Steelmaking process

The invention: 

Known as the basic oxygen, or L-D, process, a
method for producing steel that worked about twelve times
faster than earlier methods.

The people behind the invention:

Henry Bessemer (1813-1898), the English inventor of a process
for making steel from iron

Robert Durrer (1890-1978), a Swiss scientist who first proved
the workability of the oxygen process in a laboratory

F. A. Loosley (1891-1966), head of research and development at
Dofasco Steel in Canada

Theodor Suess (1894-1956), works manager at Voest




Ferrous Metal 

The modern industrial world is built on ferrous metal. Until
1857, ferrous metal meant cast iron and wrought iron, though a few
specialty uses of steel, especially for cutlery and swords, had existed
for centuries. In 1857, Henry Bessemer developed the first largescale
method of making steel, the Bessemer converter. By the 1880’s,
modification of his concepts (particularly the development of a ‘’basic”
process that could handle ores high in phosphor) had made
large-scale production of steel possible.
Bessemer’s invention depended on the use of ordinary air, infused
into the molten metal, to burn off excess carbon. Bessemer himself
had recognized that if it had been possible to use pure oxygen instead
of air, oxidation of the carbon would be far more efficient and rapid.
Pure oxygen was not available in Bessemer’s day, except at very high
prices, so steel producers settled for what was readily available, ordinary
air. In 1929, however, the Linde-Frakl process for separating the
oxygen in air from the other elements was discovered, and for the
first time inexpensive oxygen became available.
Nearly twenty years elapsed before the ready availability of pure
oxygen was applied to refining the method of making steel. The first
experiments were carried out in Switzerland by Robert Durrer. In
1949, he succeeded in making steel expeditiously in a laboratory setting
through the use of a blast of pure oxygen. Switzerland, however,
had no large-scale metallurgical industry, so the Swiss turned
the idea over to the Austrians, who for centuries had exploited the
large deposits of iron ore in a mountain in central Austria. Theodor
Suess, the works manager of the state-owned Austrian steel complex,
Voest, instituted some pilot projects. The results were sufficiently
favorable to induce Voest to authorize construction of production
converters. In 1952, the first ‘’heat” (as a batch of steel is
called) was “blown in,” at the Voest works in Linz. The following
year, another converter was put into production at the works in
Donauwitz. These two initial locations led to the basic oxygen process
sometimes being referred to as the L-D process.


The L-D Process


The basic oxygen, or L-D, process makes use of a converter similar
to the Bessemer converter. Unlike the Bessemer, however, the LD
converter blows pure oxygen into the molten metal from above
through a water-cooled injector known as a lance. The oxygen burns
off the excess carbon rapidly, and the molten metal can then be
poured off into ingots, which can later be reheated and formed into
the ultimately desired shape. The great advantage of the process is
the speed with which a “heat” reaches the desirable metallurgical
composition for steel, with a carbon content between 0.1 percent
and 2 percent. The basic oxygen process requires about forty minutes.
In contrast, the prevailing method of making steel, using an
open-hearth furnace (which transferred the technique from the
closed Bessemer converter to an open-burning furnace to which the
necessary additives could be introduced by hand) requires eight to
eleven hours for a “heat” or batch.
The L-D process was not without its drawbacks, however. It was
adopted by the Austrians because, by carefully calibrating the timing
and amount of oxygen introduced, they could turn their moderately
phosphoric ore into steel without further intervention. The
process required ore of a standardized metallurgical, or chemical,
content, for which the lancing had been calculated. It produced a
large amount of iron-oxide dust that polluted the surrounding at-
mosphere, and it required a lining in the converter of dolomitic
brick. The specific chemical content of the brick contributed to the
chemical mixture that produced the desired result.
The Austrians quickly realized that the process was an improvement.
In May, 1952, the patent specifications for the new process
were turned over to a new company, Brassert Oxygen Technik, or
BOT, which filed patent applications around the world. BOT embarked
on an aggressive marketing campaign, bringing potential
customers to Austria to observe the process in action. Despite BOT’s
efforts, the new process was slow to catch on, even though in 1953
BOT licensed a U.S. firm, Kaiser Engineers, to spread the process in
the United States.
Many factors serve to explain the reluctance of steel producers
around the world to adopt the new process. One of these was the
large investment most major steel producers had in their openhearth
furnaces. Another was uncertainty about the pollution factor.
Later, special pollution-control equipment would be developed
to deal with this problem. A third concern was whether the necessary
refractory liners for the new converters would be available. A
fourth was the fact that the new process could handle a load that
contained no more than 30 percent scrap, preferably less. In practice,
therefore, it would only work where a blast furnace smelting
ore was already set up.
One of the earliest firms to show serious interest in the new technology
was Dofasco, a Canadian steel producer. Between 1952 and
1954, Dofasco, pushed by its head of research and development, F.
A. Loosley, built pilot operations to test the methodology. The results
were sufficiently promising that in 1954 Dofasco built the first
basic oxygen furnace outside Austria. Dofasco had recently built its
own blast furnace, so it had ore available on site. It was able to devise
ways of dealing with the pollution problem, and it found refractory
liners that would work. It became the first North American
producer of basic oxygen steel.
Having bought the licensing rights in 1953, Kaiser Engineers was
looking for a U.S. steel producer adventuresome enough to invest in
the new technology. It found that producer in McLouth Steel, a
small steel plant in Detroit, Michigan. Kaiser Engineers supplied
much of the technical advice that enabled McLouth to build the first
U.S. basic oxygen steel facility, though McLouth also sent one of its
engineers to Europe to observe the Austrian operations. McLouth,
which had backing from General Motors, also made use of technical
descriptions in the literature.


The Specifications Question





One factor that held back adoption of basic oxygen steelmaking
was the question of specifications. Many major engineering projects
came with precise specifications detailing the type of steel to be
used and even the method of its manufacture. Until basic oxygen
steel was recognized as an acceptable form by the engineering fra-
ternity, so that job specifications included it as appropriate in specific
applications, it could not find large-scale markets. It took a
number of years for engineers to modify their specifications so that
basic oxygen steel could be used.
The next major conversion to the new steelmaking process occurred
in Japan. The Japanese had learned of the process early,
while Japanese metallurgical engineers were touring Europe in
1951. Some of them stopped off at the Voest works to look at the pilot
projects there, and they talked with the Swiss inventor, Robert
Durrer. These engineers carried knowledge of the new technique
back to Japan. In 1957 and 1958, Yawata Steel and Nippon Kokan,
the largest and third-largest steel producers in Japan, decided to implement
the basic oxygen process. An important contributor to this
decision was the Ministry of International Trade and Industry, which
brokered a licensing arrangement through Nippon Kokan, which in
turn had signed a one-time payment arrangement with BOT. The
licensing arrangement allowed other producers besides Nippon
Kokan to use the technique in Japan.
The Japanese made two important technical improvements in
the basic oxygen technology. They developed a multiholed lance for
blowing in oxygen, thus dispersing it more effectively in the molten
metal and prolonging the life of the refractory lining of the converter
vessel. They also pioneered the OG process for recovering
some of the gases produced in the converter. This procedure reduced
the pollution generated by the basic oxygen converter.
The first large American steel producer to adopt the basic oxygen
process was Jones and Laughlin, which decided to implement the
new process for several reasons. It had some of the oldest equipment
in the American steel industry, ripe for replacement. It also
had experienced significant technical difficulties at its Aliquippa
plant, difficulties it was unable to solve by modifying its openhearth
procedures. It therefore signed an agreement with Kaiser Engineers
to build some of the new converters for Aliquippa. These
converters were constructed on license from Kaiser Engineers by
Pennsylvania Engineering, with the exception of the lances, which
were imported from Voest in Austria. Subsequent lances, however,
were built in the United States. Some of Jones and Laughlin’s production
managers were sent to Dofasco for training, and technical
advisers were brought to the Aliquippa plant both from Kaiser Engineers
and from Austria.
Other European countries were somewhat slower to adopt the
new process. Amajor cause for the delay was the necessary modification
of the process to fit the high phosphoric ores available in Germany
and France. Europeans also experimented with modifications
of the basic oxygen technique by developing converters that revolved.
These converters, known as Kaldo in Sweden and Rotor in
Germany, proved in the end to have sufficient technical difficulties
that they were abandoned in favor of the standard basic oxygen
converter. The problems they had been designed to solve could be
better dealt with through modifications of the lance and through
adjustments in additives.
By the mid-1980’s, the basic oxygen process had spread throughout
the world. Neither Japan nor the European Community was
producing any steel by the older, open-hearth method. In conjunction
with the electric arc furnace, fed largely on scrap metal, the basic
oxygen process had transformed the steel industry of the world.

Impact


The basic oxygen process has significant advantages over older
procedures. It does not require additional heat, whereas the openhearth
technique calls for the infusion of nine to twelve gallons of
fuel oil to raise the temperature of the metal to the level necessary to
burn off all the excess carbon. The investment cost of the converter
is about half that of an open-hearth furnace. Fewer refractories are
required, less than half those needed in an open-hearth furnace.
Most important of all, however, a “heat” requires less than an hour,
as compared with the eight or more hours needed for a “heat” in an
open-hearth furnace.
There were some disadvantages to the basic oxygen process. Perhaps
the most important was the limited amount of scrap that could
be included in a “heat,” a maximum of 30 percent. Because the process
required at least 70 percent new ore, it could be operated most
effectively only in conjunction with a blast furnace. Counterbalancing
this last factor was the rapid development of the electric arc
furnace, which could operate with 100 percent scrap. Afirm with its
own blast furnace could, with both an oxygen converter and an electric
arc furnace, handle the available raw material.
The advantages of the basic oxygen process overrode the disadvantages.
Some other new technologies combined to produce this
effect. The most important of these was continuous casting. Because
of the short time required for a “heat,” it was possible, if a plant had
two or three converters, to synchronize output with the fill needs of
a continuous caster, thus largely canceling out some of the economic
drawbacks of the batch process. Continuous production, always
more economical, was now possible in the basic steel industry, particularly
after development of computer-controlled rolling mills.
These new technologies forced major changes in the world’s steel
industry. Labor requirements for the basic oxygen converter were
about half those for the open-hearth furnace. The high speed of the
new technology required far less manual labor but much more technical
expertise. Labor requirements were significantly reduced, producing
major social dislocations in steel-producing regions. This effect
was magnified by the fact that demand for steel dropped
sharply in the 1970’s, further reducing the need for steelworkers.
The U.S. steel industry was slower than either the Japanese or the
European to convert to the basic oxygen technique. The U.S. industry
generally operated with larger quantities, and it took a number
of years before the basic oxygen technique was adapted to converters
with an output equivalent to that of the open-hearth furnace. By
the time that had happened, world steel demand had begun to
drop. U.S. companies were less profitable, failing to generate internally
the capital needed for the major investment involved in
abandoning open-hearth furnaces for oxygen converters. Although
union contracts enabled companies to change work assignments
when new technologies were introduced, there was stiff resistance
to reducing employment of steelworkers, most of whom had lived
all their lives in one-industry towns. Finally, engineers at the steel
firms were wedded to the old methods and reluctant to change, as
were the large bureaucracies of the big U.S. steel firms.
The basic oxygen technology in steel is part of a spate of new
technical developments that have revolutionized industrial production,
drastically reducing the role of manual labor and dramatically
increasing the need for highly skilled individuals with technical ex-
pertise. Because capital costs are significantly lower than for alternative
processes, it has allowed a number of developing countries
to enter a heavy industry and compete successfully with the old industrial
giants. It has thus changed the face of the steel industry.



Henry Bessemer

Henry Bessemer was born in the small village of Charlton,
England, in 1813. His father was an early example of a technician,
specializing in steam engines, and operated a business
making metal type for printing presses. The elder Bessemer
wanted his son to attend university, but Henry preferred to
study under his father. During his apprenticeship, he learned
the properties of alloys. At seventeen he moved to London to
open his own business, which fabricated specialty metals.
Three years later the Royal Academy held an exhibition of
Bessemer’s work. His career, well begun, moved from one invention
to another until at his death in 1898 he held 114 patents.
Among them were processes for casting type and producing
graphite for pencils; methods for manufacturing glass, sugar,
bronze powder, and ships; and his best known creation, the Bessemer
converter for making steel from iron. Bessemer built his
first converter in 1855; fifteen years later Great Britain was producing
half of the world’s steel.
Bessemer’s life and career were models of early Industrial
Age industry, prosperity, and longevity. Amillionaire from patent
royalties, he retired at fifty-nine, lived another twenty-six
years, working on yet more inventions and cultivating astronomy
as a hobby, and was married for sixty-four years. Among
his many awards and honors was a knighthood, bestowed by
Queen Victoria.

See also : Assembly line; Buna rubber; Disposable razor; Laminated glass;
 Memory metal; Neoprene; Oil-well drill bit; Steelmaking Wikipedia .



Further Reading :

Restructuring of the Steel Industry in Eight Countries.

Steel Phoenix: The Fall and Rise of the U.S. Steel Industry

Secondary Steelmaking: Principles and Applications