Cannon cast-iron

The first of these reactions takes place at temperatures of about 150°C, the second reaction proceeds at about 550—660°C. Typical furnaces used to carry out the reaction include cast-iron retorts the Mannheim mechanical furnace, which consists of an enclosed stationary circular muffle having a concave bottom pan and a domed cover and the Laury furnace, which employs a horizontal two-chambered rotating cylinder for the reaction vessel. The most recent design is the Cannon fluid-bed reactor in which the sulfuric acid vapor is injected with the combustion gases into a fluidized bed of salts. The Mannaheim furnace has also been used with potassium chloride as the feed. 

The problem was that cannon were then made with cast iron, a form of iron that contains relatively large amounts of carbon. Cast iron is very hard, but it breaks very easily. The only substitute available for cast iron at the time was wrought iron, which is nearly pure iron. Wrought iron, however, was not suitable for making cannon (or almost anything else) because it was too soft. 

Before Capt- Rodman cast his 450-pounder cannon, illustrated on page 305 of our last volume, he made a series of experiments to determine not only the best kind of iron to be used in the casting, but also the proper form for the mammoth ordnance. The extent and variety of knowledge made available in determining the form of ibis simple mass of cast-iron, maybe judged by the following list of only a small part of the subjects Bscussed in Capt. Rodman s report ... 

Brass guns are said to have been made for the Sheriff of Northumberland in 1385 but guns of this alloy soon proved too weak and were superseded by wrought-iron and cast-iron cannon (pp. 274, 2,77). ... 

In 1822 some cast iron cannon were fished up off Holyheadf they had belonged to a pirate vessel sunk there a century or so earlier and had oxidised through their whole mass. When raised from the water they were quite soft and could be cut with a knife. On exposure to air they hardened and were used along with other truly metal ones to fire salutes when King George iv passed through Holyhead somewhat later ett route for Dublin. It was noticed that these old cannon made more noise than any others when fired it was a marvel they didn t burst. 

Dudley took a prominent part in the Civil War as a Royalist and in 1642 he was busy making cast iron cannon at his foundries for use by the King s troops. He died in 1684 at the ripe age of 85, and in the church of St Helen s at Worcester a large monument was erected on the South Wall to his memory. 

The consumption of cast iron rose considerably with the frequency of wars and the mechanization of the armies. It is said that during the Thirty Years War the Cathohc army under Tilly sent about 15 000 cannon balls of cast iron every day into Magdeburg at the siege of this town in 1631. Iron cannons were cast directly from the blast furnace. These pieces were inexpensive - compared to bronze cannons - but very heavy. They were not used for light field artillery but for permanent installations in forts and on ships. 

Although the French naval architecture and shipbuilding was usually superior to the British during the eighteenth century, their cast iron naval cannons were generally less reliable than those used by the British and the bursting of the French cannons was influential in the 1805 battle of Trafalgar. 

At that time and well into the 1900 s, Stockholm had no sewage treatment and the ship was gradually covered and buried in dirt and silt from the raw sewage outlet. As a result, very little oxygen had access to the ship. The oak wood did not decay very much, the iron metal rusted away, but the cannons, cast from brass, remained virtually unchanged. The Stockholm water is brackish and no wood shipworms can live there. The Vasa shipwreck was located in 1956 and was raised to... 

Kahn visited an iron works at Trois Rivieres, between Quebec and Montreal, on the St. Lawrence River. The ore is got, said he, two French miles and a half from the iron works and is carried thither on sledges.. . . This iron work was first founded in 1737 by private persons who afterwards ceded it to the king they cast cannon and mortars here of different sizes, iron stoves which are used all over Canada, kettles, etc.. . . They have likewise tried to make steel here, but cannot bring it to any great perfection. . . (187). 

Accdg to Greener (Ref 7, p 22), the earliest cast cannons made of copper and tin were produced by a founder named Aran at Augsburg, Germany. They were primitive breech-loaders, built up of iron strips surrounded by iron rings — a method which continued for several centuries (See illustrations on p 22 of Ref 7)... 

Gas Cannons. The first cannons were small, crudely made cast metal pots shaped like a vase which fired iron darts. The invention of gun powder about the middle of the 13th century made possible the use of cannon to throw projectiles by use of expanding gas. 

The general process with iron cannon is very similar. In all such large castings a laige head or sprue must be allowed to maintain a pressure adequate to produce a suffleient solidification at the breech, where the metal should be strongest. 

Guu-met al. A bronze Iron) which cannon iniiy be cast. tiiiUnarily 9 jKirts copjKT and 1 tin. Other niutids have. 1)een sonictiiiies added or substituted foi the till copfier still temaining the l>asis of the alloy,... 

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