Teknik Penyaduran Chrome Electro Plating Sedikit tentang sejarah...

Mengikut sejarah, Pada tahun 1863 -1914 Paul Louis Toussaint Hroult ( warga Perancis) dan Charles Martin Hall (warga Amerika) kedua-dua mengemukakan satu proses meleburkan aluminium oksida dihasilkan melalui pengunaan arus elektrik. Bila ini telah dilakukan aluminium tulen dapat dihasilkan. Proses dinamakan sempena kedua-dua ahli-ahli sains dan kita masih menggunakan Hall Herout Method Teori Mereka ini lah menjadi asas yang diguna pakai pada Electroless Plating ( Teknik Penyaduran) sehingga zaman sekarang

Ok.. Teknik penyaduran ni masa zaman sekolah dulu lah ada belajar kan.. Kalau korang ada buat eksperiment kat makmal sains sekolah korang atau tengok soalan kertas peperiksaan Sains ada benda ni...Dalam sel elektrolisis, tenaga kimia dialirkan tenaga elektrik. Arus mengalir daripada elektrod positif kepada elektrod negatif di luar sel . katod (sudu besi) jisim katod bertambah.. jisim anod berkurangan melarut dan masuk ke dalam larutan sebagai ion argentum dimana logam perak dienapkan..

atom argentum (perak) - elektron -> ion argentum _______________________________Sebenarnya Teknik tersebut lebih kurang ajer dengan asas teknik Penyaduran Chrome Electro Plating yang digunakan untuk part-part kereta ni...

Peralatan asas yang sepatutnya ada

_______________________________Teknik Penyaduran Chrome Electro Plating part Kereta

1) Dapatkan part yang hendak dibuat penyaduran tersebut.. Bersihkan dan cuci dari kotoran kemudian tanggalkan kesemua cat dan membuang karat degil pada permukaan tersebuttujuan membuat pengasaran pada permukaan part supaya mudah untuk proses penyaduran melekat nanti. Kerja-kerja polishing perlu dilakukan bagi memperhaluskan kembali permukaan supaya tiada permukaan melekuk atau calar-calar setelah membuat pengasaran pada permukaan part tersebut .. Pastu basuh sekali lagi tetapi dengan menggunakan larutan bercampur asid bagi memudahkan menanggalkan habuk, minyak, gris dan dan kotoran. Kemudian bilas dan basuh bersih-bersih dengan air beberapa kali

2) Proses penyaduran electroplating chemical acid copper dilakukan dengan merendam part tersebut kedalam takungan mengandungi chemical acid copper..Tujuannya bagi membantu menutup ketidaksempurnaan dan liang halus yang ada part tersebut dan sebagai satu lapisan asas coating supaya lapisan penyaduran lebih kuat melekat tidak mudah terkakis dan pudar warnanya. Selepas itu ianya perlu di gilap ( polish copper buffing ) sekali lagi

3) Selepas itu rendam part pada takungan Semi-Bright nickel bagi melakukan proses saduran Semi-Bright nickel coat juga bertujuan lapisan asas melindungi dari kakisan dan menambah ketahanan.

4) Selepas itu Sekali lagi dipindah masuk part tersebut kedalam takungan Bright nickel untuk proses saduran Bright nickel untuk menimbulkan warna reflective lebih berkilat

5) Dan proses terakhir dengan memindahkan part ke takungan chemical chromium pula ... Tujuannya adalah sebagai proses penyaduran electroplating chemical chromium.. Ini adalah penyaduran chrome pada part tersebut supaya lebih berkilau warnanya..

Dan laast sekali part tersebut perlu dibersihkan kemudian bilas semula dari sisa chemical.. kemudian di biarkan kering... dan lihat lah hasilnya penyaduran chrome yang nampak lebih berkilat lagi..._______________________________Teknik Penyaduran Chrome Electro Plating part Motorsikal

Bagi part-part motorsikal ni sama ajerr macam kat atas kalau nak buat penyaduran Chrome ni... Boleh dilakukan pada part-part motorsikal macam kat bawah ni...

_______________________________Teknik Penyaduran Chrome Electro Plating Part plastikPenyaduran ialah pemendapan ion logam daripada larutannya ke atas permukaan yang bercas elektrik. Maka permukaan saduran sepatutnya pengalir elektrik. Tetapi Plastik tidak mengalirkan elektrik, jadi penyaduran secara terus tidak boleh dipraktikkan. Proses penyaduran plastik perlu melalui beberapa langkah dengan menutup plastik dengan pengalir elektrik yang melekit (adhesive conductor), seperti cat logam (metallicpaint), sebelum menjalankan proses penyaduran sebenar.

Terdapat dua cara untuk menyadurkan plastik

Cara pertama ialah dengan mewujudkan permukaan yang kasar supaya logamboleh melekat. Kemudian, penyaduran di atas permukaan itu untuk membina lapisanlogam. Proses ini dikenali sebagai electroless, auto-catalytic atau penyaduran kimia(chemical plating)

Cara kedua ialah dengan menggunakan cat pengalir (conductive paint) ke atas plastik, kemudian sadurkannya

i. Seperti biasa perlu buat pengasaran diatas permukaan part plastik tersebut - Mula-mula bersihkan bahagian-bahagian plastik daripada minyak, gris dan segala bendasing. -Untuk kebersihan sempurna, gunakan sedikit larutan asid - Bilas dengan air beberapa kali di dalam setiap langkah pembersihan menggunakan asid dan bes untuk membuang agen pembersihan yang telah digunakan sebelum langkah seterusnya diambil.

ii. Masukkan bahagian itu ke dalam chrome-sulfur bath. Asid akan menyebabkan lubang atau menggores permukaan plastic supaya mudah untuk logam melekat.

iii. Cat part tersebut dengan pengalir (conductive paint) terlebih dahuluiv.Kemudian, masukkan bahagian itu ke dalam palladium chloride bath. Permukaan awal logam terhasil akan membenarkan penyaduran standard berlaku. Khususnya bahagian yang akan disadurkan dengan tembaga (copper) sebagai lapisan persediaan sebelumdisadurkan dengan chrome,nickel atau logam-logam lain.

Ok back to point beza antara Polish Chrome dan electro plating Chrome Polish Chrome nampak lebih original lebih tahan lama berbanding cara celup atau Sadur Nikel Chrome guna teknik electro plating chrome yang cepat terkelupas.. klau sport rim kereta kena batu sikit ajer , Permukaan Chrome tu dah terkelupas ... Cuma guna sadur ni permukaan nya lebih bersinar dan berkilau lain macam sikit...

Segala saranan, pandangan & komen untuk kami teliti dan perbaiki.. Silalah diutuskan di ruangan Chart box atau coloum comment.. Thanks

Eating or serving with utensils made of silver, silver-plated metals or stainless steel is relatively recent. Silver needed to be discovered in sufficient quantities, the smelting processes necessary to hand-craft silver needed to be refined, and in Northern Europe it took several centuries before the more civilized Latin table manners replaced the cruder Anglo-Saxon ones. Henry VIII, the most famous of England's Tudors, used his hands to tear off large pieces of beef from an entire roast set before him, throw the meat on his trencher board, chop off smaller pieces and shovel them in his mouth. Such table manners were acceptable until the publication of books on manners by Castiglione (1478-1529) and Peacham (1576-1643). Around that time, fine silver table services and eating implements were introduced into English court life. Banquet halls started to use solid silver platters and plates, silver-mounted drinking vessels, silver-handled knives and a variety of spoons. Unassisted bare hands, however, remained the norm for the "lower orders" in England for another century or so. The spoon was one of man's earliest inventions, possibly as old as the custom of drinking hot liquids. In Northern Europe, the first spoons were carved from wood. Later specimens were fashioned out of horns of cattle, ivory tusks, bronze, and eventually silver and gold. The earliest mention of spoons made from precious metals is found in the Book of Exodus, when Moses is commanded to make dishes and spoons of pure gold for the Tabernacle. Moses asked Bezalel (the first spoon-maker known to us by name in history) to work in gold, silver and brass. Since Bezalel had come with Moses out of Egypt, he must have learned his trade there. Many Egyptian spoons were cast in the form of handled dishes with a cover and a spout, an elaborate but not very practical design. Greek and Roman spoons, on the other hand, looked much more like the spoons we are used to seeing in modern times. Pan, the patron of shepherds and huntsmen, was honored with spoons in the shape of a goat's foot. The Roman fiddle-patterned spoon, originating in the first or second century A.D., resembles the modern type we know today, except for its squared off stem-head, rather than the arched appearance with which we are familiar. The first English spoons, made of horn or wood, were probably imitations of those brought in by Roman troops in Britain. The Angles and Saxons introduced a spoon with small, pear-shaped bowl. By the fourteenth century, castings of bronze, brass, pewter and sheet tin were fairly common. The knife, used by hunters and soldiers for cutting and spearing the meat, was first made of flint, then of metal. Its main characteristic was a sharp edge. Traces of the primitive knife, such as the incurved shape at the top, or the beveling of the metal to achieve an edge, are still present in some of our styles today. Handles at first were only long enough to allow a firm grip for carving. In the 1630s, the Duke de Richelieu, chief minister to France's Louis XIII, ordered the kitchen staff to file off the sharp points of all house knives and bring them to the royal table, thereby introducing the knife as an every-day eating utensil for the aristocracy. Forks were introduced at the table around the time of the Crusades, at the beginning of the twelfth century, when Venice's Doge Domenice Silvie and his Dogess placed a fork beside each plate at one of their banquets. The forks took about three centuries to gain acceptance, probably because the custom of placing food in one's mouths with both hands, five fingers, orfor the refined fewthree fingers, was more expedient than using a new gadget. Most dinner guests first carried their own knives. After the introduction of forks, the custom of guests providing their own eating utensils continued, and attention was given to minimize the space occupied by the knife and fork when not in use, with the fork sometimes serving as a handle for the spoon. The production of tableware on a wide scale in England after 1650 played a large role in improving the dinner-table etiquette. In time, strict laws demanding high standards greatly enhanced the quality of silverware. Silversmiths were required to stamp their name, the place, and the date of their manufactured goods on their pieces. The word "sterling" came to mean "of unexcelled quality." From 1670, English homes of the upper classes had silver spoons as a matter of course, and had already started the custom of passing them on to their heirs. American silversmiths widely copied these spoons. In fact, the colonial craftsmen's first silver goods were spoons. Table knives with steel blades started to appear around this time as well. However, silver forks and sophisticated serving vessels were rare until the late eighteenth century. Before the seventeenth century, silver could be melted and poured into shaped molds to be cast into a variety of objects, but more often it was hand beaten with sledge hammers on an anvil, or coerced into flatsheets of the required thickness by a version of the old-fashioned laundry mangle with iron instead of wooden rollers. The hammering of the sheet caused it to become brittle after a certain amount of time, and therefore unfit for further working. At that point, it was annealed, or placed under heat of about 1,000 degrees Fahrenheit (540 degrees Celsius), then plunged into cold water, after which the hammering could be resumed.

Workers sit astride their grinding wheels in this photo from the Rockford (III.) Cutlery Co., taken about 1900. F irst used in the mid-nineteenth century, the term "silverware," referring to Sterling silver or silverplated tableware, has become synonymous with cutlery. Still, cutlery has been made of iron for centuries. In Great Britain, the area of Sheffield has been widely known for producing high-quality cutlery since the thirteenth century. With the introduction of silverplating in the late eighteenth century, the area also became identified with silverplated goods, thus "Sheffield plate." Not surprisingly, Americans who sought to compete with Sheffield cutlery in the nineteenth century overcame opposition by reducing the cost of their cutlery through the use of powered machinery and simplification of the production process. By 1871, the Russell Manufacturing Company of Turner's Fall, Massachusetts, had reduced the sequence to sixteen steps, each of which might be performed by different individuals. The company consumed annually 700 tons of steel, 200 tons of grindstones, and 22 tons of emery; and for handles, 18 tons of ivory, 56 tons of ebony, 29 tons of rosewood, and 150 tons of cocoawood. Despite the growth, one thing that did not improve for workers in the United States was industrial hygiene. Grinders, especially, were subjected to large doses of metallic dust and commonly succumbed to "grinders' disease," or silicosis. The most famous product innovation associated with the American cutlery trade was the Bowie knife. With its distinctive long, heavy blade, it was useful for both hunting and fighting. James Bowie, famed frontiersman, designed and popularized this large sheath knife. It became so popular and so commonly associated with violent crime during the 1830s that several states passed laws restricting its use. William S. Pretzer Later, the silversmiths (or "flatters") used more sophisticated techniques, such as waterwheels or horse-driven wheels, to pass the metal through the rollers many times until the desired thickness was attained. These techniques were replaced by the steam engine in the eighteenth century. Special hammerswithout small faces and sharp corners that might cut the metalwere used to raise the flat sheets of metal into hollow forms, such as pots or the bowls of spoons. Handles for spoons, forks, or knives were shaped by casting. The most common method was to embed a pattern (of gunmetal, wood or plaster) in a two-part frame filled with an adhesive loam mixture, bake it hard, open the frame and remove the pattern, then fill the cavity with molten silver, finally breaking the mold to remove the casting. Pieces fashioned this way showed gritty surfaces that required smoothing with file and pumice. Sheffield plating was the first silverplating technique used. It consisted of attaching a thin skin of sterling to one or both sides of a copper brick, rolling it into flatsheets, and then working it in a similar manner as silver. This technique was replaced in 1842, when electroplating (or sterling silver deposited by electrolysis on a base metal) was introduced. Raw Materials The raw material of silverware is stainless steel, sterling silver, or, in the case of silver-plate, a base metal (such as a high-quality copper alloy) over which a layer of silver is electrically deposited. Stainless steel is a combination of steel, chrome and nickel. The finest grade of metal used in producing quality lines is 18/8 stainless steel. This means that it contains 18 percent chrome, 8 percent nickel. Stainless steel is very popular because of its easy care, durability, and low price. The majority of silver is obtained as a byproduct of the extraction of lead, copper and zinc. Silver is separated from smelted lead bullion by the Parkes process, in which zinc is added to the molten bullion that has been heated to above the melting point of zinc. When the zinc has dissolved, the mixture is cooled and a crust of zinc-silver alloy forms on the surface, because the silver combines more readily with zinc than with lead. The crust is removed, pressed to remove excess lead and then processed in a retort to recover the zinc for reuse, leaving a silver-lead bullion with a high silver content. Further refining of the bullion is carried out in a cupellation furnace, where air is blown across the surface of the molten metal to oxidize the lead and other impurities to a slag, leaving the silver, which is cast into anode blocks. Final purification of the silver is made by an electrolytic process. Sterling silver consists of 925 pure silver and 75 parts of an alloy (usually copper). This proportion is fixed by law and therefore never varies. The copper alloy adds durability without sacrificing the natural beauty and workability of silver. Silverplate is the result of a process that bonds pure silver (silver more pure than sterling) to a strong base metal. The resulting tableware is durable, has the look and feel of silver, but is much less expensive than sterling. The Manufacturing Process Blanking 1 Production begins with rectangular, flat blanks of stainless steel, sterling silver, or in the case of plated flatware, an alloy. Large rolls are stamped in individual blanks, which are flat pieces roughly the same shape as the piece to be produced. Rolling 2 Through a series of rolling operations, these blanks are graded or rolled to the correct thickness and shapes required by the manufacturer's flatware patterns. First the blanks are rolled crosswise from left to right, right to left, and lengthwise, then trimmed to outline. Each spoon, for instance, must be thick at the base of the handle to resist bending. This gives graded pieces the right balance and a good feel in the hand. Each piece is now in the form of a cleanly finished shape in the rough dimension of the utensil. Annealing 3 Between operations, the blanks must pass through annealing ovens to soften the metal for further machine operations. The annealing, done under great heat, must be very accurately controlled so the final piece will be resistant to bending and to nicks and dents when in use. The last annealing is the most

The First step in cutlery manufacture involves blanking the stainless steel or sterling silver to the proper shape. A series of rolling operations then gives the piece the correct thickness. After heat treatment and trimming, the piece has a pattern embossed on it in a stamping operation. Finally, the piece is buffed and polished. important, because the pieces must be just the right degree of hardness when they are embossed. Then the metal can be forced easily into all the tiny details in the dies and the ornamentation will be faithfully reproduced. Cutting to outline 4 The rolled blanks are placed in the cutout press by an operator, to remove the excess metal and to fashion the shape of the piece. This process is similar to cutting shapes from rolled dough. The shape of the piece is cut out of the metal and the excess metal is remelted and transformed back into sheets of metal to be used again. This trimming must ensure an accurate fit of the pieces into the dies when the design is applied. Forming the pattern 5 The next step is the forming of the pattern. Each pattern has its own hardened steel diestwo dies for each piece, one with the pattern for the front of the piece, and the other with the pattern for the back of the piece. These are carefully set in the hammers by die setters. The operator quickly places a piece in place under the drop hammer, which descends with a hydraulic pressure of 200 tons. (The bases of the drop hammers are bedded in 160 cubic yards of cement.) The metal is squeezed into every tiny detail of the ornamentation in the die, embossing the pattern on the piece. The blow of the hammer hardens the piece for use in the home. Surplus metal around the outline of the piece is then removed by clipping presses. Special steps knife, spoon, and fork 6 Special steps are necessary for the creation of knives, spoons, forks, and holloware pieces. To make the hollow handle for the knife, after two strips of metal are formed to shape, they are then soldered together, buffed and polished until the seam is no longer visible. The blade and handle are

This illustrations shows how a fork looks after each operation is performed. Although the tines are pierced before the pattern is applied, the strip of metal that connects the tines together isn't removed until after the pattern is embossed. permanently joined by means of a powerful cement, which bonds with great strength and durability. 7 With the spoon, after the pattern has been embossed upon the front and back of the handle, the next step is the forming of the bowl. The forming is done again under the same powerful drop hammers from accurate steel dies. Each bowl requires two hammer blows. Surplus metal around the outline of the spoon is removed by clipping presses. A small burr still remains to be removed at a later operation. 8 The forming of fork tines is a similar process to that of the forming of the spoon's bowl, but the operation takes place before the pattern is applied to the handle. After a fork is cut to outline, it is pierced and tined: the tines are pieced out, and the small piece of metal that holds the tip of the tines together is removed in another operation after the pattern has been applied. Silver plating 9 For the silver-plated pieces, the electroplating process is an additional step. The pieces are first prepared by being buffed so that the edges are smooth and the surfaces are free from small holes. When the buffing is completed, the pieces are given a thorough cleaning with as many as 12 different chemical solutions. Finally, they undergo electrolysis, in which a layer of silver is electrically deposited over the base metal. Buffing and sand polishing 10 The knives, forks and spoons are now 1 0J buffed, then polished. Depending on the pattern, special finishing processes can give silver-plated and sterling silver pieces a bright, mirror-like finish, a soft, satiny glow, or a brushed or florentine finish. Quality Control Final inspection checks the pieces for chafes, scratches, rough spots between a fork's tines, discoloration, or any other flaws that might have occurred when the pieces were stamped, shaped and polished. The Future Stainless steel is the preferred tableware for today's customers, and represents the future for flatware manufacturers. According to a senior executive at Oneida, the last major domestic manufacturer of silverware and plated ware in the United States, purchase of sterling and silverplated ware has been declining for the past twenty years, while demand for stainless steel continues to grow. Where To Learn More Books Clayton, Michael. Christie's Pictorial History of English and American Silver. Phaidon, 1985. Ettlinger, Steve. The Kitchenware Book. Macmillan Publishing Co., Inc., 1992. Fennimore, Donald L. Silver and Pewter. Knopf, 1984. Freeman, Dr. Larry. Victorian Silver: Plated and Sterling Holloware and Flatware. Century House, 1967. Giblin, James C. From Hand to Mouth: Or, How We Invented Knives, Forks, Spoons & Chopsticks & the Table Manners to go with Them. HarperCollins Children's Books, 1987. Hamlyn, Paul. English Silver. Hamlyn Publishers, 1969. Hood, Graham. American Silver: A History of Style, 1650-1900. Praeger Publishers, 1971. "Sheet Metal," How It Works, Vol. 18. H.S. Stuttman Inc., 1987. Schwartz, Marvin D. Collector's Guide to Antique American Silver. Doubleday, 1975. Science and Technology Illustrated. Encyclopedia Britannica, 1984. Watson, Jim. Sharpening and Knife Making. Schiffer Publishing Ltd., 1987.

Read more: http://www.madehow.com/Volume-1/Cutlery.html#ixzz2vg90PhHY

IRON AND STEEL

This page looks at the use of the Blast Furnace in the extraction of iron from iron ore, and the conversion of the raw iron from the furnace into various kinds of steel.

Extracting iron from iron ore using a Blast FurnaceIntroductionThe common ores of iron are both iron oxides, and these can be reduced to iron by heating them with carbon in the form of coke. Coke is produced by heating coal in the absence of air.Coke is cheap and provides both the reducing agent for the reaction and also the heat source - as you will see below.Iron oresThe most commonly used iron ores are haematite (US: hematite), Fe2O3, and magnetite, Fe3O4.

Note: The two equations for the reduction of the ore on this page are for haematite. In the fairly unlikely event that you need the equations for magnetite, they aren't difficult to work out for yourself.

The Blast Furnace

The heat sourceThe air blown into the bottom of the furnace is heated using the hot waste gases from the top. Heat energy is valuable, and it is important not to waste any.The coke (essentially impure carbon) burns in the blast of hot air to form carbon dioxide - a strongly exothermic reaction. This reaction is the main source of heat in the furnace.

The reduction of the oreAt the high temperature at the bottom of the furnace, carbon dioxide reacts with carbon to produce carbon monoxide.

It is the carbon monoxide which is the main reducing agent in the furnace.

In the hotter parts of the furnace, the carbon itself also acts as a reducing agent. Notice that at these temperatures, the other product of the reaction is carbon monoxide, not carbon dioxide.

The temperature of the furnace is hot enough to melt the iron which trickles down to the bottom where it can be tapped off.

The function of the limestoneIron ore isn't pure iron oxide - it also contains an assortment of rocky material. This wouldn't melt at the temperature of the furnace, and would eventually clog it up. The limestone is added to convert this into slag which melts and runs to the bottom.The heat of the furnace decomposes the limestone to give calcium oxide.

This is an endothermic reaction, absorbing heat from the furnace. It is therefore important not to add too much limestone because it would otherwise cool the furnace.Calcium oxide is a basic oxide and reacts with acidic oxides such as silicon dioxide present in the rock. Calcium oxide reacts with silicon dioxide to give calcium silicate.

The calcium silicate melts and runs down through the furnace to form a layer on top of the molten iron. It can be tapped off from time to time as slag.Slag is used in road making and as "slag cement" - a final ground slag which can be used in cement, often mixed with Portland cement.

Cast ironThe molten iron from the bottom of the furnace can be used as cast iron.Cast iron is very runny when it is molten and doesn't shrink much when it solidifies. It is therefore ideal for making castings - hence its name. However, it is very impure, containing about 4% of carbon. This carbon makes it very hard, but also very brittle. If you hit it hard, it tends to shatter rather than bend or dent.Cast iron is used for things like manhole covers, guttering and drainpipes, cylinder blocks in car engines, Aga-type cookers, and very expensive and very heavy cookware.

Note: It is quite difficult to find examples of uses for cast iron, because it is nowadays often replaced by other materials. For example, although guttering and drainpipes were once made of cast iron, apart from special old buildings, it is now quite hard to find any which aren't made of plastic!

SteelMost of the molten iron from a Blast Furnace is used to make one of a number of types of steel. There isn't just one substance called steel - they are a family of alloys of iron with carbon or various metals. More about this later . . .

Steel-making: the basic oxygen processImpurities in the iron from the Blast Furnace include carbon, sulphur, phosphorus and silicon. These have to be removed.Removal of sulphurSulphur has to be removed first in a separate process. Magnesium powder is blown through the molten iron and the sulphur reacts with it to form magnesium sulphide. This forms a slag on top of the iron and can be removed.

Removal of carbon etcThe still impure molten iron is mixed with scrap iron (from recycling) and oxygen is blown on to the mixture. The oxygen reacts with the remaining impurities to form various oxides.The carbon forms carbon monoxide. Since this is a gas it removes itself from the iron! This carbon monoxide can be cleaned and used as a fuel gas.Elements like phosphorus and silicon react with the oxygen to form acidic oxides. These are removed using quicklime (calcium oxide) which is added to the furnace during the oxygen blow. They react to form compounds such as calcium silicate or calcium phosphate which form a slag on top of the iron.

Types of iron and steelCast iron has already been mentioned above. This section deals with the types of iron and steel which are produced as a result of the steel-making process.Wrought ironIf all the carbon is removed from the iron to give high purity iron, it is known as wrought iron. Wrought iron is quite soft and easily worked and has little structural strength. It was once used to make decorative gates and railings, but these days mild steel is normally used instead.Mild steelMild steel is iron containing up to about 0.25% of carbon. The presence of the carbon makes the steel stronger and harder than pure iron. The higher the percentage of carbon, the harder the steel becomes.Mild steel is used for lots of things - nails, wire, car bodies, ship building, girders and bridges amongst others.High carbon steelHigh carbon steel contains up to about 1.5% of carbon. The presence of the extra carbon makes it very hard, but it also makes it more brittle. High carbon steel is used for cutting tools and masonry nails (nails designed to be driven into concrete blocks or brickwork without bending). You have to be careful with high carbon steel because it tends to fracture rather than bend if you mistreat it.Special steelsThese are iron alloyed with other metals. For example:iron mixed withspecial propertiesuses include

stainless steelchromium and nickelresists corrosioncutlery, cooking utensils, kitchen sinks, industrial equipment for food and drink processing

titanium steeltitaniumwithstands high temperaturesgas turbines, spacecraft

manganese steelmanganesevery hardrock-breaking machinery, some railway track (e.g. points), military helmets

Some environmental considerationsThis section is designed to give you a brief idea of the sort of environmental issues involved with the extraction of iron and its conversion to steel. I wouldn't claim that it covers everything!

Note: This is deliberately brief because a lot of it is just common sense, and you will probably already have met it in detail in earlier chemistry courses, in geography, in general studies, or wherever.If you aren't sure about the various environmental problems like acid rain, global warming and the like, the very best site to find out about them is the US Environmental Protection Agency.

Environmental problems in mining and transporting the raw materialsThink about: Loss of landscape due to mining, processing and transporting the iron ore, coke and limestone. Noise and air pollution (greenhouse effect, acid rain) involved in these operations.

Extracting iron from the oreThink about: Loss of landscape due to the size of the chemical plant needed. Noise. Atmospheric pollution from the various stages of extraction. For example: carbon dioxide (greenhouse effect); carbon monoxide (poisonous); sulphur dioxide from the sulphur content of the ores (poisonous, acid rain). Disposal of slag, some of which is just dumped. Transport of the finished iron.

RecyclingThink about: Saving of raw materials and energy by not having to first extract the iron from the ore. Avoiding the pollution problems in the extraction of iron from the ore. Not having to find space to dump the unwanted iron if it wasn't recycled. (Offsetting these to a minor extent) Energy and pollution costs in collecting and transporting the recycled iron to the steel works.

Where would you like to go now?To the Metal Extraction menu . . .To the Inorganic Chemistry menu . . .To Main Menu . . .