ISO/R 191:1971

UDC 669.7.0
Ref. No. : lSO/ R 191-1961 (E)
IS0
I N T ERN AT I O N A L ORGAN IZ AT1 O N FOR STAND AR D I Z AT I O N
IS0 RECOMMENDATION
R 191
BRINELL HARDNESS TEST FOR LIGHT METALS
AND THEIR ALLOYS
1st E D IT1 O N
March 1961
\-
COPYRIGHT RESERVED
The copyright of IS0 Recommendations and IS0 Standards
belongs to IS0 Member Bodies. Reproduction of these
documents, in any country, may be authorized therefore only
by the national standards organization of that country, being
a member of ISO.
For each individual country the only valid standard is the national standard of that country.
Printed in Switzerland
Also issued in French and Russian. Copies to be obtained through the national standards organizations.

---------------------- Page: 1 ----------------------
BRIEF HISTORY
The IS0 Recommendation R 191, Brinell Hardness Test for Light Metals and their
Alloys, was drawn up by Technical Committee ISO/TC 79, Light Metals and their Alloys,
the Secretariat of which is held by the Association Française de Normalisation (AFNOR).
Work on this question by the Technical Committee began in 1955 and led in 1958 to
the adoption of a Draft IS0 Recommendation.
In December 1958, this Draft IS0 Recommendation (No. 264) was circulated to all
the IS0 Member Bodies for enquiry. It was approved by the following Member Bodies:
Austria India Portugal
Brazil Ireland Spain
Burma Israel Sweden
Canada Italy Switzerland
Finland Japan United Kingdom
France Netherlands U.S.S.R.
Germany New Zealand Yugoslavia
Hungary
Poland
Two Member Bodies opposed the approval of the Draft :
Belgium Romania
The Draft IS0 Recommendation was then submitted by correspondence to the IS0
<- Council, which decided, in March 1961, to accept it as an IS0 RECOMMENDATION.
-3-

---------------------- Page: 2 ----------------------
IS0 / R 191 - 1981 (E)
IS0 Recommendation R 191 March 1961
BRINELL HARDNESS TEST FOR LIGHT METALS
AND THEIR ALLOYS
1. PRINCIPLE OF TEST
The test consists in forcing a steel ball of diameter D, under a load F, into the test piece, and
measuring the diameter d of the indentation left in the surface after removal of the load.
The Brinell hardness HB is the ratio of the test load F (expressed in kilogrammes-force) to
the curved surface area of the indentation (expressed in square millimetres) which is assumed to
be spherical and of diameter D.
2. SYMBOLS AND DESIGNATIONS
Designation
I
1 D Diameter of the ball, in millimetres
2 F Test load, in kilogrammes-force
Diameter of indentation, in millimetres
3 d
4 HB Brinell hardness
test load
- -
surface area of indentation
2F
- -
x D (D - D2 - d2 1
5 h Depth of indentation, in millimetres
Nom
The Brinell hardness is denoted by the symbol HB supplemented by an index indicating the test conditions in the
following order:
diameter of ball,
load,
duration of loading.
Example: HB 5/250/30 = Brinell hardness
measured with a ball of 5 mm diameter and
with a load of 250 kgf applied for 30 s.

---------------------- Page: 3 ----------------------
I
IS0 / R 191 - 1961 (E)
3. TESTING EQUIPMENT
3.1 The nominal diameter of the ball should be not less than 1 mm, unless otherwise specified.
A 10 mm ball is preferred, when the thickness of the test piece permits. No diameter of
the ball should differ from the nominal diameter by more than the following:
Diameter of ball
Millimetres
I
from 1 to 3 & 0.003 5
over 3 to 6 f 0.004
over 6 to 10 k 0.004 5
3.2
The ball is of hardened steel** with a hardness of at least 850 HV (taking into account
the curvature of the ball, when testing); it should be polished and free from surface
defects. Any ball showing any deformation after the test greater than the tolerance
specified under clause 3.1 above, or any surface defect, should be rejected, and the
corresponding test discarded.
4. TEST REQUIREMENTS
The test is carried out at ambient temperature, unless otherwise specified.
4.1
4.2 The ball is placed against the surface of th
...