ISO 1083:2018

INTERNATIONAL ISO
STANDARD 1083
Fourth edition
2018-04
Spheroidal graphite cast irons —
Classification
Fontes à graphite sphéroïdal — Classification
Reference number
ISO 1083:2018(E)
©
ISO 2018

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ISO 1083:2018(E)

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ISO 1083:2018(E)

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Designation . 2
5 Order information . 3
6 Manufacture . 3
7 Requirements . 3
7.1 General . 3
7.2 Ferritic to pearlitic spheroidal graphite cast irons . 3
7.2.1 Test pieces machined from cast samples . 3
7.2.2 Test pieces machined from samples cut from a casting . 5
7.2.3 Classification by hardness . 6
7.2.4 Graphite structure . 6
7.2.5 Matrix structure. 6
7.3 Solid solution strengthened ferritic spheroidal graphite cast irons . 6
7.3.1 Test pieces machined from cast samples . 6
7.3.2 Test pieces machined from samples cut from a casting . 6
7.3.3 Classification by hardness . 7
7.3.4 Graphite structure . 7
7.3.5 Matrix structure. 7
8 Sampling . 7
8.1 General . 7
8.2 Cast samples . 8
8.2.1 Size of cast samples . 8
8.2.2 Frequency and number of tests . 8
8.2.3 Separately cast samples . 8
8.2.4 Side-by-side cast samples . 9
8.2.5 Cast-on samples . 9
8.2.6 Test pieces machined from cast samples . 9
8.3 Samples cut from a casting .14
8.4 Formation of test units and number of tests .14
8.4.1 Examples of test units .14
8.4.2 Number of tests per test unit .14
9 Test methods .14
9.1 Tensile test .14
9.2 Impact test .15
9.3 Hardness test .15
9.4 Graphite structure examination .16
10 Retests .17
10.1 Need for retests .17
10.2 Test validity .17
10.3 Non-conforming test results .17
10.4 Heat treatment of samples and castings .17
Annex A (informative) Additional information on solid solution strengthened ferritic
spheroidal graphite cast irons .18
Annex B (normative) Relationship between the elongation values obtained when using test
pieces with L = 5 × d and L = 4 × d .21
o o
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ISO 1083:2018(E)

Annex C (informative) Fracture mechanical approach to spheroidal graphite cast irons .22
Annex D (informative) Guidance values for mechanical properties measured on test pieces
machined from samples cut from the castings .24
Annex E (informative) Classification as a function of hardness .26
Annex F (informative) Nodularity .29
Annex G (informative) Additional information on mechanical and physical properties .30
Annex H (informative) Sectioning procedure for cast samples .34
Annex I (informative) Cross-references of grade designations from this document to other
standard grades of spheroidal graphite cast irons .35
Bibliography .36
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ISO 1083:2018(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: www .iso .org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 25, Cast irons and pig irons.
This fourth edition cancels and replaces the third edition (ISO 1083:2004), which has been technically
revised with the following changes:
— solid-solution strengthened ferritic spheroidal graphite cast irons grades have been added;
— side-by-side cast samples have been added;
— several definitions have been added;
— the relation between mechanical properties and wall thickness has been added;
— figures for separately cast or side-by-side cast samples have been updated;
— the tensile test piece figure has been updated and the Charpy V-notched impact test piece figure has
been removed;
— Annex A has been partially reworded;
— Annex C has been entirely reworded;
— Annex D has been developed;
— Annex E has become informative;
— Annex G has been developed;
— Annex H has been added.
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ISO 1083:2018(E)

Introduction
The properties of spheroidal graphite cast irons depend on their structure.
Spheroidal graphite cast irons covered by this document are divided into two groups:
a) ferritic to pearlitic spheroidal graphite cast irons;
b) solid-solution strengthened ferritic spheroidal graphite cast irons.
The mechanical properties of the material can be evaluated on machined test pieces prepared from the
following:
— separately cast samples;
— side-by-side cast samples;
— cast-on samples;
— samples cut from a casting.
The material grade is defined by mechanical properties measured on machined test pieces prepared
from cast samples.
If hardness is a requirement of the purchaser as being important for the application, then Annex E
provides means for its determination.
It is well known that tensile properties and hardness of spheroidal graphite cast irons are interrelated.
When considered by the purchaser as being important for the application, both tensile and hardness
properties may be specified.
Some material grades can be suitable for pressure applications.
Further technical data on spheroidal graphite cast irons is given in Annexes C and G.
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INTERNATIONAL STANDARD ISO 1083:2018(E)
Spheroidal graphite cast irons — Classification
1 Scope
This document defines the grades and the corresponding requirements for spheroidal graphite cast irons.
This document specifies two groups of spheroidal graphite cast iron grades by a classification based on
mechanical properties measured on machined test pieces prepared from cast samples. The first group
deals mainly with ferritic to pearlitic grades. The second group deals with solid-solution strengthened
ferritic grades.
This document also gives an informative classification as a function of hardness.
This document does not apply to the following:
— spheroidal graphite cast irons used for pipes, fittings and accessories which are specified in
accordance with ISO 2531 and ISO 7186;
— highly alloyed (austenitic) spheroidal cast irons which are specified in accordance with ISO 2892;
— ausferritic cast irons which are specified in accordance with ISO 17804.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 148-1, Metallic materials — Charpy pendulum impact test — Part 1: Test method
ISO 945-1, Microstructure of cast irons — Part 1: Graphite classification by visual analysis
ISO 6506-1, Metallic materials — Brinell hardness test — Part 1: Test method
ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
ISO/TR 15931, Designation system for cast irons and pig irons
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http: //www .electropedia .org/
— ISO Online browsing platform: available at http: //www .iso .org/obp
3.1
spheroidal graphite cast iron
cast material, iron, carbon and silicon-based, the carbon being present mainly in the form of spheroidal
graphite particles
Note 1 to entry: Spheroidal graphite cast iron is also known as ductile iron, and less commonly as nodular iron.
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ISO 1083:2018(E)

3.2
ferritic to pearlitic spheroidal graphite cast iron
spheroidal graphite cast iron (3.1) with a matrix containing ferrite or pearlite or a combination of both
Note 1 to entry: Pearlite can be partially or totally replaced by quenched microstructures in grades having higher
strength.
3.3
solid-solution strengthened ferritic spheroidal graphite cast iron
spheroidal graphite cast iron (3.1) with a matrix mainly consisting of ferrite, solution strengthened by
increasing the amount of silicon compared to ferritic to pearlitic spheroidal graphite cast iron (3.2)
3.4
graphite spheroidizing treatment
process that brings the liquid iron into contact with a substance to produce graphite in the
predominantly spheroidal (nodular) form during solidification
Note 1 to entry: This process is often followed by a second process called inoculation.
3.5
cast sample
quantity of material cast to represent the cast material, including separately cast sample (3.6), side-by-
side cast sample (3.7) and cast-on sample (3.8)
3.6
separately cast sample
sample cast in a separate sand mould under representative manufacturing conditions and material grade
3.7
side-by-side cast sample
sample cast in the mould alongside the casting, with a joint running system
3.8
cast-on sample
sample attached directly to the casting
3.9
sample cut from a casting
sample obtained directly from the casting
3.10
relevant wall thickness
section of the casting, agreed between the manufacturer and the purchaser, to which the determined
mechanical properties shall apply
3.11
test unit
number of pieces or the tonnage of castings to be accepted or rejected together, on the basis of the tests
carried out on test pieces in accordance with the requirements of the relevant specification, material
standard or order
Note 1 to entry: This term is sometimes referred to as “inspection lot” or “test batch”.
[SOURCE: EN 1559-1:2011, 3.12]
4 Designation
The material shall be designated in accordance with ISO/TR 15931. The relevant designations are given
in Tables 1 to 3.
NOTE Further information on designation is given in Annex I.
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ISO 1083:2018(E)

5 Order information
The following information shall be supplied by the purchaser:
a) the complete designation of the material;
b) any special requirements (including the relevant wall thickness, where necessary) that shall be
agreed upon between the manufacturer and the purchaser by the time of acceptance of the order;
c) the number of this document, i.e. ISO 1083.
6 Manufacture
The method of producing spheroidal graphite cast irons and their chemical composition shall be left to
the discretion of the manufacturer who shall ensure that the requirements of this document are met for
the material grade specified in the order.
For ferritic to pearlitic cast iron grades, the level of the mechanical properties is determined by the
ferrite to pearlite ratio. The ferrite to pearlite ratio is normally adjusted by alloying or, less commonly,
by heat treatment.
For solid-solution strengthened cast iron grades, the level of the mechanical properties is determined
by the extent of solid solution strengthening of the ferritic matrix. Solid-solution strengthening is
normally governed by the silicon content.
For spheroidal graphite cast irons to be used in special applications, the chemical composition and heat
treatment may be the subject of an agreement between the manufacturer and the purchaser.
All agreements between the manufacturer and the purchaser shall be made by the time of the
acceptance of the order.
7 Requirements
7.1 General
The property values apply to spheroidal graphite cast irons cast in sand moulds or moulds of comparable
thermal behaviour. Subject to amendments to be agreed upon in the order, they can apply to castings
obtained by alternative methods.
The material designation is based on the minimum mechanical properties obtained in cast samples
with a thickness or diameter of 25 mm. The designation is irrespective of the type of cast sample.
Mechanical properties are wall thickness dependant as shown in Tables 1, 2 and 3.
For relevant wall thicknesses greater than 200 mm, the manufacturer and the purchaser shall agree
on the minimum mechanical properties, the type and size of the cast sample, and microstructure
requirements.
NOTE Tensile testing requires sound test pieces in order to guarantee pure uni-axial stress during the test.
7.2 Ferritic to pearlitic spheroidal graphite cast irons
7.2.1 Test pieces machined from cast samples
7.2.1.1 Tensile properties
The mechanical properties of ferritic to pearlitic spheroidal graphite cast iron test pieces shall be as
specified in Table 1.
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ISO 1083:2018(E)

Table 1 — Mechanical properties measured on test pieces machined from cast samples for
ferritic to pearlitic grades
Material designation Relevant wall 0,2 % proof strength Tensile strength Elongation after
thickness R  fracture
p0,2
t MPa R A
m
mm min. MPa %
min. min.
t ≤ 30 220 350 22
a
ISO1083/JS/350-22-LT 30 < t ≤ 60 210 330 18
60 < t ≤ 200 200 320 15
t ≤ 30 220 350 22
b
ISO1083/JS/350-22-RT 30 < t ≤ 60 220 330 18
60 < t ≤ 200 210 320 15
t ≤ 30 220 350 22
ISO1083/JS/350-22 30 < t ≤ 60 220 330 18
60 < t ≤ 200 210 320 15
t ≤ 30 240 400 18
a
ISO1083/JS/400-18-LT 30 < t ≤ 60 230 380 15
60 < t ≤200 220 360 12
t ≤ 30 250 400 18
b
ISO1083/JS/400-18-RT 30 < t ≤ 60 250 390 15
60 < t ≤ 200 240 370 12
t ≤ 30 250 400 18
ISO1083/JS/400-18 30 < t ≤ 60 250 390 15
60 < t ≤ 200 240 370 12
t ≤ 30 250 400 15
ISO1083/JS/400-15 30 < t ≤ 60 250 390 14
60 < t ≤ 200 240 370 11
t ≤ 30 310 450 10
ISO1083/JS/450-10 30 < t ≤ 60
to be agreed upon between the manufacturer and the purchaser
60 < t ≤ 200
t ≤ 30 320 500 7
ISO1083/JS/500-7 30 < t ≤ 60 300 450 7
60 < t ≤ 200 290 420 5
t ≤ 30 350 550 5
ISO1083/JS/550-5 30 < t ≤ 60 330 520 4
60 < t ≤ 200 320 500 3
t ≤ 30 370 600 3
ISO1083/JS/600-3 30 < t ≤ 60 360 600 2
60 < t ≤ 200 340 550 1
t ≤ 30 420 700 2
ISO1083/JS/700-2 30 < t ≤ 60 400 700 2
60 < t ≤ 200 380 650 1
t ≤ 30 480 800 2
ISO1083/JS/800-2 30 < t ≤ 60
to be agreed upon between the manufacturer and the purchaser
60 < t ≤200
t ≤ 30 600 900 2
ISO1083/JS/900-2 30 < t ≤ 60
to be agreed upon between the manufacturer and the purchaser
60 < t ≤ 200
NOTE 1  Elongation values are determined from L = 5 d. For other gauge lengths, see 9.1 and Annex B.
0
NOTE 2  The mechanical properties of test pieces machined from cast samples do not necessary reflect exactly
the properties of the casting itself. Values for tensile properties of the casting are given in Annex D for guidance.
NOTE 3  The data apply to separately cast samples, cast on samples and side-by-side cast samples; therefore
the suffix “S” is not included.
a b
  LT for low temperature.  RT for room temperature.
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ISO 1083:2018(E)

7.2.1.2 Impact energy
The impact energy values given in Table 2 for room temperature (RT) and low temperature (LT)
applications, if applicable, shall only be determined if specified by the purchaser by the time of
acceptance of the order.
The mean value of the three Charpy impact tests and the individual values shall meet the specified
requirements in Table 2.
NOTE The relevance of the use of impact energy as a measure of resistance to brittle fracture in castings,
subjected to application loads, is currently being reassessed. Annex C gives information about a fracture
mechanical approach to spheroidal graphite cast irons.
Table 2 — Minimum impact energy values measured on V-notched test pieces machined from
cast samples for ferritic grades of the ferritic to pearlitic group
Minimum impact energy values
J
Relevant wall
Material designation
thickness
Room temperature Low temperature Low temperature
(23 ± 5) °C (−20 ± 2) °C (−40 ± 2) °C
Mean Mean Mean
T Individu- Individu- Individu-
value value value
mm al value al value al value
(3 tests) (3 tests) (3 tests)
t ≤ 30 — — — — 12 9
a
ISO1083/JS/350-22-LT 30 < t ≤ 60 — — — — 12 9
60 < t ≤ 200 — — — — 10 7
t ≤ 30 17 14 — — — —
b
ISO1083/JS/350-22-RT 30 < t ≤ 60 17 14 — — — —
60 < t ≤ 200 15 12 — — — —
t ≤ 30 — — 12 9 — —
a
ISO1083/JS/400-18-LT 30 < t ≤ 60 — — 12 9 — —
60 < t ≤ 200 — — 10 7 — —
t ≤ 30 14 11 — — — —
b
ISO1083/JS/400-18-RT 30 < t ≤ 60 14 11 — — — —
60 < t ≤ 200 12 9 — — — —
NOTE 1  These material grades can be suitable for some pressure vessel applications. (For fracture toughness, see Annex C.)
NOTE 2  The mechanical properties of test pieces machined from cast samples do not necessarily reflect exactly the
properties of the casting itself.
NOTE 3  The data apply to separately cast samples, cast on samples and side-by-side cast samples; therefore the suffix “S”
is not included.
a
LT for low temperature.
b
RT for room temperature.
7.2.2 Test pieces machined from samples cut from a casting
If applicable, the manufacturer and the purchaser shall agree on the following:
— the locations on a casting where the samples shall be taken;
— the mechanical properties that shall be measured;
— the minimum values or allowable range of values, for these mechanical properties (for information,
see Annex D).
NOTE 1 The properties of castings are often not uniform, because casting properties depend on the complexity
of the casting and variation in section thickness.
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ISO 1083:2018(E)

NOTE 2 Mechanical properties for test pieces cut from a casting are affected not only by material properties
(covered by this document) but also by the local casting soundness (not covered by this document).
7.2.3 Classification by hardness
The classification by Brinell hardness shall only be specified when agreed between the manufacturer
and the purchaser (see Annex E).
7.2.4 Graphite structure
The graphite structure shall be mainly of form VI and form V in accordance with ISO 945-1. A more
precise definition of graphite structure may be agreed between the manufacturer and the purchaser.
This structure shall be confirmed either by metallographic examination or by non-destructive methods.
In case of dispute, the result of the metallographic examination shall prevail.
NOTE Annex F gives more information on nodularity.
7.2.5 Matrix structure
Information on matrix structure is given in Table G.1 and ISO/TR 945-3.
7.3 Solid solution strengthened ferritic spheroidal graphite cast irons
7.3.1 Test pieces machined from cast samples
The mechanical properties of solid solution strengthened ferritic spheroidal graphite cast iron test
pieces shall be as specified in Table 3.
Table 3 — Mechanical properties measured on test pieces machined from cast samples for solid
solution strengthened ferritic grades
Relevant wall Elongation after
0,2 % proof strength Tensile strength
thickness fracture
Material designation
t R R A
p0,2 m
mm MPa MPa %
min. min. min.
t ≤ 30 350 450 18
30 ≤ t ≤ 60 340 430 14
ISO1083/JS/450-18
t > 60
to be agreed upon between the manufacturer and the purchaser
t ≤ 30 400 500 14
30 ≤ t ≤ 60 390 480 12
ISO1083/JS/500-14
t > 60
to be agreed upon between the manufacturer and the purchaser
t ≤ 30 470 600 10
30 ≤ t ≤ 60 450 580 8
ISO1083/JS/600-10
t > 60
to be agreed upon between the manufacturer and the purchaser
...