'DT' portable Rockwell
Hardness Tester is developed
to meet the demands of a
light weight instrument
which can be used to carry
out by a universally
recognised method of
hardness testing.
Rockwell Method :
This hardness tester can be
used in variety of
applications and is readily
adjustable to a wide range
of sizes and shapes which
are difficult to test in a
standard table model
hardness tester.
The machione os designed for
carrying out Rockwell tests
comparable to table model
hardness tester because, the
basic things, such as shape
of penetration, measurement
and loads are same in both
systems.
The photograph on the back
side gives the general
arrangement of the hardness
tester.
The system carries a weight
bar (8) pivoted at central
point. When the load is
applied by the loading screw
(9), at one end of this
weigh bar, it is deflected
and theother end of this bar
carrying penetrator forces
down into the testspecimen.
This deflection of weight
bar which is proportional to
the applied load is
indication of the loading
dial indicator (11). Besides
this loading dial indicator,
there is one penetration
measuring indicator(14)
which masures the actual
penetration of the
penterator into the test
specimen. The hardness value
of the specimen is read
directly on this indicator.
The frame carries two
adjusting screws and gear
train. By roating the
knurled knob the distance
between the penetrator and
the support-anvil can be
adjusted.
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1) Upper
clamp
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2) Lower
clamp
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3) Support
anvil
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4)
Adjusting
screws
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5) Knurled
Knob
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6)
penetrator
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7)
Penetrator
tightening
screw
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8) Weight
bar
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9) Loading
Screw
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10) Handle
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11) Loading
dial
indicator
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12)
Indocator
seat support |
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13)
Indicator
seat
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14)
Penetration
measuring
indicator
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Method of Test
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1) Select proper penetrator
(6) depending upon the
material to be tested.
2) Take precaution so thet
the penetrator does not
project beyond the Upper
clamp(1).
For this, the loading
screw (9) should be
sufficiently taken back.
3) place the test specimen
securely on suitable
anvil(3).
4) Clamp test specimen
firmly between upper clamp
(1) and support anvil (3) by
rotating the knurled
knob (5) on the lower clamp
(2). DO NOT APPLY EXTRA
PRESSURE.
5) CHECK ZERO SETTING LOAD
INDICATOR (11). Rotate bezel
to bring pointer
over small black
dot for zero load..
6) Apply 10 kgf (98.07 N).
major load screw (9) in
clockwise direction such
that the
pointer
on the load indentor
(11) comes on set position.
7) Check zero setting of
penetrator indicator (14).
Rotate bezel to bring
pointer to ‘O’ on
the black scale.
8) For ‘C’ scale use diamond
penetrator against load of
150 kgf (1471 N) and for ‘A’
scale use same diamond
penetrator against a load of
60 kgf (588.4 N). For ‘B’
scale
use 1/16 ball penetrator
against a load of 100 kgf
(980.7 N).
9) Take off major load by
turning the loading screw in
anticlockwise direction,
such that
only minor load of 10
kgf. (98.07) remains in
action – (pointer back to
‘set’ position).
10) Hardness value in
Rockwell scale is directly
indicated on the penetrator
indicator
(14).
Read of number on black
scale is diamond penetrator.
Read off number
on red scale is ball
penetrator
11) Release load completely
by taking back the loading
screw (9).
12) Turn the knurled knob
(5) in anticlockwise
direction to loosen clamp
and thus
the test speciman. |
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Maximum
test
height
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110 mm |
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Throat
capacity
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55 mm
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1) Flat
Anvil
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1 No.
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2) 'V'
Anvil
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1 No.
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3) Test
Blocks
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2 Nos.
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4) 1/16"
Ball
penetrator
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1 No.
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