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First we receive the raw material and
send all the samples to laboratory where our Quality
Control In-charge check the quality of material as
per IS or requirement. We basically recycle the
steel. All kinds of steel scrap like Turning,
Boring, Pig Iron, and Sponge Iron etc.
Scrap Yard:
Over here we segregate all
the scrap according to their density. Also we need
to carry out cutting, bundling of scrap so as to
make it comfortable to efficient charging. All these
segregated, processed scrap and sponge iron, pig
iron etc. are stocked at the scrap yard. Other Ferro
Alloys like Ferro Silicon, Silico Manganese,
Aluminum etc. are kept in store. Samples of all the
raw materials are sent to the laboratory where they
check and approve the quality of the material as
per; ISI standards.
Using electro magnet and EOT Cranes
(Electronically Operated Overhead Crane), this scrap
is charged into the Induction Furnace. In the
crucible this scrap gets heated due to the Induction
and Inductance. The Induction gets generated because
of power supplied to the copper, which is surrounded
to the crucible (Fleming Right Hand Thumb Rule). The
heat so generated is then transfer the steel scrap
into liquid metal. We take one bath sample from the
furnace when the furnace is 1/3 full. The sample is
sent to laboratory for chemical analysis where our
quality person checks c%, Mn%, S% and P% of the
sample. These testing are carried out 3-4 times at
different level of Molten Metal in the furnace.
According to laboratory report we take corrective
action and change scrap & sponge iron. Afterwards
when the furnace is full, we take one another sample
and send it to laboratory for testing. As per the
laboratory report we have done final addition of
Ferro alloys as per requirement of ISI standard and
refining of metal. Then at a temperature of 1600
degree C to 1650 degree C the liquid metal is
transferred to the refractory lined Ladle and liquid
metal is then poured to continuous casting machine
where we make billet and final sample is sent to
laboratory where we check the C%, Mn%, S% and P% by
Spectrometer and then billet is dispatched.
Testing Procedure
CARBON –
Combustion Method:
In this process carbon checked by
combustion at 1000 degree C to 1200 degree C in a
stream of purified oxygen yields carbon dioxide
which is absorbed by an alkali impregnated absorbent
in Stroh lien Apparatus and calculated by difference
of level. Temperature of combustion and state of
division of the sample are important.
MANGANESE –
Volumetric Method: Ammonium
Persulphate in the presence of Silver Nitrate
dissolves the sample in diluted Nitric Acid and
Manganese Oxidized. After precipitation of Silver
Chloride, the cold solution containing Permanganic
Acid is titrated immediately with Sodium Arsenate.
PHOSPHORUS
- Volumetric
Method: The sample is dissolved in
diluted Nitric Acid and after oxidation of
carbonaceous matter phosphorus is precipitated as
the yellow phosphomolybatate complex. The
precipitate is collected and washed and the
determination is completed volumetrically by
titration with standard alkali and acid solutions.
SILICON
–
Gravimetric Method: A solution of the
sample in hydrochloric acid is evaporated to dryness
and baked. The residue is extracted in hydrochloric
acid and the insoluble silicon residue is collected
by filtration, ignite and weighed as SiO2.
SULPHUR –
Combustion
Method: The sample is ignited in a rapid
stream of oxygen at 1300 degree and sulphur is
converted to its oxides, which are driven forward in
the gas stream and absorbed in hydrogen peroxide and
titrated with sodium hydroxide.
SECTION WEIGHT:
Take one-meter random
sample and weigh by electronic balance for
weight/meter.
Ultimate Strength, Yield Strength
and Elongation:
Mark the gauge length on sample and set in the jaw
of Universal Tensile Strength Machine. When we start
the machine and increase the load and sample
stretched due to load. After certain load the meter
reading stop for a while. This is Yield Load Point
and afterwards when increase the load, sample get
broken. This is Ultimate Load Point. We calculate
the Yield Strength and Ultimate Tensile Strength
with respect of load and area of bar.
For elongation
we measure the increased gauge length and calculate
the elongation % with respect to original gauge
length.
SPONGE IRON
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1) |
Determination of Total
Iron. Fe (T)
Take 0.2 gm. sample in 500 ml. Conical
Flask.
Add 50 ml. Con. HCL. And boil it until it
dissolve.
Add few drops of (Sncl2) in hot condition
and ensure that color disappears.
Immediately cool the flask externally in
water and add 25 ml. Hgcl2 5% solution
ensure the silky white appearance in the
flask.
Add 20 ml. Acid Mixture and dilute the
solution to 250 ml. with distilled water.
Add 3-4 drops of B.D.S. Indicator.
Titrate against with 0.1 N K2Cr207 solution.
Calculation
Fe(T) Vol. Of K2Cr207 consumed X N X
5.585
Wt. of sample. |
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2) |
Determination of Metallic
Iron Fe(M)
Take 0.2 gm. In 250 ml. Beaker.
Add 3 gm. Hgcl2 and 100-ml. hot distilled
water.
Cover the Beaker with water glass and boil
for 10 min.
Cool and filter it in 500 ml. Conical Flask;
wash the residue with hot water thoroughly.
Add 20 ml. acid mixture in filtrate
Add 3-4 drops of the B.D.S. Indicator.
Titrate against 0.1 N K2Cr207 solution.
Fe (M) %
Vol. Of K2Cr207 consumed X
N X 5.585
Wt. of sample. |
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3) |
Determination of Ferrous
Oxide Fe O
Take 0.2 gm. sample in 500 ml. Conical
Flask.
Add 2 gm. Of Na2Co3 solid + 4 drops of HF +
20 ml. Con. Hcl +
20 ml (H3Po4) + 30 ml. distilled water.
Put in two-way tube and heat for 2 min.
Cool in atmospheric temperature.
Add 3-4 drops of B.D.S. Indicator.
Titrate against 0.1 N K2Cr207 solution.
X %
Vol. Of K2Cr207 consumed X
N X 5.585
Wt. of sample.
Fe O % X % - Fe (M) % X 1.286
Where 1.286 = Fe O (M.W.) / Fe (M.W.)
= 7185 / 5585
= 1.28648 |
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4) |
Degree of Metallization.
Degree of MZ % = Metallic Iron [Fe (M) /
Total Iron] X 100 |
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