The mechanical properties of the material can be evaluated on machined test pieces prepared from cast samples or samples cut from a casting.. Five grades of ausferritic spheroidal graphi
General
The property values pertain to ausferritic spheroidal graphite cast irons produced in sand moulds or moulds with similar thermal characteristics These values may also be applicable to castings made using alternative methods, pending any agreed-upon modifications in the order.
The material designation is determined by the minimum mechanical properties derived from cast samples measuring 25 mm in thickness or diameter, regardless of the type of cast sample used.
Mechanical properties are wall thickness dependant as shown in Table 1
NOTE Tensile testing requires sound test pieces in order to guarantee pure uni-axial stress during the test.
Test pieces machined from cast samples
General
The mechanical properties of ausferritic spheroidal graphite cast iron test pieces shall be as specified in Table 1, and, if applicable, in accordance with the requirements given in 7.2.2.
Impact energy
The impact energy values given in Table 2 at room temperature, if applicable, shall only be determined if specified by the purchaser by the time of acceptance of the order.
Test pieces machined from samples cut from a casting
If applicable, the manufacturer and the purchaser shall agree on:
the location(s) on a casting where the sample(s) 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 C)
NOTE 1 The properties of castings are not uniform, depending on the complexity of the castings and variation in their section thickness
Mechanical properties of test pieces derived from a casting are influenced by both the inherent material properties, which are addressed in this standard, and the local casting soundness, which is not covered by this standard.
Table 1 — Mechanical properties measured on test pieces machined from cast samples
Symbol Number min min min
30 < t ≤ 60 1 100 To be agreed between the manufacturer and the purchaser
NOTE 1 The relevant wall thickness does not affect the minimum 0,2 % proof strength provided the heat treatment parameters and alloying are adjusted as a function of the relevant wall thickness
For Brinell hardness values of these grades, refer to Annex D When wall thicknesses exceed 100 mm, the manufacturer and purchaser must mutually agree on the type and size of the cast sample, as well as the minimum hardness values to be achieved.
Table 2 — Minimum impact energy values measured on V-notched test pieces machined from cast samples
Material designation Relevant wall thickness a
Impact energy value at room temperature
For wall thicknesses exceeding 100 mm, it is essential for the manufacturer and purchaser to reach an agreement on the type and size of the cast sample, as well as the minimum values to be achieved.
Hardness
Brinell hardness values for the grades in Table 1 will be specified only if mutually agreed upon by the manufacturer and purchaser at the time of order acceptance.
For the five grades listed in Table 1, information regarding hardness is given in Annex D and Annex E
For the two grades defined by hardness properties, Annex A applies.
Graphite structure
The graphite structure will primarily conform to forms V and Vl as specified in EN ISO 945-1, with a more detailed definition potentially established upon order acceptance.
NOTE Annex F gives more information regarding nodularity.
Matrix structure
The matrix structure of ausferritic spheroidal graphite cast iron primarily comprises ferrite and austenite, collectively referred to as ausferrite While other constituents such as martensite, bainite, and carbides may be present, their levels are minimized to ensure they do not compromise the mechanical properties outlined in Tables 1 and 2 However, these constituents can be advantageous in enhancing the abrasion resistance of specific grades, as detailed in Annex A.
In certain areas, the cooling rate may be inadequate to prevent the formation of pearlite or other high-temperature transformation products Consequently, the manufacturer and purchaser may need to agree on the maximum allowable amounts of these microconstituents, their specific locations within the casting, and the associated mechanical properties in those areas.
General
Samples shall be made from the same material as that used to produce the casting(s) which they represent
Different sample types, including separately cast samples, cast-on samples, side-by-side cast samples, and samples cut from a casting, can be utilized based on the mass and wall thickness of the casting.
The type of sample must be mutually agreed upon by the manufacturer and the purchaser In the absence of such an agreement, the manufacturer retains the discretion to choose the sample option.
For castings weighing over 2,000 kg with wall thicknesses greater than 60 mm, it is recommended to use cast-on or side-by-side samples The dimensions and placement of these samples should be mutually agreed upon by the manufacturer and purchaser at the time of order acceptance.
If the spheroidizing treatment is carried out in the mould (in-mould process), the separately cast sample should be avoided
All samples must be clearly labeled to ensure complete traceability to their corresponding castings Additionally, these samples should undergo the same heat treatment as the castings they represent, if applicable.
Tensile and impact test pieces shall be finally machined from the samples after the heat treatment.
Cast samples
Size of cast samples
The size of the sample shall be in correspondence with the relevant wall thickness of the casting as shown in
If other sizes are used, this shall be agreed between the manufacturer and purchaser
Table 3 — Types and size of cast sample and size of tensile test pieces in relation to relevant wall thickness of the casting
Type of sample Preferred diameter of tensile test piece a d mm
Option 3 Round bar Cast-on (see Figure 1) (see Figure 2) (see Figure 3) (see Figure 4) t ≤ 12,5 — I Types b, c A 7
For diameters within the range of 60 < t ≤ 100, as specified in IV — D 14, alternative diameters may be negotiated between the manufacturer and the purchaser, as illustrated in Figure 5 Additionally, the cooling rate of the cast sample is equivalent to that of a wall thickness of 40 mm.
Frequency and number of tests
Samples representative of the material shall be produced at a frequency in accordance with the process quality assurance procedures adopted by the manufacturer or as agreed with the purchaser
In the absence of a quality assurance process or agreement between the manufacturer and purchaser, at least one cast sample must be produced for tensile testing to verify the material grade, with the frequency of testing to be mutually agreed upon.
When impact tests are required, samples shall be produced at a frequency to be agreed between the manufacturer and the purchaser.
Separately cast samples
The samples shall be cast separately in sand moulds and under representative manufacturing conditions
The moulds used to cast the separately cast samples shall have comparable thermal behaviour to the moulding material used to cast the castings
The samples shall meet the requirements of either Figures 1, 2 or 3
The samples shall be removed from the mould at a temperature similar to that of the castings.
Side-by-side cast samples
Side-by-side cast samples are representative of the castings concurrently cast and also of all other castings of a similar relevant wall thickness from the same test unit
When mechanical properties are required for a series of castings belonging to the same test unit, the side-by- side cast sample(s) shall be produced in the last mould(s) poured
The samples shall meet the requirements of either Figures 1, 2 or 3.
Cast-on samples
Cast-on samples are representative of the castings to which they are attached and also of all other castings of a similar relevant wall thickness from the same test unit
When mechanical properties are required for a series of castings belonging to the same test unit, the cast-on sample(s) shall be produced in the last mould(s) poured
The sample shall have a general shape as indicated in Figure 4 and the dimensions shown therein
The manufacturer and purchaser must agree on the location of the cast-on sample at the time of order acceptance, considering the casting shape and running system to prevent any negative impact on the properties of the surrounding material.
Test pieces machined from cast samples
The tensile test specimen illustrated in Figure 5, along with the impact test specimen depicted in Figure 6, must be machined from the sample presented in Figure 3 or from the hatched sections of Figures 1, 2, or 4.
The sectioning procedure for cast samples shall be in accordance with Annex G
Unless otherwise agreed, the preferred diameter for the test piece shall be used.
Samples cut from a casting
The manufacturer and purchaser can mutually agree on specific properties required at designated locations in the casting, as detailed in Annex C These properties will be assessed through tests conducted on samples taken from these locations Additionally, both parties must reach an agreement on the dimensions of the test pieces used for this testing.
In the absence of any directions by the purchaser, the manufacturer may choose the locations from which to cut the samples and the dimensions of the test pieces
The centreline of the test piece should be located at a point half way between the surface and the centre
NOTE 1 When the zone of last solidification in the casting is included in the test piece diameter, the minimum elongation guidance value may not be obtained
NOTE 2 In the case of large individual castings trepanned samples may be taken at agreed positions in the casting which are to be stated
The length \( z \) must be selected to enable the machining of a test piece with the dimensions illustrated in Figure 5 from the sample Additionally, the thickness of the sand mold encasing the samples should be no less than 40 mm.
Figure 1 — Separately cast or side-by-side cast sample — Option 1: U-shaped sample
The dimensions of the test piece length, denoted as \( a \), are provided for informational purposes The value of \( z \) must be selected to ensure that a test piece, as illustrated in Figure 5, can be machined from the cast sample.
The thickness of the sand mould surrounding the samples shall be at least:
40 mm for types I and II;
80 mm for type III and lV
Figure 2 — Separately cast or side-by-side cast samples — Option 2: Y-shaped sample
100 b 4,5 5,5 25 50 — L t + 20 L t – 50 50 c 4,0 5,0 25 35 15 L t + 20 L t – 50 50 a L t shall be chosen to allow a test piece of dimensions shown in Figure 5 to be machined from the cast sample.
The thickness of the sand mould surrounding the samples shall be at least 40 mm
Figure 3 — Separately cast or side-by-side cast samples — Option 3: Round bar-shaped sample
Type Relevant wall thickness t a b c h L t max min
D 60 < t ≤ 100 70 52,5 35 65 to 105 a L t shall be chosen to allow a test piece of a dimension shown in Figure 5 to be machined from the cast sample
The thickness of the sand mould surrounding the samples shall be at least:
If smaller dimensions are agreed, the followings relationships apply: b = 0,75 × a c = 0,5 × a
Tensile test
The tensile test shall be carried out in accordance with EN ISO 6892-1:2009
The standard test piece diameter is 14 mm; however, due to technical considerations or when using test pieces machined from samples cut from castings, a different diameter may be utilized (refer to Figure 5).
In all cases the original gauge length of the test piece shall conform to the equation: d S
L o is the original gauge length;
S o is the original cross-section area of the test piece; d is the diameter of the test piece along the gauge length
If the equation for L o is not suitable, the manufacturer and purchaser must reach an agreement on the dimensions of the test piece They may also decide on a test piece with an alternative gauge length.
20 100 120 a Preferred dimension for 25 mm cast sample diameter. where
L o is the original gauge length, i.e L o = 5×d; d is the diameter of the test piece along the gauge length;
L c is the parallel length; L c > L o (in principle, L c – L o ≥ d);
L t is the total length of the test piece, which depends on L c ; r is the transition radius, which shall be at least 4 mm
NOTE The method of gripping the ends of the test piece, together with their length l t , may be agreed between the manufacturer and the purchaser.
Impact test
The Charpy V-notched impact test will be conducted on three test pieces, following the guidelines of EN ISO 148-1:2010 This will utilize test equipment with suitable energy levels to accurately assess the material properties.
Hardness test
The hardness shall be determined as Brinell hardness in accordance with EN ISO 6506-1
Alternative hardness tests and the corresponding required hardness values may also be agreed
The testing will be conducted on the test piece or at designated points on the casting, following the preparation of the testing area as agreed upon by the manufacturer and the purchaser.
If the measurement locations are not the subject of an agreement, they shall be chosen by the manufacturer
If conducting a hardness test directly on the casting is not feasible, the manufacturer and purchaser may agree to perform the test on a knob that is cast onto the casting.
Graphite and matrix structure examination
The graphite and matrix structure shall be confirmed by metallographic examination
Non-destructive methods can also give information regarding the graphite structure
An indirect method to determine if the required microstructure after the heat treatment has been obtained is the impact testing of un-notched Charpy test samples
The minimum impact energy values to be obtained and details of the un-notched Charpy impact test are given in Annex H
In case of dispute, the results of the microscopic examination shall prevail
Need for retest
Retests are permitted to be carried out if a test result does not meet the mechanical property requirements for the specified grade.
Test validity
A test is deemed invalid under several conditions: if the test piece is improperly mounted or the testing machine malfunctions, if the test piece is defective due to incorrect pouring or machining, if a fracture occurs outside the gauge length of the tensile test piece, or if a casting defect is visible in the test piece after fracture.
In instances of invalid test results, a new test specimen must be obtained from the same cast sample or a duplicate sample that was cast simultaneously and subjected to identical heat treatment.
Non-conforming test results
If any test gives results which do not conform to the specified requirements, for reasons other than those given in 10.2, the manufacturer shall have the option to conduct retests
If the manufacturer conducts retests, two retests shall be carried out for each failed test
If both retests give results that meet the specified requirements, the material shall be deemed to conform to this European Standard
If one or both retests give results that fail to meet the specified requirements, the material shall be deemed not to conform to this European Standard.
Heat treatment of samples and castings
For castings that have undergone heat treatment but yield invalid or unsatisfactory test results, manufacturers are allowed to re-heat treat both the castings and representative samples It is essential that the samples undergo the same number of heat treatments as the castings to ensure consistency in testing.
If the test results from the machined samples of re-heat treated castings are satisfactory, these castings will be considered compliant with the specified requirements of this European Standard.
When requested by the purchaser and agreed with the manufacturer, the manufacturer shall issue for the products the appropriate inspection documentation according to EN 10204:2004
When ordering material for pressure equipment applications, the equipment manufacturer has the obligation to request appropriate inspection documentation according to the applicable product or application standard(s), EN 764-5:2002 and EN 10204:2004
The material manufacturer is responsible for affirming conformity with the specification for the material ordered.
informative) Additional information on mechanical and physical properties
Abrasion resistant grades of ausferritic spheroidal graphite cast irons
This annex defines the grades of abrasion resistant ausferritic spheroidal graphite cast irons
It specifies the grades in terms of hardness
The Brinell hardness for the different grades shall be as specified in Table A.1 Table A.1 also gives other properties for information only
The manufacturer and the purchaser may agree on the maximum Brinell hardness
Table A.1 — Abrasion resistant ausferritic spheroidal graphite cast irons
Symbol Number min MPa MPa %
Unless stated otherwise by the purchaser at the time of order acceptance, the manufacturer will determine the number and frequency of Brinell hardness tests based on their process quality assurance procedures.
If conducting a hardness test directly on the casting is not feasible, the manufacturer and purchaser may agree to perform the test on a knob that is cast onto and heat treated with the casting.
The Brinell hardness test shall be carried out in accordance with EN ISO 6506-1
Hardness measurements obtained through different testing methods are not directly comparable To facilitate hardness conversion between various test methods, an agreement must be established between the manufacturer and the purchaser.
Each Brinell hardness test shall be carried out on a casting at locations agreed between the manufacturer and the purchaser, or on a cast–on test block
Unless otherwise specified by the purchaser, the dimensions and location of the cast-on block shall be left to
NOTE 2 A cast-on test block can be used when the size of the casting or the number of castings to be tested makes direct testing on the castings impracticable
The cast-on block must remain in place until the heat treatment is completed before any testing is conducted.
For large or complex castings that cannot be tested with standard hardness testing machines, or when there is a requirement for on-line inspection of numerous castings, a portable hardness testing device is an effective solution.
When using portable hardness testing devices, reference shall be made to appropriately calibrated test blocks
Retests shall be permitted and carried out under the same conditions as those specified in Clause 10
Comparison of ausferritic spheroidal graphite cast iron material designations according to EN 1560 and ISO/TR 15931 [2] [7]
This informative annex compares the material designation of the standardized grades of ausferritic spheroidal graphite cast irons based on the ISO and EN designation systems
Table B.1 — Material designations of ausferritic spheroidal graphite cast irons — Classification based on mechanical properties measured on machined test pieces prepared from cast samples
EN-GJS-800-10-RT 5.3401 ISO17804/JS/800-10RT
EN-GJS-1400-1 5.3405 a ISO17804/JS/1400-1 a The designation by number for this grade in the previous edition of this standard was: EN-JS1130
Table B.2 — Material designations of abrasion resistant grades of ausferritic spheroidal graphite cast irons — Classification based on hardness
EN-GJS-HB400 5.3406 ISO17804/JS/HBW400 EN-GJS-HB450 5.3407 ISO17804/JS/HBW450
Guidance values for tensile strength and elongation for test pieces machined from samples cut from a casting
Table C.1 — Guidance values for tensile strength and elongation for test pieces machined from samples cut from a casting
Relevant wall thickness in millimetres t ≤ 30 30 < t ≤ 60 60 < t ≤ 100 t ≤ 30 30 < t ≤ 60 60 < t ≤ 100
EN-GJS-1400-1C 1 100 1 360 To be agreed between the manufacturer and the purchaser
Guidance values for Brinell hardness
Table D.1 Guidance values for Brinell hardness
Material designation Brinell hardness range
HBW EN-GJS-800-10, EN-GJS-800-10-RT 250 to 310
When necessary or required for machinability, and by agreement between the manufacturer and the purchaser, a narrower range may be adopted at an agreed location on the casting
A range between 30 HBW and 40 HBW units is commonly acceptable for grades EN-GJS-800-10 and EN-GJS-800-10-RT Wider ranges may be required as tensile strength and hardness increase
Determination of the hardness range
To establish the hardness range for a specific foundry process that meets the tensile property requirements outlined in Table 1, the following procedure can be utilized This method is particularly suited for the serial production of castings.
E.2.1 Select the required material grade from Table 1
E.2.2 Select the type of sample to be used according to Table 3
E.2.3 Use test samples covering the given hardness range for the specified grade as shown in Table D.1
E.2.4 Determine tensile strength, 0,2 % proof strength, elongation, and Brinell hardness for each test piece and for the corresponding castings at the agreed locations Round the hardness values to the nearest
Conduct multiple tests to determine the minimum number required for each HBW value, as agreed upon by the manufacturer and purchaser, or to achieve the desired level of statistical confidence.
E.2.5 Plot tensile strength, 0,2 % proof strength and elongation versus hardness of castings and/or test pieces in histograms, with HBW as the independent variable
E.2.6 For each HBW value, adopt the minimum value for each tensile property as the process capability indicator
The minimum hardness for casting and test pieces must be specified as the minimum HBW value, ensuring that both tensile strength and 0.2% proof strength meet the requirements outlined for the specified grade in Table 1.
E.2.8 Specify the maximum hardness for castings and/or test pieces, a range between 30 HBW and
40 HBW units is commonly acceptable for grades EN-GJS-800-10 and EN-GJS-800-10-RT Wider ranges may be required as tensile strength and hardness increase
E.2.9 Using the graph plotted in E.2.5, determine if the required minimum elongation, as given in Table 1, is met at the maximum hardness specified in E.2.8
If the required minimum elongation is not met, there are three options:
maintain this maximum hardness and specify a lower minimum elongation;
specify a lower maximum hardness and a narrower hardness range;
specify a lower minimum and maximum hardness In this case a lower minimum tensile strength and 0,2 % proof strength should be specified
The chosen option should be agreed between the manufacturer and the purchaser
E.2.10 If the required minimum elongation is met, a higher minimum elongation for the specified grade may be agreed between the manufacturer and the purchaser
The nodularity of spheroidal graphite cast iron is defined as the percentage of graphite particles that are spheroidal or nodular in shape (form V and VI of EN ISO 945-1)
To accurately determine the form and percentage of graphite particles, a magnification that reveals their size in accordance with EN ISO 945-1:2008 is essential, despite the initial detection of particles at 100 × magnification Classification of the graphite form is based on this standard and reference images, while computer-aided image analysis using specific software parameters can also be utilized for enhanced accuracy.
Ultrasonic velocity and sound resonance frequency are influenced by graphite structure Their measurement, after calibration, can give information on nodularity However, this measurement cannot replace metallographic examination
The nodularity level is influenced by various factors, including the manufacturing process—such as charge material, residual magnesium content, and inoculation mode—as well as the cooling modulus of the melt Additionally, the graphite form in the surface rim is impacted by its interaction with the mould.
The roundness of nodules is just one factor affecting material properties; other important parameters include the quantity and distribution of graphite particles, the matrix, and microshrinkage Consequently, accurately defining the graphite structure across different grades and thicknesses is challenging.
A nodularity level of 90% or higher typically guarantees the minimum tensile properties required by the standard, exceeding the needs for R p0.2 Additionally, most of the remaining graphite, which is not classified as forms V and VI, is predominantly of form IV.
Sectioning procedure for cast samples
Type I Type II Type III Type IV
Figure G.1 — Sectioning procedure for Y-shaped samples (see Figure 2)
Figure G.2 — Sectioning procedure for cast-on samples (see Figure 4)
This annex gives an indirect method to determine conformance to the required microstructure after heat treatment, provided that the required mechanical properties have been verified by other means
This annex is applicable only when its requirements have been agreed between the manufacturer and the purchaser by the time of acceptance of the order
The minimum impact resistance values for the different material grades should be as specified in Table H.1
Table H.1 — Un-notched impact energy values for ausferritic spheroidal graphite cast irons [6]
EN-GJS-800-10 EN-GJS-800-10-RT 110
NOTE Values obtained from un-notched test pieces tested at
23 °C ± 5 °C The values in the table are the average of the three highest values of four separate tests
The casting process for samples must be mutually agreed upon by the manufacturer and the purchaser Impact resistance requirements are applicable only after the test material undergoes austempering Additionally, the impact test specimens should be prepared without notches and conform to the dimensions specified in Figure 6 following heat treatment.
The impact test should be carried out on four un-notched test pieces based on EN ISO 148-1, using test equipment with an appropriate energy to determine the properties correctly
The lowest impact energy value should be discarded, and the average of the three remaining values should be used
Retests should be permitted and carried out under the same conditions as those specified in Clause 10
Additional information on mechanical and physical properties
Technical data for ausferritic spheroidal graphite cast irons [8]
HB400 HB450 Characteristic unit Indicative values for properties a
Linear expansion coefficient α from 20 ° C to 200 ° C [1] àM(m ã K) 18 c to 14
Unless stated otherwise, the values in this table are applicable to measurements taken at ambient temperature For wall thicknesses up to 50 mm, minimum values can be achieved; however, for thicker sections, it is advisable to reach an agreement between the purchaser and the manufacturer Notched samples after heat treatment should feature a circumferential 45° V-notch with a radius of 0.25 mm Additionally, lower strength grades exhibit a higher linear expansion coefficient (\(\alpha\)) and increased thermal conductivity (\(\lambda\)).
Table I.2 — Typical properties of ausferritic spheroidal graphite cast irons for gear design [9]
Technical data for ausferritic spheroidal graphite cast irons
EN-GJS-800-10 EN-GJS-800-10-RT EN-GJS-900-8 EN-GJS-1050-6 EN-GJS-1200-3 Characteristic Unit Typical values for properties
Herzian pressure fatigue strength σH lim 90%
Tooth root bending fatigue strength σF lim 90%
Machinability of ausferritic spheroidal graphite cast irons
In general, the machinability of a material can be described by four criteria:
tool wear and tool life
This article discusses the machinability of ausferritic spheroidal graphite cast irons, focusing on four key criteria It also examines how chemical composition and heat treatment parameters affect machinability.