EN 13262:2026
(Main)Railway applications - Wheelsets and bogies - Wheels - Product requirements
- Abstract
This document specifies the characteristics of wheels for all heavy rail track gauges.
This document applies to heavy rail vehicles and applies, in principle, to other vehicles such as urban rail vehicles. Five steel grades, ER6, ER7, ER8, ERS8 and ER9, are defined in this document.
NOTE 1 Steel grade ERS8 has been introduced in this document as an optimization of steel grades ER8 and ER9 due to contact fatigue (RCF), taking into account service feedback from Europe, for example, BS 5892-3 in force in the United Kingdom.
Some features are provided as a Category 1 or Category 2 function.
The requirements defined in this document apply to cylindrical bores. Most requirements also apply to wheels with tapered bores. Specific requirements for tapered bores (e.g. geometrical dimensions, etc.) are defined in the technical specification.
This document applies to monobloc wheels in vacuum degassed steel, forged and rolled, with surface treated rims, which have already been the subject of extensive commercial applications on a European network or have complied with a technical approval procedure according to EN 13979-1:2020 to validate their design.
Annex A describes the evaluation process for accepting new materials that are not included in this document.
This document defines the requirements to be met for wheels; the technical approval procedure is not part of the scope of this document.
NOTE 2 A "surface-treated rim" is achieved by heat treatment which aims to harden the rim and create compressive residual stress.
- Status
- Published
- Publication Date
- 23-Jun-2026
- Technical Committee
- CEN/TC 256 - Railway applications
- Drafting Committee
- CEN/TC 256/SC 2/WG 11 - Wheels - Wheelsets
- Current Stage
- 6060 - Definitive text made available (DAV) - Publishing
- Start Date
- 24-Jun-2026
- Due Date
- 11-Sep-2024
- Completion Date
- 24-Jun-2026
EN 13262:2026 is a CEN European Standard for railway wheel product requirements. EN 13262:2026 specifies the characteristics, test methods and supply conditions for monobloc wheels for heavy rail track gauges, mainly for heavy rail vehicles and, in principle, for urban rail vehicles. It covers five steel grades - ER6, ER7, ER8, ERS8 and ER9 - and applies to wheels with cylindrical bores, with most requirements also used for tapered bores where the technical specification adds the detailed geometry.
What does EN 13262:2026 specify?
EN 13262:2026 specifies the requirements for monobloc railway wheels in vacuum degassed steel, forged and rolled, with surface-treated rims. The document sets product requirements, qualification rules and supply conditions for wheels that have already seen extensive use on European networks or have been technically approved to validate the design.
The document is organized into:
- Clause 1 - Scope
- Clause 2 - Normative references
- Clause 3 - Terms and definitions
- Clause 4 - Product definition
- Clause 5 - Product qualification
- Clause 6 - Conditions of supply of the product
- Clause 7 - Tips for choosing the steel grade
Annexes A, D, E and F are normative, so their procedures form part of compliance. Annexes B, C, G and ZA are informative and give examples, guidance or legal context.
| Annex | What it covers |
|---|---|
| A | Evaluation process for accepting new materials |
| B | Examples of fatigue test benches |
| C | Destructive strain-gauge method for residual stress measurement |
| D | Product qualification |
| E | Conditions of supply of the product |
| F | Measurement of hydrogen content in steel for monobloc wheels |
| G | Common applications of steel grades |
| ZA | Relationship with EU Directive (EU) 2016/797/EC |
What are the key requirements of EN 13262:2026?
EN 13262:2026 sets the wheel material, mechanical, geometric and quality-control requirements that manufacturers and buyers need to verify. In practice, the document is used to specify what a wheel must be made of, how it is tested, how it is delivered and how conformity is checked in production and qualification.
Material and mechanical properties
Clause 4.1 limits the chemical composition for each steel grade and fixes the sampling position 15 mm under the running tread at nominal diameter. That matters because the chemical check has to represent the wheel material where it is most relevant in service.
Clause 4.2 requires tensile, hardness, impact, fatigue and rim toughness performance. The practical effect is that the rim and web must be checked separately, and the required values depend on the steel grade, the wheel category and, for some properties, the braking or running-surface use.
Clause 4.2.4 requires the wheel web to withstand fatigue loading for 10 million cycles without crack initiation at the defined probability level. Annex B gives example fatigue test rigs, so laboratories can reproduce the loading in a controlled way.
Cleanliness, internal integrity and residual stress
Clause 4.4 covers micrographic cleanliness and internal integrity. This means the wheel material is checked for non-metallic inclusions and internal defects by microscopy and ultrasonic testing, with separate acceptance levels for the rim, web and hub.
Clause 4.5 requires compressive circumferential residual stress in the rim after heat treatment. This matters because residual stress is part of the wheel’s fatigue resistance and overheating behaviour, and the standard links excessive tensile effects in the web to further assessment.
Annex C gives a destructive strain-gauge method for measuring the variation of circumferential residual stress deep under the running surface. It is a measurement route for situations where the technical specification asks for a defined residual-stress method.
Geometry, imbalance and surface condition
Clause 4.6 sets surface finish and surface integrity requirements, including visual checks and magnetic particle testing or an equivalent method defined in the technical specification. Clause 4.7 then fixes geometric tolerances for the wheel drawing, tread profile, run-out, hub bore and other key dimensions.
Clause 4.8 limits static imbalance according to vehicle speed. In practice, this is the part that controls how much mass correction is acceptable before delivery or assembly.
Clause 4.9 requires corrosion protection on machined and non-machined wheel areas, and it makes thermo-sensitive paint mandatory on tread braked freight wagon wheels. For other tread braked applications it is recommended, and the paint has its own product checks in Clause 4.9.2.
Marking, injection hole and wheel category
Clause 4.10 requires traceability marking, including the manufacturer’s mark, cast or batch number, steel grade, manufacture date, imbalance position and serial number after heat treatment. That gives the wheel a permanent identity for production control and service traceability.
Clause 4.11 covers the injection hole thread used for dismantling a wheel from an axle. Where no other design constraint applies, the hole is on the external side of the wheel and uses a G ¼" cylindrical thread unless the technical specification says otherwise.
Qualification and supply controls
Annex D makes product qualification a structured process with documentation, factory assessment, laboratory tests and operational testing in service. It also defines product groups, requalification after manufacturing changes, and the contents of the qualification record.
Annex E defines the conditions of supply. The technical specification must state the wheel geometry, category, delivery state, quality-check method, test-piece dimensions, corrosion protection, markings and measurement methods. It also sets the choice between batch sampling and an approved quality plan, plus the required checks on every delivered wheel.
What terms does EN 13262:2026 define?
- Technical specification - A document that adds specific parameters or product requirements to those in EN 13262:2026.
- Batch - A group of wheels assumed to have the same characteristics, usually from the same design, cast, forging process and heat treatment.
- Nominal diameter - The diameter of the running tread of a new wheel as shown on the wheel drawing.
- Wheel categories - A classification based on operating conditions that determines which requirements apply; Category 1 is generally for speeds above 200 km/h and Category 2 for speeds at or below 200 km/h.
Who uses EN 13262:2026?
EN 13262:2026 is used by wheel manufacturers, steel suppliers, railway vehicle builders, qualification laboratories, inspection bodies and railway operators. It supports design selection, material approval, manufacturing control, delivery inspection and in-service qualification of railway wheels.
Buyers and quality managers use EN 13262:2026 to write procurement specifications and acceptance plans. Engineers use it to choose steel grade, wheel category, surface state and qualification route for the intended service duty.
What changed in EN 13262:2026 from the previous edition?
EN 13262:2026 supersedes EN 13262:2020. The foreword states these main changes:
- mandatory application of thermo-sensitive paint in tread braked freight application
- definition of assessment and product requirements for thermo-sensitive paint
- improved definition of the product groups submitted to qualification
- improved requirements for assessing product qualification after manufacturing-process changes
- definition of the wheel nominal diameter
Which standards are used with EN 13262:2026?
EN 13262:2026 relies on several normative references that supply the test methods and control rules used in the document:
- EN 13979-1:2023 - technical approval procedure for forged and rolled monobloc wheels, and a reference for wheel design and fatigue evaluation
- EN ISO 148-1:2016 - Charpy pendulum impact test method
- EN ISO 6506-1:2014 - Brinell hardness test method
- EN ISO 6892-1:2019 - tensile testing at room temperature
- EN ISO 9712:2022 - qualification and certification of NDT personnel
- EN ISO 14284:2022 - sampling and preparation of steel samples for chemical composition
- ISO 4967:2013 - micrographic determination of non-metallic inclusions
- ISO 5948:2018 - ultrasonic acceptance testing for railway rolling stock material
- ISO 6933:1986 - magnetic particle acceptance testing for railway rolling stock material
- ASTM E399-22 - fracture toughness test method for metallic materials
What does the EN 13262:2026 document contain?
EN 13262:2026 contains detailed requirement tables for chemical composition, tensile properties, hardness, impact resistance, fatigue, toughness, cleanliness, residual stresses, surface condition, geometry and static imbalance. It also includes figures that show test-piece locations, measurement points, wear groove geometry, marking positions and residual-stress sample preparation.
Annex B gives three example fatigue test bench arrangements, with the wheel as the test piece. Annex C gives formulas and a step-by-step procedure for calculating circumferential residual stress from strain-gauge measurements after cutting operations.
Annex D and Annex E are the most operational parts of the document for industry. Annex D covers qualification evidence, audits, laboratory tests, provisional qualification and in-service monitoring, while Annex E covers delivery states, unit checks, batch sampling, quality plans, permitted repairs and retesting.
Annex F defines how to measure hydrogen content in steel for monobloc wheels, including sampling routes, analysis methods and precautions. Annex ZA links the standard to EU rail interoperability requirements for locomotives and passenger vehicles.
Relations
- Effective Date
- 18-Jan-2023
- Effective Date
- 15-Jul-2026
- Effective Date
- 15-Jul-2026
- Effective Date
- 15-Jul-2026
- Effective Date
- 15-Jul-2026
- Effective Date
- 15-Jul-2026
- Effective Date
- 15-Jul-2026
- Effective Date
- 15-Jul-2026
- Effective Date
- 15-Jul-2026
- Effective Date
- 15-Jul-2026
- Effective Date
- 01-Jul-2026
- Referred By
EN 13260:2020 - Railway applications - Wheelsets and bogies - Wheelsets - Product requirements - Effective Date
- 01-Jul-2026
- Effective Date
- 01-Jul-2026
- Effective Date
- 01-Jul-2026
- Effective Date
- 01-Jul-2026
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Frequently Asked Questions
EN 13262:2026 is a standard published by the European Committee for Standardization (CEN). Its full title is "Railway applications - Wheelsets and bogies - Wheels - Product requirements". This standard covers: This document specifies the characteristics of wheels for all heavy rail track gauges. This document applies to heavy rail vehicles and applies, in principle, to other vehicles such as urban rail vehicles. Five steel grades, ER6, ER7, ER8, ERS8 and ER9, are defined in this document. NOTE 1 Steel grade ERS8 has been introduced in this document as an optimization of steel grades ER8 and ER9 due to contact fatigue (RCF), taking into account service feedback from Europe, for example, BS 5892-3 in force in the United Kingdom. Some features are provided as a Category 1 or Category 2 function. The requirements defined in this document apply to cylindrical bores. Most requirements also apply to wheels with tapered bores. Specific requirements for tapered bores (e.g. geometrical dimensions, etc.) are defined in the technical specification. This document applies to monobloc wheels in vacuum degassed steel, forged and rolled, with surface treated rims, which have already been the subject of extensive commercial applications on a European network or have complied with a technical approval procedure according to EN 13979-1:2020 to validate their design. Annex A describes the evaluation process for accepting new materials that are not included in this document. This document defines the requirements to be met for wheels; the technical approval procedure is not part of the scope of this document. NOTE 2 A "surface-treated rim" is achieved by heat treatment which aims to harden the rim and create compressive residual stress.
This document specifies the characteristics of wheels for all heavy rail track gauges. This document applies to heavy rail vehicles and applies, in principle, to other vehicles such as urban rail vehicles. Five steel grades, ER6, ER7, ER8, ERS8 and ER9, are defined in this document. NOTE 1 Steel grade ERS8 has been introduced in this document as an optimization of steel grades ER8 and ER9 due to contact fatigue (RCF), taking into account service feedback from Europe, for example, BS 5892-3 in force in the United Kingdom. Some features are provided as a Category 1 or Category 2 function. The requirements defined in this document apply to cylindrical bores. Most requirements also apply to wheels with tapered bores. Specific requirements for tapered bores (e.g. geometrical dimensions, etc.) are defined in the technical specification. This document applies to monobloc wheels in vacuum degassed steel, forged and rolled, with surface treated rims, which have already been the subject of extensive commercial applications on a European network or have complied with a technical approval procedure according to EN 13979-1:2020 to validate their design. Annex A describes the evaluation process for accepting new materials that are not included in this document. This document defines the requirements to be met for wheels; the technical approval procedure is not part of the scope of this document. NOTE 2 A "surface-treated rim" is achieved by heat treatment which aims to harden the rim and create compressive residual stress.
EN 13262:2026 is classified under the following ICS (International Classification for Standards) categories: 45.040 - Materials and components for railway engineering. The ICS classification helps identify the subject area and facilitates finding related standards.
EN 13262:2026 has the following relationships with other standards: It is inter standard links to EN 13262:2020, EN ISO 6892-1:2019, ISO 4967:2013, EN ISO 9712:2022, EN ISO 14284:2022, ISO 6933:1986, EN ISO 148-1:2016, ISO 5948:2018, EN 13979-1:2023, EN ISO 6506-1:2014, EN 14033-1:2017, EN 13260:2020, EN 13260:2009+A1:2010, EN 15313:2016, EN 14535-2:2019. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
EN 13262:2026 is associated with the following European legislation: EU Directives/Regulations: 2016/797/EU, 2016/797/EU, 2016/797/EU, 2016/797/EU, 2016/797/EU, 2016/797/EU, 2016/797/EU, 2016/797/EU, 2016/797/EU, 2016/797/EU, 2016/797/EU, 2016/797/EU, 2016/797/EU; Standardization Mandates: M/483, M/591. When a standard is cited in the Official Journal of the European Union, products manufactured in conformity with it benefit from a presumption of conformity with the essential requirements of the corresponding EU directive or regulation.
EN 13262:2026 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
SLOVENSKI STANDARD
01-september-2026
Nadomešča:
SIST EN 13262:2020
Železniške naprave - Kolesne dvojice in podstavni vozički - Kolesa - Zahtevane
lastnosti proizvoda
Railway applications - Wheelsets and bogies - Wheels - Product requirements
Bahnanwendungen - Radsätze und Drehgestelle - Räder - Produktanforderungen
Applications ferroviaires - Essieux montés et bogies - Roues - Prescriptions pour le
produit
Ta slovenski standard je istoveten z: EN 13262:2026
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.
EN 13262
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2026
EUROPÄISCHE NORM
ICS 45.040 Supersedes EN 13262:2020
English Version
Railway applications - Wheelsets and bogies - Wheels -
Product requirements
Applications ferroviaires - Essieux montés et bogies - Bahnanwendungen - Radsätze und Drehgestelle -
Roues - Prescriptions pour le produit Räder - Produktanforderungen
This European Standard was approved by CEN on 1 December 2025.
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. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists 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-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 13262:2026 E
worldwide for CEN national Members.
Contents
European foreword . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
4 Product definition . 7
4.1 Chemical composition . 7
4.1.1 Values to be achieved . 7
4.1.2 Sampling position . 7
4.1.3 Chemical analysis . 7
4.2 Mechanical characteristics . 7
4.2.1 Characteristics from the tensile test . 7
4.2.2 Hardness characteristics in the rim . 9
4.2.3 Impact resistance characteristics . 12
4.2.4 Fatigue characteristics . 12
4.2.5 Toughness characteristics of the rim . 13
4.3 Heat treatment homogeneity . 14
4.3.1 Values to be achieved . 14
4.3.2 Test pieces . 15
4.3.3 Test method . 15
4.4 Material cleanliness . 15
4.4.1 Micrographic cleanliness . 15
4.4.2 Internal integrity . 17
4.5 Residual stresses. 19
4.5.1 General. 19
4.5.2 Values to be achieved . 19
4.5.3 Test piece . 20
4.5.4 Measurement methods . 20
4.6 Surface characteristics. 20
4.6.1 Surface finish . 20
4.6.2 Surface condition for the oil injection hole . 21
4.6.3 Surface integrity . 21
4.7 Geometrical tolerances . 22
4.7.1 General. 22
4.7.2 Wear groove. 25
4.8 Static imbalance . 25
4.9 Coating and protection against corrosion . 26
4.9.1 General requirements . 26
4.9.2 Thermo-sensitive paint on tread braked wheels. 26
4.10 Marking . 27
4.11 Injection hole thread . 28
5 Product qualification. 28
6 Conditions of supply of the product . 28
7 Tips for choosing the steel grade . 28
Annex A (normative) Evaluation process for the acceptance of new materials . 29
A.1 General . 29
A.2 First step: Characterization of a new steel grade . 29
A.3 Step two: Testing in service . 29
A.4 Step three: Report . 30
Annex B (informative) Examples of test benches for fatigue testing . 31
B.1 Test piece . 31
B.2 First test method . 31
B.3 Second test method . 33
B.4 Third test method . 34
Annex C (informative) Strain gauge method of determining the variation in circumferential residual
stresses deep under the running surface (destructive method) . 36
C.1 Method principle . 36
C.2 Procedure . 36
C.3 Calculation of the variation of the circumferential residual stress deep under the running surface
........................................................................................................................................................................................... 37
Annex D (normative) Product qualification . 41
D.1 Introduction . 41
D.2 General . 41
D.3 Requirements . 43
D.4 Qualification procedure . 44
D.5 Validity of the qualification . 47
D.6 Qualification record . 48
Annex E (normative) Conditions of supply of the product . 49
E.1 Introduction . 49
E.2 General . 49
E.3 Delivery states . 50
E.4 Unit checks . 50
E.5 Batch sampling check . 50
E.6 Quality plan . 52
E.7 Permissible repairs . 53
E.8 Retest . 53
Annex F (normative) Measurement of the hydrogen content of steel for monobloc wheels . 54
F.1 General . 54
F.2 Sampling . 54
F.3 Analysis method . 54
F.4 Precautions . 54
Annex G (informative) Common applications of steel grades . 55
Annex ZA (informative) Relationship between this European Standard and the essential requirements of
EU Directive (EU) 2016/797/EC aimed to be covered . 56
Bibliography . 58
European foreword
This document (EN 13262:2026) has been prepared by the CEN/TC 256 “Railway applications” Technical
Committee, the secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by December 2026, and conflicting national standards shall
be withdrawn at the latest by December 2026.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 13262:2020.
The main changes compared with EN 13262:2020 are as follows:
— mandatory application of thermo-sensitive paint in tread braked freight application;
— definition of assessment/ product requirements for thermo-sensitive paint;
— an improved definition of the product groups submitted to qualification;
— improved requirements to assess product qualification after changes made in the manufacturing
process;
— definition of the wheel nominal diameter.
The informative annexes to this document provide additional guidance that is not mandatory but that
helps to understand or use the document.
This document has been prepared under a standardization request addressed to CEN by the European
Commission. The Standing Committee of the EFTA States subsequently approves these requests for its
Member States.
For the relationship with EU Legislation, see informative Annex ZA, which is an integral part of this
document.
NOTE The informative annexes can contain optional requirements. For example, a test method that is optional,
or presented as an example, can contain requirements, but it is not necessary to meet these requirements to be in
compliance with the document.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland,
Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North
Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the United
Kingdom.
1 Scope
This document specifies the characteristics of wheels for all heavy rail track gauges.
This document applies to heavy rail vehicles and applies, in principle, to other vehicles such as urban rail
vehicles. Five steel grades, ER6, ER7, ER8, ERS8 and ER9, are defined in this document.
NOTE 1 Steel grade ERS8 has been introduced in this document as an optimization of steel grades ER8 and ER9
due to rolling contact fatigue (RCF), taking into account service feedback from Europe, for example, BS 5892-3 in
force in the United Kingdom.
Some features are provided as a Category 1 or Category 2 function.
The requirements defined in this document apply to cylindrical bores. Most requirements also apply to
wheels with tapered bores. Specific requirements for tapered bores (e.g. geometrical dimensions, etc.)
are defined in the technical specification.
This document applies to monobloc wheels in vacuum degassed steel, forged and rolled, with surface
treated rims, which have already been the subject of extensive commercial applications on a European
network or have complied with a technical approval procedure according to EN 13979-1:2023 to validate
their design.
Annex A describes the evaluation process for accepting new materials that are not included in this
document.
This document defines the requirements to be met for wheels; the technical approval procedure is not
part of the scope of this document.
NOTE 2 A “surface-treated rim” is achieved by heat treatment which aims to harden the rim and create
compressive residual stress.
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.
EN 13979-1:2023, Railway applications - Wheelsets and bogies - Monobloc Wheels - Technical approval
procedure - Part 1: Forged and rolled wheels
EN ISO 148-1:2016, Metallic materials - Charpy pendulum impact test - Part 1: Test method (ISO 148-
1:2016)
EN ISO 6506-1:2014, Metallic materials - Brinell hardness test - Part 1: Test method (ISO 6506-1:2014)
EN ISO 6892-1:2019, Metallic materials - Tensile testing - Part 1: Method of test at room temperature (ISO
6892-1:2019)
EN ISO 9712:2022, Non-destructive testing - Qualification and certification of NDT personnel (ISO
9712:2021)
EN ISO 14284:2022, Steel and iron - Sampling and preparation of samples for the determination of chemical
composition (ISO 14284:2022)
ISO 4967:2013, Steel — Determination of content of non-metallic inclusions — Micrographic method using
standard diagrams
ISO 5948:2018, Railway rolling stock material — Ultrasonic acceptance testing
ISO 6933:1986, Railway rolling stock material — Magnetic particle acceptance testing
ASTM E399-22, Standard test method for linear-elastic plane-strain fracture toughness KIc of metallic
materials
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— IEC Electropedia: available at https://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
3.1
technical specification
document describing specific parameters and/or product requirements in addition to the requirements
of this document
3.2
batch
group of wheels assumed to have the same characteristics
Note 1 to entry: A batch consists of wheels of the same design, forged with the raw material from a single cast
with the same warm forging process and a single heat treatment process. If the raw material is obtained from several
casts with the expected chemical composition, the resulting wheels can be combined in a batch. In this case, it is
necessary to demonstrate in the product qualification that the wheels manufactured from these different casts meet
the requirements for product qualification.
3.3
nominal diameter
diameter of the running tread of a new wheel as indicated on the wheel drawing
3.4
wheel categories
classification of the component, based on operational aspects, which determines the list of requirements
to be applied
Note 1 to entry: Category 1 is generally selected when the operating train speed is greater than 200 km/h.
Note 2 to entry: Category 2 is generally selected when the operating speed is 200 km/h or less
Note 3 to entry: These categories can also be defined in accordance with the technical specification.
4 Product definition
4.1 Chemical composition
4.1.1 Values to be achieved
The maximum percentages of the different elements specified are given in Table 1.
Table 1 — Limit values by product analysis
a
Maximum content in %
Cr +
Steel
b b c
C Si Mn P S Cr Cu Mo Ni V Mo +
grade
Ni
ER6 0,48 0,40 0,75 0,020 0,015 0,30 0,30 0,08 0,30 0,06 0,50
ER7 0,52 0,40 0,80 0,020 0,015 0,30 0,30 0,08 0,30 0,06 0,50
ER8 0,56 0,40 0,80 0,020 0,015 0,30 0,30 0,08 0,30 0,06 0,50
ERS8 0,57 1,10 1,10 0,020 0,015 0,30 0,30 0,08 0,30 0,06 0,60
ER9 0,60 0,40 0,80 0,020 0,015 0,30 0,30 0,08 0,30 0,06 0,50
a
For specific applications, variations of requirements within the limits of the maximum levels can be agreed in
the technical specification.
b
A maximum content of 0,025 % may be agreed in the technical specification for specific applications.
c
A minimum sulphur content may be agreed in the technical specification based on the steel development
process to protect against hydrogen embrittlement.
4.1.2 Sampling position
The sample for determining the chemical composition shall be taken 15 mm under the running tread at
nominal diameter. See key 4 in Figure 1.
NOTE The running tread is the nominal position on the running surface where the wheel and rail are in contact.
The chemical composition can also be determined by casting analysis. In this case, the chemical
composition shall be adapted in the technical specification.
4.1.3 Chemical analysis
The chemical composition analysis shall be performed.
NOTE Potential methods are listed in ISO/TR 9769:2018 or ASTM E415-21 and ASTM E1019-18.
4.2 Mechanical characteristics
4.2.1 Characteristics from the tensile test
4.2.1.1 Values to be achieved
Characteristics in the wheel rim and web are given in Table 2.
Table 2 — Characteristics in the wheel rim and web
Rim Web
a b
Steel grade R R A Reduction of R A
eH m 5 m 5
(MPa) (MPa) % (MPa) %
ER6 ≥ 500 780/900 ≥ 15 ≥ 100 ≥ 16
ER7 ≥ 520 820/940 ≥ 14 ≥ 110 ≥ 16
ER8 ≥ 540 860/980 ≥ 13 ≥ 120 ≥ 16
ERS8 ≥ 580 900/1020 ≥ 13 ≥ 110 ≥ 14
ER9 ≥ 580 900/1050 ≥ 12 ≥ 130 ≥ 14
If there is no distinctive yield strength, the conventional R limit shall be determined.
p0,2
Decrease in tensile strength of the web relative to the rim for the same wheel.
If there are no other requirements in the technical specification, for steel grades ER7, ER8, ERS8 and ER9,
a minimum value of 355 MPa for the yield strength in the web is required. For steel grade ER6, a minimum
value of 310 MPa for the yield strength in the web is required.
4.2.1.2 Position of the test pieces
The test pieces shall be taken from the wheel rim and web. Their positions are shown in Figure 1.
Dimensions in millimetres
Key
1 tensile test piece in the rim (15 mm axis under the running surface considering its nominal diameter), position
determining the chemical composition
2 tensile test piece in the web
3 impact bending test piece (a, b and c)
4 nominal diameter
5 notch
Figure 1 — Position of test pieces
4.2.1.3 Test method
The test shall be carried out in accordance with the requirements of EN ISO 6892-1:2019. The nominal
diameter of the test piece shall be at least 10 mm and the length of the deformation gauge shall be five
times the diameter. If the test pieces cannot be taken from the web, a smaller diameter shall be agreed in
the technical specification.
4.2.2 Hardness characteristics in the rim
4.2.2.1 Values to be achieved
The minimum Brinell hardness values given in Table 3 apply up to a maximum of 35 mm of wear range
under the running surface. If the thickness of the wear range is greater than 35 mm, the values shall be
defined in the technical specification.
The hardness value at the connection between the web and the rim (point A in Figure 2) shall be at least
10 points lower than that measured at the wear range limit.
Table 3 — Values to be achieved for hardness characteristics in the rim
Minimum Brinell hardness value
Steel grade Category 1 Category 2
ER6 — 225
ER7 245 235
ER8 245 245
ERS8 250 250
ER9 255 255
4.2.2.2 Position of measuring points
Four measurements are made on a radial section of the rim, as shown in Figure 2.
Dimensions in millimetres
Key
1 limit of wear range or diameter of last achievable re-profiling (according to technical specification).
2 nominal diameter
3 internal diameter (on external face)
Figure 2 — Measurements made on a radial section of the rim
The values in Figure 2 are valid for standard gauge axles and for a rim profile width of 135 mm and above.
Other gauges and rim profiles may be defined in the technical specification.
4.2.2.3 Test method
It shall be carried out according to EN ISO 6506-1:2014. The diameter of the ball is 5 mm.
4.2.3 Impact resistance characteristics
4.2.3.1 Values to be achieved
The values to be achieved for the impact test are given in Table 4. For each temperature, they represent
the average value and the minimum value for the three test pieces defined in 4.2.3.2. At + 20 °C, U-notch
test pieces shall be used. At – 20 °C, V-notch test pieces shall be used.
Table 4 — Values to be achieved for impact resistance characteristics
KU (Joules) at + 20 °C KV (Joules) at – 20 °C
Steel grade
Average values Minimum values Average values Minimum values
ER6 ≥ 17 ≥ 12 ≥ 12 ≥ 8
ER7 ≥ 17 ≥ 12 ≥ 10 ≥ 7
ER8 ≥ 17 ≥ 12 ≥ 10 ≥ 5
ERS8 ≥ 15 ≥ 11 ≥ 9 ≥ 5
ER9 ≥ 13 ≥ 9 ≥ 8 ≥ 5
4.2.3.2 Position of the test pieces
The position of the three test pieces is given in Figure 1. The axis of the bottom of the notches shall be
parallel to the A-A axis in Figure 1.
4.2.3.3 Test method
The test shall be carried out in accordance with EN ISO 148-1:2016.
4.2.4 Fatigue characteristics
4.2.4.1 Values to be achieved
The stress magnitude Δσ that a wheel web shall withstand, regardless of the steel grade, for 10 million
cycles without showing crack initiation with a probability of 99,7 % is given in Table 5.
This requirement is met by testing two wheels, in accordance with D.4.4.
Table 5 — Values to be achieved for fatigue characteristics of the web
Maximum roughness Fatigue stress limits according to Values to be achieved
the wheel design evaluation for fatigue
Ra
procedure (EN 13979-1:2023) characteristics
µm
Δσ Δσ (99,7 %)
(MPa) (MPa)
6,3 360 450
12,5 290 315
NOTE The purpose of obtaining these values is to ensure that the product has characteristics superior to those
used to define the allowable stresses required to size the wheel web under fatigue.
Given the approximations inherent in a fatigue calculation, the differentiation of five steel grades is
unrealistic for this characteristic. For steel grade ER6, if a lower value is expected, it shall be specified and
justified in the technical specification.
4.2.4.2 Fatigue test pieces
The test pieces shall be made up from wheels as delivered. In particular, the surface finishes of the web
are those defined in 4.6.
4.2.4.3 Test method
The test method shall enable bending stresses to be created in a section of the wheel web.
The tests shall be conducted in order to be able to use a fatigue test statistical counting method.
The tests are controlled from the radial stresses existing in the cracking area of the wheel web.
The ten million cycles shall be applied after setting the required stress level depending on the test bench
and specimen geometry.
Examples of test methods are given in Annex B.
4.2.5 Toughness characteristics of the rim
4.2.5.1 General
This characteristic need only to be verified on tread braked wheels (service brake or parking brake) or
equipped with a running surface cleaning system (e.g. scrubbers), whether they are Category 1 or
Category 2.
4.2.5.2 Values to be achieved
For steel wheels of grade ER6, the average value obtained on six test pieces shall be greater than or equal
to 100 MPa m and each individual value shall be greater than or equal to 80 MPa m .
For steel wheels of grade ER7, the average value obtained on six test pieces shall be greater than or equal
to 80 MPa m and each individual value shall be greater than or equal to 70 MPa m .
For wheels of other steel grades, the values to be achieved shall be contained in the technical specification.
4.2.5.3 Position of the test pieces
Six test pieces shall be taken from the rim as shown in Figure 3.
The test pieces shall be evenly distributed across the entire rim.
Dimensions in millimetres
Key
1 nominal diameter
Figure 3 — Test pieces collected from the rim
4.2.5.4 Test method
The test shall be performed according to ASTM E399-22.
The special conditions that shall be used are:
— compact 30 mm thick tensile test pieces (CT30), with chevron notch with aperture angle of 90°;
— test temperature between + 15 °C and + 25 °C;
— measurement of the notch opening at the end of the test piece;
— rate of increase of stress intensity ΔK/s, for the tensile test, between 0,55 MPa ms / and 1 MPa
ms / .
The toughness value considered shall be the value K , calculated from the force P , determined on the
Q Q
tensile test curve.
For steel grade ER6, when P /P ≥ 1,4, the value P can be used to determine the value of K .
max q max Q
NOTE This option is explained in document ERRI B169 DT 251.
4.3 Heat treatment homogeneity
4.3.1 Values to be achieved
For Category 1 wheels, the variation in the Brinell hardness value measured on the outer face of the rim
of the tested wheel shall be 30 HB or less.
NOTE The values are not correlated with the hardness values measured in the rim according to 4.2.2 or with
the results of the wheel rim tensile test according to 4.2.1.
4.3.2 Test pieces
The hardness values shall be measured at three points located at 120° on the outer face of the rim. The
impressions shall be made on the same diameter in an area whose position is defined in Figure 4.
Dimensions in millimetres
Key
1 nominal diameter on the running tread
2 area for Brinell hardness measurement
Figure 4 — Hardness impression area
4.3.3 Test method
The measurements shall be carried out in accordance with EN ISO 6506-1:2014. The diameter of the ball
is 10 mm.
4.4 Material cleanliness
4.4.1 Micrographic cleanliness
4.4.1.1 Level to be achieved
The assessment shall be determined from the micrographic examination according to 4.4.1.3. The values
to be achieved are given in Table 6.
Table 6 — Level to be achieved for the micrographic examination
Category 1 Category 2
Type of
Thick Thick
Thin series Thin series
inclusions
series series
(max) (max)
(max) (max)
A (Sulphide) 1,5 1,5 1,5 2
B (Aluminium) 1 1,5 1,5 2
C (Silicates) 1 1,5 1,5 2
D (Globular 1 1,5 1,5 2
oxides)
B + C + D 2 3 3 4
DS 1,5 2
4.4.1.2 Position of the micrographic sample
The field to be examined corresponds to the hatched area in Figure 5.
Its centre “F” is located 15 mm below the running surface.
Dimensions in millimetres
Key
1 nominal running tread
Figure 5 — Position of the micrographic sample
4.4.1.3 Test method
The level of cleanliness shall be determined in accordance with ISO 4967:2013, Method “A”.
4.4.2 Internal integrity
4.4.2.1 General
The internal integrity of the wheels shall be determined from an ultrasound examination. Standard
defects are flat bottomed holes of different diameters.
4.4.2.2 Level to be achieved
4.4.2.2.1 Wheel rim
The wheel rims shall not have internal defects giving indications of anomalies equal to or greater than
those obtained for standard defects, located at the same depth. The diameter of this standard defect is
given in Table 7.
Table 7 — Diameter of the standard defect
Category 1 Category 2
a
Standard defect diameter (mm) 1 2
A value of 3 mm can only be adopted for wheels up to 120 km/h, and shall be indicated in the technical
specification.
For the axial examination, a drop of backwall echo equal or greater than 4 dB due to internal
discontinuities is not tolerated.
NOTE This allows to identify non-coaxially-reflective discontinuities, clusters of discontinuities lower than the
acceptance criteria and other acoustic attenuation phenomena that cause local signal absorption or diffusion
4.4.2.2.2 Wheel web
The wheel web shall not have:
— More than 10 indications of anomalies equal to or greater than those observed for standard defects
of ∅ 3 mm. Each of these indications shall also be at least 50mm apart;
— Indications of anomalies equal to or greater than those observed for standard defects of ∅ 5 mm.
4.4.2.2.3 Wheel hub
The wheel hub shall not have:
— More than 3 indications of anomalies equal to or greater than those observed for standard defects of
∅ 3 mm. Each of these indications shall also be at least 50mm apart;
— Indications of anomalies equal to or greater than those observed for standard defects of ∅ 5 mm.
For the same circumferential examination, a drop of backwall echo equal or greater than 6 dB due to
internal discontinuities is not tolerated.
NOTE This allows to identify non-coaxially-reflective discontinuities, clusters of discontinuities lower than the
acceptance criteria and other acoustic attenuation phenomena that cause local signal absorption or diffusion
4.4.2.3 Test piece
The test piece shall consist of the complete wheel, after heat treatment, regardless its surface status
(forged, rough, machined), but before corrosion protection.
4.4.2.4 Examination methods
4.4.2.4.1 General
For ultrasonic testing of the wheel rim, an automatic (mechanized) method shall be used. When the
automatic system is temporarily not available, a manual process can be used, if specified in the technical
specification.
The test shall be conducted by qualified personnel.
EN ISO 9712:2022 shall be used to meet this requirement.
The general conditions of ultrasound examinations are given by ISO 5948:2018 and shall be
supplemented by the following special terms and conditions.
4.4.2.4.2 Wheel rim
The rim shall be examined using methods D1 and D2 in ISO 5948:2018, Table 1.
Defect estimation shall be made by comparison with the artificial defects of the standard rim described
in ISO 5948:2018, Annex A.
4.4.2.4.3 Wheel web
The type of curvature (convex/concave) of the wheel web shall be taken into account in determining the
sensitivity of the test procedure.
The artificial reference defect shall be positioned both on the inner face and on the outer face of the wheel
web.
The web shall be examined on both sides. The examination is carried out in a direction perpendicular to
the surface.
Defect estimation shall be made by comparison with the artificial defects of the standard web.
The web is defined as the portion of the wheel between the two diameters where m and n are defined
in Figure 7.
The thickness e of the web is defined by:
mn+
e =
The position of the artificial defects is given according to the value of e. Two artificial defects shall be
circumferentially spaced at least 100 mm apart.
— e ≤ 10 mm:
— a 3 mm diameter flat-bottomed hole located 5 mm below the surface of the inner face of the web;
— a 5 mm diameter flat-bottomed hole located 5 mm below the surface of the inner face of the web;
— 10 mm < e ≤ 20 mm:
— two 3 mm diameter flat-bottomed holes located 5 mm and (e – 5) mm below the surface of the
inner face of the web;
— two 5 mm diameter flat-bottomed holes located 5 mm and (e – 5) mm below the surface of the
inner face of the web;
— e > 20 mm:
— three 3 mm diameter flat-bottomed holes located 5 mm, (e/2) mm and (e - 5) mm below the
surface of the inner face of the web;
— three 5 mm diameter flat-bottomed holes located 5 mm, (e/2) mm and (e - 5) mm below the
surface of the inner face of the web.
4.4.2.4.4 Wheel hub
The hub shall be examined on both sides. The direction of the examination is perpendicular to the surface.
Defect estimation is made by comparison with the artificial defects:
— three 3 mm diameter flat-bottomed holes,
— three 5 mm diameter flat-bottomed holes,
Spaced according to Figure 6 on a standard hub.
Dimensions in millimetres
Figure 6 — Standard hub for ultrasound examination
4.5 Residual stresses
4.5.1 General
The heat treatment performed on the wheel shall create a compressive circumferential residual stress
field in the rim.
4.5.2 Values to be achieved
The circumferential residual stresses σ on the surface of the finished wheel running surface shall be in
crs
compression where σcrs ≤ − 80 MPa. If the value of the circumferential residual stress on the surface of the
finished wheel running surface is less than −200 MPa, it shall be demonstrated that the level of radial
residual stresses in the wheel web as a result is acceptable.
The residual tensile stresses in the wheel web can influence the fatigue resistance of the wheel web. An
assessment of this effect can be demonstrated, for example, by means of feedback, a fatigue test on the
wheel web, a calculation taking into account the effect of the mean stress in relation to residual stress, etc.
Circumferential residual stresses shall be compressed over the entire wear range.
NOTE The compression stress value is assumed to reach zero in the rim. A typical depth of this transition is in
the area between the wear limit and 15 mm below.
4.5.3 Test piece
The test piece shall consist of the complete wheel, after heat treatment and final machining.
4.5.4 Measurement methods
Measurement methods (for example, ultrasound or destructive) shall determine the variation in
circumferential stresses deep under the running surface. This method shall be defined in the technical
specification.
Annex C sets out a method for this destructive testing measurement.
4.6 Surface characteristics
4.6.1 Surface finish
4.6.1.1 General
Machined wheel webs are recommended for all wheel applications. When non-machined wheel webs are
used (for example for double ripple wheels), magnetic particle examination shall be performed in
accordance with 4.6.3.
Parts that remain “as-forged” and/or “as-rolled” shall be cleaned by mechanical means (e.g. shot-blasting)
to remove any irregularities from the forging and heat treatment process and shall be smoothly blended
into the machined areas.
4.6.1.2 Characteristics to be achieved
Depending on their use, the wheels can be fully machined or not. They shall have no surface marks (for
example, tightening marks) other than those specified at the positions provided in this document
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