CAST IRON
A PRELIMINARY REVIEW
AE 681
JOHN MYERS










CAST IRON DEFINITION

HISTORY OF DEVELOPMENT

USES

EXAMPLES




DEFIN ITION

Cast iron is a saturated solution of carbon in iron. The

content varies from one and a half to four percent depending on other

impurities. Cast iron is hard, brittle, non-malleable and very fluid

when melted. It is extremely suited to casting into complex forms.

Cast iron is produced in a foundry by re-melting pig iron

or pig iron and scrap in a cupola and pouring into moulds. The moulds

used are specially prepared sand formed around wooden patterns. Wood

was used for the patterns because it was easily worked, but for

frequently used patterns metal was sometimes used for durability.

Very intricate patterns wTere sometimes made of wax, wood and metal.

The characteristics of the metal castings depended on the ingredients

in the iron. The more carbon in the iron, the harder it was. Silicon

made it softer, and phosphorous and sulphur make it brittle. Sulphur

also contributes to corrosion of the iron if too much is present.

Cast iron is harder and more brittle than mild steel, and it cannot be

forged or bent. Casting can be easily filed, drilled, tapped or

machined. It requires bolted or screwed connections, for it cannot

be welded.









HISTORY OF DEVELOPMENT


The earliest examples of iron are believed to have come from

meteors and were broken or chipped of by the men who discovered the

meteor. At this point, men thought the iron was a gift from

the gods. Later the early campfires were accidental sources of

iron as the metal melted from ironstone inadvertently used to ring

the fire. When the fire had gone out and cooled, the molten iron was

found in the bottom of the campfire.

The first crude furnaces intended to produce iron were simply

improvements on the campfire. Areas would be scooped out to collect

the molten metal and the effect of blasts of air was discovered.

Sometimes holes would be left to blow in air, and sometimes the

furnace would be placed to receive natural wind currents.

The ages of development of this technology varied widely over

the world. It is estimated that the Mayan's were still neolithic

as late as 400 A.D. when most of Europe had moved from the Iron Age

to the Bronze Age.

Some examples of the state of iron use are as follows:

Egypt Evidence of iron beads was found as

early as 4000 B.C. Iron was found in the Great

Pyramid in the form of a tool dating to 3100 B.C.

An iron wedge was found with a copper adze which

dated back to 2800 B.C.

Assyria Iron bars from twelve to nineteen inches

long by about two and a half to five and a half

inches were found in the Palace of Sargon.

Iron at this time was forged into bars for trade

and ease of transportation. This was in Sweden

and Finland as late as 1900 A.D. The use of iron in












Assyria dated back to 2000 B.C.

Indo-China Weapons wore in use here between

2000 and 1000 B.C. Records show that China levied

a tax on iron in about 675 B.C. Evidence

of casting by patterns and sand moulds has

been found.

Europe It is thought that the Creeks were

the first to use iron in Europe. Homer, Vrigil,

Aristotle and Pliny wrote about the- :;e of it.

Aristotle writes about the different types

of iron and how it was smelted. The Romans

also had a good knowledge of metallurgy.

Britain Britain was famous for using iron in

chariots during the pre-Roman period. After the

Roman conquest, Britain was developed as a major

producer of iron. The Roman occupation had a

stimulating effect on British industry later

because it developed reserves of skill and

knowledge which would emerge.

The process which took place to produce iron in the I th and

16th centuries was basically to crush the iron ore and mix it

with marl and lime to hold it together. The resultant mix was

divided into lumps and surrounded by charcoal in a forge.

A bellows was used to force air over the fire until the substance











became spongy or pasty. In this state it was taken out and

hammered and reheated successively to beat out the impurities.

As might be imagined there was a great deal of waste in this

procedure and quite a low yield.

The early furnaces were built of clay several feet tall and

the ironstone and charcoal stacked in alternate layers. The

furnace was fired for several hours and then torn apart to

reveal, hopefully, the block of iron.

Better and more efficient furnaces were b.-,lt of masonry

later, but when the temperature got too hot the iron would

dissolve some of the carbon and run out the bottom of the

furnace. The molten iron was thought to be useless and it

was some time before this fluid iron came to be a desired product.

Probably the oldest piece of cast iron in Britain is the

Joan Collins grave slab which dates about 1350 A.D. (Grave slabs

were a chief product of early cast iron.) Most of the early

molten iron was cast into moulds to be refined into wrou ht iron

later, since wrought iron was the material in demand.

Ironmasters did discover the usefullness of cast iron finally,

and a patent was granted to Lord Dudly in 1621 for use by his

son, Dud Dudley, of a process using coal as a mineral fuel. The

real growth of the cast iron industry began around 1650, and in 1676

Abraham Darby was born. By the early 1700's Darby was experimenting

and finally became the first man to smelt iron ore with coke.

By the 18th century cast iron was being used for machinery





5




such as the Newcomen fire engine. In the drought of 1743, one

of the Darby's used fire engines to pump water to drive the

bellows at the ironworks. This became a study in perpetual

development iron lead to cheaper engines, which wereised to

make more iron, which was used to make cheaper engines, etc..



USES OF CAST IRON


Prior to 1750, there was very little use of cast iron in

architecture and engineering. By the end of the 1700's, however,

the were many foundress going strong to produce the material needed

by the many experimenters who came along during this period. (Some

of these foundries were in the hands of the same families as late

as twenty years ago.) Between 1750 and 1800, many experimenters

recognized the potential of cast iron and used it in bridges,

locks and gates, beams, limtels, columns, rails and decorative

elements. Some of the earliest uses were in the bridges the

English erected at Severn which still stood in the fifties.

Thomas Telford designed many bridges which uutilized the properties

of cast iron, and did not imitate other building materials such

as stone. Several examples of Telford's bridges still exist.

One of the first buildings was a mill in Manchester by Phillip

and Lee which was a model for twenty years. The decorate ve use

of cast iron created a vast demand for the material. Some early

decorative railings were used in St. Pauls and can still be seen

there.. The earliest example of columns can be seen in the










Cistercian Monastery in Portugal where the hold up the hearth hood.

Other early cast iron columns may be seen supporting the galleries

at St. Anne's in Liverpool. A well known use of cast iron as a

structural element was the Brighton Pavilion by John Nash.

In America, one of the earliest attempts to make iron

was at Falling Creek near Jamestown. Some colonists took samples

of the iron they made in America over to England and solicited

workers to return with them and open plants in New England. Two

such important plants were in Massachusetts, one at Lynn, the other

at Braintree. These works were comparable to their English

counterparts in all respects.

By 1750, American iron was cheaper than imported iron. The

bulk of production was hollow ware, but the German's in Pennsylvania

became noted for their firebacks. Production was spurred by the

Revolutionary War and American technology was on a. par with that

in England. The use of catalogs for listing products was a

big factor in increasing the demand for cast iron.

A number of slides were used in this report to illustrate

other developments and examples such as the extensive use of c'ist

iron in the architecture of New Orleans. Almost every product can

be seen in the cast iron fare of New Orleans, except for structural

cast iron. The water works was the major example of the structural

use and apart from it examples are rare.

One of the prime movers in cast iron architecture was J.mes

Bogardus. He expanded the use of cast iron into total buildings.

See Bogardus' publication, Cast Iron Buildings; Construction and










Advantages. To of the major reasons why Bogardus's buildings

were so popular were speed and economy of erection.

Though cast iron was a remarkable material for its day, and

its advantages fostered its widespread acceptance, the same rapid

technological development which made large scale production possible

was at the same time producing the new alloys and metals that would

replace it. As the 20th century arrived, cast iron as a building

material was almost entirely replaced by rolled iron steel

products which were stronger and more workable. It became possible

to produce metals which were specifically suited to the tasks

required with new processes and metallurgical knowledge.