Rockwell Hardness Testing Machines

Rockwell & Rockwell Superficial tests consists of forcing an indentor (Diamond or Ball) into the surface
of a test piece in two steps i.e. first with preliminary test force and thereafter with additional test force
and then measuring depth of indentation after removal of additional test force (Remaining preliminary
test force active) for measurement of hardness value.
Brinell test consists of forcing a hardened ball into surface of a test piece with a specified test-force and
measuring the diameter of indentation for evaluation of Brinell hardness number.
Operation :
For Rockwell & Rockwell Superficial Test :
In case of ‘RASN’ series machines for Rockwell & Rockwell superficial tests a preliminary test force in
first applied and then indicator is automatically set for zero. Quickly thereafter an additional test force
is applied without removing the preliminary test force. When the penetration is stabilised, the
additional test force is removed and the hardness number is shown directly on the indicator.
For Brinell Test :
The operation is exactly same as above. However, the diameter of impression is measured outside of
machine by Brinell microscope. Brinell hardness number is found out by referring corresponding
hardness tables showing hardness number against dia. of indentation for specified ball diameter and
test force.

ARUN’ new ‘RASN’ series of Hardness Testing Machines come with much improved design and
look with following major design changes.
1) The machine body is having a taper front look and a big size dial gauge in the front. The machine is
powder coated for far better look. The paint shade do not fade and machine looks like new over
year.
2) The elevating screw of machine is guided in a hardened and ground bush, not allowing movement
of elevating screw more than 0.05 mm when raised to full height. The accessory is returned for years
together due to hardened bush.
3) A hardened and ground stepped bush is fixed on top of main screw for location and rest surface.
This guarantees no change in results due to rough handling of test table or test piece. It means a
trouble free long life machine accuracy.
4) An antifriction linear bearing with almost no clearance is provided for a perfect vertical movement
of loading plunger with minimum friction. This enable testing of small dia. pin or ball upto 3 mm
dia.
5) All machine models are provided with automatic zero setting dial gauge or digital readout. Hence
zero setting at every test is avoided.
6) All four models confirm to respective standard as under.
IS : 3804, BS 10109-2 & ASTM E-18 for Rockwell Test.
IS : 5073, BS 10189-2 & ASTM E-18 for Rockwell Superficial Test.
IS : 2281, BS 10003-2 & ASTM E-10 for Brinell Test.