ISO 16112:2017

Compacted (vermicular) graphite cast irons - Classification

ISO 16112:2016 specifies five grades of compacted (vermicular) graphite cast irons. ISO 16112:2016 specifies five grades based on the minimum mechanical properties measured on machined test pieces prepared from - separately cast samples, - side-by-side cast samples, - cast-on samples, or - samples cut from a casting.

Fontes à graphite vermiculaire (compacté) — Classification

General Information

• Status: Published
• Publication Date: 12-Jan-2017
• ICS: 77.080.10 - Irons
• Technical Committee: ISO/TC 25 - Cast irons and pig irons
• Drafting Committee: ISO/TC 25 - Cast irons and pig irons
• Current Stage: 9093 - International Standard confirmed
• Start Date: 01-Dec-2022
• Completion Date: 13-Dec-2025

Relations

• Revises: ISO 16112:2006 - Compacted (vermicular) graphite cast irons - Classification
• Effective Date: 01-Nov-2014

Overview

ISO 16112:2017 - Compacted (vermicular) graphite cast irons - Classification defines a clear, test‑based grading system for compacted (vermicular) graphite cast iron (CGI). The standard specifies five CGI grades based on minimum mechanical properties measured on machined test pieces prepared from separately cast samples, side‑by‑side cast samples, cast‑on samples, or - by agreement - samples cut from a casting. ISO 16112:2017 sets how grades are designated, sampled and tested to ensure consistent material performance for manufacturing and procurement.

Key topics and technical requirements

• Five material grades (ISO 16112/JV/300/S through ISO 16112/JV/500/S) are defined by minimum tensile properties. Example minimum values for test pieces from separately cast samples:
  • ISO 16112/JV/300/S: Rm ≥ 300 MPa, Rp0.2 ≥ 210 MPa, A ≥ 2.0%
  • ISO 16112/JV/350/S: Rm ≥ 350 MPa, Rp0.2 ≥ 245 MPa, A ≥ 1.5%
  • ISO 16112/JV/400/S: Rm ≥ 400 MPa, Rp0.2 ≥ 280 MPa, A ≥ 1.0%
  • ISO 16112/JV/450/S: Rm ≥ 450 MPa, Rp0.2 ≥ 315 MPa, A ≥ 1.0%
  • ISO 16112/JV/500/S: Rm ≥ 500 MPa, Rp0.2 ≥ 350 MPa, A ≥ 0.5%
• Sample types and designations: suffix “S” indicates properties from separately cast samples; “U” is used for side‑by‑side or cast‑on samples. Samples cut from castings may be used only by purchaser–manufacturer agreement.
• Testing and sampling: tensile testing, hardness testing and microstructure assessment are required. The standard references ISO tensile and hardness test methods and gives detailed sampling rules (frequency, sample types, test unit formation).
• Microstructure and nodularity: graphite form and matrix (ferrite/pearlite) affect properties; Annex B explains nodularity evaluation for CGI.
• Process control: production tests must meet minimums; statistical analysis is recommended to demonstrate process capability. Manufacture and chemistry are left to the producer provided the grade requirements are met.
• Additional provisions: retest rules, heat treatment considerations, and ordering information (designation and special requirements).

Applications and who uses this standard

ISO 16112:2017 is used by:

• Foundries and casting engineers for material specification and quality control
• Design and mechanical engineers specifying CGI components
• Procurement and quality assurance teams setting acceptance criteria
• Test laboratories performing tensile, hardness and microstructure evaluations

Annex C (informative) provides examples of typical applications and property guidance to aid selection of CGI grades for specific component requirements.

Related standards (referenced)

• ISO 6892‑1 - Tensile testing at room temperature
• ISO 6506‑1 - Brinell hardness test method
• ISO 945‑1 - Graphite classification by visual analysis
• ISO/TR 15931 - Designation system for cast irons and pig irons

Keywords: ISO 16112:2017, compacted (vermicular) graphite cast iron, CGI classification, CGI grades, tensile strength, sampling, nodularity, foundry quality control.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 16112
Second edition
2017-02
Compacted (vermicular) graphite cast
irons — Classification
Fontes à graphite vermiculaire (compacté) — Classification
Reference number
©
ISO 2017
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
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ii © ISO 2017 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3  Terms and definitions . 1
4 Designation . 2
5 Order information . 2
6 Manufacture . 2
7 Requirements . 3
7.1 General . 3
7.2 Test pieces machined from separately cast samples . 3
7.3 Test pieces machined from side-by-side and cast-on samples . 6
7.4 Test pieces machined from samples cut from a casting . 8
7.5 Hardness . 9
7.6 Graphite structure . 9
8 Sampling . 9
8.1 General . 9
8.2 Cast samples .10
8.2.1 Frequency and number of tests .10
8.2.2 Separately cast samples .10
8.2.3 Side-by-side cast samples .10
8.2.4 Cast-on samples .10
8.2.5 Test pieces machined from cast samples .11
8.3 Samples cut from a casting .11
8.3.1 General.11
8.3.2 Other conditions.11
8.4 Formation of test units and number of tests .11
8.4.1 Examples of test units .11
8.4.2 Number of tests per test unit .11
9 Test methods .12
9.1 Tensile test .12
9.2 Hardness test .13
10 Retests .14
10.1 Need for retests .14
10.2 Test validity .14
10.3 Nonconforming test results .14
10.4 Heat treatment of samples and castings .14
Annex A (informative) Additional information on compacted (vermicular) graphite cast irons .15
Annex B (informative) Compacted (vermicular) graphite cast iron nodularity evaluation .18
Annex C (informative) Compacted (vermicular) graphite cast irons — Properties
and typical applications .22
Annex D (informative) Cross-references of ISO 16112 grade designations to other standard
grades of compacted (vermicular) graphite cast iron .23
Bibliography .24
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 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 . i so .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 25, Cast irons and pig irons.
This second edition cancels and replaces the first edition (ISO 16112:2006), which has been technically
revised with the following changes:
— Brinell hardness values have been moved from Table 1 and Table 2 to Table A.1;
— property values for cast-on samples with relevant wall thickness t ≤ 12,5 mm have been removed
from Table 2 because all data entries for t ≤ 12,5 mm were the same as the values for relevant wall
thickness 12,5 mm < t ≤ 30 mm;
— Annex B has been expanded to provide a more comprehensive explanation of the nodularity
evaluation technique;
— Annex C has been deleted and replaced because the series production experience gained since the
first publication of ISO 16112 in 2006 has surpassed the scope of the annex.
iv © ISO 2017 – All rights reserved

Introduction
This document deals with the classification of compacted (vermicular) graphite cast irons (CGI) in
accordance with the mechanical properties of the material.
The properties of compacted (vermicular) graphite cast irons depend on their graphite and matrix
microstructure.
The mechanical properties of the material can be evaluated on machined test pieces prepared from
— separately cast samples,
— samples cast in the mould alongside the casting, with a joint running system, hereafter called side-
by-side samples, or
— samples cast onto either the casting or the running system, hereafter referred to as cast-on
samples, or
— samples cut from a casting (only when an agreement is made between the manufacturer and the
purchaser).
The material grade is defined by mechanical properties measured on machined test pieces prepared
from separately cast samples, cast-on samples, or samples cut from the casting by agreement between
the manufacturer and the purchaser.
Annex A provides typical properties for compacted (vermicular) graphite cast irons obtained in
separately cast test bars.
Annex B provides information on a procedure to determine the graphite nodularity of the
microstructure.
Annex C provides information on properties and examples for typical applications of compacted
(vermicular) graphite cast irons.
Annex D provides cross-references of ISO 16112 grade designations to other national and international
standard grades of compacted (vermicular) graphite cast iron.
References used in the preparation of this document are listed in the Bibliography.
INTERNATIONAL STANDARD ISO 16112:2017(E)
Compacted (vermicular) graphite cast irons —
Classification
1 Scope
This document specifies five grades of compacted (vermicular) graphite cast irons.
This document specifies five grades based on the minimum mechanical properties measured on
machined test pieces prepared from
— separately cast samples,
— side-by-side cast samples,
— cast-on samples, or
— samples cut from a casting.
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 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
compacted (vermicular) graphite cast iron
cast material, iron and carbon based, the carbon being present mainly in the form of compacted
(vermicular) graphite particles that appear vermicular on a two-dimensional plane of polish, the
graphite particles being embedded in a matrix consisting of ferrite, ferrite/pearlite, or pearlite
Note 1 to entry: Reference micrographs are provided in Annex B.
3.2
graphite modification treatment
process that brings the liquid iron into contact with a substance to produce graphite in the
predominantly compacted (vermicular) form during solidification
3.3
separately cast sample
sample cast in a separate sand mould under representative manufacturing conditions and material grade
3.4
side-by-side cast sample
sample cast in the mould alongside the casting, with a connected but separate running system
3.5
cast-on sample
sample attached directly to the running system or the casting
3.6
sample cut from the casting
sample obtained directly from the casting
3.7
relevant wall thickness
section of the casting, agreed between the manufacturer and the purchaser, to which the determined
mechanical properties shall apply
Note 1 to entry: The cooling rate of the relevant wall thickness can be used to determine the size of separately
cast or cast-on samples to ensure representative microstructures and properties.
4 Designation
The material is designated according to ISO/TR 15931. The relevant designations are given in
Tables 1 and 2.
In the case of test pieces prepared from separately cast samples, the letter “S” is added at the end of the
grade designation. In the case of test pieces prepared from side-by-side or cast-on samples, the letter
“U” is added at the end of the grade designation.
5 Order information
The following information shall be supplied by the purchaser:
a) the complete designation of the material;
b) any special requirements which shall be agreed upon between the manufacturer and the purchaser.
All agreements between the manufacturer and the purchaser shall be made by the time of acceptance
of the order.
6 Manufacture
The method of producing compacted (vermicular) graphite cast iron and its 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.
NOTE When compacted (vermicular) graphite cast iron is to be used for special applications, the chemical
composition and heat treatment can be agreed upon between the manufacturer and the purchaser.
2 © ISO 2017 – All rights reserved

7 Requirements
7.1 General
The minimum tensile properties of compacted (vermicular) graphite cast irons shall be as specified in
Tables 1 and 2.
Production test results shall meet the minimum tensile property requirements specified in Table 1 or
Table 2. Statistical analysis methods shall be used to establish process capability to meet the tensile
property requirements.
7.2 Test pieces machined from separately cast samples
The minimum measured mechanical properties of compacted (vermicular) graphite cast irons,
determined using test pieces machined from separately cast samples according to Figure 1, Figure 2 or
Figure 3 shall be as specified in Table 1. The material designation is based on the minimum mechanical
properties obtained in cast samples with a thickness of 25 mm. This designation is irrespective of the
type of cast sample.
Table 1 — Mechanical properties measured on test pieces machined from separately cast samples
0,2 % proof
Tensile strength Elongation
strength
R R A
m p0,2
Material designation
MPa MPa %
min min min
ISO 16112/JV/300/S 300 210 2,0
ISO 16112/JV/350/S 350 245 1,5
ISO 16112/JV/400/S 400 280 1,0
ISO 16112/JV/450/S 450 315 1,0
ISO 16112/JV/500/S 500 350 0,5
NOTE 1  The values for these materials apply to castings cast in sand moulds of comparable
thermal behaviour. Subject to amendments agreed upon in the order, they can apply to castings
obtained by alternative methods.
NOTE 2  Whatever the method used for obtaining the castings, the grades are based on the
mechanical properties measured on test pieces machined from samples separately cast in a sand
mould or a mould of comparable thermal behaviour.
NOTE 3  Tensile testing requires sound test pieces in order to ensure pure uniaxial stress during
the test.
Dimensions in millimetres
a)  Types I, IIa and III b)  Type IIb
Type
Dimension
I IIa IIb III
u 12,5 25 25 50
v 40 55 90 90
x 30 40 40 to 50 60
a
y 80 100 100 150
b
z A function of the test-piece length
a
For information only.
b
z shall be chosen to allow a test piece of the dimensions shown in Figure 5
to be machined from the sample.
Figure 1 — Separately cast or side-by-side cast samples (option 1)
The thickness of the sand mould surrounding the samples shall be
— 40 mm minimum for types I, IIa and IIb, or
— 80 mm minimum for type III.
NOTE For the manufacture of thin-walled castings or castings in metal moulds, the tensile properties can,
by agreement between the manufacturer and the purchaser, be determined on test pieces taken from samples of
thickness, u, less than 12,5 mm.
4 © ISO 2017 – All rights reserved

Dimensions in millimetres
Type
Dimension
I II III IV
u 12,5 25 50 75
v 40 55 100 125
x 25 40 50 65
a
y 135 140 150 175
b
z A function of the test-piece length
a
For information only.
b
z shall be chosen to allow a test piece of the dimensions shown in Figure 5
to be machined from the sample.
Figure 2 — Separately cast or side-by-side cast samples (option 2)
The thickness of the sand mould surrounding the samples shall be
— 40 mm minimum for types I and II, or
— 80 mm minimum for types III and IV.
NOTE For the manufacture of thin-walled castings or castings in metal moulds, the tensile properties can,
by agreement between the manufacturer and the purchaser, be determined on test pieces taken from samples of
thickness, u, less than 12,5 mm.
Dimensions in millimetres
a)  Type a
b)  Type b
c)  Type c
Type A B D H H L L L W
b f n t
a 4,5 5,5 25 50 — L + 20 L – 50 100
t t
a
b 4,5 5,5 25 50 — L + 20 L – 50 50
t t
c 4,0 5,0 25 35 15 L + 20 L – 50 50
t t
a
L shall be chosen to allow a test piece of dimensions shown in Figure 5 to be machined from the cast sample.
t
Figure 3 — Separately cast or side-by-side cast samples (option 3)
The thickness of the sand mould surrounding the samples shall be at least 40 mm.
7.3 Test pieces machined from side-by-side and cast-on samples
The minimum mechanical properties of compacted (vermicular) graphite cast irons, determined using
test pieces machined from side-by-side cast samples according to Figure 1, Figure 2 or Figure 3, or to
cast-on samples according to Figure 4, shall be as specified in Table 2.
The material designation is based on the minimum mechanical properties obtained in samples with a
relevant wall thickness of 25 mm. This designation is irrespective of the type of cast sample.
6 © ISO 2017 – All rights reserved

Table 2 — Mechanical properties measured on test pieces machined from side-by-side samples
or cast-on samples
Relevant wall Tensile 0,2 % proof
Elongation
thickness strength strength
t R R A
m p0,2
Material designation
mm MPa MPa %
min min min
12,5 < t ≤ 30 300 210 2,0
ISO 16112/JV/300/U 30 < t ≤ 60 275 195 2,0
60 < t ≤ 200 250 175 2,0
12,5 < t ≤ 30 350 245 1,5
ISO 16112/JV/350/U 30 < t ≤ 60 325 230 1,5
60 < t ≤ 200 300 210 1,5
12,5 < t ≤ 30 400 280 1,0
ISO 16112/JV/400/U 30 < t ≤ 60 375 260 1,0
60 < t ≤ 200 325 230 1,0
12,5 < t ≤ 30 450 315 1,0
ISO 16112/JV/450/U 30 < t ≤ 60 400 280 1,0
60 < t ≤ 200 375 260 1,0
12,5 < t ≤ 30 500 350 0,5
ISO 16112/JV/500/U 30 < t ≤ 60 450 315 0,5
60 < t ≤ 200 400 280 0,5
NOTE 1  The mechanical properties of test pieces machined from cast-on samples can be different from
the properties of the casting itself, but usually give a better approximation than those obtained from
separately cast samples. Additional values are given in Annex A for guidance.
NOTE 2  The percentage reduction in mechanical properties in thick sections depends upon the casting
geometry and its cooling conditions.
NOTE 3  For relevant wall thickness greater than 200 mm, the manufacturer and the purchaser can
agree on the type and size of the cast sample and the minimum values to be obtained.

Dimensions in millimetres
Key
1 casting or running system
Relevant wall b c
thickness of
Type a h L
t
castings
max min
t
a
A t ≤ 12,5 15 11 7,5 20 to 30
a
B 12,5 < t ≤ 30 25 19 12,5 30 to 40
a
C 30 < t ≤ 60 40 30 20 40 to 65
a
D 60 < t ≤ 200 70 52,5 35 65 to 105
a
L shall be chosen to allow a test piece of a dimension shown in Figure 5 to be machined from the sample.
t
Figure 4 — Cast-on sample
The thickness of the sand mould surrounding the samples shall be
— 40 mm minimum for types A and B, and
— 80 mm minimum for types C and D.
NOTE If smaller dimensions are agreed, the following relationships apply:
b = 0,75 × a and c = 0,5 × a.
7.4 Test pieces machined from samples cut from a casting
Samples obtained directly from the casting best represent the properties of the casting itself. If
applicable, the manufacturer and the purchaser shall agree on:
— the locations on the casting where the samples shall be taken;
— the mechanical properties that shall be measured;
— the values of these mechanical properties (for information, see Annex A).
NOTE 1 The properties of castings can vary depending on the complexity of the castings and variation in their
section thicknesses and cooling rates.
8 © ISO 2017 – All rights reserved

NOTE 2 Samples cut from a casting often have a slower cooling rate than separately cast samples. Therefore,
the mechanical properties are often lower, even if the section thickness and microstructure are similar.
NOTE 3 Mechanical properties for test pieces cut from a casting are affected not only by material properties
(subject of this document) but also by the local casting soundness (
...