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67-466: Copper rolling is the process of converting large blocks of copper into thin sheets by rolling them gradually down to size. These sheets of copper were used in the 18th and 19th centuries mainly to plate the bottoms of ships. This process of plating ship bottoms, referred to as “sheathing” or “ coppering ”, helped increase the speed and lifespan of ships. Copper was desired for this process because it reacts with seawater to create an oxide coating that prevents

134-591: A Mr. Fisher, a Liverpool shipbuilder (who did a brisk trade with West Africa) sent a letter to the Navy Board. In it he recommended "copper sheathing" as a solution to the problems of ship worm in warm tropical waters, and the effect on speed of tendrils of seaweed latching onto hulls. The letter itself does not survive and is obliquely referred to in other official correspondence held by the National Maritime Museum; it may have contained or been coincidental with

201-482: A critical new technical breakthrough of protecting the iron bolting by applying thick paper between the copper plates and the hull. This had recently been trialled successfully (probably) on HMS  Jupiter . This breakthrough was to be what would win over the Admiralty. Fisher's letter was seen by the new Navy Board Controller Charles Middleton , who had the major problem at the time with supplying over 100 ships for

268-422: A lower yield strength and a lower tensile strength . This process is also called LP annealing for lamellar pearlite in the steel industry as opposed to a process anneal , which does not specify a microstructure and only has the goal of softening the material. Often the material to be machined is annealed, and then subject to further heat treatment to achieve the final desired properties. Short cycle annealing

335-537: A metal object to deform more easily, increasing its ductility. The amount of process-initiating Gibbs free energy in a deformed metal is also reduced by the annealing process. In practice and industry, this reduction of Gibbs free energy is termed stress relief . The relief of internal stresses is a thermodynamically spontaneous process ; however, at room temperatures, it is a very slow process. The high temperatures at which annealing occurs serve to accelerate this process. The reaction that facilitates returning

402-414: A suitable temperature for an appropriate amount of time and then cooling. In annealing, atoms migrate in the crystal lattice and the number of dislocations decreases, leading to a change in ductility and hardness. As the material cools it recrystallizes. For many alloys, including carbon steel, the crystal grain size and phase composition, which ultimately determine the material properties, are dependent on

469-580: A tighter seal with the ship’s hull”, while a final pass of cold rolling improved the finish and slightly increased the strength. Eventually, Paul Revere's copper sheets would provide sheathing for more ships in the American fleet, cover the original wooden dome of the Massachusetts State House , and even be used for the boilers of one of Robert Fulton ’s early steamboats . When the Canton Viaduct

536-522: A warship. However he could refurbish the existing fleet, he grasped Fisher's solution and on 21 January 1779 wrote to the Admiralty. He also petitioned King George III directly on this "matter of the gravest importance" for the necessary funding. He took with him a model of HMS  Bellona showing a coppered bottom to illustrate the method. The King backed him for what was an expensive process for an untested technology. Each ship on average required 15 tonnes of copper applied on average as 300 plates. All

603-400: Is a heat treatment cycle that restores some of the ductility to a product being cold-worked so it can be cold-worked further without breaking. The temperature range for process annealing ranges from 260 °C (500 °F) to 760 °C (1400 °F), depending on the alloy in question. This process is mainly suited for low-carbon steel. The material is heated up to a temperature just below

670-450: Is a much more complex process and, as a beginner in this field, Revere's first copper sheets were not of the same quality as those of the British. Revere had several questions about the superior British process, but the British closely guarded their methods. Whilst Revere had a rough idea of how to roll copper, he sent his son, Joseph Warren Revere , to Britain in 1804 to try to learn more about

737-565: Is also done in forming gas , a mixture of hydrogen and nitrogen. The magnetic properties of mu-metal (Espey cores) are introduced by annealing the alloy in a hydrogen atmosphere. Typically, large ovens are used for the annealing process. The inside of the oven is large enough to place the workpiece in a position to receive maximum exposure to the circulating heated air. For high volume process annealing, gas fired conveyor furnaces are often used. For large workpieces or high quantity parts, car-bottom furnaces are used so workers can easily move

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804-440: Is performed by heating the material (generally until glowing) for a while and then slowly letting it cool to room temperature in still air. Copper , silver and brass can be either cooled slowly in air, or quickly by quenching in water. In this fashion, the metal is softened and prepared for further work such as shaping, stamping, or forming. Many other materials, including glass and plastic films , use annealing to improve

871-419: Is to originate a uniform and stable microstructure that most closely resembles the metal's phase diagram equilibrium microstructure, thus letting the metal attain relatively low levels of hardness, yield strength and ultimate strength with high plasticity and toughness. To perform a full anneal on a steel for example, steel is heated to slightly above the austenitic temperature and held for sufficient time to allow

938-408: Is used as a medium for quenching usually in the form of brine (salt water). Brine provides faster cooling rates than water. This is because when an object is quenched in water steam bubbles form on the surface of the object reducing the surface area the water is in contact with. The salt in the brine reduces the formation of steam bubbles on the object's surface, meaning there is a larger surface area of

1005-468: Is used for turning normal ferrite into malleable ferrite. It consists of heating, cooling and then heating again from 4 to 8 hours. Resistive heating can be used to efficiently anneal copper wire ; the heating system employs a controlled electrical short circuit . It can be advantageous because it does not require a temperature -regulated furnace like other methods of annealing. The process consists of two conductive pulleys ( step pulleys ), which

1072-454: Is used similarly, though with the nuance of "secured, unambiguous", rather than "trustworthy, reliable". Annealing (metallurgy) In metallurgy and materials science , annealing is a heat treatment that alters the physical and sometimes chemical properties of a material to increase its ductility and reduce its hardness , making it more workable. It involves heating a material above its recrystallization temperature, maintaining

1139-610: The Anglo-French War (1778–1783) . The Royal Navy's newly coppered ships, as yet untested, were used successfully by Rodney in defeating the French at the Battle of the Saintes off Dominica in 1782. By the time the war ended in 1783, problems with the hull bolting were once more becoming apparent. Finally, a suitable alloy for the hull bolts was found, that of copper and zinc. At great cost

1206-425: The austenite transform into bainite or martensite , but rather have it completely transform to pearlite and ferrite or cementite . This means that steels that are very hardenable (i.e. tend to form martensite under moderately low cooling rates) have to be furnace cooled. The details of the process depend on the type of metal and the precise alloy involved. In any case the result is a more ductile material but

1273-416: The Admiralty decided in 1786 to go ahead with the re-bolting of every ship in the navy, thus finally eliminating the bolt corrosion problem. This process lasted several years, after which no significant changes to the coppering system were required and metal plating remained a standard method of protecting a ship's underwater hull until the advent of modern anti-fouling paint . In the 19th century, pure copper

1340-422: The Admiralty when it was inspected by Sandwich in 1775 at Sheerness after a 5-year voyage to India. By 1786, 275 vessels (around 3% of the merchant fleet) were coppered. By 1816, this had risen to 18% of British merchant ships. Copper sheets were exported to India for use on ships built there. In the late 18th and early 19th century, around 30% of Indian ships were coppered. Merchant ship owners were attracted by

1407-552: The American Revolutionary War (1775–1783), which was compounded that same year (1778) by French opportunism in declaring war on Britain to support the American rebels. This effectively turned what was a local civil war into a global conflict. Spain followed in 1779 and the Netherlands in 1780, and so Britain had to face its three greatest rivals. Middleton took the view that Britain was "outnumbered at every station", and

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1474-463: The Navy to fund metalworkers such as Paul Revere in the hopes that American manufacturers might be able to develop copper rolling technology of their own and reduce America's reliance on Britain for the majority of its copper products, especially for industrial and military needs. Revere saw the Navy's desire for copper sheathing as an opportunity to increase both his income and social standing, so he rose to

1541-410: The Navy was required to "extricate us from present danger". He understood that coppering allowed the navy to stay at sea for much longer without the need for cleaning and repairs to the underwater hull, making it a very attractive, if expensive, proposition. He had to expand the Navy but there was no time to add to the fleet, and limited resources available. It could take five years and 2000 trees to build

1608-502: The Slave Trade Act became British law in 1807, the slave trade became illegal so slavers valued fast ships that were more likely to evade patrolling Royal Navy vessels intent on capturing them. In the late 18th to early 19th century, Sir Humphry Davy performed many experiments to determine how to lessen the corrosion that the seawater caused on unprotected copper sheathing. To this end he had various thicknesses of copper submerged on

1675-434: The build-up of barnacles , weeds, and other detritus, in addition to physically stopping shipworms from burrowing into and degrading the wood. Not only did copper sheathing help ships sail faster by keeping their hulls clean, but it also drastically increased the amount of time a ship could remain in service between overhauls. In fact, “British Navy Comptroller Charles Middleton estimated that copper sheathing might double

1742-403: The challenge presented by Stoddert. Revere began rolling copper using his established knowledge of metallurgy gained from his experience as a silversmith and in other endeavors such as bell casting, cannon casting, and the forging of copper bolts and spikes. He had already been rolling silver sheets since 1785, which had taught him the fundamental principles of rolling. However, copper rolling

1809-523: The city for 147 years—ceased in 2008. Coppering Copper sheathing is a method for protecting the hull of a wooden vessel from attack by shipworm , barnacles and other marine growth through the use of copper plates affixed to the surface of the hull, below the waterline . It was pioneered and developed by the Royal Navy during the 18th century. In antiquity, ancient Chinese used copper plates while ancient Greeks used lead plates to protect

1876-483: The cold-worked metal to its stress-free state has many reaction pathways, mostly involving the elimination of lattice vacancy gradients within the body of the metal. The creation of lattice vacancies is governed by the Arrhenius equation , and the migration/diffusion of lattice vacancies are governed by Fick's laws of diffusion. In steel, there is a decarburization mechanism that can be described as three distinct events:

1943-403: The copper and iron, lead sheathing was tried again, though it was found to be unsuitable to the task, as the plates tended to fall from the hull alarmingly quickly. By 1764, a second vessel, HMS  Dolphin , had been sheathed in copper, specifically to prepare her for a voyage of discovery in tropical waters. Dolphin ' s hull was inspected in 1768 after the ship had twice circumnavigated

2010-544: The copper was supplied by British mines (the only country in the world at that time that could do so), the largest mine being Parys Mountain in Anglesey , north Wales. The Parys mine had recently begun large-scale production and had glutted the British market with cheap copper; however, the 14 tons of metal required to copper a 74-gun third-rate ship of the line still cost £ 1,500, compared to £262 for wood. The benefits of increased speed and time at sea were deemed to justify

2077-548: The costs involved. Middleton, in May 1779, placed orders at the Portsmouth Docks for coppering all ships up to and including 32 guns when next they entered dry dock. In July, this order was expanded to include ships of 44 guns and fewer, in total 51 ships within a year. It was then decided that the entire fleet should be coppered, due to the difficulties in maintaining a mixed fleet of coppered and non-coppered ships. By 1781, 82 ships of

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2144-452: The crystal lattice, which allows these dopant atoms to function properly as dopants in the semiconducting material. Normalization is an annealing process applied to ferrous alloys to give the material a uniform fine-grained structure and to avoid excess softening in steel. It involves heating the steel to 20–50 °C above its upper critical point, soaking it for a short period at that temperature and then allowing it to cool in air. Heating

2211-670: The details of the British process. Revere purchased a mill in Canton, Massachusetts , for $ 6,000 in late 1800 to provide a dedicated copper producing facility. The mill was originally an ironworks , but Revere used a loan from the Department of the Navy to convert it into a copper foundry, completing America's first copper rolling mill. The most important pieces of equipment were the rollers themselves, which consisted of large iron cylinders through which raw copper would be inserted and compressed. While Revere admitted that Britain had superior rollers,

2278-410: The difficulty of purchasing equipment related to copper rolling forced him to produce his own. One of the many insights Revere had gleaned from his son's espionage mission was a rolling mill design with both rollers mechanically coupled and powered by the same source. This mechanism was simpler than that of many other mills. Combining these British practices with his own knowledge and experiments, Revere

2345-431: The finished properties. Annealing occurs by the diffusion of atoms within a solid material, so that the material progresses towards its equilibrium state. Heat increases the rate of diffusion by providing the energy needed to break bonds. The movement of atoms has the effect of redistributing and eradicating the dislocations in metals and (to a lesser extent) in ceramics. This alteration to existing dislocations allows

2412-550: The focus off the bolting issue necessary to allow a full-scale coppering programme. By the 1780s the technology had spread to India. The ruler of Mysore , Tipu Sultan , ordered that all his navy vessels receive copper sheathing after observing the benefits in French and East India Company ships. With the American war in full swing, the Royal Navy set about coppering the bottoms of the entire fleet in 1778. This would not have happened but for war. This also came about because in 1778

2479-408: The heating rate and cooling rate. Hot working or cold working after the annealing process alters the metal structure, so further heat treatments may be used to achieve the properties required. With knowledge of the composition and phase diagram , heat treatment can be used to adjust from harder and more brittle to softer and more ductile. In the case of ferrous metals , such as steel , annealing

2546-455: The hull of USS  Constitution . Originally, the Navy had contracted Revere to roll the sheets using a cold rolling technique, but Revere petitioned to roll them hot , with a final cold pass after they annealed . Revere was confident in his technique of mixing hot and cold rolling, claiming it gave a superior combination of flexibility and strength. Hot rolling “would make them less brittle, allows nails to pass through them easily, and form

2613-477: The internal stresses they cause. Recovery occurs at the lower temperature stage of all annealing processes and before the appearance of new strain-free grains. The grain size and shape do not change. The second stage is recrystallization , where new strain-free grains nucleate and grow to replace those deformed by internal stresses. If annealing is allowed to continue once recrystallization has completed, then grain growth (the third stage) occurs. In grain growth,

2680-484: The line had been coppered, along with fourteen 50-gun ships, 115 frigates, and 182 unrated vessels. All this was too late to avert the loss of the American colonies, however; meanwhile the French were threatening the lucrative sugar trade in the Caribbean, reckoned at the time as being of more importance to British interests than the 13 colonies . The sugar trade was paying for the costs of the American Revolutionary War and

2747-446: The lower critical temperature of steel. Cold-worked steel normally tends to possess increased hardness and decreased ductility, making it difficult to work. Process annealing tends to improve these characteristics. This is mainly carried out on cold-rolled steel like wire-drawn steel, centrifugally cast ductile iron pipe etc. A full annealing typically results in the second most ductile state a metal can assume for metal alloy. Its purpose

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2814-424: The material to fully form austenite or austenite-cementite grain structure. The material is then allowed to cool very slowly so that the equilibrium microstructure is obtained. In most cases this means the material is allowed to furnace cool (the furnace is turned off and the steel is let cool down inside) but in some cases it is air cooled. The cooling rate of the steel has to be sufficiently slow so as to not let

2881-415: The metal, the copper sheets that were connected to cast iron or zinc parts were free of any attached life forms or discoloration. Unprotected copper would quickly go from a reddish color to a greenish color of corrosion. When the other metals were mixed with copper in ratios from 1:40 to 1:150, there was no visible sign of corrosion and minimal weight loss. When the ratio was changed to 1:200 and 1:400, there

2948-456: The microstructure starts to coarsen and may cause the metal to lose a substantial part of its original strength. This can however be regained with hardening . The high temperature of annealing may result in oxidation of the metal's surface, resulting in scale. If scale must be avoided, annealing is carried out in a special atmosphere , such as with endothermic gas (a mixture of carbon monoxide , hydrogen gas , and nitrogen gas ). Annealing

3015-573: The number of ships at sea at any time”. Paul Revere's interest in copper rolling began when, after the American Revolution , the American navy wanted to begin using this process of copper sheathing the nation's ships. Benjamin Stoddert , a successful businessman and ardent Federalist , recognized the importance of a powerful Navy in preserving the economic and political independence of the new United States. Stoddert used his position as Secretary of

3082-464: The object in contact with the water, thus facilitating better conduction of heat from the object to the surrounding water. Quench hardening is generally applicable to some ferrous alloys, but not copper alloys. In the semiconductor industry, silicon wafers are annealed to repair atomic level disorder from steps like ion implantation . In the process step, dopant atoms, usually boron , phosphorus or arsenic , move into substitutional positions in

3149-503: The parts in and out. Once the annealing process is successfully completed, workpieces are sometimes left in the oven so the parts cool in a controllable way. While some workpieces are left in the oven to cool in a controlled fashion, other materials and alloys are removed from the oven. Once removed from the oven, the workpieces are often quickly cooled off in a process known as quench hardening. Typical methods of quench hardening materials involve media such as air, water, oil, or salt. Salt

3216-435: The reaction at the steel surface, the interstitial diffusion of carbon atoms and the dissolution of carbides within the steel. The three stages of the annealing process that proceed as the temperature of the material is increased are: recovery , recrystallization , and grain growth . The first stage is recovery , and it results in softening of the metal through removal of primarily linear defects called dislocations and

3283-447: The savings made possible by copper sheathing, despite the initial outlay. As the coppering was expensive, only the better owners tended to invest in the method, and as a result the use of copper sheathing tended to indicate a well-found and maintained ship, which led to Lloyd's of London charging lower insurance premiums, as the vessels were better risks. From this stems the phrase "copper-bottomed" as an indication of quality. Coppering

3350-460: The sheathing methods were the various graving and paying techniques. There were three main substances used: white stuff, which was a mixture of whale oil , rosin and brimstone ; black stuff, a mixture of tar and pitch ; and brown stuff, which was simply brimstone added to black stuff. It was common practice to coat the hull with the selected substance, then cover that with a thin outer layer of wooden planking. The use of copper sheathing

3417-477: The ship. However, it was soon discovered by the Admiralty that the copper bolts used to hold the plates to the hull had reacted with the iron bolts used in the construction of the ship, rendering many bolts nearly useless. In 1766, because of the poor condition of the iron bolts, Alarm ' s copper was removed. After this experiment, and deterred by the unanticipated and not understood galvanic reaction between

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3484-424: The shore and then measured how much the sea water had degraded each one. Sheets of different metals remained in the seawater for four months and then were examined. Two harbour ships were also used in this test, one with an additional zinc band, the other with an iron one. Davy observed, that while the zinc and iron themselves became covered in carbonate that allowed weeds, plant life and insects to attach themselves to

3551-601: The steel just above its upper critical point creates austenitic grains (much smaller than the previous ferritic grains), which during cooling, form new ferritic grains with a further refined grain size. The process produces a tougher, more ductile material, and eliminates columnar grains and dendritic segregation that sometimes occurs during casting. Normalizing improves machinability of a component and provides dimensional stability if subjected to further heat treatment processes. Process annealing, also called intermediate annealing , subcritical annealing , or in-process annealing ,

3618-473: The underwater hull. Deterioration of the hull of a wooden ship was a significant problem during the Age of Sail . Ships' hulls were under continuous attack by shipworm, barnacles and other marine growth, all of which had some adverse effect on the ship, be it structurally, in the case of the worm, or affecting speed and handling in the case of the weeds. The most common methods of dealing with these problems were through

3685-414: The use of wood, and sometimes lead , sheathing. Expendable wood sheathing effectively provided a non-structural skin to the hull for the worm to attack, and could be easily replaced in dry dock at regular intervals. However, weed grew rapidly and slowed ships. Lead sheathing, while more effective than wood in mitigating these problems, reacted badly with the iron bolts of the ships. Even older than

3752-475: The value of World War II military production contracts. By 1938, James M. Kennedy, an employee, had invented copper-clad cookware, which went into production and is now known as Revere Ware . The Detroit plant, in collaboration with DuPont, was commissioned to assist the United States Mint in the production of a new copper and copper-nickel composite coin to replace silver coins in 1964. The Detroit plant

3819-408: The wire passes across after it is drawn. The two pulleys have an electrical potential across them, which causes the wire to form a short circuit. The Joule effect causes the temperature of the wire to rise to approximately 400 °C. This temperature is affected by the rotational speed of the pulleys, the ambient temperature, and the voltage applied. Where t is the temperature of the wire, K

3886-418: The world; there was significant corrosion of the hull's iron components, which had to be replaced. In 1769 another attempt was made at coppering a ship's hull, this time on a new ship that had been constructed using bolts made from a copper alloy. The results were far more favourable this time, but still the problems with the bolting remained. The onset and intensification from 1773 of the war with America took

3953-501: Was able to ultimately develop a method to produce copper sheathing of at least equal quality to that which the British produced; in 1803, Revere wrote a letter to Joshua Humphreys discussing his copper rolling endeavor. In it, he concluded “Our sheets are as well finished and as soft & as free from scales & cannot be distinguished from English” In 1803, the Department of the Navy commissioned Revere to roll copper sheets to sheathe

4020-710: Was constructed in 1835 for the Boston and Providence Railroad mainline, a spur was added to the Revere site. Joseph Warren Revere, then owner of Revere, was a director of the Boston and Providence Railroad Corporation. Through a series of mergers in 1928 and 1929, Revere Copper became Revere Copper and Brass, Inc., headquartered in Rome, New York with the first president being George H. Allen, with several plants and product divisions. Revere Copper and Brass ranked 96th among United States corporations in

4087-462: Was first suggested by Charles Perry in 1708, though it was rejected by the Navy Board on grounds of high cost and perceived maintenance difficulties. The first experiments with copper sheathing were made in the late 1750s: the bottoms and sides of several ships' keels and false keels were sheathed with copper plates. In 1761, the experiment was expanded, and the 32-gun frigate HMS  Alarm

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4154-467: Was more commonly used on merchant ships sailing in warm waters. Ships sailing in colder, northern waters often continued to use replaceable, wooden sheathing planks. Wood-boring organisms were less of a problem for these vessels and they were often routinely careened – an operation that could cause considerable damage to expensive coppering. Coppering was widely used on slave ships . After the Abolition of

4221-475: Was ordered to have her entire bottom coppered, in response to the terrible condition in which she had returned from service in the West Indies . HMS Alarm was chosen because, in 1761, a letter had been sent regarding the ship's condition, saying that the worms from the waters had taken a significant toll on the ship’s wooden hull. Before the copper plates were applied, the hull was covered with "soft stuff", which

4288-440: Was partially superseded by Muntz metal , an alloy of 60% copper, 40% zinc and a trace of iron. Muntz metal had the advantage of being somewhat cheaper than copper. With its widespread adoption by the Royal Navy, some shipping owners employed the method on their merchant vessels. A single coppered vessel was recorded on the register of Lloyd's of London in 1777, a slaver sloop Hawke , 140 tons. This particular vessel impressed

4355-527: Was responsible for the hot rolling process of the coinage metal, according to a June 3, 2013 article in Coin World News . The composition metal used a DuPont explosive bonding process called Detaclad, patented by DuPont on June 23, 1964. The company—now employee-owned—exists as Revere Copper Products, with headquarters in Rome, New York. Revere Copper's New Bedford, Massachusetts -based operations—a presence in

4422-424: Was significant corrosion and weight loss. Davy therefore advocated cast iron for protecting copper, since it was the cheapest to manufacture, and in his observations malleable iron and zinc seemed to wear down faster. The term copper-bottomed continues to be used to describe a venture, plan or investment that is safe and is certain to be successful. The related copper-fastened (and verb form copperfasten )

4489-430: Was simply hair, yarn and brown paper. The copper performed very well, both in protecting the hull from worm invasion and in preventing weed growth for, when in contact with water, the copper produced a poisonous film, composed mainly of copper oxychloride , that deterred these marine organisms. Furthermore, as this film was slightly soluble, it gradually washed away, leaving no way in which marine life could attach itself to

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