Instruct: Given a question, retrieve relevant passages that can help answer the question.
Query: What is cast iron made of?
Cast iron is a group of iron-carbon alloys with a carbon content greater than 2%.[1] Its usefulness derives from its relatively low melting temperature. The alloy constituents affect its colour when fractured: white cast iron has carbide impurities which allow cracks to pass straight through, grey cast iron has graphite flakes which deflect a passing crack and initiate countless new cracks as the material breaks, and ductile cast iron has spherical graphite "nodules" which stop the crack from further progressing.
The iron lion was cast using a piece-moulding technique in a single mould. In this technique, which has also been used in ancient Chinese bronze-casting, a clay model of the sculpture is made and covered with a new layer of clay after drying. This outer layer of clay is then cut into pieces and removed before it dries completely. In the next step, material is taken off the surface of the inner clay model in order to provide room for pouring the iron between the outer and inner mould. Hence, "seams" visible on the cast do not represent boundaries between separate iron pieces, but are impressions of the seams between the pieces of the outer mould. Casting did proceed in several stages between which the iron already poured into the mould did cool down. As a result, fault lines were introduced into the cast at regular intervals which mark the filling height of the mould at successive casting stages. These fault lines were bridged by the craftsmen carrying out the cast with pieces of wrought iron which were plunged into the solidifying surface of the iron from the previous pour and then covered in the next pour. Traces of these bridging pegs as well as those of wrought iron spacers used to separate the outer mould from the core can still be found in the sculpture.
Among Richmond's most interesting architectural features is its Cast-iron architecture. Second only to New Orleans in its concentration of cast iron work, the city is home to a unique collection of cast iron porches, balconies, fences, and finials. Richmond's position as a center of iron production helped to fuel its popularity within the city. At the height of production in the 1890, 25 foundries operated in the city employing nearly 3,500 metal workers. This number is seven times the number of general construction workers being employed in Richmond at the time which illustrates the importance of its iron exports. Porches and fences in urban neighborhoods such as Jackson Ward, Church Hill, and Monroe Ward are particularly elaborate, often featuring ornate iron casts never replicated outside of Richmond. In some cases cast were made for a single residential or commercial application.
Iron was now being made in large quantities for many customers. In the 1720s and 1730s, its main products were cast-iron cooking pots, kettles and other domestic articles. It also cast the cylinders for steam engines, and pig iron for use by other foundries. In the late 18th century, it sometimes produced structural ironwork, including for Buildwas Bridge. This was built in 1795, 2 miles up the river from the original Ironbridge. Due to advances in technology, it used only half as much cast iron despite being 30 feet (9 m) wider than the Ironbridge. The year after that, in 1796, Thomas Telford began a new project, Longdon-on-Tern Aqueduct. It carried the Shrewsbury Canal over the River Tern and was supported by cast-iron columns. Charles Bage designed and built the world's first multi-storey cast-iron-framed mill. It used only brick and iron, with no wood, to improve its fire-resistance. In the 19th century ornamental ironwork became a speciality.
The earliest cast iron artifacts, dating to 5th century BC, were discovered by archaeologists in what is now modern Luhe County, Jiangsu in China. Cast iron was used in ancient China for warfare, agriculture and architecture. Around 500 BC, metalworkers in the southern state of Wu achieved a temperature of 1130 °C. At this temperature, iron combines with 4.3% carbon and melts. The liquid iron can be cast into molds, a method far less laborious than individually forging each piece of iron from a bloom.
In 1844, a new cast-iron lighthouse was constructed on Long Island Head. This was the second lighthouse built on the Head. It appears to be the first cast-iron lighthouse constructed in the United States. The South Boston Iron Company performed the work. This lighthouse was cast in sections of about seven feet in height and twelve feet in diameter at the base. It was furnished with an iron deck providing a twenty-inch walkway around the lantern. The deck had a railing. A cast iron circular staircase on the interior led to the lantern room. The lantern was made of upright wrought iron bars to receive the glass with sixteen 48" x 16" side over which was a cast iron dome with a cast-iron pipe in the center that served as a smoke flue for the lighthouse's stove.
The word "wrought" is an archaic past participle of the verb "to work," and so "wrought iron" literally means "worked iron". Wrought iron is a general term for the commodity, but is also used more specifically for finished iron goods, as manufactured by a blacksmith. It was used in that narrower sense in British Customs records, such manufactured iron was subject to a higher rate of duty than what might be called "unwrought" iron. Cast iron, unlike wrought iron, is brittle and cannot be worked either hot or cold. Cast iron can break if struck with a hammer.
An engineer's vise, also known as a "metalworking vise" or "machinist's vise", is used to clamp metal instead of wood. It is used to hold metal when filing or cutting. It is sometimes made of cast steel or malleable cast iron, but most are made of cast iron. However, most heavy duty vises are 55,000 psi cast steel or 65,000 psi ductile iron. Some vises have a cast iron body but a steel channel bar. Cast iron is popular because it is typically 30 ksi grey iron which is rigid, strong and inexpensive. The jaws are often separate and replaceable, usually engraved with serrated or diamond teeth. Soft jaw covers made of aluminum, copper, wood (for woodworking) or plastic may be used to protect delicate work. The jaw opening of an engineer's vise is almost always the same size as the jaw width, if not bigger.
A whimbling iron is a bell clapper made from ductile iron. Traditionally bell clappers were standard cast grey iron with a razor-like crystalline structure that led to sudden catastrophic failure over time. The standard clapper is distinguished by the experienced ear as a whefting iron. Whilst some believe that the advent of "health and safety" led to the search for an alternative, it is more likely that the ability to forge the bottom end ready for use practically died out early in World War II. Some attempts at composite clappers were made, but advances in casting technology, driven as much by the motor industry as by the war, resulted in the adoption of spheroidal graphite iron castings.
For such intricate detail and thin-sectioned castings to be produced as were done with Berlin iron jewellery, a very pure iron which contained up to 0.7% phosphorus was used. This was done to make the iron slightly more fluid than what it would be when normally molten. Although this type of phosphoric cast iron is rather hard and brittle, strength is not the main purpose of the metal when it is used in jewellery. The molten iron was cast into metal chill moulds.
The process of making cast iron was known before the 3rd century AD in China. Cast iron production reached Europe in the 14th century and Britain around 1500. Cast iron was useful for casting into pots and other implements, but was too brittle for making most tools. However, cast iron had a lower melting temperature than wrought iron and was much easier to make with primitive technology. Wrought iron was the material used for making many hardware items, tools and other implements. Before cast iron was made in Europe, wrought iron was made in small batches by the bloomery process, which was never used in China. Wrought iron could be made from cast iron more cheaply than it could be made with a bloomery.
The earliest of these in general use were the so-called cast iron fishbelly rails from their shape. Rails made from cast iron were brittle and broke easily. They could only be made in short lengths which would soon become uneven. John Birkinshaw's 1820 patent, as rolling techniques improved, introduced wrought iron in longer lengths, replaced cast iron and contributed significantly to the explosive growth of railroads in the period 1825-40. The cross-section varied widely from one line to another, but were of three basic types as shown in the diagram. The parallel cross-section which developed in later years was referred to as Bullhead.
The earliest cast-iron artifacts date to the 5th century BC, and were discovered by archaeologists in what is now Jiangsu in China. Cast iron was used in ancient China for warfare, agriculture, and architecture.[2] During the 15th century, cast iron became utilized for cannon in Burgundy, France, and in England during the Reformation. The amounts of cast iron used for cannon required large scale production.[3] The first cast-iron bridge was built during the 1770s by Abraham Darby III, and is known as The Iron Bridge. Cast iron was also used in the construction of buildings.
"Grinny" deals with a normal family in middle England whose lives change when they are visited by aliens. The alien takes the form of an apparently benign elderly relative who can play mind tricks on the adults in the family but not on the children. This Granny-esque figure is eventually caught out by the children's ingenuity (they realise she is no normal human being when she expects what they describe to her as a "cast-iron conker" to be made of cast iron). Published 1973. Animated as an episode of CBS Storybreak.
Two types of cast iron woks can be found in the market. Chinese-made cast iron woks are very thin (), weighing only a little more than a carbon steel wok of similar size, while cast iron woks typically produced in the West tend to be much thicker (), and very heavy. Because of the thickness of the cast iron, Western-style cast iron woks take much longer to bring up to cooking temperature, and their weight also makes stir-frying and "bao" techniques difficult.
Malleable iron starts as a white iron casting that is then heat treated for a day or two at about 950°C (1,740°F) and then cooled over a day or two. As a result, the carbon in iron carbide transforms into graphite and ferrite plus carbon (austenite). The slow process allows the surface tension to form the graphite into spheroidal particles rather than flakes. Due to their lower aspect ratio, the spheroids are relatively short and far from one another, and have a lower cross section vis-a-vis a propagating crack or phonon. They also have blunt boundaries, as opposed to flakes, which alleviates the stress concentration problems found in grey cast iron. In general, the properties of malleable cast iron are more like those of mild steel. There is a limit to how large a part can be cast in malleable iron, as it is made from white cast iron.
Cast iron is made from pig iron, which is the product of smelting iron ore in a blast furnace. Cast iron can be made directly from the molten pig iron or by re-melting pig iron[4], often along with substantial quantities of iron, steel, limestone, carbon (coke) and taking various steps to remove undesirable contaminants. Phosphorus and sulfur may be burnt out of the molten iron, but this also burns out the carbon, which must be replaced. Depending on the application, carbon and silicon content are adjusted to the desired levels, which may be anywhere from 2–3.5% and 1–3%, respectively. If desired, other elements are then added to the melt before the final form is produced by casting.[5]
The Iron Bridge is made of cast iron, which is not a good structural material for handling tension or bending moments because of its brittleness and relatively low tensile strength compared to steel and wrought iron. In a few instances bridges and buildings built with cast iron failed. Cast iron has good compressive strength and was successfully used for certain structural components in well designed old bridges and buildings. Puddled wrought iron, which was introduced after the Iron Bridge was constructed, was a much better structural material. Puddled iron became widely available after 1800 and eventually became the preferred material for bridges, rails, ships and buildings until new steel making processes were developed in the late 19th century.
Ductile iron, also known as ductile cast iron, nodular cast iron, spheroidal graphite iron, spheroidal graphite cast iron and SG iron, is a type of graphite-rich cast iron discovered in 1943 by Keith Millis. While most varieties of cast iron are weak in tension and brittle, ductile iron has much more impact and fatigue resistance, due to its "nodular graphite" inclusions.
Traditional waffle irons are attached to tongs with wooden handles and are held over an open flame, or set on a stove. Most modern waffle irons are self-contained tabletop electrical appliances, heated by an electric heating element controlled by an internal thermostat. There are also two variants of the electric iron: one with removable plates and ones with non-removable plates. Professional waffle makers are usually made of cast iron whereas domestic models are often teflon coated. Many have a light that goes off when the iron is at the set temperature. Most modern waffle irons - particularly cast aluminum ones - are coated with a non-stick coating (e.g. teflon) to prevent the waffles from sticking to them. Cast-iron waffle makers are usually not coated and require seasoning like a cast-iron frying pan.
Before the widespread use of malleable iron in everyday items, heavy-duty bench vises were made from cast steel. The use of cast steel has rapidly declined in most application due to its poor castability, and hence high-quality cast vises (as opposed to forged ones), among other tools and machine elements, are now almost exclusively made of malleable iron.
The cast-iron windshaft was probably not made for the mill originally. It carries a diameter composite brake wheel with 81 cogs which has been converted from clasp arm construction. This drives a cast-iron wallower with 25 teeth. The cast-iron upright shaft is diameter and in three parts, with dog clutches at the fourth and fifth floor. The cast-iron great spur wheel is diameter with 76 cogs. It drove three pairs of underdrift millstones of , and diameter.References for above:-
Cast iron was first produced in China during 5th century BC, but was hardly in Europe until the medieval period. The earliest cast iron artifacts were discovered by archaeologists in what is now modern Luhe County, Jiangsu in China. Cast iron was used in ancient China for warfare, agriculture, and architecture. During the medieval period, means were found in Europe of producing wrought iron from cast iron (in this context known as pig iron) using finery forges. For all these processes, charcoal was required as fuel.
The earliest cast-iron artifacts date to the 5th century BC, and were discovered by archaeologists in what is now modern Luhe County, Jiangsu in China. This is based on an analysis of the artifact's microstructures.[2]
Machine tools filled a need created by textile machinery during the Industrial Revolution in England in the middle to late 1700s. Until that time machinery was made mostly from wood, often including gearing and shafts. The increase in mechanization required more metal parts, which were usually made of cast iron or wrought iron. Cast iron could be cast in molds for larger parts, such as engine cylinders and gears, but was difficult to work with a file and could not be hammered. Red hot wrought iron could be hammered into shapes. Room temperature wrought iron was worked with a file and chisel and could be made into gears and other complex parts; however, hand working lacked precision and was a slow and expensive process.