cast iron is the voltage value of Iron Castings Violent these HB is between 155 to HB 320 depending on their level. gray cast iron (gray cast iron) is used in the manufacture of crankcases, machine tool bed, brake drums, cylinder head and others.Gray cast iron (gray cast iron) can be given a heat treatment (heat treatment) to relieve tension in the aftermath of the casting process with a "stress reliefing" (see the heat treatment process) to provide a slow heating between 500oC up to 5750C, with a holding time of about 3 hours followed by cooling slowly. Other processes in the heat treatment (heat treatment) that allows to do this on a gray cast iron is softening (anealing), this process will occur with improvements in its structure so that it is possible for a rapid machining process, for anealing process is done by providing heating to the temperature anealing the 7000c with heating time (holding time) and a half to two hours, which will form a closed structure in the unity of ferrite pearlite matrix, however, the level of violence would be reduced by up to 180 HB 240 HB.3. Cast iron "Able Wrought" (Malleable Cast Iron)Capable of wrought iron (cast Malleable Iron) is a type of cast iron that has a white structure, which has elements of graphite which is so fine that the distribution of elemental carbon to be more evenly and easily formed. Capable of wrought iron (cast Malleable Iron) found in 3 form types, namely: Whitehearth, Blackhearth, and Pearlitic these names are in accordance with the terms microstruktur form of cast iron is.4. Whiteheart Malleable Cast IronWhite cast iron (white cast Iron) are in good working order is placed in cans where they are surrounded by a mixture of the useless and the useful particles such as haematite ore (haematite ore), tin is a container which will then be fed into the kitchen, then heated slowly up to 9500C. Once deposited in the kitchen is then removed and cooled slowly and removed from the cans and then cleaned and prepared for the macining. This process gives the opposite effect of carburising process for surface hardening, which will move the element carbon, and only from a thin section. The core part of the thick material will consist of two elements of the element carbon pearlite and some elements in the form of nodules.
CLASSIFICATION OF IRON POURCast iron is an alloy of iron and carbon with a carbon content higher than 2.0%, but commonly used about 2.5 - 4.0%. Classification is determined by the structure of cast iron metalografinya highly influenced by the carbon content in the alloy. Carbon in cast iron can be either cementite (Fe3C) or free carbon (graphite). Graphite shape and distribution will affect the physical and mechanical properties of cast iron. But in addition to carbon, there are also other elements such as silicon, manganese, phosphorus, and sulfur which can affect the structure of cast iron metallography.In general, cast iron can be grouped based on the circumstances and form of the carbon contained in them into four groups as follows:a. White cast iron (white cast iron) in which all the carbon in the form of cementite
 b. Capable of wrought iron (malleable cast iron), where the carbon in the form of temper carbon, perlite and ferrite matrix withc. Gray cast iron (gray cast iron), where the carbon in the form of shaped graphite flake (flakes) with a matrix of ferrite and pearlited. Nodular cast iron (nodular cast iron) Diman nodular graphite carbon in the form of spherical ferrite matrix and pearlite. (Avner, 1987). Based on the chemical composition of cast iron can be classified as in Table 2.1


 EFFECT ON THE IRON POUR ELEMENTS The composition of cast iron consists of 5 are:1) CarbonCarbon as the most important element to have a profound influence on the mechanical properties, such as tensile strength, tensile fracture, hardness, etc.. The amount of carbon in cast iron about 2 to 3.7%, he put himself on two conditions, namely the form of chemical compounds known as cementite Fe3C, and in a free state, known as graphite.
2) SiliconSilicon has a considerable influence on changes in mechanical properties. Carbon and silicon have similar functions, both of which encourage the formation of graphite so that the content of these two elements is determined based on the saturation level of carbon price (sattigungsgrad). Approximately 1.4 to 2.3% silicon is added to promote the formation of graphite. Silicon in the iron to put yourself in the ferrite.
3) PhosphorusPhosphor material is easy to make iron melt and grow brittle. when the phosphorus content of more than 0.3 percent iron loses its strength and not easy to do and when desired iron very fine and thin so fosfornya content varies between 1% - 1.5%.phosphorus in cast iron to 0.3% will be able to form a compound Fe3P and flow to be higher because the eutectic temperature down to 956 0C. phosphorus is necessary for the manufacture of the casting of thin, but giving too much could lead to the emergence of small holes on the surface, the phosphorus content is restricted between 0.2 to 2.0%.
 4) ManganeseThis material makes a strong and ductile cast iron and manganese content of 0.7% should not be. Manganese is needed to stimulate the formation of pearlite structure, is also required for binding sulfur compounds to form MnS. Amount of about 0.5 to 0.7% manganese kandunngan.
5) SulfurSulfur material is made of cast iron hard and brittle. This makes the material quickly hardens cast iron, which resulted in a defect in the form of trapped air pori2 sulfur content is generally not more than 0.1 persentidak benefit, because at the expense of the liquid, the metal becomes more viscous and dense as the metal becomes brittle. Maximum sulfur content of 0.15%. Sulfur into the iron by direct contact with coke or carried away by the raw material: pig iron (crude iron), cast iron or steel scrap used.
Effect of Silicon (Si)In the steel melting process, silicon (Si) is usually derived from the lining furnaces, especially blast furnace slag as a result of acid and reduction of SiO2 contained therein. However, Si in the form of ferrosilicon (FeSi) are used also as a medium for deoxidation and reduction of iron oxide (FeO) back to Fe and the remaining SiO2 slag.Si content of 0.2 - 0.5% is useful as an alloying element which resulted in melting of steel to be quiet (not volatile). While the content of Si = 0.1% will cause the steel melting process is still quite volatile. Steel melting process will be very volatile when the Si content below 0.02%, unless the other elements incorporated into it which also serves as deoksidator such as Aluminum or Titanium.The ability of α iron (ferrite) in Si is very high and dissolve at room temperature still at 14%. Hence the structure of plain carbon steels with Si content below 0.5% was not found phases other than those contained in the steel in general. The small amount will dissolve completely in a mixture of α-crystalline silicon (silikoferit).On the carbon steel portion of the Si will also form carbides (silikonkarbid), so in general when compared with the element carbon, Si had almost no influence on changes in the steel structure.Si has a very high affinity for O2. The reactions that occur during the melting process into SiO2 compound will react with other oxides to various types of silicates, such as (FeO) 2.SiO2, (MnO) 2.SiO2, MnO.SiO2, (MnO) 2.FeO.SiO2 and 3Al2O3.2SiO2. Silicate compounds is what caused the steel with high silicon content will be stringy when plastically deformed.The melting point of steel will decrease drastically with temperature interfal liquidus - solidus is so small that Si segregation had not occurred. However, the content of 2%, Si will result in the transition zone of the crystal (transkristalisationszona) in massive castings.The elements included in the class to shrink the γ (austenint) on iron-carbon system such that the Si content of more than 3.5% will have a ferritic structure since it started freezing up to room temperature. Attenuation γ region will also raise the temperature of transformation in which for every 1% Si will raise the temperature of the transformation of γ at 50 ° C, where it will lead to the growth of coarse grains in the process of annealing, recrystallization and hardening.In the steel with a high Si content, the atoms that make up the unit cell will be arranged evenly and form a structure that has the characteristics of uniform saturated. This arrangement will increase the electrical conductivity properties as well as well as the fragility of the material so the process of cold work is only possible on steel with a maximum of 3% Si content, even on the Si content of more than 7%, workmanship panaspun process can only be done with a poor outcome. In the Si content above 10%, had lost the ability to form alloys.The general influence of the elements of carbon steel alloy can be seen in the picture. The presence of Si is then either eutectoid or eutectic point will be shifted towards lower C content.
 Establishment of a steel structure under the influence of Si element.Si is an element that would lower the solubility of C in ferrite and cementite reduces the level of stability so that the annealing process will easily decompose to Fe and C in the form of graphite, particularly at high Si content. For example, steel containing C = Si = 0.8% and 2% will reveal the structure of the fault has been colored black. Easy decomposition of C will also impact on the trend of decarburization on the surface of the product.To the tensile strength and elongation limit, every 1% Si will raise up to 100 N/mm2 with no means of violence and the influence of elongasinya. Elongation will be reduced quite a lot on the Si content greater than 2.2%. While violence and better frictional resistance will be looked after through hardening process.Another important technical influence of this element is the increasing nature of the specific electrical resistance. Compared with ordinary steel which has a specific electrical resistivity 0.1 W m-1 mm2, with the addition of 4% Si will increase to 0.6 W m-1 mm2. So that as a base for the transformer, the energy loss due to the current playlist can be significantly reduced.
Effect of Sulfur (S)Iron (Fe) and sulfur (S) will form the compound FeS (besisulfida). Formed between the iron with besisulfit eutektikum the S content of 30.5% and the temperature of 985 oC. Iron δ at a temperature of 1365 ° C, capable of dissolving S of 0.17%, while the γ iron at 0.07%. Still questionable whether α is also capable of dissolving the iron element S is. What is certain is that the iron α has a very low ability in dissolving S.
 Figure 1. Binary diagram of Fe - S.However, in contrast to the elements of other iron chaperone, although the S on the content of a very few will actually membetuk phases with specific characteristics in ikiatannya with elements Si, Mn and P in addition to the compound FeS. These phases form patches of non-metallic impurities that have been recognizable in polished samples that have not been etched.Based on the binary Fe-S diagram should be on the low content of S, Fe + FeS eutektikum who have low melting points are to be found in the crystal grain boundaries of iron. However, because of degradation eutektikum, it does not happen. Iron contained in eutektikum crystallized on crystals of iron primer, while iron sulfide that remains then is formed as the layers are slightly thicker at grain boundaries.
 Figure 2. Besisulfida iron at the boundaries of crystal grains. (Non-etching)
 Figure 3. Mangansulfida (MnS) in steel castingsThis resulted in the temperature of wrought iron to become brittle, thereby decreasing workability. This is because the phase that has a low melting point and contained in the grain boundaries will soon melt, so that between each crystal grains are no longer solid crystals that become binding media.Most of the steel has only a very low S content. Maximum to 0.06%. Although at a temperature of 985 ° C have not been there eutektikum (Fe-FeS) liquid, but the danger of fragility still have to watch out for, especially when the steel contains only elements of Mn is very low.Mn elements in steel can reduce the risk of heat perapuhan, since Mn will be immiscible with S mangansulfida (MnS) which has a melting point 1610 ° C and even at the primary form of liquid steel. MnS under the microscope appear as islands of blue-gray (Fig. 15) between the steel matrix. Such forms are the typical form of the crystals formed in the primary, where the formation is influenced by the surface tension of liquids. MnS is spread in the structure of steel and cast iron is also without influence on the mechanical properties.In contrast to the generally non-metallic impurities in the steel, such as silicates and alumina, the sulfide either cold or hot at the time, have a good plasticity. Sulfides are not to be destroyed due to plastic deformation of the material, but it will be flattened and elongated, and will kembeli-forms the rounded shape after undergoing a process of heating the steel with a very slow cooling.Sulfur (S) as phosphorus (P) has a tendency to segregation as segregation and gas blocks. This will happen particularly if the steel melting process in particular is done carefully and not place a lot of turmoil. Thus these elements are also included within the category of undesirable elements. Mn (0.5% - 0.9%) is an element that is added to prevent adverse effects caused by S.
MECHANICAL PROPERTIES OF IRON POUR- Hard and easy to melt / thaw- Getas, so it can not withstand the impact- Melting temperature of 1250 degrees.- Does not rust- It can not be given a magnetic charge- Can be toughened to be heated and cooled with a sudden- Shrinking the cooling / time cast- Strong in restraining the compressive force, weak in tensile hold about 600 MPa compressive strength,
   tensile strength of 50 Mpa- It can not be spliced ​​by welding and rivets, bolts and screws are connected with.

USE OF IRON POUR- Pipe that withstand extremely high pressure from the curved- Close the hole drainage channels and other sanitary equipment- The structural framework that holds the style press- The engine, engine block- The gate, light poles- The joints, roller bridge

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