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Manufaturing Process C.R Strips: |
Process
includes judicious selection of H.R. Coils that
are sourced from the best steel producers in the
country/imports, cold reduction to develop desired
mechanical properties & crystallographic orientation
subsequent to annealing & skin pass.
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Product
Testing & Quality Assurance
Quality in Surya Roshni is above everything else. The
accent on quality commences with raw material selection
and evaluation for various end products by thorough
testing of metallurgical and physical properties. They
are followed by strict quality checks at different stages
of production processes to ensure that the finished
CR Steel strips meet the required specifications.
The quality department is fully equipped to carry out
variety of tests required.
1. Rockwell Hardness Tester and Vickers Hardness Tester
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2. Universal Tensile Testing machine.
3. Erichsen Cupping Tester.
4. Fully equipped quality laboratory has, amongst others,
the following facilities;
* YS/TS automatic testing machine
Pickling
In the semi continuous picking
line the surface oxide layers of H.R.coils are
removed by the action of warm Hydrochloric Acid
which is subsequently rinsed by cold & hot
water such that pickled.H.R.coils does not carry
any acid & neither under or over pickled.
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Cold Rolling
Process comprises reducing
thickness of H.R.Coils to desired thickness in
several passes(According to a set pass schedule),
Major parameters critical to quality, are thickness,
shape & surface. |
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Annealing
Steel after cold rolling
become extremely hard and cannot be used because
of loss of ductility. In order to restore ductility
and formability, cold rolled coils are annealed
in protective atmosphere to attain desired grain
size and orientation.
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Skin Passing
Purpose of skin passing is four fold
• Suppression of yields point phenomenon
• Attainment of flatness in annealed product
• Improvement of mechanical properties
• Imparting bright or matt finish to material
as desired by customer
In addition to this semi processed electrical steels
are given about 7-8% critical reduction so as to
improve their magnetic properties after decarb annealing
(process carried out by customer) |
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Slitting and
Shearing
After skin passing, the coils are slit to the required
width by precision slitting machine.
The coils are further sheared to the desired length
by use of cut to length facility. The coils/sheets
are thus supplied to the exact dimensional requirements
for each end users to improve the yield of cold
rolled steel coils/sheets. |
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Oiling and
Packing
The coils are provided with uniform coating of special
rust preventive oil to guard against rusting, atmospheric
corrosion and to allow storage for long duration.
The oil coating can be easily removed by normal
degreasing.
Generally coils/sheets are securely packed in
bituminized polythene lined hessian and tied with
steel straps to avoid any damage during handling
and storage. Special types can also be provided,
such as metal envelope, sheets packed with a wooden
skid etc.
All finished products are tested for various quality
parameters like hardness, tensile strength, elogation,
Erichsen value. Only those products that meet
the required specifications are dispatched to
customers with proper packing in polythene and
Hessian cloth wrapping/wooden pallets after applying
rust preventive oil.
The coil number and other details are marked clearly
with stickers on the coil. |
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