'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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