prEN 15718

Railway applications - Monoblock wheel products - Cast wheels

This European Standard specifies the characteristics of cast railway wheels for use on European networks.Two steel grades; C ER7 and C ER8, are defined in this standard. For tread braked wheels; only C ER7 shall be used.This standard is applicable to cast wheels which have a chilled rim1). The standard is only applicable to cast wheels that have satisfied technical approval procedure prEN13979-2:2005.This standard applies only to wheels used in freight wagon applications for speeds up to and including 120 km/h.
Note 1:"Rim Chilled" describes heat treatment of the rim, the aim of which is to harden the rim and to create circumferential compressive residual stresses in the rim.

Bahnanwendungen - Vollräder - Gussräder

Diese europäische Norm spezifiziert die Merkmale von gegossenen Eisenbahnrädern, die auf europäischen Streckennetzen verwendet werden sollen.
In dieser europäischen Norm werden zwei Stahlgüten, C  ER7 und C  ER8 definiert. Für über die Laufflächen gebremste Räder wird nur C  ER7 verwendet.
Diese europäische Norm ist auf Gussräder mit gehärteten Radreifen )anwendbar. Diese europäische Norm ist nur auf Gussräder anwendbar, die das technische Genehmigungsverfahren nach prEN 13979-2 erfüllt haben.
Diese europäische Norm gilt nur für Räder, die in Güterwagenanwendungen für Geschwindigkeiten bis zu einschließlich 120 km/h verwendet werden.

Applications ferroviaires - Roues monobloc - Roues en acier moulé

Železniške naprave - Monoblok kolesa - Lita kolesa

General Information

• Status: Not Published
• Publication Date: 01-Jun-2009
• ICS: 45.040 - Materials and components for railway engineering
• Technical Committee: CEN/TC 256 - Railway applications
• Drafting Committee: CEN/TC 256 - Railway applications
• Current Stage: 4598 - Decision to abandon - Finalization for Vote
• Start Date: 10-Oct-2008
• Completion Date: 10-Oct-2008
• Directive: 2001/16/EC - Directive 2001/16/EC of the European Parliament and of the Council of 19 March 2001 on the interoperability of the trans-European conventional rail system
• Directive: 2008/57/EC - DIRECTIVE 2008/57/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 17 June 2008 on the interoperability of the rail system within the Community (Recast)
• Mandate: M/334 - Mandate for programming and standardisation addressed to CEN, CENELEC and ETSI in the field of the Interoperability of the trans-european conventional rail system
• Ref Project: oSIST prEN 15718:2007 - Railway applications - Monoblock wheel products - Cast wheels

Overview

prEN 15718 - "Railway applications - Monoblock wheel products - Cast wheels" is a CEN draft/European standard that defines the requirements for cast railway wheels with a chilled rim used on European networks. It covers material grades, mechanical and metallurgical characteristics, testing and quality assurance for monoblock cast wheels intended for freight wagon applications at speeds up to and including 120 km/h. Two steel grades are specified (C ER7 and C ER8); for tread-braked wheels only C ER7 is permitted. The standard applies only to cast wheels that have passed the technical approval procedure prEN 13979-2:2005.

Key topics and requirements

The standard addresses technical areas essential to safe, durable railway wheels:

• Product definition and chemistry: required chemical composition and sampling locations for cast wheel steels (C ER7, C ER8).
• Mechanical characteristics: tensile tests, rim hardness, impact tests, fatigue performance and rim toughness.
• Heat treatment and chilled rim control: homogeneity of heat treatment to achieve a hardened rim and intended circumferential compressive residual stresses.
• Residual stresses: methods and acceptance criteria for verifying compressive stresses in the rim (including strain‑gauge and ultrasonic approaches).
• Material cleanliness and internal integrity: micrographic cleanliness and non‑destructive inspection (ultrasonic) procedures.
• Surface and geometric requirements: surface integrity, tolerances, static imbalance limits and allowable rectifications.
• Shot peening and corrosion protection: process control, quality assurance and marking requirements.
• Qualification, testing and delivery: product qualification procedures, batch control, per‑wheel checks and documentation requirements.
• Supporting methods and annexes: hydrogen control at melt, fatigue test examples, strain‑gauge methods, ultrasonic residual stress measurement, and product qualification/delivery guidance.

Applications and who uses it

prEN 15718 is used by organizations involved in the design, manufacture, procurement and maintenance of railway wheels:

• Wheel manufacturers (cast wheel producers) to design and qualify monoblock cast wheels with a chilled rim.
• Freight wagon builders and OEMs specifying wheels for wagons limited to 120 km/h.
• Rolling stock procurement and maintenance teams to ensure conformity of supplied wheels.
• Inspection and testing laboratories performing mechanical, metallurgical and non‑destructive tests.
• Regulatory bodies and conformity assessors verifying compliance with European requirements.

Related standards

• prEN 13979-2:2005 - Technical approval procedure required before application of prEN 15718.
• Annex ZA in the document references EU Directive 2001/16/EC (as amended) for interoperability and essential requirements.
• Developed under CEN/TC 256 (railway applications).

This standard is essential for ensuring safe, reliable cast monoblock wheel products (chilled rim) for European freight rail operations and supports consistent quality, testing and traceability across the supply chain.

Standards Content (Sample)

SLOVENSKI STANDARD
01-december-2007
Železniške naprave - Monoblok kolesa - Lita kolesa
Railway applications - Monoblock wheel products - Cast wheels
Ta slovenski standard je istoveten z: prEN 15718
ICS:
45.040 Materiali in deli za železniško Materials and components
tehniko for railway engineering
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
DRAFT
NORME EUROPÉENNE
EUROPÄISCHE NORM
September 2007
ICS 45.040
English Version
Railway applications - Monoblock wheel products - Cast wheels
Applications ferroviaires - Roues monobloc - Roues en
acier moulé
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee CEN/TC 256.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations which
stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other language
made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the
same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2007 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 15718:2007: E
worldwide for CEN national Members.

Contents Page
Foreword. 6
Introduction . 7
1 Scope. 8
2 Normative references . 8
3 Product definition . 9
3.1 Chemical composition. 9
3.1.1 Values to be achieved. 9
3.1.2 Location of the sample. 9
3.1.3 Chemical analysis. 10
3.2 Mechanical characteristics . 10
3.2.1 Tensile test characteristics. 10
3.2.2 Hardness characteristics in the rim . 11
3.2.3 Impact test characteristics. 12
3.2.4 Fatigue characteristics. 13
3.2.5 Toughness characteristic of the rim. 14
3.3 Heat treatment homogeneity . 15
3.3.1 Location of measurement . 15
3.3.2 Values to be achieved. 15
3.3.3 Test method. 15
3.4 Material cleanliness . 15
3.4.1 Micrographic cleanliness . 15
3.4.2 Internal integrity. 15
3.5 Residual stresses. 18
3.5.1 General. 18
3.5.2 Values to be achieved. 18
3.5.3 Test piece. 19
3.5.4 Measurement methods. 19
3.6 Surface characteristics. 19
3.6.1 Surface appearance. 19
3.6.2 Surface integrity. 20
3.7 Geometric tolerances . 20
3.8 Static imbalance. 22
3.9 Shot peening . 23
3.9.1 Requirements . 23
3.9.2 Quality assurance provisions. 23
3.10 Protection against corrosion . 24
3.11 Manufacture’s Markings. 24
Annex A (normative) Hydrogen control at the point of steel melt for monobloc wheels. 25
A.1 Sampling . 25
A.2 Analysis methods . 25
A.3 Operating precautions. 25
Annex B (informative) Example of a test method for the determination of fatigue
characteristics. 26
B.1 Test piece. 26
B.2 Test rig . 26
B.3 Test monitoring. 26
B.4 Analysis of results . 26
Annex C (informative) Strain gauge method for determining the variation of
circumferential residual stresses located deep under the tread . 27
C.1 Principle . 27
C.2 Procedure . 27
C.2.1 Fitting of a rim cross section with strain gauges prior to wheel cutting . 27
C.2.2 Execution of cutting. 27
C.2.3 Operations to be executed during cutting.28
C.3 Expression of results. 28
C.3.1 Calculation of the variation of the circumferential residual stress located deep
under the tread . 28
C.3.2 Calculation of the variation of the circumferential stress created by cutting
operation 1. 28
C.3.3 Calculation of the variation of the circumferential stress created by cutting
operation 2. 29
C.3.4 Calculation of the variation of the circumferential stress created by cutting
operation 3. 29
C.3.5 Final diagram representing the variation of the circumferential stress located
deep under the tread. 29
Annex D (informative) Ultrasonic method for determining the residual stress in the rim
(non destructive method). 33
D.1 Description of Measurement Method. 33
D.2 Acceptance Criteria . 34
Annex E (informative) Product qualification. 35
E.1 General. 35
E.2 Requirements . 35
E.2.1 Requirements for the producer . 35
E.2.2 Requirements for the product . 36
E.3 Qualification procedure. 36
E.3.1 General. 36
E.3.2 Documentation required. 36
E.3.3 Evaluation of manufacturing equipment and of the production processes. 37
E.3.4 Laboratory tests . 37
E.3.5 Testing of wheels. 38
E.4 Qualification certificate . 38
E.4.1 Condition of the validity . 38
E.4.2 Modification and extension. 38
E.4.3 Transference. 39
E.4.4 Lapsed certificate. 39
E.4.5 Cancellation. 39
E.5 Qualification documents . 39
Annex F (informative) Product delivery. 40
F.1 General. 40
F.2 Delivery condition. 40
F.3 Controls on each wheel. 41
F.4 Batch Control . 41
F.4.1 Controls . 41
F.4.2 Uniformity of batches by measurement of rim hardness . 42
F.4.3 Orientation of residual stresses on rim chilled wheels . 43
F.4.4 Visual inspection. 43
F.4.5 Quality plan. 43
F.5 Allowable rectification. 44
Annex ZA (informative) Relationship between this European Standard and the Essential
Requirements of EU Directive 2001/16/EC as amended by 2004/50/EC. 45
Bibliography . 47

Figures
Figure 1 — Location of test pieces . 11
Figure 2 — Readings taken on a radial section of the rim. 12
Figure 3 — Test pieces taken from the rim . 14
Figure 4 — Standard hub for ultrasonic examination . 18
Figure 5 — Range in variation of circumferential stress values. 18
Figure 6 — Symbols. 22
Figure B.1 — The Bastenaire fatigue method . 26
Figure C.1 — Fitting of strain-gauges. 30
Figure C.2a — Operation 1. 30
Figure C.2b — Operation 2. 31
Figure C.2c — Operation 3. 31
Figure C.3 — Cutting operations. 31
Figure C.3a — Variation of the stress created by operation 1 .32
Figure C.3b — Variation of the stress created by operation 2 .32
Figure C.3c — Variation of the stress created by operation 3 .32
Figure C.3d — Variation of the stress final diagram . 32
Figure C.4 — Method for determining the variation of the circumferential stress located
deep under the tread. 32
Figure D.1. 34
Figure F.1— Location of hardness measurements . 43

Tables
Table 1 — Maximum content of various element within cast wheels. 9
Table 2 — Minimum tensile test values of the rim and web .10
Table 3 — Minimum hardness values . 12
Table 4 — Average and minimum impact test characteristics. 13
Table 5 — Minimum fatigue characteristics. 13
Table 6 — Average surface roughness. 19
Table 7 — Geometric tolerances . 20
Table E.1 — Radial stress levels . 37
Table F.1 — Type and number of controls to be carried out.41

Foreword
This document (prEN 15718:2007) has been prepared by Technical Committee CEN/TC 256 “Railway
Applications”, the secretariat of which is held by DIN.
This document is currently submitted to the CEN Enquiry.
This document has been prepared under a mandate given to CEN by the European Commission and
the European Free Trade Association, and supports essential requirements of EC Directive(s).
For relationship with EC Directive(s), see informative Annex ZA, B, C or D, which is an integral part of
this document.
Introduction
Normative documents that up until now have been used in Europe for wheel delivery (UIC leaflets,
national standards) had, for the main purpose, a complete definition of the delivery procedures and
the wheel characteristics to be measured.
Product qualification was sometimes mentioned but the procedures and the characteristics that had to
be verified for the qualification were not given.
This standard addresses these issues by:
a) defining all the wheel characteristics;
NOTE These are either verified during the qualification or for the delivery of the product (see Clause 3).
b) defining qualification procedures (see Annex E);
c) defining delivery conditions (see Annex F).
NOTE A choice is given to the supplier, of either:
1) a traditional delivery procedure with a control by batch sampling as in existing documents
(see F.4);
2) delivery procedure using quality assurance concepts (see F.5).
The standard defines the wheel product qualification, the technical approval procedure is not within
the scope of this standard.
1 Scope
This European Standard specifies the characteristics of cast railway wheels for use on European
networks.
Two steel grades; C ER7 and C ER8, are defined in this standard. For tread braked wheels; only
C ER7 is used.
1)
This standard is applicable to cast wheels which have a chilled rim . The standard is only applicable
to cast wheels that have satisfied the technical approval procedure according to prEN 13979-2.
This standard applies only to wheels used in freight wagon applications for speeds up to and including
120 km/h.
2 Normative references
The following referenced documents are indispensable for the application 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.
prEN 13979-2, Railway applications — Wheelsets and bogies — Monobloc wheels — Technical
approval procedure — Part 2: Cast wheels
EN 473, Non destructive testing — Qualification and certification of NDT personnel — General
principles
EN 10002-1, Metallic materials — Tensile testing — Part 1: Method of test at ambient temperature
EN 10045-1, Metallic materials — Charpy impact tes — Part 1: Test method
EN 10293:2005, Steel — Castings for General Engineering Uses
EN ISO 6506-1, Metallic materials — Brinell hardness test — Part 1: Test method
EN ISO 6506-2, Metallic materials — Brinell hardness test — Part 2: Verification and calibration of
testing machines
EN ISO 6506-3, Metallic materials — Brinell hardness test — Part 3: Calibration of reference blocks
EN ISO 9000, Quality management systems — Fundamentals and vocabulary
ISO 1101, Geometrical Product Specifications (GPS) — Geometrical tolerancing — Tolerances of
form, orientation, location and run-out
ISO 4967:1998, Steel — Determination of content of nonmetallic inclusions — Micrographic method
using standard diagrams
ISO 5948:1994, Railway rolling stock material — Ultrasonic acceptance testing
ISO 6933:1986, Railway rolling stock material — Magnetic particle acceptance testing

1) Note “Rim Chilled” describes heat treatment of the rim, the aim of which is to harden the rim and to create
circumferential compressive residual stresses in the rim.
2)
ISO/TR 9769, Steel and iron — Review of available methods of analysis
ASTM E 399-90:1990, Test method for plane-strain fracture toughness of metallic materials
SAE J827, High carbon cast steel shot
SAE J442, Test strip, holder and gage for shot peening
SAE J443, Procedures for using standard shot peening test strip
SAE J444, Cast shot and grit size specifications for peening and cleaning
NF A 03-405
3 Product definition
3.1 Chemical composition
3.1.1 Values to be achieved
The maximum percentage contents of the various elements contained within cast wheels shall be as
given in Table 1.
Table 1 — Maximum content of various element within cast wheels
Steel Maximum content (unless otherwise stated)
grade
%
c a a, b c
C Si Mn P S Cr Cu Mo Ni V Cr +
Mo +
Ni
CER7 0,52 0,6 0,80 0,020 0,02 0,30 0,30 0,12 0,30 0,06 0,52
CER8 0,56 0,6 0,80 0,020 0,02 0,30 0,30 0,12 0,30 0,06 0,52
NOTE For special applications, variations within the maximum limit of these values may be agreed.
a
A maximum content of 0,025 % may be agreed at the time of enquiry or order (values reflect those in
the master draft of EN 13262).
b
minimum sulphur content may be agreed at the time of enquiry and at the time of order, in order to
safeguard against hydrogen cracking.
c
These values have been taken from EN 10293:2005, the supplier shall ensure that use of these values
(which exceed those in EN 13262) do not adversely affect the metallurgical structure of the wheel.

3.1.2 Location of the sample
The sample used for determining the chemical composition shall be taken 15 mm below the tread at
its nominal diameter.
2) See also CEN report CR 10261:1995
3.1.3 Chemical analysis
The chemical composition analysis shall be performed according to methods and definitions that are
described in ISO/TR 9769.
3.2 Mechanical characteristics
3.2.1 Tensile test characteristics
3.2.1.1 Values to be achieved
Cast wheels shall have rim and web characteristics of at least the values given in Table 2.
Table 2 — Minimum tensile test values of the rim and web
Steel grade Rim Web
a b
R
R ≥≥≥≥ A ≥≥≥≥ Rm reduction ≥≥≥≥ A ≥≥≥≥
m
eH 5 5
2 2 2
N/mm N/mm % N/mm %
CER7 ≥ 520 820/940 ≥ 14 ≥ 110 ≥ 16
CER8 ≥ 540 860/980 ≥ 13 > 120 ≥ 16
a
If no distinctive yield strength is present, the proof stress R shall be determined.
p0,2
b
Reduction of tensile strength as compared to that of the rim on the same wheel.

3.2.1.2 Location of test pieces
Test pieces shall be taken from the rim and the web of the wheel, as indicated in Figure 1.

Key
3 Nominal diameter 5 Impact test pieces
4 Tensile test pieces 6 Notch
NOTE Where the micro-structure of the wheel varies as a result of the casting process the test piece shall
be taken from the worst-case location.
Figure 1 — Location of test pieces
3.2.1.3 Test method
This shall be performed in accordance with EN 10002-1. The test piece diameter shall be at least
10 mm in the parallel length, and the gauge length shall be 5 times the diameter.
NOTE If the wheel design prevents a sample of the stated size being taken, a smaller sized sample may be
taken after agreement between the customer and supplier.
3.2.2 Hardness characteristics in the rim
3.2.2.1 Values to be achieved
Minimum values of Brinell hardness applicable to the whole wear zone of the rim shall be as given in
Table 3. These values shall be achieved up to a maximum depth of 35 mm under the tread, even if
the wear-depth is higher than 35 mm. These measurements shall be taken from the points defined by
B, C and D on Figure 2.
Hardness values in the rim-web transition (point A on Figure 2) shall be at least 10 points lower than
the wear limit values.
Table 3 — Minimum hardness values
Steel grade Minimum value for Brinell hardness
CER7 235
CER8 245
3.2.2.2 Location of readings
Four readings shall be carried out on a radial section of the rim as shown in Figure 2. Where the
microstructure of the wheel varies as a result of the casting process the test locations shall occur in
the worst-case areas of the wheel.

Key
1 Limit of wear or last turning diameter (according to customer’s requirements)
Inside surface of finished wheel
3 Nominal diameter
Figure 2 — Readings taken on a radial section of the rim
3.2.2.3 Test method
This shall be performed in accordance with EN ISO 6506-1. The ball diameter is 5 mm.
3.2.3 Impact test characteristics
3.2.3.1 Values to be achieved
Cast wheels shall have the average and minimum impact values as given in Table 4.
NOTE The values represent the average and minimum values for the three test specimens defined
in 3.2.3.2.
At +20 °C, U notch specimens shall be used. At -20 °C, V notch specimens shall be used.
Table 4 — Average and minimum impact test characteristics
Steel grade
KU (J) at +20 °°°°C KV (J) at -20 °°°°C
Average values Minimum values Average values Minimum values
CER7 ≥ 17 ≥ 12 ≥ 10 ≥ 7
CER8 ≥ 17 ≥ 12 ≥ 10 ≥ 5
3.2.3.2 Location of the test pieces
Test pieces shall be taken from the rim and the web of the wheel, as indicated in Figure 1.
The bottom notch axis shall be parallel to the A-A axis of Figure 1.
3.2.3.3 Test method
This shall be performed in accordance with EN 10045-1.
3.2.4 Fatigue characteristics
3.2.4.1 Values to be achieved
Independent of the steel grade, the web shall withstand the stress variation, ∆σ, given in Table 5
during 10 cycles without any crack initiation, with a probability of 99,7 %.
Table 5 — Minimum fatigue characteristics
State of delivery of the web ∆σ∆σ
∆∆σσ
N/mm
Fully Machined 450
Partially machined or as cast 315
and shot peened
NOTE 1 The aim of these characteristics is to guarantee that product characteristics are higher than those
used for the definition of permissible stresses for the fatigue design of the web.
NOTE 2 As there are many approximations in a fatigue calculation, it is not realistic to distinguish between the
two steel grades.
3.2.4.2 Specimens for fatigue test
Specimens shall consist of wheels as delivered. Their surface appearances shall be those defined
in 3.6.
3.2.4.3 Test method
The test method shall allow bending stresses to be created in a web section.
The tests to demonstrate the fatigue properties shall be performed in such a manner that statistical
evaluation to assess the results can be applied.
Tests shall be monitored by measuring the radial stresses which exist in the crack initiation area.
NOTE An example of the method is given in Annex B.
3.2.5 Toughness characteristic of the rim
3.2.5.1 General
This characteristic shall only be verified on tread braked wheels (service brake or parking brake).
3.2.5.2 Values to be achieved
For CER7 steel grade, the average value obtained from six test pieces shall be greater than or equal
2 2
to 80 N/mm m , and any single value shall not be below a minimum of 70 N/mm m .
For CER8 steel grade, the average value obtained from six test pieces shall be greater than or equal
2 2
to 70 N/mm m , and any single value shall not be below a minimum of 60 N/mm m .
3.2.5.3 Location of test pieces
Six test pieces shall be taken from the rim as indicated in Figure 3. Where the microstructure of the
wheel varies as a result of the casting process the test locations shall occur in the worst-case areas of
the wheel.
Figure 3 — Test pieces taken from the rim
3.2.5.4 Test method
The test shall be performed according to ASTM E 399-90.
The test conditions shall be as follows:
a) the compact specimen shall have a CT thickness of 30 mm (CT 30 specimen), with chevron
notch having an aperture angle of 90° (see Figure 4 of ASTM E 399.90);
b) temperature during the test between +15 °C and +25 °C;
c) measurement of the crack displacement of the specimen as indicated in Figure 3 of ASTM E 399.90;
d) rate of increase of stress intensity, ∆K/s (stress intensity per second), shall be within the range
2 2
0.55 N/mm√m/s to 1 N/mm√m/s (see ASTM E 399-90:1990, 8.3);
e) The value of the toughness to be considered shall be the value K which is calculated from the
Q
value of the load F from the load-displacement record.
Q
3.3 Heat treatment homogeneity
3.3.1 Location of measurement
The hardness measurements shall be taken at three points on the outside surface of the rim. Where
the casting process uses risers (see Note), the test locations shall occur both in-line and between the
riser positions.
The impressions shall be made on a same diameter in the area located as defined in Figure F.1.
NOTE Risers are defined in this document as the reservoir of molten metal from which the casting feeds as
it shrinks during solidification.
3.3.2 Values to be achieved
The hardness value variation shall be within a 30 HB range for the whole wheel batch.
3.3.3 Test method
The test shall be performed in accordance with EN ISO 6506-1. The ball diameter is 10 mm.
3.4 Material cleanliness
3.4.1 Micrographic cleanliness
Open issue: for forged and rolled wheels it is possible to distinguish different types of non-metallic
inclusions visually (as they distort differently during the forming process). For cast wheels they all look
alike, so a different method to ISO 4967:1998 needs to be used whilst demonstrating an equivalent
level of safety compared to a forged and rolled wheel.
NOTE For enquiry purposes consideration shall be given to the following:
 in the European standard for cast steels (EN 10293) there are no requirements for cleanliness;
 the relative level of safety given by the adoption of AAR M107-208 section 9 compared to that of
ISO 4967:1998 and the levels to be achieved as specified in EN 13262;
 whether the fracture toughness requirements applied to all wheels encompasses all the safety
characteristics of the micrographic cleanliness checks covered in ISO 4967:1998.
3.4.2 Internal integrity
3.4.2.1 General
Internal integrity shall be determined from ultrasonic examination. Examination shall be carried out
before shot peening.
NOTE Standard defects are flat bottom holes with different diameters.
3.4.2.2 Level to be achieved
3.4.2.2.1 Rim
The rim shall have no internal defects that give echo magnitudes higher than or equal to those
obtained for a standard defect situated at the same depth. The diameter of this standard defect shall
be 2 mm.
There shall be no attenuation of the back echo higher than 4 dB during axial examination.
3.4.2.2.2 Web
The web shall not have:
a) more than 10 echoes with magnitudes greater than or equal to those obtained for standard
defects of diameter 3 mm;
b) echoes with magnitudes greater than or equal to those obtained for standard defects of diameter
5 mm.
The distance between two acceptable defects shall be at least 50 mm.
Open issue: The practicality of applying this method/achieving these values for cast wheels is to be
established.
3.4.2.2.3 Hub
The hub shall not have:
a) more than 3 echoes of magnitude greater than or equal to those obtained for standard defects of
3 mm diameter;
b) echoes of magnitude greater than or equal to those obtained for standard defects of 5 mm
diameter.
The distance between two acceptable defects shall be at least 50 mm.
For one circumferential examination, no attenuation of the back echo equal to or greater than 6 dB
shall be permitted.
3.4.2.3 Test piece
Examination shall be made of the complete wheel, after heat treatment, either before machining or in
the finish machined condition, before any corrosion protection is applied.
3.4.2.4 Method of examination
3.4.2.4.1 General
Samples shall undergo ultrasonic examination in accordance with ISO 5948 in accordance with the
following special conditions of 3.4.2.4.2, 3.4.2.4.3 and 3.4.2.4.4.
3.4.2.4.2 Rim
The rim examination shall be made in accordance with ISO 5948:1994, Table 1 methods D and D
1 2
.
The examination in this area shall cover the rim-to-web transition.
Defect estimation shall be made by comparison to artificial defects in the standard rim in accordance
with ISO 5948:1994, Figures 1 and 2.
3.4.2.4.3 Web
The web examination shall be made on both faces. The direction of the examination is perpendicular
to the surface.
Defect estimation shall be made by comparison to artificial defects in a standard web.
The web shall be defined as the part of the wheel between the two diameters at “m” and “n”, which
shall be agreed between the customer and supplier (see Figure 7).
The thickness, “e”, of the web shall be defined as:
m+ n
e =
The location of the artificial defects shall be given as a function of e. They shall be spaced by at least
100 mm in a circumferential orientation.
 e ≤ 10 mm
One 3 mm diameter flat bottom hole located 5 mm below the inner surface of the web
One 5 mm diameter flat bottom hole located 5 mm below the inner surface of the web
 10 mm < e ≤ 20 mm
Two 3 mm diameter flat bottom holes located 5 mm and (e - 5) mm below the inner surface of the web
Two 5 mm diameter flat bottom holes located 5 mm and (e - 5) mm below the inner surface of the web
 e > 20 mm
Three 3 mm diameter flat bottom holes located 5 mm, (e) mm and (e - 5) mm below the inner surface
of the web
Three 5 mm diameter flat bottom holes located 5 mm, (e) mm and (e - 5) mm below the inner surface
of the web
3.4.2.4.4 Hub
The Hub examination shall be made from both faces. The direction of the examination shall be
perpendicular to the surface.
Defect estimation shall be made by comparison to artificial defects in the standard hub shown in
Figure 4.
Calibration references are:
 3 standard defects of diameter 3 mm located at different depths;
 3 standard defects of diameter 5 mm located at different depths.
Spacing as shown on the Figure 4.
Figure 4 — Standard hub for ultrasonic examination
3.5 Residual stresses
3.5.1 General
Wheel heat treatment shall induce a compressive circumferential residual stress field inside the rim.
3.5.2 Values to be achieved
The level of compressive circumferential stresses shall be measured near the surface of the tread,
2 2
and shall be in the range 80 N/mm to 150 N/mm . These stresses shall be equal to zero between
35 mm and 50 mm.
NOTE The stress distribution is shown in Figure 5 below the rolling contact line.

Figure 5 — Range in variation of circumferential stress values
3.5.3 Test piece
The test piece shall be the complete wheel after heat treatment.
3.5.4 Measurement methods
Measurement methods shall estimate the variation of circumferential stresses located deep under the
tread. This method shall be agreed between the supplier and the customer.
Annex C gives an example method that can be used for this measurement, the stress distribution
values given in Figure 5 shall be applied to this method.
Annex D gives another method which is non-destructive, for this method the values to be achieved
shall not be those defined by Figure 5. However, it shall be demonstrated that the values to be
achieved using this method give the same stress distribution as those prescribed in Figure 5.
3.6 Surface characteristics
3.6.1 Surface appearance
3.6.1.1 Characteristics to be achieved
The wheel surface shall not show any marks other than those at the positions stipulated in this
standard.
NOTE According to their use, wheels may be fully or part machined.
The “as cast” faces of the web extending approximately one half of the way into the hub and rim fillet
radii on the front and on the back of the wheel, shall be shot-peened.
Average surface roughness (R ) area values of “finished” or “ready for assembly” wheels shall be as
a
given in Table 6.
Table 6 — Average surface roughness
a
Area of the wheel State of Delivery Roughness, R
a
µm
Bore Finished
≤ 12,5
b
Ready for assembly 0,8 to 3,2
c
Web and hub Finished ≤ 12,5
c
Rim Tread Finished
≤ 6,3
c
Rim Faces Finished
≤ 6,3
a
see F.2
b
If the wheel has to be fitted on a hollow axle, other values may be required, for the purpose of

the in-service ultrasonic inspection
c
If defined in the order, this area of the wheel may remain unmachined, provided the tolerances

indicated in this table are achieved

3.6.1.2 Measurement method
The roughness of the wheel surfaces (R ) at the delivery stage indicated in Table 6 shall be inspected
a
by comparison with the roughness specimen described in or measured with a profile meter on the
plane surface.
3.6.2 Surface integrity
3.6.2.1 General
Surface integrity shall be determined by a magnetic particle test of the web, carried out in accordance
with 3.6.2.4 and visual inspection (for porosity and other visible defects) both in the web and
elsewhere.
3.6.2.2 Level to be achieved
The maximum indicated length of permissible surface breaking defects on a finished wheel shall be
2 mm.
3.6.2.3 Test piece
Examination shall be made on the complete wheel after heat treatment and after shot cleaning but
before shot peening. The examination shall occur on the final surface of the wheel (as delivered)
before the application of any temporary corrosion protection.
3.6.2.4 Methods of inspection
General requirements for the magnetic particle test shall be defined in accordance with ISO 6933 with
the following exceptions:
a) the level of surface magnetic induction shall be greater than 4 mT;
b) the level of ultra-violet light energy shall be greater than 15 W/m².
The magnetisation method shall be performed in accordance with ISO 6933:1986, Figure C.
The apparatus used shall scan the entire wheel surface and be able to detect the defects whatever
their orientation.
3.7 Geometric tolerances
The geometry and dimensions of wheels shall be defined by a drawing included with the order.
The geometric tolerances shall conform to those given in Table 7.
NOTE The symbols are defined in Figure 6.
Table 7 — Geometric tolerances
a
Designation Symbols Values (mm)
b
Dimensions Geometric Unmachined Machined
Rim
External diameter a 0 / +4
Internal diameter (outer) b1  0 / -4
Internal diameter (inner) b2 0 / -6 0 / -4
Width d  ± 1
e
Tread profile  v
≤ 0,5
Circularity of the tread s
≤ 0,2
Total run o
...