Cast iron is a type of iron that contains carbon, silicon and small amount of manganese. It was used in earlier times to build structures like cast iron bridges. Like wrought iron however, most of its uses have been replaced by steel. The Iron Age was a prehistoric time when useful tools and weapons were first made from iron and steel. The dates this occurred in various parts of the world varies, with historians suggesting around 12th century BC in ancient Greece and 6th century BC in Northern Europe.
Machines, vehicles and building structures are commonly built from iron usually in the form of steel. To prevent iron and steel suffering from rust damage, they can be painted, coated with plastic, galvanized coated with zinc or by other methods that keep out water and oxygen. Iron in the human body has a number of important functions including carrying oxygen to the body in the form of hemoglobin.
Iron deficiency can be quite common especially among women , with a number of possible symptoms including fatigue and weakness.
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Iron is the 6th most common element found in the Universe. Steel can be around times stronger than iron in its pure form.
How Is It Made? An Infographic of the Iron and Steel Manufacturing Process
The early wrought iron used in human history actually came from meteors! Iron is relatively cheap to produce and has a large number of different uses. Iron rich foods include red meat, fish, tofu, beans and chickpeas.
Alloy steel is defined as steel with additional metals. This is made by smelting mixed ores that may either be added with the steel in the furnace or in the molten bath near the end of the finishing period, in the ladle, or in the moulds. Stainless steel is defined as alloy steel containing, by weight, 1. Cast iron is iron mixed with other metals. The iron must predominate by weight over these additional metals.
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These additional metals must not be in the quantities stated for the chemical composition of steel - see the page in this guide on iron and steel metal composition. Hot-drop forging and drop stamping are methods in the production of metal shapes or sections usually on a conveyor line by the hot shaping of cut blanks in dies by means of special tools.
These are carried out by pressure or impact, generally in successive phases, following preliminary operations of rolling, hammering, hand forging or bending. Wire drawing is a cold process in which bars or rods in irregularly wound coils are drawn through one or more dies at high speed to obtain coiled wire of a smaller diameter. Bright drawing is a cold process in which bars or rods, whether or not in irregularly wound coils, are drawn at slow speed through one or more dies to obtain products of smaller or different shaped sections. Rolled or obtained by continuous casting is a method of casting molten steel directly into useful or semi-finished shapes.
Hot extrusion is a process consisting of enclosing a piece of metal heated to forging temperature in a chamber called a container. High pressure is applied to the metal which is then forced through a die. Cold extrusion is a process similar to hot extrusion above except that the metal is at room temperature. Dies are metallic or other permanent devices that provide a given shape to a piece of metal.
The word in metallurgy covers a range of meanings and includes dies that are used to shape solid metal in presses and those for making die casting from. Hot drawing is a process in which metal is heated and passed through a die to produce the finished shape.
Sintering is where compacted metal powder obtained by moulding, usually coupled with pressing is spread out and passed under a burner. The powder ignites. Air is then drawn through the powder causing any sulphur or carbon present to oxidise. This causes a partial fusion of the particles in the powder, leaving them to adhere together in the form of a porous cellular clinker known as a sinter.
Closed-die forging is where hot metal is shaped within the walls of two dies that come together to enclose the work piece on all sides. The process starts with a rod or bar cut to the length required to fill the die. Open-die forging is the process of hammering hot metal between flat or contoured dies.
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There are three basic types of dies for this process - flat dies, V dies, and swage dies. Annealing is the process of heating a metal or alloy to a predetermined temperature below its melting point maintaining that temperature for a time, then cooling it slowly. Annealing generally provides softness. Finished products may be subjected to further finishing treatments such as mechanical workings including turning, milling, grinding, perforation or punching or surface treatments such as polishing, burnishing, artificial oxidation or chemical surface treatment.
There are several thousand steel and alloy-steel grades - all of which have different chemical compositions. In addition, there are all the different possible heat treatments, cold forming conditions, shapes and surface finishes that can make classification of these products difficult. However, steels can be classified reasonably easily into a few major groups according to their chemical composition, applications, shapes and surface conditions. All steels contain a small amount of incidental elements such as manganese, silicon, aluminium, phosphorus, sulphur and copper left over from the steel-making process.
These are grouped into:. If the concentration is any higher, the goods are considered to constitute high-alloy steels. Alloying elements include:. Flat-rolled products which under a current of 50 Hz and a magnetic flux of 1 T have a watt-loss per kg, calculated by the Epstein method, of:. Flat-rolled products of a thickness of less than 0. Less than 0.
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Alloy steels containing less than 0. Alloy steels containing 0. In principle, steel is either formed into flat products or long products, both of which have either a hot-rolled, cold-formed or coated surface. Flat products include plates, hot-rolled strip and sheets, and cold-rolled strip and sheets.
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They can have a variety of surface conditions and are rolled from slabs. Long products are made of either blooms or billets. Long products include bars, rods and wires, structural shapes and rails, and tubes. Any steel not containing one or more of the above elements in the weight proportions shown, is treated as a non-alloy steel.
The tables below provide you with the key four-digit heading codes to start with when classifying iron and steel not in finished product form. To be classified as such, they must be alloys in pigs, blocks, lumps or similar primary forms obtained by continuous casting or in granular or powder forms. These can be agglomerated, used as an additive in the manufacture of other alloys or as deoxidants, desulphurising agents or other similar usage. Otherwise it must be classified as a ternary or quaternary alloy as appropriate. Use the online UK Trade Tariff tool to find the rest of your commodity code and other measures applying to imports and exports.
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Introduction This guide will help you to correctly classify iron and steel products, ranging from base metals, waste and scrap and other primary forms through treated and semi-manufactured items to specific finished products. This guide covers iron and steel products including: iron and steel primary materials iron and non-alloy steel stainless steel alloy steel flat products long products, for example tubes, pipes, bars and rods ingots and semi-finished products specific finished products made from iron or steel If you wish to classify finished products use chapter 73, which contains detailed descriptions and classification codes.
How iron and steel are classified Classifying iron and steel products may appear daunting - chapter 72 and chapter 73 of the Tariff are dedicated to these products and are lengthy and detailed. It also covers specific and detailed finished products made from iron and steel, such as barbed wire, nails and screws, containers and boxes, sewing and knitting needles, springs, radiators and kitchen and tableware Key questions There are three key questions you need to bear in mind when you start classifying iron and steel products: What are the goods made of?
What do they do? How do they function? In most cases answering these questions fully will lead you to the correct classification code. Shots and grit are used for: cleaning up and de-scaling surface hardening shot peeling metal polishing or engraving metal or glass working stone or like material sometimes adding to concrete as a hardener or to increase its impermeability to X-rays or gamma rays Heading code also covers wire pellets, produced by cutting iron or steel wire.
Other primary forms are classified under heading code These include: steel in the molten state blocks and lumps chiefly obtained from agglomerates or build-ups produced by a direct reduction of iron ore or by electrolytic deposition puddled bars and pilings after rolling, provide a product with a characteristic fibrous structure by virtue of its slag content However, heading code excludes: remelting scrap ingots heading code products obtained by continuous casting heading code Semi-finished products are classified under heading code Flat-rolled products classified under heading code may be subject to surface treatment: includes corrugated flat-rolled products excludes ribbed products with an angular profile heading code excludes flat-rolled products which have been coated, plated or clad with metal, or coated with non-metallic substances for example paints, enamels or plastics heading code Hot rolled - this is a method of shaping steel by rolling.
These must have the following characteristics: the sections most commonly falling in this heading are H, I, T, Z, U including channels capital omega, obtuse, acute and right L angles corners can be square or rounded, the limbs equal or unequal and the edges may or may not be bulbed Alloy steel is defined as steel with additional metals.