EN 12080:2025

SLOVENSKI STANDARD
oSIST prEN 12080:2024
01-oktober-2024
Nadomešča:
SIST EN 12080:2017+A1:2022
Železniške naprave - Ohišja ležajev kolesnih dvojic - Kotalni ležaji
Railway applications - Axleboxes - Rolling bearings
Bahnanwendungen - Radsatzlager - Wälzlager
Applications ferroviaires - Boîtes d'essieux - Roulements
Ta slovenski standard je istoveten z: prEN 12080
ICS:
21.100.20 Kotalni ležaji Rolling bearings
45.040 Materiali in deli za železniško Materials and components
tehniko for railway engineering
oSIST prEN 12080:2024 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN 12080:2024
oSIST prEN 12080:2024
CEN/TC 256
Date: 2024-05
prEN 12080: 2024
Secretariat: DIN
Railway applications — Axleboxes — Rolling bearings
Bahnanwendungen — Radsatzlager — Wälzlager
Applications ferroviaires — Boîtes d'essieux — Roulements
ICS:
oSIST prEN 12080:2024
prEN 12080:2024 (E)
Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Technical specification . 9
4.1 General requirements . 9
4.2 Technical specification content . 9
4.2.1 New bearing development . 9
4.2.2 Information from bearing supplier . 10
4.2.3 Bearing supplier quality management system . 10
5 Quality systems . 11
6 Manufacture . 11
6.1 Steel manufacturing . 11
6.2 Heat treatment . 11
6.3 Traceability . 11
6.4 Coatings . 13
6.4.1 General. 13
6.4.2 Permanent coating . 13
6.4.3 Non-permanent coating . 13
7 Material properties . 13
7.1 General. 13
7.2 Steel for rings and rolling elements . 13
7.2.1 Grades . 13
7.2.2 Inclusion content . 14
7.3 Materials of other components (cages, spacers, seals etc.) . 14
8 Geometry and dimensions . 14
8.1 Dimensions and tolerances . 14
8.2 Rolling bearing internal clearance . 14
8.2.1 Rolling bearing clearance before mounting . 14
8.2.2 Rolling bearing clearance after mounting . 14
9 Mechanical properties — inner ring expanding ability . 14
10 Physical properties . 15
10.1 Visual aspect . 15
10.1.1 Rings and rolling elements . 15
10.1.2 Cages . 15
10.2 Soundness of rings and rolling elements . 15
10.2.1 General rules . 15
10.2.2 Internal soundness of rings . 16
10.2.3 Soundness of ring surfaces . 16
10.2.4 Soundness of roller raceway surfaces . 16
10.2.5 Grinding burns . 16
10.3 Case depth . 16
oSIST prEN 12080:2024
prEN 12080:2024 (E)
10.4 Surface hardness . 16
11 Marking . 17
11.1 General . 17
11.2 Marking of rings for cylindrical roller bearings (CRB) . 17
11.3 Marking of cartridge bearings for axleboxes . 19
11.4 Marking of spherical roller bearings (SRB) . 20
11.5 Prefix and postfix . 21
12 Inspection . 21
12.1 Inspection plan . 21
12.2 Sampling . 23
13 Quality records . 23
14 Deployment. 23
15 Delivery and packing . 23
15.1 Greasing of rolling bearings. 23
15.2 Corrosion protection . 23
15.3 Packaging . 23
Annex A (normative) Ultrasonic inspection of rolling bearing rings . 25
Annex B (normative) Magnetic particle inspection of ring surfaces . 30
Annex C (normative) Eddy current inspection of the raceways of the rollers. 32
Annex D (normative) Cages of polymeric material . 35
Annex E (informative)  Eddy current testing of ring surfaces . 47
Annex ZA (informative) Relationship between this European Standard and the Essential
Requirements of Directive (EU) 2016/797 aimed to be covered . 51
Bibliography . 53

oSIST prEN 12080:2024
prEN 12080:2024 (E)
European foreword
This document (prEN 12080:2024) 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 will supersede EN 12080:2017.
EN 12080 includes the following significant technical changes with respect to EN 12080:2017:
— Focus is only on rolling bearing related product requirements. As a consequence, product
requirements not related to the rolling bearing or requirements connected with conformity
assessment of the rolling bearing have been deleted or transferred to EN 12082-2
— Clause 4 on Technical Specification is revised
— Annex E Approval Procedures and Annex F Criteria to determine the extent of approval procedures
are deleted and respective content transferred to EN 12082-2
— Annex G is transferred to EN 12082-2
— With respect to Clause 10.2.3 Soundness of ring surfaces, eddy current testing is more emphasized
as an alternative to Magnetic Particle Inspection. A new Annex E is introduced with requirements
on how eddy current testing of ring surfaces should be processed
— Concerning Clause 11 Marking, changes are made to harmonize requirements for different rolling
bearing types and to address modern practices such as Data Matrix Coding
— Annex D Cages of polymeric material is reviewed with changes across the annex.
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 Z, which is an integral part of this
document
oSIST prEN 12080:2024
prEN 12080:2024 (E)
Introduction
This standard is part of a set of standards: EN 12080, EN 12081, EN 12082-1 and EN 12082-2.
This documenthas been drawn up with the purpose of aiming at optimum performance in rail
transportation. Performance implies a certain quality level of the vehicle running gear, which every
railway undertaking may require, notably by imposing procedures in approval and requesting the
existence of a quality assurance system for the supply of rolling bearings intended for rolling stock
operating on its network or other networks in Europe.
oSIST prEN 12080:2024
prEN 12080:2024 (E)
1 Scope
This document specifies the quality parameters of axlebox rolling bearings supporting the load of the
vehicle, required for reliable operation of trains on European networks. It covers metallurgical and
material properties as well as geometric and dimensional characteristics. It also defines methods for
quality assurance and conditions for approval of the products.
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 10204:2004, Metallic products - Types of inspection documents
prEN 12081:2024, Railway applications — Axleboxes — Lubricating greases
prEN 12082-2:2024, Railway applications — Axleboxes — Deployment Procedure
EN 13018:2016, Non-destructive testing - Visual testing - General principles
EN ISO 178:2010, Plastics — Determination of flexural properties (ISO 178:2010)
EN ISO 179-1:2010, Plastics — Determination of Charpy impact properties — Part 1: Non-instrumented
impact test (ISO 179-1-:2010)
EN ISO 307:2007, Plastics — Polyamides — Determination of viscosity number (ISO 307:2007)
EN ISO 683-17:2014, Heat-treated steels, alloy steels and free-cutting steels — Part 17: Ball and roller
bearing steels (ISO 683-17:2014)
EN ISO 1172:2003, Textile-glass-reinforced plastics — Prepregs, moulding compounds and laminates -
Determination of the textile-glass and mineral-filler content - Calcination methods (ISO 1172:1996)
EN ISO 1183-1:2012, Plastics — Methods for determining the density of non-cellular plastics —- Part 1:
Immersion method, liquid pyknometer method and titration method (ISO 1183-1:2012)
EN ISO 1183-2:2004, Plastics — Methods for determining the density of non-cellular plastics — Part 2:
Density gradient column method (ISO 1183-2:2004)
EN ISO 2639:2002, Steels — Determination and verification of the depth of carburized and hardened
cases (ISO 2639:2002)
EN ISO 3059:2012, Non-destructive testing - Penetrant testing and magnetic particle testing - Viewing
conditions (ISO 3059:2012)
EN ISO 3451-1:2008, Plastics — Determination of ash — Part 1: General methods (ISO 3451-1:2008)

Currently under revision
Currently under revision
oSIST prEN 12080:2024
prEN 12080:2024 (E)
EN ISO 6507-1:2005, Metallic materials — Vickers hardness test — Part 1: Test method (ISO 6507-1-
:2005)
EN ISO 6508-1:2016, Metallic materials — Rockwell hardness test — Part 1: Test method
(ISO 6508-1:2016)
EN ISO 6508-2:2015, Metallic materials — Rockwell hardness test — Part 2: Verification and calibration
of testing machines and indenters (ISO 6508-2:2015)
EN ISO 6508-3:2015, Metallic materials— Rockwell hardness test — Part 3: Calibration of reference
blocks (ISO 6508-3:2015)
EN ISO 11357-3:2013, Plastics — Differential scanning calorimetry (DSC) — Part 3: Determination of
temperature and enthalpy of melting and crystallization (ISO 11357-3:2011)
ISO 492:2014, Rolling bearings — Radial bearings — Geometrical product specifications (GPS) and
tolerance values
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 12082-2:—, Annex B and the
following apply.
ISO and IEC maintain terminological 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
customer
railway undertaking, rolling stock manufacturer, Entity in Charge of Maintenance (ECM) or buyer of
railway rolling stock or subassemblies, or their representative
3.2
railway undertaking
organization or its representative, whatever status it has, which is responsible for the registration of
rolling stock
3.3
manufacturer
manufacturer of axlebox rolling bearings produced under their responsibility
3.4
network
infrastructure, on which any railway undertaking can operate rolling stock
3.5
axlebox (assembly)
axlebox
assembly consisting of the following major components: rolling bearing(s), grease, seal(s) and box
housing
oSIST prEN 12080:2024
prEN 12080:2024 (E)
Note 1 to entry: Further components such as axle end cap components, box cover(s), distance rings, fasteners,
labyrinth(s) may be also part of the assembly but are not considered as major components. Their presence
depends on the axlebox type design.
3.6
bearing sleeve
component of box housing which contains rolling bearing(s), grease and sealing
3.7
housing cover
component which retains the bearing in the housing or bearing sleeve
3.8
axle end cap components
components which secure the rolling bearing axially on the journal
3.9
rolling bearing
bearing, operating with rolling motion between the parts supporting load and moving in relation to
each other
3.10
cartridge bearing
rolling bearing with two or more rows of rolling elements within a self-contained unit, greased and
equipped with integral seals
3.11
ring
annular part of a rolling bearing incorporating one or more raceways with rolling element contact
3.12
rolling elements
cylindrical, tapered or convex rollers or balls
3.13
cage
component, which partly surrounds the rolling elements and moves with them
3.14
grease
semi-solid lubricant, which consists of a thickener and additives dispersed in a lubricating oil
3.15
seal
component that protects the bearing(s) against ingress of water and dust and retains the grease in the
rolling bearing(s)
3.16
box housing
structural component which contains rolling bearing(s), seal(s) and grease
Note 1 to entry: It may consist of several components such as an upper part, a lower part, bearing sleeve.
oSIST prEN 12080:2024
prEN 12080:2024 (E)
3.17
rolling bearing type
designation of the rolling bearing or cartridge bearing according to the shape of the rolling elements
(e.g. tapered roller bearing, cylindrical roller bearing, and spherical roller bearing)
3.18
rolling bearing design
designation of a specific rolling bearing or cartridge bearing design within a rolling bearing type (e. g.
WJ/WJP 130x240x80 P.C3), bearing design is a subset of a bearing type
3.19
ribs and thrust collars
annular component of a rolling bearing transmitting axial forces (separate from the bearing inner or
outer rings) in contact with the rolling element end face in cylindrical roller bearings
3.20
deployment process
methodical procedure of introducing an axlebox or a change to an axlebox into vehicle service
4 Technical specification
4.1 General requirements
The supply of a component shall be based on a comprehensive specification. This specification shall
consist of all the information relevant for design and manufacture of the bearing describing the
functional requirements over its complete life cycle and the interfaces with associated components and
assemblies.
The design and validation process requires the integration of different disciplines and areas of expertise
and the knowledge associated with them. Therefore, the specification shall include information defining
the intended operating conditions and calculation parameters.
The following information shall be part of the deployment process and be fully documented in the
technical specification by either of the contracting parties. Both the requirements specified throughout
this document and the following documented requirements shall be satisfied before a claim of
compliance with this document can be made and verified.
The technical specification shall cover the items listed in Clause 4.2 in the most suitable format
(drawing, text etc.).
4.2 Technical specification content
4.2.1 New bearing development
The following information should be considered during the development of a new bearing:
— interface drawing showing mounting conditions as in service; all dimensions of the space available
for the rolling bearings; dimensions, tolerances and materials of shaft and box housing;
— load specification at least according to EN 12082-1;
— ambient temperatures in operation;
— deployment procedure type and conditions to be applied (see Clause 14 and EN 12082-2, Annex E);
— clearance values after mounting (see Clause 8);
oSIST prEN 12080:2024
prEN 12080:2024 (E)
4.2.2 Information from bearing supplier
The following information of the bearing shall be made available by the bearing supplier
— boundary dimensions and tolerances of the rolling bearing (see Clause 8);
— internal clearance measurement process and clearance values before mounting (see Clause 8);
— type of coating and influence on boundary dimensions (see 6.4);
— type of heat treatment to be applied
— soundness Class, 1 or 2, and the test methods to be used (see 10.2, A.4.2 and E.4.1);
— for cartridge bearings grease designation, quantity and distribution (see 15.1);
— marking (see Clause 11);
4.2.3 Bearing supplier quality management system
Additionally the following requirements which are specified in the clauses referred to shall be fully
documented in the bearing supplier quality management system:
— if required, special steel composition, cleanliness and soundness class (see 7.1 and 10.2);
— special conditions for quality records and traceability (see 6.3 and Clause 13);
— references to standards and special requirements (see Clause 7 and 10.2);
— use of steel of special composition, manufacture or metallurgical quality (see 7.1);
— type of heat treatment to be applied and methods of testing (see 6.2, 10.3, 10.4 and 12.2);
— inspection plan (see 12.1);
— selection of mechanical testing method for cages of polymeric material (see D.4.1)
— material data sheet for polymer cage material;
— proof of batch release according to EN 12081 for traceability;
— method for determining steel cleanliness.
oSIST prEN 12080:2024
prEN 12080:2024 (E)
5 Quality systems
The quality of workmanship and manufacturing shall be demonstrated to ensure the requirements of
the technical specification are met.
NOTE 1 The manufacturer is responsible for this.
NOTE 2 Quality management system according to EN ISO 9001 is usually used.
NOTE 3 Competency of non-destructive testing staff can be demonstrated, e.g. according to ISO 9712, ASNT
recommended practice No. SNT-TC-1A or NAS 410.
6 Manufacture
6.1 Steel manufacturing
The process of steel manufacture in mass production shall be such that the metallurgical characteristics
are the same as those of the rolling bearings submitted for the deployment procedure.
6.2 Heat treatment
The heat treatment processes for the rolling bearing components shall be such that the hardness values
specified in 10.3 and/or 10.4 are respected. The heat treatment processes shall be such that all the
rolling bearings produced in a production batch are treated uniformly.
The temperature category shall be given and documented in the Technical specification (Clause 4).
The bearings (inner and outer rings) shall be heat-treated to retain dimensional stability at least for
operating temperatures up to 150 °C.
Inner rings of cylindrical roller bearings that are heated during mounting or dismounting shall be
dimensionally stable up to 200 °C.
For other steels, the retained austenite content must be defined in the course of the (type) deployment
procedure.
The inspection frequency of the retained austenite content is specified in Table 3 — Inspection plan,
12.1. The method of measurement of retained austenite is according to ASTM E975 -or to be defined in
the technical specification (Clause 4).
6.3 Traceability
For the manufacturing process a system of identification and traceability of finished products shall be
set up and maintained. This system shall allow identification, of the following elements:
— raw material for rings and rollers;
— inspection certificate 3.1 in accordance with EN 10204 or equivalent. Minimum content:
— chemical analysis (all elements according steel grade specification);
— steel production method;
— microstructure (CN, CG, CZ);
— inclusion content (see 7.2.2);
oSIST prEN 12080:2024
prEN 12080:2024 (E)
— polymeric cages:
— raw material (granulate material) + raw material manufacturer;
— inspection results; inspections at least in accordance with EN 12080, Annex D;
— manufacturer, manufacturer's mark, date of manufacture;
— rolling bearing grease:
— name, manufacturer;
— inspection certificate 3.1 in accordance with EN 10204 or equivalent. The content of the
certificate is according to EN 12081.
— production locations of rings and rollers;
— traceability of heat treatment:
— method;
— temperature variations including nominal and actual values per heat treatment batch;
— microstructural examination per heat treatment batch;
— hardness values/case-hardening depth of rings and rollers in accordance with EN 12080,
Table 3;
— retained austenite content, inspection frequency in accordance with 6.2;
— if there are several heat treatment batches per production batch they must be assignable to the
production batch;
— significant changes in the finishing process after heat treatment that could lead to defects, e.g. so
called “grinding burns”;
— traceability of the inspection results in accordance with the inspection plan (see 12.1);
— quality records in accordance with Clause 13 and records of inspection plans, inspection
instructions and calibrations.
— production of cartridge bearings
— name, manufacturer
— amount of grease
— assembly date
oSIST prEN 12080:2024
prEN 12080:2024 (E)
6.4 Coatings
6.4.1 General
The type of coating used for the bearing boundary surfaces shall be agreed and documented in
accordance with Clause 4. Distinction shall be made between permanent coatings (e.g. for electrical
insulation) and non-permanent coatings (e.g. phosphate coating for corrosion protection).
6.4.2 Permanent coating
The dimensions in the finished state (including the coating) shall apply for approval and use of the
bearing.
6.4.3 Non-permanent coating
The dimensions before coating shall apply for deployment and use of the bearing and the thickness of
the non-permanent coating shall be considered separately. Boundary dimensions shall be documented
both for the coated and the uncoated state.
7 Material properties
7.1 General
The grades and qualities of materials used shall conform to the requirements in 7.2 and 7.3.
7.2 Steel for rings and rolling elements
7.2.1 Grades
Steels should be selected from the grades specified in EN ISO 683-17. Alternative steel grades may be
used if specified in the technical specification. For particular applications (high rotational speed,
reliability etc.) it may be requested that the rolling bearings are made from steel with special
composition, metallurgical quality or manufacturing processes (Clause 4).
Additional requirements regarding the chemical composition (content in %) after the ladle analysis in
accordance with EN ISO 683-17 are listed below in Table 1 — Additional requirements, chemical
composition, through hardened steel and Table 2 — Additional requirements, chemical composition,
case carburised steel below.
Table 1 — Additional requirements, chemical composition, through hardened steel
Element Minimum Maximum
Ti 0 0.003
H 0 0.000 2
Table 2 — Additional requirements, chemical composition, case carburised steel
Element Minimum Maximum
Ti 0 0.005
H 0 0.000 25
oSIST prEN 12080:2024
prEN 12080:2024 (E)
7.2.2 Inclusion content
The methods for determining the inclusion content shall be in the technical specification.
The methods in accordance with ASTM E45 (Method A) and ISO 4967 (Method A) are permitted. For the
methods mentioned above, the limit values in accordance with EN ISO 683-17:2014, Annex A, Tables
A.1 and A.2 are authoritative.
The frequency and scope of inspection for inclusion content of raw material (bar, tube or billet) is
specified in Table 3 — Inspection plan, Clause 12.1).
When needed - inspection of single rings and rollers can also be made according to the methods and
requirements specified above providing enough samples are taken to form an average value.
NOTE ASTM E45 gives a recommendation for number of samples.
For steel with special composition, metallurgical quality or manufacturing processes, the inclusion
content shall be documented in accordance with Clause 4.
7.3 Materials of other components (cages, spacers, seals etc.)
The materials of each one of these components shall be documented in in the technical specification in
accordance with Clause 4. For cages of polymeric material, if not otherwise specified, refer to Annex D.
8 Geometry and dimensions
8.1 Dimensions and tolerances
The boundary dimensions shall be given in the technical specification, and the applicable tolerances
shall be those given in ISO 492, normal tolerance class, unless given and documented in the technical
specification in accordance with Clause 4.
8.2 Rolling bearing internal clearance
8.2.1 Rolling bearing clearance before mounting
Rolling bearing internal clearance, axial and/or radial, depending on the type of rolling bearing, shall
conform to the values given in the technical specification. The methods for radial and/or axial clearance
inspection shall be described and documented in the technical specification in accordance with
Clause 4.
8.2.2 Rolling bearing clearance after mounting
Rolling bearing clearance after mounting on an axle is a calculated value used for checking the clearance
after mounting. The values for clearance after mounting shall be described and documented by the
manufacturer in accordance with Clause 4.
9 Mechanical properties — inner ring expanding ability
With the exception of case-hardened rings and bainite hardened rings, an expansion test shall be
performed to guarantee that the inner rings can withstand an increase of the bore diameter without
causing fracture in service. This test shall be performed before the inspection for surface soundness.
The value of this diameter increase shall not be less than 0.0015 times the diameter. The rings shall
neither rupture nor show any traces of cracks (see 10.2.3). This expansion test shall be made with an
expandable mandrel that is inserted in the bore of the inner ring. The expansion shall be achieved
progressively in a few seconds.
oSIST prEN 12080:2024
prEN 12080:2024 (E)
10 Physical properties
10.1 Visual aspect
10.1.1 Rings and rolling elements
Rings and rolling elements shall be free of any defects which can be harmful to their function (such as
burrs, scratches, rust stains, nicks and dents). A defect catalogue to define the acceptance limits for
visual defects shall be created and maintained.
NOTE Usually the manufacturer is responsible for maintaining a defect catalogue.
10.1.2 Cages
Rolling bearing cages shall exhibit no defects that might affect their function (such as burrs, scratches,
rust). To avoid crack initiation, the connection between the cage bars and the annular body shall be
smooth and conform to the rounding-off shown on the detail drawing.
The requirements for cages of polymeric material shall be taken into account (see Annex D).
For cages other than polymeric cages the approval process shall be defined in the technical
specification. Steel riveted brass cages are not allowed.
10.2 Soundness of rings and rolling elements
10.2.1 General rules
Rings and rolling elements shall have no internal defects, nor any form of surface defect that may be
harmful to their function. The methods for the soundness inspection are described in Annex A, Annex B,
Annex C and Annex E. Any alternative methods to be used, which give equivalent results, shall be
documented in the technical specification in accordance with Clause 4.
Two soundness classes are defined:
— class 1 for vehicles with n × dm > 250 000 [mm/min] or a vehicle speed > 200 km/h or axle
load ≥ 25.0t;
— class 2 for vehicles with n × dm ≤ 250 000 [mm/min].
The classification only concerns the internal soundness of the ring (see Annex A). The soundness class
is assigned as part of the approval procedure where:
— n is the maximum operational speed of rotation of the inner ring, in revolutions per minute;
— dm is the bearing mean diameter (D + d)/2, in millimetres;
— D is the bearing outside diameter, in mm;
— d is the bearing bore diameter, in mm.
NOTE The value n × dm = 250 000 [mm/min] corresponds to a wheel diameter of 840 mm, a bearing mean
= 195 [mm] and a vehicle speed of 200 [km/h].
diameter of dm
oSIST prEN 12080:2024
prEN 12080:2024 (E)
10.2.2 Internal soundness of rings
The reference method for the inspection of internal soundness of rings is described in Annex A.
Inspection of internal soundness of rings can also be carried out with an approved equivalent,
standardized inspection method capable of detecting at least the same defects as the reference method.
Use of an equivalent method shall be agreed and documented in in the technical specification in
accordance with Clause 4.
When tested, no ring shall exhibit defect indications on the raceway, or in a section of 4 [mm] depth
below the raceway, with the amplitude equal to or greater than that observed with the master defect
corresponding to the soundness class in question in accordance with Annex A. Larger defects are
tolerated deeper than this section, though the defect indications shall not be more than twice the
amplitude of that observed with the master defect.
10.2.3 Soundness of ring surfaces
The reference method for the inspection of surface soundness of rings is described in Annex B. In
Annex H an alternative method is described. Both inspection methods should be considered as
equivalent. When tested, no evidence of defects shall be observed on any of the ring surfaces.
10.2.4 Soundness of roller raceway surfaces
The reference method for the inspection of the raceway surface soundness of rollers is described in
Annex C. When tested, no roller shall exhibit defect indications on its raceway with amplitude equal to
or greater than that observed with the master defect as defined in Annex C.
10.2.5 Grinding burns
There shall be no grinding burns during the different grinding operations.
10.3 Case depth
For rolling bearings manufactured of case-hardened steel, the effective depth of the hardened case shall
be documented in accordance with Clause 4. The depth of the hardened case is determined as a function
of the change in hardness of the transversal cross section of a test piece or a prepared sample. The
hardness shall be measured in accordance with EN ISO 6507-1 and EN ISO 2639 or another process
agreed and documented in accordance with Clause 4. At this depth, the Vickers hardness shall be at
least 550 HV1.
Inspection methods other than those described in EN ISO 6507-1 and EN ISO 2639 can be approved
during the course of the approval procedure if equivalence is demonstrated.
10.4 Surface hardness
Rings and rolling elements shall have a Rockwell hardness (HRC) between 57 HRC and 66 HRC.
There shall be no more than 4 HRC difference between the values measured:
— on all the rings of one rolling bearing;
— on all the rolling elements in one rolling bearing.
Surface hardness shall be inspected according to the Rockwell method, referred to in EN ISO 6508-1,
EN ISO 6508-2 and EN ISO 6508-3. For case-hardened steel rolling bearings, surface hardness may be
measured by the Vickers HV 30 method, referred to in EN ISO 6507-1, or by another equivalent method
agreed and documented in accordance with Clause 4.
Inspection methods other than those described in EN ISO 6507-1 can be approved in the course of the
deployment procedure if requested by the manufacturer who needs to demonstrate equivalence.
oSIST prEN 12080:2024
prEN 12080:2024 (E)
11 Marking
11.1 General
Rolling bearings shall be marked visibly and indelibly away from any surfaces in contact with spacers,
thrust rings etc. Should this not be possible, the marking area shall be documented in the technical
specification in accordance with Clause 4.
The format of marking shall be documented on the bearing drawing.
Where marking punches are used, these shall not have any sharp edges. Marking by electric pencil
(spark erosion) is prohibited.
If no other indications are given, the following marking is compulsory:
— manufacturer’s name;
— production plant code;
— rolling bearing designation;
— country of origin, reference to this European Standard and the soundness class are all optional as
marking;
— year of manufacture in un-coded form and indication of month (coded or un-coded) or instead of
month – day of manufacture within the year:
— Two digits or one letter shall be used to indicate month of manufacture. The date refers to the
assembly date unless otherwise indicated in the manufacturers drawing;
— Three digits shall be used to indicate day of manufacture within the year;
— the preferred marking format is MY where M stands for the number of the month (01-12) and Y
stands for the two last digits of the year. For example, a bearing manufactured in May 2018 would
have the marking 0518, or 12518 for 125:th day of the year 2018 or E18 for month coded with a
letter.
— GTIN (Global trade item number) can be optionally marked;
— Data Matrix code acc. GS1 can be optionally marked.
Each part of this marking information shall be separated by a space or special character.
When rolling bearing components or sub-assemblies are not allowed to be interchanged, they shall be
marked with a unique identification number.
11.2 Marking of rings for cylindrical roller bearings (CRB)
Cylindrical rolling bearings (CRB) for axleboxes shall be marked with capital letters W, WU, WJ, WJP,
etc. regardless of whether a manufacturer uses a drawing number or NJ-, NU or other designations
internally.
Inner rings of cylindrical roller bearings with ribs or thrust collars (for example NJ/NJP or WJ/WJP
design) shall be marked on the relevant “Front face” (see Figure 2) according to Clause 11.1 and
Figure 1. On the “Chamfer side” according to Figure 2 — Marking of CRB inner rings. Additional marking
shall be according to Clause 11.1.
oSIST prEN 12080:2024
prEN 12080:2024 (E)
Deviations from marking on “Chamfer side” according to Figure 2 — Marking of CRB inner rings, shall
be defined in the technical specification according to Clause 4.

Key
A C* B D EN 12080* CLASS n* MY Z T* G*
A Manufacturers name
C Country of origin*
B production plant code
D Bearing Designation
M Month or day of manufacture (un-coded or coded format)
Y Year of manufacture (un-coded)
Number which (as unique serial number or in combination with other marking on the ring) allows
Z
unique traceability of that inner ring. This number may be the same as on the corresponding outer ring
T Global Trade Item Nummer (GTIN)*
G GS1-Data-Matrix-Code DMC*
*Optional
Figure 1 — Marking of Rolling bearings

Key
F Front face Optional Marking
CH Chamfer side D Abbreviation of inner ring
Marking requirements A Manufacturer code
E Manufacturer code number in accordance with C Country of origin *)
type approval
R Inner ring creep marking M Month or day of manufacture (un-coded or coded
format) *)
Y Year of manufacture, un-coded
Figure 2 — Marking of CRB inner rings
oSIST prEN 12080:2024
prEN 12080:2024 (E)
11.3 Marking of cartridge bearings for axleboxes
For self-contained cartridge bearings for TRB (Taper roller cartridge bearings) it is sufficient to mark
only the outer ring provided that the marking is visible on the exterior of the bearing. Bearings shall be
marked (location and format) according to Figure 4 — Marking of cartridge bearings.
CRB (Cylindrical roller cartridge bearings) shall be marked (location and format) according to
Figure 3 — Marking of CRB cartridge bearings.
Deviations in the location of the marking for cartridge bearings shall be defined in the technical
specification according to Clause 4.

Key
Arrows indicate location of marking. Marking format shall be:
A C* B* D EN12080* CLASS n* MY Z T* G* where (*) is optional and:
A Manufacturer name
C Country of origin*
B production plant code*
D Bearing Designation
M Month or day of manufacture (un-coded or coded format)
Y Year of manufacture (un-coded)
Z Serial number
T Global Trade Item Nummer (GTIN)*
G GS1-Data-Matrix-Code DMC*
Marking of inner rings is optional for taper roller cartridge bearings.
NOTE see Figure 1 for order of marking
Figure 3 — Marking of CRB cartridge bearings
oSIST prEN 12080:2024
prEN 12080:2024 (E)
Key
Arrows indicate location of marking. Marking format shall be:
A C* D EN 12080* class n* MY Z where (*) is optional and:
A – Manufacturer code
C – Country of origin
D – Bearing Designation
M – Month or day of manufacture (un-coded or coded format)
Y – Year of manufacture (un-coded)
Z – Serial number
T Global Trade Item Nummer (GTIN)*
G GS1-Data-Matrix-Code DMC*
Marking of inner rings is optional for taper roller cartridge bearings (TBU)
Figure 4 — Marking of TRB cartridge bearings
11.4 Marking of spherical roller bearings (SRB)
For spherical roller bearings (SRB) the outer ring shall be marked according to Figure 3 — Marking of
spherical roller bearings.
oSIST prEN 12080:2024
prEN 12080:2024 (E)
Key
Marking format shall be:
A C* D EN 12080* class n* MY Z where (*) is op
...