NVR
offers wide range of Spanners, forged from high grade Chrome
Vanadium Steel using the latest production methods. NVR Spanners
made to DIN, ANSI and ISO standards meets the latest
requirements of screw - joint engineering.
Shearing & Heating of Cropped Piece
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Using
highly efficient eccentric presses the blank is cut according to
the size of double open end spanner to be forged.
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Then
the blank is heated up to the exact pre-selected temperature
(1000-1200° C) in the pusher furnace before forging it to its
form.
Hot Forging & Trimming Process
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The
red hot cropped piece is pulled out of the furnace with the
help of tongs and kept under lower and upper dies to give it a
shape under tons of pressure from the blows of the drop
hammer.
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Then the trimming process is carried out to remove the surplus
steel.
The Grinding Process
Broaching Operation to Dimensional
Accuracy
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This is an important operation to produce the exact size of
the jaws.
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The
broaching tool is pressed through the forged jaw opening to
produce the exact size in case of open end wrenches and the
broaching tool is passed through the ring surface to give it
profile in case of Combination & ring Spanner.
Over Drive Broach
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With our constant R & D we have developed the new profile in
the ring wrench head.
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In
this design the force is applied to the flanks of the bolt
heads & not to the corners.
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This type is also suitable even for 50% worn rounded
fasteners.
Hardening & Tempering Process
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Hardening & tempering is done in an automatic shaker hearth
furnace in which both hardening & tempering temperature are
controlled.
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By
this process the structure of steel is made finer. The
hardness achieved in this way guarantees the high value in the
tools use, the great torque can be transferred, and service
life of our tools.
The Plating Treatment
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Different kinds of surface protection is given to wrenches by
the process of plating treatment.
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Here the tool is first degreased carefully, then nickel plated
and finally chromium plated.
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At
NVR we are proud to produce various following finishes.
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