ISO/R 147:1960

Load calibration of testing machines for tensile testing of steel

Tarage du point de vue des charges des machines utilisées pour l'essai de traction de l'acier

General Information

• Status: Withdrawn
• Publication Date: 31-Jan-1960
• Withdrawal Date: 31-Jan-1960
• ICS: 77.040.10 - Mechanical testing of metals
• Technical Committee: ISO/TC 164/SC 1 - Uniaxial testing
• Drafting Committee: ISO/TC 164/SC 1 - Uniaxial testing
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 01-Mar-1986

Relations

• Revised: ISO 7500-1:1986 - Metallic materials — Verification of static uniaxial testing machines — Part 1: Tensile testing machines
• Effective Date: 15-Apr-2008

Standards Content (Sample)

UDC 669.14:62O.l .O5 Ref. No.: IS0 I R 147 - 1960 (E)
._
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 oniy 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 147, Load Calibration of Testing Machines for Tensile
Testing of Steel, was drawn up by Technical Committee ISO/TC 17, Steel, the Secretariat
of which is held by the British Standards Institution (B.S.T.).
During a meeting held by Working Group ISO/TC 17/WG 1, Methods of Mechanical
Testing for Steel, in Paris, in May 1953, study was begun on the draft proposal concerning
this IS0 Recommendation.
The draft proposal drawn up by the Working Group was submitted to the Technical
Committee for examination during its meeting, held in Stockholm, in June 1955. As a
result of the comments put forward at that meeting, the draft proposal was referred back
to the Working Group, which modified it accordingly. The Technical Committee re-
examined this draft proposal during its plenary meeting, held in London, in March 1957. 1
At that time it was decided that the Technical Committee Secretariat would set up a new
draft proposal; this latter was submitted by correspondence to the members of the Tech-
nical Committee, which accepted it with slight changes, the draft proposal thus revised
being adopted as a Draft IS0 Recommendation.
On 11 July 1958, the Draft IS0 Recommendation (No. 206) was distributed to all the
IS0 Member Bodies and was approved, subject to small modifications, by the following
(23 out of a total of 40) Member Bodies:
Hungary Rom ani a
Austria
India Spain
Belgium
Bulgaria Israel Sweden
Burma Italy Switzerland
Chile Japan United Kingdom
New Zealand U.S.S.R.
Czechoslovakia
Denmark Norway Yugoslavia
Finland Poland
Two Member Bodies opposed the approval of the Draft: France, Germany.
The Draft IS0 Recommendation was then submitted by correspondence to the IS0
Council, which decided, in February 1960, to accept it as an IS0 RECOMMENDATION.
-2-

---------------------- Page: 2 ----------------------
iSO/ R 147 - 1960 (E)
IS0 Recommendation R 147 February 1960
LOAD CALIBRATION OF TESTING MACHINES
FOR TENSILE TESTING OF STEEL
1. SCOPE
1.1 This IS0 Recommendation applies to the load calibration of machines used for the tensile
testing of steel in accordance with IS0 Recommendation R 82, Tensile Testing of Steel.
The machine is calibrated under conditions of increasing load.
1.1.1 The following methods of load calibration are described :
(a) by means of weights (masses), see section 3, page 4
(b) by means of elastic devices (dynamometers), see section 4, page 5
(c) by means of proving levers, see section 5, page 6.
I. 2 Whatever method is used, the calibration should check both the repeatability and the
accuracy of the machine.
1 .2.1 This check involves the comparison between
the load determined by means of the calibrating device,
designated hereinafter by convention as true load (F), and
the load read on the machine being calibrated,
designated hereinafter by convention as indicated load (Fi).
2. DEFINITIONS
2.1 Repeatability
2.1.1 Repeatability for a given true load : the greatest difference observed between the indicated
loads corresponding to repeated application of the true load.
2.1.2 Repeatability for a given indicated load : The greatest difference observed between the
true loads corresponding to repeated values of the indicated load.
NOTE: The larger the difference, the worse the repeatability.
2.2 Error
2.2.1 Error for a given true load : the difference between the true load and the arithmetic mean
of readings corresponding to repeated applications of the load. It is expressed as a per-
centage of the true load.
2.2.2 Error for a given indicated load: the difference between the indicated load and the
arithmetic mean of the readings of the true loads corresponding to repeated values of
the indicated load. It is expressed as a percentage of the indicated load.

---------------------- Page: 3 ----------------------
[SO/ R 147 - 1960 (E)
3. DIRECT CALIBRATION BY MEANS OF WEIGHTS (MASSES)
3.1 As a general rule, each scale of the machine to be calibrated should be verified over the
upper four fifths of its range. For each scale, it should be verified at not less than 5 points
approximately equally spaced over that part of the scale, the lowest of the points correspond-
ing to the minimum load at which it is proposed to use the machine. These operations
constitute one series of tests.
3.1.1 If it is intended to use the machine under conditions where readings are taken in the
first fifth of the scale, verification of that portion of the scale should be made at not less
than 3 points approximately equally spaced over that portion of the scale, the lowest
of the points corresponding to the minimum load at which it is proposed to use the
machine. These operations over the whole scale then constitute one series of tests.
3.2 For each scale, at least two separate series of tests in ascending order of load should be
carried out.
3.2.1 For hydraulic machines, the positions of the ram should, if practicable, be changed for
each series.
To verify what indicated load Fi corresponds to a true load F, a scale-pan attached to the
3.3
loading shackle of the machine is so loaded that the total weight is equal to F. The weight
should be accurate to & 0.1 per cent. This tolerance may require the difference between
gravity in different places to be taken into account. The indicated load Fi, shown on the
graduated scale, is read. The operation is repeated five times, the whole or part of the load
being removed between each reading.
3.3.1 Thus, at each point, for each series of tests, the following readings are obtained:
Fil, Fi,, Fi,, Fi, and Fi5
Error is expressed as a percentage by the quantity:
Fi-F
~~ __
x 100
F
Fi, + Fi2 + Fi8 + Fi, + Fi5
-
Fi=FiFi= ~ - .-
where
5
Repeatability is determined by the difference between the highest and the lowest of the
ten values of Fi obtained in the two series of tests.
3.4 For verification described in clause 3.3, the number of tests at each point may, by agreement
between the parties concerned, be reduced, but there should be not less than three tests.
NOTE :
The following points should be noted with this method:
(a) The range of load which can be covered is limited (generally to 5 O00 kg).
(b) The transportation of large numbers of standardized weights is difficult.
(c) In some cases the application of standardized weights is difficult.
-4-

---------------------- Page: 4 ----------------------
iSO/ R 147 - 1960 (E)
4. CALIBRATION BY MEANS OF ELASTIC DEVICES PYNAMOMETERS)
4.1 This method of calibration consists in measuring the deformation due to the load on an
elastic device (dynamometer) which has been previously calibrated, and deducing the
magnitude of the true load F from the measured deformat
...