
If you consider
historical periods from the point of view of the materials of the tools used,
e.g. Stone Age, Bronze Age and so on, then it appears to be that we are still
living in era that should be called the Steel Age, because the majority of
modern production means and ready-made products are made of steel. The Iron Age has left us the problem
of corrosion, but this problem can be solved by means of the process called
alloying. Today we are going to talk about the history of alloy steel with
different additives.
The secrets of
ancient times
Iron alloys have
been known to mankind ever since the Ancient times, archeologists have found
iron adornments in the graves and burial sites that date back to the beginning
of the Bronze Age. The interesting fact is that pure iron was quarried and used
much later, and the first iron items were made by humans from the meteoric iron
that, according to classification, refers to steel alloy. Around 5.7% of
meteorites which fall to Earth are iron and consist of an iron-nickel alloy
that comprises 8.5% nickel. Ancient people probably used the celestial metal
for more practical purposes than adornments, but it was a very rare metal.
In about 1500 BC,
in Asia Minor, the secret of obtaining hotter flames was discovered. It was
hotter than that used for melting of cuprum and bronze. It was found out that
if you blow air through ore mixed with charcoal, the temperature will increase
considerably. The technology of bellows enabled the melting of iron and laid
the foundation of the arms race. Iron, in its pure form, is not very hard, but
during the treatment process the metal’s surface absorbs carbon and steel is
formed. The ancient tools had only thin surface layers steel, but it was enough
to make the iron-tipped spears and arrows harder and sharper than the bronze
ones.
In Isaac Asimov’s
History of Chemistry we find, “The Dorians, a barbaric Greek tribe equipped
with some iron weapons, invaded the Balkan peninsular in about 1100 BC and
gradually overcame the more civilized but only bronze-armed Mycenaean Greeks.
Some Greeks penetrated as far as Canaan and brought iron weapons with them.
These were Philistines, who played such an important role in the Old Testament.
Against them the Israelites were helpless until they obtained iron weapons for
themselves under King Saul. The Assyrian army was the first army that was fully
equipped with good iron weapons. Due to this superiority in armament, the
Assyrians conquered many neighboring countries and by 900 BC had built a mighty
empire for themselves.”
Until the New Age,
the main material for arms and labor production were iron alloys that were
found by means of accidental additives as iron ore occurs rarely in its pure
form. The famous Damascus steel is considered an exception, and its peculiarity
is the absence of alloy elements. The technology of its treatment was aimed at
burning off all the additives, so that metal would attain a unique quality.
However it would suffer from corrosion
and have a weakness as well.
For a hundred
years, the technology of iron’s treatment in Europe didn’t undergo any
substantial transformation, and only in 14th century did the method of iron
smelting appeared, as well as the so-called bloomer process, the process of
iron’s purification, i.e. getting rid of unnecessary carbon additives and
silica with manganese to obtain malleable bloomer iron. But in 18th century the
need for metal was increasing, and that is why the new methods of steel
production were researched, simultaneously studying and changing its qualities.
Blades made of famous Damascus steel.
The Recipes of New
Age
Puddling, which
replaced the bloomery process, was the first step in steel’s industrial
production. The new technology was characterized by a higher productivity rate,
as expensive and rare charcoal could be replaced by the harder coal or other
types of fuel. The reverberatory furnace for malleable iron was first used with
hard coal as a fuel by the Granage brothers in 1766. In 1784, the method was
improved by Henry Cort, who played a large role in the expansion of puddling.
By the middle of
the 19th century, a method was developed that ensured mass-production of cast
steel. A big contribution belongs to English metallurgist, Henry Bessemer (1813
– 1898). When Bessemer was working on the creation of the artillery shell that
would rotate in a flight and fly on the desired path, he faced the need to use
stronger steel than was used at that time. The talk was about weapons with the
gun’s barrel having rifling in the wall. There was a need for strong steel,
while the bore had to withstand high pressure that would be needed to press in
the expansion of the shell through its rifling. High-grade steel production was
very expensive at that time, which was why there was a need for a new type of
tool and a new approach to steel was needed.
Bessemer was
looking for a method of steel production that would allow steel to be obtained
directly from the raw iron - skipping the expensive stage of obtaining wrought
iron that was usual in the production of steel those days. In order to remove
the surplus carbon from the raw iron, he let air stream through the metal. The
metal, at the same time, was didn’t cool off or harden; on the contrary, as a
result of the carbon’s reaction with oxygen the heat increased, and the alloy’s temperature also
increased. Consequently Bessemer could obtain steel stopping the process at
exactly the right moment. In 1856, Bessemer published an article about the
conveyor. The first attempts by Bessemer to repeat the experiments were
unsuccessful, as he could obtain steel by this method only from phosphor-free
ore. But as soon as this problem was solved, the production became dramatically
cheaper.
When this main
technical barrier was overcome, the question on the steel’s added qualities by
means of alloy additives arose. The first successful experiment of directional
alloying was the invention of steel by Robert Mushet, which included 1.8%
oxygen, 9% tungsten and 2.5% manganese.
In 1871, Mushet’s industrial
production of steel began. His alloy steel was, specifically, used for the
production of the corner teeth for the metal-working machinery. Moreover, this
steel later typified the modern line of high-speed steel.
The English
metallurgist Robert Abbot Hadfield (1858-1940) studied the influence of other
metal additives on steel’s quality. It was already known that manganese
additives can make steel more brittle, so Hadfield decided to add more
manganese than other metallurgists did. When the manganese content reached 12%,
the frailty of the material decreased. Furthermore, it was found that when this
steel was heated up to 1000°С, and then quenched, it becomes harder the than initial metal. Hadfield
patented manganese steel in 1882, and from that moment the mass production of
steel alloy began.
In 1900, during the
World Exhibition, the specialists heard about Frederick Winslow Taylor’s rapid
steel for the first time. Frederick Taylor and his friend, Moncel White, who
held a degree in chemistry, had worked at the steel mill at the Bethlehem Steel
Corporation, Philadelphia, USA. Taylor and White decided to try and create an
alloy with tungsten steel and chrome. The new steel contained not less than 18%
tungsten and 4% chrome. The red-hot teeth from this steel didn’t lose their
resistance during bar treatment of other steel. The cutting speed was 4 times
quicker than usual. It was on this the basis of high-speed steel was formed.
By 1919, the
American inventor, Elwood Haynes (1857-1925) patented stainless steel, which
comprised chrome and nickel as additives. In 1916, the Japanese metallurgist,
Kotaro Honda (1870-1954) found out that magnets made from the tungsten steel
and cobalt had a stronger capacity, than those made from the ordinary steel.
This invention paved the way to the development of the stronger magnetic
alloys.
Today and tomorrow
in numbers
The 20th century
brought new methods of obtaining alloy steel, particularly, electric-arc
melting, and the development of powder metallurgy. But generally speaking, the
iron industry hasn’t changed much over the last one and half centuries and the
basic oxygen steelmaking and open furnace technology, first implemented at the
middle to end of the century before last, are still used.
21st century metals
are left as the main constructing material, while their qualities, production
and consumption efficiency has no equal in the majority of fields. About one
third of the iron produced is used in mechanical engineering, and approximately
one fourth goes into construction. Nowadays, the production ratio of iron and
basic metal consumption comprises 72 - 74% of a states’ gross domestic product.
Annually, more than 90% of steel is used of the gross mass of consumable
metals. During the economic crisis of 2008 it was recorded and confirmed in
that the traffic volume of iron production is the most important indicator of
the state of economy.
In recent years,
because of different crisis notions, the consumption of steel has been varied,
and the tendency of decrease in demand for iron is noticeable. Nowadays, 600
million tons of the world’s iron is considered as overcapacity. However, in the
next few years the forecasts of analysts are more optimistic. According to the
estimates of the WSA (World Steel Association) in 2013 the apparent consumption
of steel on a global scale will increase to 3.1% to 1.475 billion tons in
comparison to growth of the previous year of 2%. According to their forecasts,
in 2014, the global demand for steel will increase further to 3.3% and will
reach 1.523 billion tons. Hans Jürgen Kerkoff, the head of the WSA Economic
Committee, says that except China, for the last one and a half years steel
consumption in a global scale has been lower than was forecast. According to
today’s estimates, the demand for steel production in 2013 in the People’s
Republic of China will increase by 6%.
The easing of the situation is also expected in our country as well. The CIS region even received a more optimistic forecast from WSA than Europe. The growth of commercial construction activity and the set of expansionary measures in the auto industry development adopted by Russian government has influenced the growth of metal’s consumption in Russia. According to the estimates of the WSA analysts, the demand for steel in Russia will increase on 3.8% to 43.6 million tons in 2013, and in 2014 – by 4.6% to 45.6%.