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How do I make steel from iron
In the bowels of the earth where we live there are many contain substances that are useful for the purposes of our daily lives, such as kerosene, gasoline, diesel and other so-called minyaka earth. Besides, there are chemical elements that are useful for humans such as iron ore, nickel, copper, uranium, titanium, tin and many more, along with minerals and rocks. One of the substances contained in the earth which is very useful for human beings is the water with the chemical formula H2O, because without water is very difficult to sustain human life. Minerals are a lot of material found in the earth, which has the shape and specific characteristics and has a fixed chemical composition. While the rocks are a combination of two or more kinds of minerals and do not have a fixed chemical composition.
Ore is a mineral or rock containing one kind of metal in the percentage ataubeberapa kind enough to be a mineral. Number of metal contained in ore that is different. In a state of pure metal is rarely found in the earth, most of the compounds of oxides, sulfides, carbonates, and sulfate which is a metallic ore that needs to be processed into metal materials that are beneficial to humans.
1. Rough Iron Making
The main ingredient for making pig iron are iron ore. Various kinds of iron ore found in the skin of the earth in the form of iron oxide and iron carbonate, among which the most important are as follows.
1. Brown iron stone (2Fe2O3 + 3H2O) with iron content ranging from 40%.
2. Red iron stone which is also known as hematite (FeO3) with iron content ranging 50%.
3. Stone magnetic iron (Fe2O4) dark green-black, magnetic iron with around 60%.
4. Calcite or iron stone Spat (FeCO3) which is also called sferosiderit to contain 40% iron.
Iron ore from the mine usually is mixed with sand, clay, and rocks in the boulder-big chunk of that is not the same. For the smooth processing of iron ore, chunks are solved by breaking machine, and then sorted between the ore and rocks besih follow-up with magnetic drum. The next job is to wash and iron ore are classified according to size, fine iron ores and small grains in the kitchen diaglomir sinter or roll up to form balls that can be used again as the contents of the kitchen. After iron ore was baked in the kitchen baking to dry and the elements that easily become gases out of the ore was taken to a high kitchen processed into pig iron. High kitchen has two cone shapes which stand one above the other on its base. At the top is the hearth that extends downward, so that its cargo easily slid down and it does not jam. The lower part extends upwards with the intention to remain in charge of this section. Kitchen tall stone structure made of refractory steel cover plate was given to strengthen the construction. The kitchen is filled from above with a filler. Coke in a row is inserted, additional materials (limestone) and iron ore. Coke is coal that is charcoal that has been didestilasikan coal is dry and contains sulfur which is very low. Coke serves as fuel and require a lot of acid as pengembus. In order for the process can run fast, it is necessary pengembus air preheated in air furnace.
Limestone as additional materials useful to bind the coke ash and stones follow-up to be a slag which can easily be separated from crude iron. Slag itself in the process serves as a protective liquid pig iron from the oxide which may reduce results obtained by the burning of the liquid pig iron. Stone kapu (CaCO3) decomposes follow-up binding stones and other elements.
2. Process in Higher Kitchen
The principle of the high kitchen is the principle of reduction. In this process the carbon monoxide substance can absorb oxygen from the iron bonds of oxygen at high temperatures. At high temperature combustion + 18000C with hot air, then the resulting temperature reduction that can hold it. To avoid pembuntuan because the process took place then were given limestone as additional material. Additional material is acidic if its iron ore has a basic character and vice versa provided additional material which is alkaline when iron ore is acidic. The gas formed in the kitchen the next high flow out through the top and into the air heater. Slag is trickling down to protect the pig iron from the oxide by the hot air entered, slag is then separated.
Reduction process in a high kitchen took place as follows:
Substance of coke burning charcoal by the reaction: C + O2CO2 part of CO2 along with carbon to form a substance that is in place more for the gas CO.
CO2 + C 2CO At the top of a high kitchen temperatures 8000C 3000sampai higher iron oxide is converted into a lower oxide by indirect reduction by CO according to the principle: Fe2O3 + CO + CO2Pada 2FeO process load time down to the bottom and there was reduction indirectly according to the principle: FeO + CO + CO2 reduction FeO is called indirect because it is not pure carbon but which reduce carbon compounds with oxygen. while the direct reduction occurred in the hottest part of the kitchen, which is directly above the pipe pengembus. This reduction took place as berikut.FeO + C Fe + COCO formed that rises to the top to hold indirect reduction earlier. Every 4 to 6 hours of high dicerat kitchen, first issued teraknya and then iron. Iron that comes out of the kitchen higher-called pig iron or steel raw material used to make steel on steel processing kitchen or poured into cast blocks are sent to factories making steel as a material baku.Besi dicerat and poured liquid into pig iron in the form blocks of pig iron used to manufacture sebagaibahan ancuran cast iron (in the kitchen dome) or are still in a liquid state is transferred to the manufacture of steel (kitchen Siemens Martin). Slag high out of the kitchen can also be used to manufacture materials or slag sand slag wool as insulation material or as raw cement mixture. Liquid iron produced from the high kitchen before it was poured into blocks besin ancuran rough as the material in the casting plant, it should be first mixed in a mixing vessel for quality and uniform composition. In a mixing vessel collected liquid pig iron from a variety of existing high kitchen to get the same liquid crude iron and evenly. To produce pig iron which contains little sulfur in the mixing vessel is heated using a gas kitchen again high.
3. Steel Making Process of Iron Rough
Pig iron as a result of the high kitchen still contains many elements that are not suitable for construction materials, such as carbon (carbon) that is too high, phosphorus, sulfur, silicon and so forth. These elements should be as low as possible in various ways.
To reduce levels of carbon and other additional elements of pig iron used in the following manner.
Converter Process:
a. Bessemer process for pig iron with low phosphorus content.
b. Thomas process for pig iron with high phosphorus content.
c. The process of oxy, LD process, Kaldo and Oberhauser.
Process Martin (kitchen Siemens Martin)
a. Martin acid process for pig iron with low phosphorus content.
b. Martin alkaline process for pig iron with high phosphorus content.
Kitchen Electricity for steel mixture consists of:
a. Kitchen electric arc flame.
b. Induction electric kitchen.
(A). Bessemer Process
Bessemer converter is a steel vessel with flame-resistant rock layers that are acidic. On top of it open while at the bottom there are a number of holes for air lines. This vessel can diguling roll. Bessemer Korvertor filled with rough gray iron which contains silicon. Silicon and manganese on fire the first time, after which a new substance that burned charcoal. When air flows through the air pig iron and charcoal burning substance so that the contents dapr additional mixture remains in liquid state. After approximately 20 minutes, all substances have been burned charcoal and slag that happens is issued. Given the need karbo steel of 0.0 to 1.7%, then the processing time is too much missing on fire, it must ditambahy deficiency in the form of iron that contains carbon.
In this way carbon levels increased again. formed from iron oxidation and acid containing substances can be reduced by iron-containing manganese. The air is exhaled into the vessel earlier in order to get a good mix. Then the slag discarded again and then the charge is poured into the pouring pot. In the Bessemer process using pig iron with phosphorus content and low sulfur content of phosphorus and sulfur but still remains rather high because in the process, the two elements do not burn at all. Results of the Bessemer converter called Bessemer steel is widely used for construction materials. Bessemer process is also called acid process because it is acidic and stone cargo hold fire also acidic. When used the charge that is alkaline layer of rock will be damaged due to the salting reaction.
(B). Thomas process
Thomas also called a converter converter alkali and alkaline process is a process, because the fire-resistant stone is alkaline and is used to process pig iron which is alkaline. The load converters Thomas is a white pig iron which contains phosphorus. Combustion process similar to the converter Bessemer process, only on the Thomas phosphor burn after substances not air terbakar.Pengaliran ashes are continuously carried out since the iron itself will burn. Prevention arson was carried out by assuming the process is complete, although still high phosphorus content. In order to bind the phosphorus that formed in this process is then given additional material to be limestone slag. Which is alkaline slag can be utilized as a fertilizer made known cousin phosphate. The result of the process of coming out of the converter steel Thomas Thomas called commonly used as construction materials and boiler plate.
(C). Martin Process
Another process for making steel from pig iron materials is to use the kitchen Siemens Martin is often called the Martin. This kitchen consists of a furnace for material melted and usually use the four rooms as heating gas and air. In the process of loading scrap metal is used which is mixed with pig iron so as to produce steel with better quality when compared with Bessemer steel and Thomas. The gas will be burned with air to flow into the combustion chambers through fireproof stone that has been heated to temperatures between 600 and 9000C. thus the flame of the fire has a high temperature, approximately 18000C. combustion gases moving out still provide heat into the second room, using the regulator tap the hot gas and combustion air into the room alternately heated and cooled.
The fuel used is a high kitchen gas, oil digaskan (stookolie) and also gas generators. In the burning charcoal substance occurs CO and CO2 gas went up and cause turbulent fluid, thereby will occur hubungann a close connection between the fire with a material that is inserted into the kitchen load high. Additional materials will be fused with acid to form slag which closes the liquid thereby protecting it from the oxide liquid further.
After the process runs for 6 hours, the slag is removed by tilting the kitchen and then the liquid steel to dicerat. The end result of a process called Martin Martin steel. The steel of good quality because the composition can be regulated and determined by carefully at the processes that take a lama.Lapisan kitchen at Martin process may be acid or alkaline depending on the iron contains phosphorus crude little or a lot. Martin Process teradi acid when processing pig iron which contains phosphorus acidic or low and vice versa Martin said the base when the cargo is alkaline and contains high phosphorus.
The advantage of the process of disbanding Martin Bessemer and Thomas processes are as follows:
a. Longer process that can produce a better arrangement with road trials.
b. The elements and unwanted impurities can be avoided or cleaned.
c. The addition of scrap metal and other additional materials at the end of the process cause the structure to be the best.
In addition to the above benefits and because the combustion air flowing above the liquid then the end result will be slightly acidic substances and substances containing limp. Martin Process bases are usually still contain some impurities such as oxygen, sulfur, phosphorus and so on. While in the process of acid Martin dirt levels are smaller.
(D). The process of oxy
Converter process more modern is the process of oxy, the process uses materials that have a composition of pig iron is not good if done with the Bessemer converter and Thomas. Here exhaled pure oxygen above the liquid and sometimes also into liquid iron, so that the carbon, silicon, manganese and so on fire.
Combustion products such elements are accommodated by additional material limestone and bound into slag which floats on the liquid oxygen combustion besi.Proses with charcoal substance occurs at very high heat, it is necessary to provide additional cooling by way of steel scrap. The end result of this process is oxy-quality steel is very good because the bad influence of the air element does not exist. Therefore, oxy excellent steel used as construction material and machine components, such as shafts, bolts, pins, drive shaft and others. The advantage of oxy process is as follows:
a. When the process is relatively short.
b. The results of phosphorus (P) and sulfur (S) is low.
c.Hasil produced relatively more in the same tempo than other processes.
d. Production costs per ton of steel is cheaper.
(E). Process Hoecsch
The process is a refinement of the process Hoecsch Martin. The trick is that after the charge in the kitchen Siemens Martin thaw and then immediately removed and placed in an open pot for burning phosphorus and sulfur. While burning conducted Siemens Martin cleaned the kitchen and then the kitchen floor is paved with iron ore powder (Fe2O3atau Fe3O4). After finishing hold burning phosphorus, sulfur and molten iron inside the pot was put back into the kitchen Siemens Martin to complete the combustion of other elements that have not been lost, especially carbon. After the carbon burning process is considered completed, slag which occurred subsequently issued accommodated in a pan of liquid steel casting to cast or molded into the block casting.
(F). Bertrand process Thield
This process uses two kitchen Siemens Martin. In the kitchen the first conducted pemijaran and combustion to separate phosphorus in the kitchen while the second is filled with molten iron from the kitchen of the first results after teraknya issued. Process in the second kitchen was also given a new addition to iron ore.
(G). Duplex Process
This process is done by first decarbonize who are converter-converter and purify it in the kitchen Siemens Martin. Duplex process is mainly done by steel mills near the company kitchen high. After the process in a high kitchen (after teraknya omitted) liquid pig iron was inserted into the converter (Bessemer or Thomas) and mixed with limestone and steel scrap in the desired amount. Pengembusan air in the converter is carried out until a low phosphorus content of approximately 1 to 1.5%, coupled with the coke that has been milled then move the contents into the kitchen Siemens Martin.
(H). Process Thalbot
Thalbot process carried out by using Siemens Martin's kitchen that can be twisted around and dijungkitkan. After pemijaran Martinnnnnn in the kitchen, poured some liquid into a panic and pour into the kitchen before she added pig iron, iron ore and limestone. The next process is to keep the liquid cast iron in the panic was not the case of oxidation, meaning that seek fast cooling. As a result of this method is the result obtained in each process of a kitchen is not the same quality. Steel produced from Thalbot process is ordinary steel as a result of the Bessemer converter process as well as Thomas.
(I). Process Electric Kitchen
Electric kitchen used for the manufacture of steel that is resistant to high temperatures. This kitchen has the following advantages:
a. The amount of heat needed to to set the best.
b. Effect of acid practically does not exist.
c.Susunan iron is not affected by the flow of electricity.
While the drawbacks are the price of electricity is expensive. Electric kitchen is divided into two groups: the kitchen and kitchen electric arc electric light induction.
• Kitchen arc light
The kitchen is based on the principle of heat emanating from the arc of fire, the kitchen is also known as kitchen arc flame. This kitchen is a stove-top hung two charcoal rods as electrodes in an alternating current or with three electrodes that are drawn charcoal rotating flow. For example in the kitchen Stassano arcing occurs between the three electrode tip charcoal on the top of the steel that melted through the electrode tip with rotating flow. In the kitchen Girod, alternating current flowing through a single electrode that forms the arc between the liquid steel poles and then expelled through the six pieces of steel electrode which was cooled with water to the bottom of the furnace. In the kitchen using the two electrode Heroult charcoal with alternating current and can also use three electrodes on the flow of play. Flame arc forming an electric current from electrodes to the fluid dankembali of fluid into the other electrode.
• Kitchen induction
Kitchen induction can be distinguished on low-frequency induction kitchen and kitchen high frequency induction. In the kitchen induction raised an induced current in the liquid steel, causing heat in the liquid steel kitchen wall this yourself while only receiving a small electrical effect.
• Kitchen low frequency induction
Working under the principle of the transformer. The kitchen is a channel around the core of steel and its contents is considered as a transformer secondary winding connected short, due to short-circuit in the kitchen to flow a large electric current and generate high heat. As a result the contents of the kitchen to melt and blend the mixture an additional dioksidasikan.
• Kitchen high frequency induction
This kitchen consists of a large cauldron which was given coil around it. If the coil flowed in an alternating current flows then pass play in the kitchen. This current is an electric short-circuit and the heat is raised so high that dilute the contents of the kitchen and added another mix and mengkoksidasikannya. The end result of electric kitchen called electro-quality steel is very good for use as a tool of tools such as chisels, tools and other mashed.
J). Kitchen Stir Process
Kitchen stirring a conventional way of making steel by melting pig iron in the kitchen flame together with the slag (FeO) to obtain acid. By way of stirring with an iron rod and inserted into the bottom surface of the air, and there was a period of soft steel which contains slag. If the clumps are made in the kitchen has reached approximately 60 kg issued, then this step is to remove the slag hereinafter by way menempanya or pressed. In this stirring process involves more handwork and a small production capacity, the way it is deemed inefficient and rarely used in steel mills.
Steel material
1. Type - Steel type
With steel meant a material with great homogeneity, which mainly consists of Ferrum (Fe) in the form of crystal and 0.04 @ 1.6% carbon (C); charcoal substance was obtained by way of cleaning materials at extremely high temperatures, by using a process - a process which will be referred to the majority of pig iron, produced by the kitchen - the kitchen high.
All types - the type of steel a little more can be forged and can be plated, while for mild steel at voltages far below the tensile strength or the fracture limit of TB, namely the so-called boundary melt or melt tension Tv, there is a strange situation, where changes in current form continue for some time, with no increase load.
Properties - properties of steel depend completely on carbon content, increasing these levels, the increased stress fracture and strain according to per cent, which occurred in an experimental stem loaded with traction, which is broken into smaller strain.
A very small percentage of the elements - other elements, can influence the properties - properties with a strong steel, ririskiky good or bad. In order to distinguish them, the type - the type of steel which are numbered according to the stress fracture that is guaranteed and the lowest in a normal tensile test, but for each type of steel is also determined a TBmaks.
2. Steel Classification
• Based on the composition
a. Carbon steel
b. Low alloy steel
c. Stainless steel
• Based on the process of making
a. Open steel furnaces
b. Electric kitchen
c. Basic oxygen process
• Based on product form
a. Plates bars
b. Tube
c. Sheet
d. Ribbon
e. Structural form
• Based on the micro structure
a. Ferritic
b. Perlitik
c. Martensitik
d. Austenitic
• Based on use in construction
a. Structural Steel
b. Non-Structural Steel
1. Carbon Steel
Carbon steel is divided into four categories based on the percentage of carbon: carbon is low (less than 0.15%); Carbon software (0.15 to 0.29%); Carbon medium (0.3 - 0:59%), and high-carbon (0.6 - 1.7%). Carbon steel structural included in the category of soft carbon. Carbon steel structure dfinit shows the melting point, increase in carbon perentase will boost the hardness but reduce kekenyalannya, making it more difficult to weld.
2. Steel Combination of Low High-magnitude
This category includes steel - steel that has a yield stress of 40-70 KSI (275-480 MPa), which showed a clear melting point, similar to those seen in carbon steel. The addition of alloying elements of steel such as chrome, kolubium, copper, manganese, molybdenum, nickel, phosphorus, vanadium or zirconium, will improve the properties - mechanical properties. When Carbon gain strength with the addition of carbon content, the elements - elements blend to create more added strength with a fine microstructure than that rough microstructure obtained during the cooling process of steel. Berkkuatan low alloy steel used in conditions such as high-wrought or normal condition ie unused condition in which the heat treatment.
3. Alloy Steel
Low alloy steel can be cooled and plated in order to achieve yield strength of 80-110 KSI (550-760 MPa). Yield strength is usually defined as the voltage at 0.2% strain offset, because the steel does not show a clear melting point. With proper procedures can be welded steel, and usually do not require additional heat treatment after welding is done. For some special purposes, sometimes it takes relaxation of tension. Some carbon steel, such as certain steel fluid pressure, can be cooled and plated in order to provide about 80 KSI yield strength (550 MPa), but most of the strength of steel with such a low alloy steel. Low alloy steel is in general have about 0.2% carbon in order to limit the violence btiran coarse microstructure (martensite), which may be formed during heat treatment or welding, so as to reduce the danger of cracks.
Heat treatment consists of cooling (rapid cooling with water or oil at tidk 16500F (9000C) to about 300 - 4000F); then gilding with warming back up to at least about 11500F (6200C) and then allowed to cool. Gilding, although a little less strength and hardness of the material that has been cooled, but can increase the resilience and tenacity. The reduction in strength and hardness with increasing temperature slightly countered by the emergence of secondary hardening occurs due to absorption kolubium, titanium or vanadium carbide. Absorption begins at a temperature of about 9500F (5100C) and became more rapid until about 12500F (6800C). Gilding on or about 12500F to obtain maximum absorption of carbide would probably lead to the inclusion of these elements into the microstructure of the transformation zone and the results become weaker which may be obtained without cooling and gilding.
In summary, the cooling produced martensite, a brittle microstructure is very hard and strong; reheating will slightly reduce the strength and hardness, but will improve the ductility and elasticity.
Ref. htysite - Restsindo
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