ISO/TR 10809-1:2009
(Main)Cast irons — Part 1: Materials and properties for design
Cast irons — Part 1: Materials and properties for design
The purpose of ISO/TR 10809-1:2009 is to assist the designer and engineer in understanding the family of cast iron materials and to utilize them with a more complete knowledge of their potential, among the wide range of other engineering materials and fabrication methods now available. A considerable amount of the data provided is metallurgical, but it is usually the metallurgical aspects of the cast irons that create misunderstandings when these materials are specified. This is because metallurgy is not one of the scientific disciplines taught to engineering students. Thus, such students often have a lack of knowledge regarding the fundamentals underpinning the material properties of cast irons. ISO/TR 10809-1:2009 suggests what can be achieved, what cannot be achieved and why, if and when cast irons are specified. It is not designed to be a textbook of metallurgy. It is intended to help people to choose the correct material for the right reasons and also to help to obviate the specification or expectation of unrealistic additional requirements, which are unlikely to be met and which can be detrimental to the intended application.
Fontes — Partie 1: Matériaux et propriétés pour la conception
General Information
Relations
Standards Content (Sample)
TECHNICAL ISO/TR
REPORT 10809-1
First edition
2009-11-01
Cast irons —
Part 1:
Materials and properties for design
Fontes —
Partie 1: Matériaux et propriétés pour la conception
Reference number
ISO/TR 10809-1:2009(E)
©
ISO 2009
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ISO/TR 10809-1:2009(E)
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ISO/TR 10809-1:2009(E)
Contents Page
Foreword .v
Introduction.vi
1 Scope.1
2 Why use cast irons as an engineering material?.1
2.1 Why use grey cast iron?.1
2.2 Why use spheroidal graphite cast iron?.2
2.3 Why use compacted cast iron? .2
2.4 Why use malleable cast iron? .2
2.5 Why use ausferritic cast iron? .2
2.6 Why use abrasion-resistant cast iron? .2
2.7 Why use austenitic cast iron?.3
3 Commentary.3
3.1 Recent changes in standardization .3
3.2 General metallurgy of the cast irons .5
3.3 Section sensitivity and its effects on material properties.6
3.4 Understanding hardness .8
3.5 Heat treatment .8
3.6 Welding.9
4 ISO 185 Grey cast irons .9
4.1 Overview.9
4.2 Effect of structure on properties .12
4.3 Metal composition and carbon equivalent.12
4.4 Graphite form, distribution and size.13
4.5 Section sensitivity.13
4.6 Effect of alloying elements.15
4.7 Heat treatment .15
4.8 Choosing the grade.16
5 ISO 1083 Spheroidal graphite cast irons .16
5.1 Overview.16
5.2 Effect of structure on properties .17
5.3 Metal composition and carbon equivalent.17
5.4 Graphite form and size.18
5.5 Section sensitivity in spheroidal graphite cast iron .18
5.6 Effect of alloying elements.20
5.7 Matrix structure and resultant properties .20
5.8 Spheroidal graphite cast iron with high silicon content .21
5.9 Special case of impact-resistant grades.22
5.10 Heat treatment .22
5.11 Relationship between ferritic spheroidal graphite cast iron and ferritic steel.23
6 ISO 16112 Compacted (vermicular) graphite cast irons.25
6.1 Overview.25
6.2 Why use compacted graphite cast iron? .26
6.3 Effect of structure on properties .27
6.4 Metal composition and carbon equivalent.27
6.5 Graphite form and size.28
6.6 Section sensitivity in compacted graphite cast iron .28
6.7 Matrix structure and the resultant properties.29
6.8 Heat treatment .29
6.9 Choosing the grade.29
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ISO/TR 10809-1:2009(E)
7 ISO 5922 Malleable cast irons .29
7.1 Overview.29
7.2 Metal composition and carbon equivalent.32
7.3 Heat treatment.32
7.4 Graphite form and size.34
7.5 Mechanical property requirements and the influence of structure.34
7.6 Impact properties.35
7.7 Section sensitivity .35
7.8 Choosing the grade .35
8 ISO 17804 Ausferrite spheroidal cast irons .36
8.1 Overview.36
8.2 Heat treatment process.38
8.3 Effects of alloying elements .40
8.4 Graphite form and size.40
8.5 Matrix structure and the resultant properties.41
8.6 Section sensitivity .41
8.7 Special case of the impact grade.41
8.8 Special case of the abrasion-resistant grades .41
8.9 Machinability .41
8.10 Choosing the grade .42
9 ISO 21988 Abrasion-resistant cast irons.42
9.1 Overview.42
9.2 Effects of structure on properties.44
9.3 Chemical composition .45
9.4 Unalloyed and low-alloy cast irons.45
9.5 Nickel-chromium cast iron.45
9.6 High-chromium cast iron .45
9.7 Influence of chemical composition on properties and performance .45
9.8 Section sensitivity .46
9.9 Heat treatment.47
9.10 Choosing the material grade .48
10 ISO 2892 Austenitic cast irons .49
10.1 Overview.49
10.2 Effect of structure on properties.50
10.3 Chemical composition and its effect .51
10.4 Effect of composition on carbon equivalent.52
10.5 Graphite form, distribution and size.52
10.6 Heat treatment.52
10.7 Choosing the material grade .53
Annex A (informative) Glossary of terms related to cast iron International Standards.54
Bibliography .56
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ISO/TR 10809-1:2009(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
In exceptional circumstances, when a technical committee has collected data of a different kind from that
which is normally published as an International Standard (“state of the art”, for example), it may decide by a
simple majority vote of its participating members to publish a Technical Report. A Technical Report is entirely
informative in nature and does not have to be reviewed until the data it provides are considered to be no
longer valid or useful.
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.
ISO/TR 10809-1 was prepared by Technical Committee ISO/TC 25, Cast irons and pig irons.
ISO/TR 10809 consists of the following parts, under the general title Cast irons:
⎯ Part 1: Materials and properties for design
⎯ Part 2: Welding
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ISO/TR 10809-1:2009(E)
Introduction
Worldwide cast iron production is in excess of 60 000 000 tonnes per annum. It is manufactured in a wide
range of alloys and has applications in all sectors of world production and manufacture. Its use spans many
industries, including automotive, oil, mining, etc.
The technology of cast irons is not widely taught or understood around the globe. This part of ISO/TR 10809 is
intended to provide information about cast iron materials so that users and designers are better able to
understand cast iron as a design material in its own right and correctly specify cast iron for suitable
applications.
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TECHNICAL REPORT ISO/TR 10809-1:2009(E)
Cast irons —
Part 1:
Materials and properties for design
1 Scope
The purpose of this part of ISO/TR 10809 is to assist the designer and engineer in understanding the family of
cast iron materials and to utilize them with a more complete knowledge of their potential, among the wide
range of other engineering materials and fabrication methods now available. A considerable amount of the
data provided are metallurgical, but it is usually the metallurgical aspects of the cast irons that create
misunderstandings when these materials are specified. This is because metallurgy is not one of the scientific
disciplines taught to engineering students. Thus, such students often have a lack of knowledge regarding the
fundamentals underpinning the material properties of cast irons. This part of ISO/TR 10809 suggests what can
be achieved, what cannot be achieved and why, if and when cast irons are specified. It is not designed to be a
textbook of metallurgy. It is intended to help people to choose the correct material for the right reasons and
also to help to obviate the specification or expectation of unrealistic additional requirements, which are unlikely
to be met and which can be detrimental to the intended application.
2 Why use cast irons as an engineering material?
The first questions that the designer and engineer will probably ask are:
⎯ Can I use a cast iron?
⎯ Should I use a cast iron?
⎯ Which type and grade are applicable?
⎯ What are the advantages?
The following sub-clauses give general information on the cast iron types currently standardized in
International Standards.
2.1 Why use grey cast iron?
Grey cast iron provides the largest worldwide tonnage of all cast irons produced, mainly because of its wide
range of uses within general engineering, its ease of machining, and its cost advantage. The material has the
highest thermal conductivity among the range of cast irons, which is why it is used in applications where this
property is important. Typical examples are automotive parts such as brake drums, discs, clutch plates, and
cylinder blocks and heads. Grey cast iron lacks ductility, but for parts where requirements for ductility and
impact strength are low or unimportant, a huge range of applications can be found. These include, for
example, the manufacture of machine tools such as lathe beds, where slideways can easily be surface
hardened and the “self-lubricating” properties of the material are advantageous. This highly versatile material
should be considered for a potential application unless there are ductility issues, or the design requires
2
ultimate strengths in excess of 300 N/mm .
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ISO/TR 10809-1:2009(E)
2.2 Why use spheroidal graphite cast iron?
Spheroidal graphite cast iron has the benefit of ductility as well as strength, which is why it is often considered
to be a material superior to grey cast iron. Its main disadvantage in this respect is that it does not have the
thermal conductivity provided by grey cast iron and is not normally used where this property is important. A
large number of grades of spheroidal graphite cast iron are available to the designer, based on the fact that as
tensile strength increases, ductility decreases. Thus the designer has the opportunity to utilize different
combinations of tensile/ductility properties, depending upon the application. The lower-strength grades with
high ductility also have good impact properties and, for this reason, spheroidal graphite cast iron is
increasingly being used to produce cast parts to replace steel fabrications. Large tonnages of spheroidal
graphite cast iron are used to produce centrifugally cast pipe for water and sometimes gas transportation, but
the majority is used in general engineering applications where its considerably higher tensile properties
compared with grey cast iron are of advantage.
2.3 Why use compacted cast iron?
Compacted graphite cast irons have applications as components which require additional strength, stiffness,
and ductility over and above that offered by grey cast iron. Typical applications include cylinder blocks and
heads, brake drums and brake discs, pump housings, hydraulic components, and cylinder liners. The benefits
of the material are that it provides higher tensile strengths and some ductility in conjunction with thermal
conductivity properties similar to those found in grey cast irons.
2.4 Why use malleable cast iron?
There are two different types of malleable cast iron, blackheart and whiteheart. The blackheart grades have
properties similar to the spheroidal graphite cast irons and the materials have traditionally been considered
interchangeable in most general engineering applications. The main advantage of blackheart malleable iron,
compared with spheroidal graphite cast iron, is that it is easier to machine, because of the different metal
composition. The whiteheart malleable grades are still used to produce traditional thin section castings,
particularly fittings such as hinges and locks. Now, however, their uses are more usually confined to the
production of thin section castings where the heat treatment process involved can be adjusted to completely
decarburize the material. This is of considerable advantage to designers; it allows malleable whiteheart
castings to be welded to steels as part of a fabrication process, because the whiteheart material possesses
properties that are not dissimilar to the steel to which it is welded.
2.5 Why use ausferritic cast iron?
The austempering heat treatment carried out on a normal spheroidal graphite cast iron enhances its
properties to produce a range of grades with exceptionally high tensile strengths. The highest tensile strength
grade also has a high hardness that allows it to be used in abrasion-resisting applications, the most common
one being as digger teeth on earth-moving equipment. As with all spheroidal graphite cast iron materials,
increases in tensile strength and hardness are accompanied by decreases in ductility. This allows for a wide
range of properties that can be exploited, provided that their combination is applicable to the component
2
design. Tensile strengths up to 1 400 N/mm , hardness greater than 400 HBW, and tensile elongation up to
10 % are possible (although not all three simultaneously in the same grade of material). These mechanical
properties also generate a high fatigue strength that is useful in gears and other components for use in a
rotating/bending application.
2.6 Why use abrasion-resistant cast iron?
The abrasion-resisting cast irons are a range of hard and tough materials that compete with other alloys such
as manganese steel, mainly in the mining and extraction industries, in wear-resistant applications such as
slurry pumps and in more generalized applications such as in the operation of shot-cleaning plants. Thus they
are rightly considered to be a consumable item where the rate of wear, or operational life, is important in the
decision-making process regarding the choice of material. Generally speaking, they tend to be less expensive
and easier to manufacture than the abrasion-resisting steels with which they are usually compared. They
perform well in a variety of applications and should not be casually dismissed as the material of choice in any
application that requires abrasion resistance. The effectiveness of any abrasion-resisting material is highly
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ISO/TR 10809-1:2009(E)
dependent upon the materials which it is in contact with and the circumstances under which it performs. For
example, slight changes in the composition of an ore in an extraction application, and even its water content,
can significantly influence the wear rate. The 13 grades of abrasion-resisting irons specified in ISO 21988
offer a wide choice of alloys for matching the material against the intended application.
2.7 Why use austenitic cast iron?
The austenitic cast irons (sometimes called Ni-resists) are a range of materials that provide corrosion
resistance, heat resistance or a combination of both. Austenitic cast irons are often compared with stainless
steels when a design is being considered. One specific application for which the austenitic cast iron grades
are considered is where the component to be produced needs to be non-magnetizable and other properties
are of secondary importance. Both flake graphite and spheroidal graphite iron grades are produced: the
spheroidal graphite iron grades exhibit superior tensile properties to those of the flake graphite grades. These
materials vary widely in their metal composition in order to meet a broad range of applications; in general, the
most arduous applications are met by those grades containing the highest nickel content. The 12 grades of
austenitic cast iron cover the spectrum of applications where highly alloyed materials are required in order to
meet arduous conditions in service.
3 Commentary
Cast irons have particular and peculiar metallurgical and other properties which are unique to the material and
which give it specific valuable attributes that make it a useful material in certain applications.
3.1 Recent changes in standardization
ISO/TC 25 is the International Technical Committee responsible for the development of International
Standards for cast irons. Since 1998, when it was reactivated after a dormancy of 14 years, ISO/TC 25 has
been working through a programme of creation, revision, assessment and publication of cast iron material and
related standards. These International Standards include annexes of additional information about material
properties, which are not requirements of the standards, but which provide helpful technical and application
information to designers and engineers.
The International Standards that have been reviewed, created, published or retained in their current form are
shown in Table 1.
Table 1 — International Standards for cast iron materials and microstructure
Scope Standard number
Grey cast irons ISO 185
Spheroidal graphite cast irons ISO 1083
Compacted (vermicular) graphite cast irons ISO 16112
Malleable cast irons ISO 5922
Ausferritic spheroidal graphite cast irons ISO 17804
Abrasion-resistant cast irons ISO 21988
Austenitic cast irons ISO 2892
Designation of microstructure of cast irons – visual analysis ISO 945-1
The seven International Standards for cast iron materials (see Table 1) encompass a huge international
tonnage. In 1999, reported world production reached 49,3 million tonnes/annum, and this figure had increased
to 61,6 million tonnes/annum by 2006 (the last available statistics). The trend is continuing for cast irons
utilized in the manufacture of a wide range of different components ranging in mass from a few grams to more
than 100 tonnes.
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ISO/TR 10809-1:2009(E)
The International Standards for cast irons detail the properties of seven individual types of cast iron material
which together specify 84 different grades. It is recommended that these standards and the associated
annexes of supporting information be carefully consulted, in order to allow the most appropriate material to be
chosen for the application. Table 2 provides a short résumé of properties that will lead the user to the relevant
International Standard. It also compares one cast iron material type with another, but does not compare the
cast irons with other materials. For example, if a cast iron with high strength and ductility were required then
an examination of ISO 1083 or ISO 17804 would
...
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