Cast iron is a group of iron-carbon alloys with a carbon content greater than 2%. Its usefulness derives from its 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, ductile cast iron has spherical graphite "nodules" which stop the crack from further progressing. Carbon ranging from 1.8 to 4 wt%, silicon 1–3 wt%, are the main alloying elements of cast iron. Iron alloys with lower carbon content are known as steel. Cast iron tends to be brittle, except for malleable cast irons. With its low melting point, good fluidity, excellent machinability, resistance to deformation and wear resistance, cast irons have become an engineering material with a wide range of applications and are used in pipes and automotive industry parts, such as cylinder heads, cylinder blocks and gearbox cases.
It is resistant to damage by oxidation. The earliest cast-iron artefacts date to the 5th century BC, were discovered by archaeologists in what is now Jiangsu in China. Cast iron was used in ancient China for warfare and architecture. During the 15th century, cast iron became utilized for cannon in Burgundy, in England during the Reformation; the amounts of cast iron used for cannon required large scale production. The first cast-iron bridge was built during the 1770s by Abraham Darby III, is known as The Iron Bridge in Shropshire, England. Cast iron was used in the construction of buildings. Cast iron is made from pig iron, the product of melting iron ore in a blast furnace. Cast iron can be made directly from the molten pig iron or by re-melting pig iron along with substantial quantities of iron, limestone and taking various steps to remove undesirable contaminants. Phosphorus and sulfur may be burnt out of the molten iron, but this burns out the carbon, which must be replaced. Depending on the application 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 added to the melt before the final form is produced by casting. Cast iron is sometimes melted in a special type of blast furnace known as a cupola, but in modern applications, it is more melted in electric induction furnaces or electric arc furnaces. After melting is complete, the molten cast iron is poured into ladle. Cast iron's properties alloyants. Next to carbon, silicon is the most important alloyant. A low percentage of silicon allows carbon to remain in solution forming iron carbide and the production of white cast iron. A high percentage of silicon forces carbon out of solution forming graphite and the production of grey cast iron. Other alloying agents, chromium, molybdenum and vanadium counteracts silicon, promotes the retention of carbon, the formation of those carbides. Nickel and copper increase strength, machinability, but do not change the amount of graphite formed; the carbon in the form of graphite results in a softer iron, reduces shrinkage, lowers strength, decreases density.
Sulfur a contaminant when present, forms iron sulfide, which prevents the formation of graphite and increases hardness. The problem with sulfur is. To counter the effects of sulfur, manganese is added because the two form into manganese sulfide instead of iron sulfide; the manganese sulfide is lighter than the melt, so it tends to float out of the melt and into the slag. The amount of manganese required to neutralize sulfur is 1.7 × sulfur content + 0.3%. If more than this amount of manganese is added manganese carbide forms, which increases hardness and chilling, except in grey iron, where up to 1% of manganese increases strength and density. Nickel is one of the most common alloying elements because it refines the pearlite and graphite structure, improves toughness, evens out hardness differences between section thicknesses. Chromium is added in small amounts to reduce free graphite, produce chill, because it is a powerful carbide stabilizer. A small amount of tin can be added as a substitute for 0.5% chromium.
Copper is added in the ladle or in the furnace, on the order of 0.5–2.5%, to decrease chill, refine graphite, increase fluidity. Molybdenum is added on the order of 0.3–1% to increase chill and refine the graphite and pearlite structure. Titanium is added as a degasser and deoxidizer, but it increases fluidity. 0.15–0.5% vanadium is added to cast iron to stabilize cementite, increase hardness, increase resistance to wear and heat. 0.1–0.3% zirconium helps to form graphite and increase fluidity. In malleable iron melts, bismuth is added, on the scale of 0.002–0.01%, to increase how much silicon can be added. In white iron, boron is added to aid in the production of malleable iron. Grey cast iron is characterised by its graphitic microstructure, which causes fractures of the material to have a grey appearance, it is the most used cast iron and the most used cast material based on weight. Most cast irons have a chemical composition of 2.5–4.0% carbon, 1–3% silicon, the remainder iron. Grey cast iron has less tensile strength and shock resistance than steel, but its compressive strength is comparable to low- and medium-carbon s
Sasha Issenberg is an American journalist. His articles have been published in Philadelphia, the Washington Monthly, The New York Times Magazine, The Atlantic, The Boston Globe and George, where he was a contributing editor. Issenberg was born to a Jewish family and is a 2002 graduate of Swarthmore College. In 2016, he covered the 2016 presidential campaign for Bloomberg News. In 2016, he co-founded the company Votecastr, to track the 2016 Presidential Election in real-time, publishing the results of turnout tracking at Poll Locations online throughout the day. In 2018, he was named the UC Regents' Professor at UCLA, where he taught a course on understanding presidential campaign victories through the stories reporters and historians tell about those victories, his writing focuses on politics, business and culture. Issenberg covered the 2008 election as a reporter for The Boston Globe, he is the author of the book The Sushi Economy, about sushi and globalization, published in May 2007. He is the author of The Victory Lab: The Secret Science of Winning Campaigns about the new science of political campaigns.
The Whyalla Steelworks is a integrated steelworks and the only manufacturer of rail in Australia. Iron ore is mined in the Middleback Range to feed the steelworks, resulting in the distribution of finished steel products of over 90 different grades, it occupies a 1,000 ha site on the shore of False Bay, Spencer Gulf and is the largest employer in Whyalla, South Australia. 1.2 million tonnes of raw steel is produced in the steelworks each year, with about 65% of that transferred by rail to Arrium's Market Mills as billets for further processing. The balance of the steel is converted to finished products at the Whyalla Rolling Mill; these products service the rail transport industries. Dust emissions from the steelworks became a controversial topic in 2005 after legislation was rewritten to nullify a legal battle between OneSteel and the South Australian Environmental Protection Agency; the steelworks is open to the public for guided tours which can be booked at the Whyalla Visitors Centre. The Whyalla Steelworks receives iron ore mined at various sites along the Middleback Range.
Iron ore mining in this region dates back to at least 1900. Prior to the steelworks' construction, the ore was shipped from Whyalla to Port Pirie for use as a flux in smelters, it was supplied to steel-making facilities at Port Kembla, New South Wales. The first shipment of iron ore by sea for Port Pirie departed Whyalla in 1903; the first mines to be developed were Iron Knob and Iron Monarch, with developments including Iron Baron, Iron Knight, Iron Princess, Iron Chieftain and Iron Duke. The mines were developed by the Broken Hill Proprietary Company, which went on to develop the steelworks and shipyards; the steelworks first established a plant for the production of pig-iron for sale or use at other BHP plants. The announcement was made in 1937 and South Australian legislation was prepared to facilitate the development. Water security for the project was guaranteed by the development of the Morgan-Whyalla pipeline; the Whyalla Steelworks was opened in May 1941 with the first blast furnace'blown in'.
A shipyard was constructed, designed to aid the British Commonwealth's efforts in World War II. After the war, the steelworks and shipyards continued to produce a range of products including rail track and maritime vessels for commercial use. In the 1960s, a BOS rolling mills and coke ovens were constructed, enabling the Whyalla plant to become a integrated steelworks. Various records were milestone met by the Whyalla shipyards. In 1947, Australia's largest domestically built the bulk carrier Iron Yampi, was launched, it was built for BHP Shipping to transport iron ore from Yampi Sound in Western Australia. In 1965, the honor was claimed again. With the launch of the tanker Arthur Phillip in 1974, the Whyalla shipyard passed a major milestone, having produced over one million tonnes of merchant vessels in total; the shipyard produced the world's first gas turbine-electric powered ship, the Seaway Prince in 1975. BHP's shipyards continued to operate until 1978. Many of the vessels were produced for the use of BHP Shipping.
The eventual closure of the shipyards came as a major blow to the town of Whyalla and plunged it into an economic recession, with 1,800 workers made redundant. In 1982, the steelworks employed 5,000 people. In 2011, the steelworks employed 1,600 people, down from a peak of around 6,000; the steelworks is owned by Liberty House Group, who purchased Arrium in September 2017. Arrium was known as OneSteel, was spun off from BHP in 2000; the iron-making department incorporates the blast furnace, coke ovens and the power and services departments of the Whyalla steelworks. Molten iron is supplied from here to the BOS for manufacture into steel. Coke is produced on site from coal supplied to the plant from Newcastle or Port Kembla and ships are loaded with iron ore for shipment from Whyalla's port. Finished steel products are distributed by sea and rail. Blast Furnace No.1 was built between 1938 and 1941, blown in 1941, relined in 1965, closed in 1981 and demolished 1997. Blast Furnace No.2 was built in 1965, relined 1981 and again in 2004.
The Boilerhouse was built in 1941 with 3 boilers. Boiler No. 4 was added in Nos. 5 and 6 in the late 1960s. Only Nos. 5 and 6 remain with No. 4 on standby. The Salt Water Pump House was built in 1941 with 3 salt water pumps with another 3 pumps added later. Only 5 remain, with No.1 now serving as a backup diesel pump. The Coke Ovens were built in the 1960s with 2 batteries. Another battery was added in the 1980s. A 1.5 GL reverse osmosis seawater desalination plant was commissioned in December 2011. The Broken Hill Proprietary Company was responsible for bringing electricity to the townships of Iron Knob, their associated mines and the Whyalla steelworks; this was achieved by the construction of three powerhouses and network infrastructure to reticulate the power. BHP commenced power supply to Whyalla in 1908 and Iron Knob in 1922. A second powerhouse was built in the 1920s to replace the first and was decommissioned in late 1941; the third powerhouse was built in 1941 as part of the No.1 Blast furnace.
It remains in operation. It air to the blast furnace. Compressed air is utilised around the plant by a number of other departments; the South Australian grid, run by the Electricity Trust of South Australia, was extended to Whyalla by the late 1950s. While the town's supply was progressively transferred to ETSA during the 1960s, BHP continued to supply much of its own