Steel making process How to make steel
Steel making. process where is the alloy iron , carbon and other metals, wherein the carbon is not more than 2.1% by weight of the composition of the alloy, typically reaching percentages between 0.2% and 0, 3%. For variety and availability of its two key elements in nature facilitating its production in industrial quantities, combine the strength steels and the possibility of being worked, which is suitable for fabrication by many methods, their properties can be handled in According to the specific needs by heat treatments, mechanical work or by alloys. Are the alloys used in the construction of machinery, tools, buildings and public works, having contributed to the high level of technological development of industrialized societies?Sheet Metal Job work In Coimbatore | Sheet Metal Components In Coimbatore CNC Sheet Metal Fabrication | Steel Fabrication In Coimbatore | CNC Turret Punch Press |
Content [hide]
1 Historical development of steel-making process
1.1 Methods
2 Development of the process technology steel
2.1 Process of making steel with Electric Arc Furnace
2.2 Phases of the manufacturing process
3 Continuous casting
4 See also
5 Sources
Historical evolution of the steel making process
Although there are no precise data on the date on which it
was discovered the technique of smelting iron ore to produce metals that can be
used, the utensils of this metal first discovered by archaeologists in Egypt
dating from 3000 BC it is also known that before that time were used iron
ornaments. Steel was known in antiquity, and perhaps could have been produced
by the method of boomer for your product; a porous mass of iron (bloom) would
contain coal. The China old under the Han Dynasty between 202 BC and 220 AD,
created steel by melting together wrought iron with cast iron, gaining the best
Intermediate product coal, steel, around the first century BC Along with its
methods Original steel forging, the Chinese also adopted the production methods
for creating Woods steel, produced in India and Sri Lanka from about the year
300 BC This early method used a wind furnace, blown by the monsoon. Also known
as Damascus steel, woods steel is famous for its durability and ability to hold
an edge. Was originally created for a different number of materials, including
traces of other elements at concentrations less than 1000 parts per million or
0.1% of the composition of the rock. It was essentially a complicated alloy
with iron as its main component. Recent studies have suggested that its
structure is included carbon annotates, which may explain some of its legendary
qualities, though given the technology available at that time were probably
produced more by chance than by design. The crucible steel based on different
techniques to produce steel alloys using slow heat and cooling pure iron and
carbon, was produced in Marv between the ninth century and the tenth century. Iron
artisans learn to make steel and wrought iron heating charcoal clay vessels for
several days, thereby enough absorbing the iron carbon steel to become true.
The harden ability characteristics conferred by their having been known to the
Middle Ages, and until 1740 there was what today is called steel.
Methods
Older methods for the manufacture of steel consisted obtain
soft iron in the furnace, with charcoal and air draft. A subsequent expulsion
of slag by hammering and soft iron carburization for cementing. The alloys
produced by the early craftsmen of iron (and, indeed, all iron alloys made
until the fourteenth century AD) would be classified today as wrought iron.
Heating learned to make steel and wrought iron charcoal clay vessels for
several days, thereby enough absorbing the iron carbon steel to become true.
After the fourteenth century increased the size of the
furnaces used for melting and increased shot to force the gas combustion by the
load or mixture of raw materials. In these larger furnaces iron ore from the
top of the furnace was reduced to metallic iron and then more carbon absorbed
as a result of the gases passed through it. The product from these furnaces was
called pig iron, an alloy which melts at a lower temperature than steel or cast
iron. The pig iron was refined later to make steel.
Then he perfected cementation steel melting pots cemented
clay and Sheffield (England) were obtained from 1740, crucible steel. Was
Benjamin Huntsman who developed a procedure for wrought iron carbon melt, thus
obtaining the first known steel?
The pig iron refining process by air jets is due to the
British inventor Henry Bessemer, who in 1855 developed the furnace or converter
that bears his name. This made possible the manufacture of steel in large
quantities, but the procedure has fallen into disuse because it could use only
that contained iron phosphorus and sulfur in small proportions.
In 1857, William Siemens devised other industrial
manufacturing process of steel, which is the one that has lasted until today: decarburization
of soft iron smelting and iron oxide.
Siemens had experienced in 1878 with electricity to heat
steel furnaces, but it was the French metallurgist Paul Harold, who started in
1902 commercial production of steel in electric furnaces, a method that was to
introduce into the furnace steel scrap of known composition blowing up an
electric arc between junk and a large carbon electrodes located on the roof of
the oven.
After World War II began experiments in several countries
with pure oxygen instead of air for steel refining processes. Success was
achieved in Austria in 1948 , when a steel mill located near the city of Linz,
Donawitz developed the basic oxygen process or LD. In 1950 he invents the
continuous casting process is used when required produce rolled steel constant
section and in large quantities.
Evolution of process technology steel
Can be synthesized by the technology of steel production has
followed an evolutionary transition from the ovens used:
Ovens small craft: (until the fourteenth century AD). Alloys
used to produce heat from a mass of iron ore and charcoal.
Altos Horns: (after the fourteenth century AD). Larger
furnaces wherein iron ore from the top is reduced to metallic iron and carbon
absorbs more as a result of the gases flowing through it. Cast iron is
obtained, which is refined to make steel. The modern furnaces operate in
combination with basic furnaces Oxygen and sometimes open-hearth furnaces,
older as part of a single steel plant. In these plants, steel furnaces are
loaded with pig iron. The molten metal from various furnaces can be blended in
a large spoon before converting it into steel in order to minimize the effect
of any possible irregularities of the furnaces.
Open Crucible Furnaces (1740). Operate at high temperatures
due to the regenerative preheating of the gaseous fuel and air used for combustion.
In the regenerative preheating the oven gases escaping posing as a series of
chambers filled with bricks, which yield most of its heat. Then the flow is
reversed through the furnace, and the fuel and air pass through the chambers
and are heated by the bricks. From the chemical point of view, is reduced by
oxidation of the carbon content of the load and remove impurities such as
silicon, phosphorus, manganese and sulfur, which combine with lime and form
slag. These reactions take place while the metal furnace is the melting
temperature, and the furnace is maintained between 1550 and 1650 ° C for
several hours until the molten metal having the desired carbon content. When
the carbon content of the cast at the desired level, the furnace is tapped through
a hole located in the rear. The molten steel flows through a short channel into
a large bucket located at ground level, below the oven. Since the bucket is
poured steel cast iron molds to form ingots. Recently, methods have been
implemented to process steel continuously without having to go through the
process of making ingots.
Bessemer furnaces (1855). It employs a high-rise oven pear
shaped, I could lean sideways for loading and dumping. By passing large amounts
of air through the molten metal, oxygen from the air is combined chemically
with impurities and removed. In the basic oxygen process, steel is also refined
in a pear-shaped furnace that can be tilted sideways. However, the air is
replaced by a stream of nearly pure oxygen at high pressure. When the oven is
loaded and placed upright, is lowered inside a spear of oxygen. Then injected
into the furnace thousands of cubic meters of oxygen at supersonic speeds.
Oxygen combines with carbon and other unwanted elements and starts a reaction
stirring rapidly burning cast iron impurities and transforms it into steel.
Electric Arc Furnaces (1902) some heat furnaces for smelting
and refining steel come from the electricity and gas combustion. As refined
conditions of these furnaces can be more tightly than those of open-hearth
furnaces and basic oxygen furnaces, electric furnaces are mostly useful for
producing stainless steel and alloy steel to be manufactured to specifications
very demanding. Refining occurs in a sealed chamber where the temperature and
other conditions are strictly controlled by automatic devices. In the early
stages of this refining process injects high purity oxygen through a lance,
increasing the oven temperature and decreases the time required to produce the
steel. The amount of oxygen entering the furnace can be precisely regulated at
all times, which prevents unwanted oxidation reactions.
Process of making steel with Electric Arc Furnace
Steelmaking electric furnace based on the melting of scrap
by means of an electric current, and subsequent refining of the molten bath.
The oven consists of a large cylindrical container plate (15-30 mm thick) lined
with refractory material forming the hearth and home to the liquid steel bath
and slag. The remainder of the furnace is formed by water cooled panels. The
vault is movable to allow the loading of the scrap through a suitable baskets.
The dome is provided with a series of holes through which the electrodes are
introduced, usually three, which are thick graphite rods up to 700 mm diameter.
The electrodes are moved so that their distance can be adjusted to the load as
they are consumed. The electrodes are connected to a transformer that provides
conditions suitable voltage and current to blow the arc, with varying
intensity, depending on the phase of operation of the furnace. Another hole in
the dome allows capturing the exhaust gases, which are conveniently purified to
avoid polluting the atmosphere. The furnace is mounted on an oscillating
structure which allows tilting to proceed with slag tapping and emptying the
bath.
Phases of the manufacturing process
Merger phase: once the scrap into the furnace and slag
forming agents and reagents (mainly lime) moves the dome to close the oven and
lower the electrodes to the proper distance, making the arcing to completely
melt the charged materials . The process is repeated until completing the
capacity of the furnace, this steel constituting a wash.
Refining step: the refining is carried out in two stages.
The first in the furnace itself and the second on a ladle furnace. In the first
composition is analyzed refining molten bath and proceed to the removal of
impurities and undesirable elements (silicon, manganese, phosphorus, etc.) And
perform a first adjustment of the chemical composition by adding ferroalloys
containing the elements (chromium, nickel, molybdenum, vanadium or titanium).
The obtained steel is poured into a ladle, refractory lined, which makes the
role of Cuba a second refining furnace which ends to adjust the steel
composition and given the right temperature for the next phase in the
manufacturing process.
Continuous casting
After the refinement, the ladle is transported to the tunic
of continuous casting which empties its contents into a tunic provided for this
purpose. A continuous casting steelmaking process in which the steel is poured
directly into a movable bottom mold, the cross section has the geometry of the
semi-product to be produced, in this case the billet. The tunic has a bottom
hole, or nozzle, which distributes the liquid steel in various casting lines,
each of which has its mold or mold, usually copper and hollow walls to allow
cooling water which serves to shape the product. During the process the mold is
moved alternately up and down in order to detach the solid crust is formed
during cooling. Then applied a cooling system controlled by cold showers first,
and then air, cutting the material in the desired lengths by moving torches
during cutting. At all times the semi finished product is continuously moving
through pinch rollers arranged to throughout the system. Finally, all billets
are identified with the reference number of the casting to which they belong,
as part of the implemented system to determine the traceability of the product,
carefully monitored squaring its section, inner healing, the absence of
external defects and length obtained.
See also
Steel
Stainless steel
Sources
Microsoft Encarta 2008 "Steel."
Microsoft Encarta 2008 "Industry."
History of Steel [1]
Cubaindustria.cu [2]
Juventud Rebelled [3]
Categories : Steel Metallurgy | Metallurgy Technology
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