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UDC 669.131.8
IS0
I N T E RN AT1 O N A L ORGAN 1 Z AT 1 ON FOR STAN DA RD 1 ZATl O N
IS0 RECO M M EN DATI O N
t .
R 942
WHITEHEART MALLEABLE CAST IRON
1st EDITION
January 1969
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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.
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BRIEF HISTORY
The IS0 Recommendation R 942, Whiteheart malleable cast iron, was drawn up by Technical
Committee ISO/TC 25, Cast iron, the Secretariat of which is held by the British Standards Institution
(BSI).
Detailed work on this question by the Technical Committee led, in 1966, to the adoption of a
Draft IS0 Recommendation.
i
In February 1967, this Draft IS0 Recommendation (No. 1193) was circulated to all the IS0
Member Bodies for enquiry. It was approved, subject to a few modifications of an editorial nature, by
the following Member Bodies :
Argentina Germany Romania
South Africa, Rep. of
Australia Greece
Belgium India Sweden
Brazil Israel Switzerland
Thailand
Canada Korea, Rep. of
Chile Netherlands Turkey
Czechoslovakia New Zealand U.A.R.
Finland Norway United Kingdom
France Portugal Yugoslavia
One Member Body opposed the approval of the Draft :
Italy
The Draft IS0 Recommendation was then submitted by correspondence to the IS0 Council,
L
which decided, in January 1969, to accept it as an IS0 RECOMMENDATION.
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ISO/R 942-1969 (1
IS0 Recommendation R 942 January 1969
WHITEHEART MALLEABLE CAST IRON
1. SCOPE
This IS0 Recommendation refers to the characteristics of whiteheart malleable cast iron and its
classification by mechanical properties. Details are also included on testing conditions, dimensions of
test bars and sampling.
2. GENERAL
Malleable cast iron is a heat-treated iron-carbon alloy, which solidifies in the as-cast condition
2.1
with a graphite-free structure, i.e. the total carbon content at the moment of solidification is
present in the dissolved form and in the combined form as cementite (Fe,C).
2.2 Three groups of malleable cast iron are specified, differentiated by the temperature and time
cycle of the annealing process, by the annealing atmosphere and by the properties resulting
therefrom, as follows :
- whiteheart malleable cast iron (covered by this IS0 Recommendation);
- blackheart malleable cast iron (see IS0 Recommendation R 943);
- pearlitic malleable cast iron (see IS0 Recommendation R 944).
2.3 Whiteheart malleable cast iron is annealed in a decarburizing atmosphere.
3. CHARACTERISTICS OF WHITEHEART MALLEABLE CAST IROF
3.1 Fracture appearance
Surface zone : silvery-grey.
Core zone : dark-grey to black.
3.2 Microstructure
The microstructure is dependent on section size, as follows :
small section size : ferrite
...