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UDC 669.7.0
Ref. No.: ISO/R 190-1961 (E)
IS0
I NT ERN AT1 ON A L O RG A N I ZATl O N FOR STA N DARD IZ AT1 O N
IS0 RECOMMENDATION
R I90
TENSILE TESTING OF LIGHT METALS
AND THEIR ALLOYS
._
COPYRIGHT RESERVED
The copyright of IS0 Recommendations and IS0 Standards
IS0 Member Bodies. Reproduction of these
belongs to
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.
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BRIEF HISTORY
The IS0 Recommendation R 190, Tensile Testing of 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 1956 to
the adoption of a Draft IS0 Recommendation.
'1
This first Draft IS0 Recommendation (No. 263) was circulated to all the IS0 Member
Bodies for enquiry. As the results of this consultation were not considered satisfactory,
the Technical Committee presented a second Draft IS0 Recommendation, which was
circulated to all the Member Bodies in December 1958, and which 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
Poland
Hungary
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.
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iSO/ R 190-1961 (E)
IS0 Recommendation R 190 March 1961
TENSILE TESTING OF LIGHT METALS
AND THEIR ALLOYS
1. SCOPE
This IS0 Recommendation applies to wrought products of diameter or thickness equal to or
greater than 0.2 mm, and to castings. For the tensile testing of certain products, such as foils or
wires of small diameter, special methods are required, and for tubes special test pieces.
Methods of selection and preparation of test samples are to be the subject of a separate
Recommendation.
2. PRINCIPLE OF TEST
The test consists in subjecting a test piece to tensile stress, generally to fracture, with a view to
determining one or more of the mechanical properties enumerated below. The test is carried
out at ambient temperature, unless otherwise specified.
3. DEFINITIONS
3.1 Gauge length. At any moment during the test, the prescribed part of the cylindrical or
prismatic portion of the test piece on which elongation is measured. In particular, a dis-
tinction should be made between the following:
(a) the original gauge length (Lo). Gauge length before the test piece is strained, and
(6) the $na1 gauge length (Lu). Gauge. length after the test piece has been fractured and
the fractured parts have been carefully fitted together so that they lie in a straight line.
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k
IS0 / R 190 - 1961 (E)
3.2 Percentage permanent elongation. Variation of the gauge length of a test piece subjected to
a prescribed stress (see clause 3.7) and, after removal of the stress, expressed as a
percentage of the original gauge length. The symbol of this elongation is supplemented
by an index indicating the prescribed stress.
3.3
Percentage elongation after fracture (A). Permanent elongation of the gauge length after
fracture Lu-Lo, expressed as a percentage of the original gauge length Lo.
3.4 Percentage reduction of area (Z). Ratio of the maximum change in cross-sectional area
which has occurred during the test, So- Su, to the original cross-sectional area So, expressed
as a percentage.
3.5 Maximum load (F,,,). The highest load which the test piece withstands during the test.
3.6 Final load (Fu). Load imposed on the test piece at the moment of fracture.
3.7 Stress (actually " nominal stress "). At any moment during the test, load divided by the
original cross-sectional area of the test piece.
3.8 Tensile strength (R,). Maximum load divided by the original cross-sectional area of the
test piece, i.e. stress corresponding to the maximuin load.
3.9 Stress at specified permanent set [R,.). Stress at which, after removal of load, a specified
permanent elongation, expressed as a percentage of the original gauge length, occurs
(see Fig. 4 (a), page 7).
3.9.1 The symbol used for this stress is followed by a suffix giving the specified per-
centage of the original gauge length (frequently 0.2).
3.10 Proof stress or Yield strength (offset) * (Rp). Stress at which a non-proportional elongation,
equal to a specified percentage of the original gauge length, occurs (see Fig. 4 (b), page 7).
3.10.1 The symbol used for this stress is followed by a suffix giving the specified percentage
of the original gauge length (e.g. 0.1 or 0.2).
* This last term is used in the U.S.A. and Canada.
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lSO/ R 190-1961 (E)
4. SYMBOLS AND DESIGNATIONS
Designation
Number
Diameter of the round part of a round bar, or, with other
1
sections, diameter of the minimum circumscribing circle *
Thickness of a flat bar
2
Width of a flat bar
3
Original gauge length
4
Parallel length
5
Total length
6
Gripped ends
7
Original cross-sectional area of the gauge length
8
Final gauge length
9
Minimum cross-sectional area after testing
10
Maximum load
11
Tensile strength
12
Final load, i.e. load at moment of fracture
13
Permanent elongation after fracture
14
Percentage elongation after fracture
15
Lu -Lo x 100
LO
so - su
Percentage reduction of area ___ x 100
16
SO
Stress at specified permanent set
17
18 Specified permanent set
19 Proof stress
Specified non-proportional elongation
20
The minimum circumscribing circle is the smallest circle which completely circumscribes the whole periphery of the cross-section, but it
need not pass through more than two points.
** In correspondence and where no misunderstanding is possible, the symbols Lo and R, may be replaced by L and R respectively.
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lSO/ R 190-1981 (E)
I
I
(67
-1
Fig. 1
n
r-
Fig. 2
Nofe: The form of end of test piece as shown is intended oniy as a guide.
I
load i
1
I
11
I
I
I
I
I
I
t
. .-.-. .-.-.-.I.-
JeIongation
Fig. 3
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1
lSO/ R 190-1981 (E)
I
l
I
Stress I //--
I
I
I
I
I
.-.-.-.-
Percentage
e longot ion
Fig. 4 (b)
Fig. 4 (a)
5. TEST PIECES
5.1 Machined test pieces. The cross-section of the test piece may be circular, square, rectan-
gular or, in special cases, of other form.
5.1 .I There is a transition curve of radius sufficient to avoid stress concentration between the
gripped heads and the parallel length, and the gripped heads may be of any shape to
suit the holders of the testing machine.
5.1.2 Machined dimensions to be a standard f 0.2 mm (0.01 in) for test pieces of 10 mm
(0.5 in) or greater diameter or width and -J= 0.1 mm (0.005 in) for test pieces less than
10 mm diameter or width. The machined portion should be parallel within 0.1 mm
(0.005 in) but may be tapered from the ends to the centre within this same tolerance.
The ends of a sample should be concentric with the centre line of the reduced portion
0.25 mm (0.010 in).
within
5.1.3 As a rule, the diameter of the calibrated portion of the machined cylindrical test pieces
is not less than 4.0 mm (0.16 in).
5.2 Unmachined test pieces.
(U) Wrought. For unmachined test pieces of uniform section, e.g. bars, sections, etc., it
is recommended that the elongation should be measured on a gaug
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