EN 16771:2016

Railway applications - Infrastructure - Aluminothermic welding of grooved rails

This standard defines the laboratory tests and requirements for approval of an aluminothermic welding process using welds produced in workshop conditions.
It applies to the joining of new, grooved rails as described in EN 14811 of the same profile and steel grade. Welding of construction profiles and machined profiles are not covered in this standard.
Compliance with the requirements of this standard does not in itself ensure the suitability of a welding process for specific conditions of track and traffic.
The standard does not cover welds made between different rail sections, worn rails or different rail grades.
In addition to the definitive requirements, this standard also requires the items detailed in Clause 4 to be documented. For compliance with this standard, it is important that both the definitive requirements and the documented items be satisfied.

Bahnanwendungen - Infrastruktur - Aluminothermisches Schweißen von Rillenschienen

Diese Norm legt Laborprüfungen und Anforderungen zur Zulassung eines aluminothermischen Schweißverfahrens unter Verwendung von Schweißungen fest, die unter Werkstattbedingungen hergestellt wurden.
Diese Norm umfasst die Verbindung neuer Rillenschienen, wie in EN 14811 beschrieben, des gleichen Profils und der gleichen Stahlsorte. Das Schweißen von Bauprofilen und bearbeiteten Profilen wird in dieser Norm nicht behandelt.
Die Erfüllung der Anforderungen dieser Norm bedingt jedoch nicht notwendigerweise die Eignung des Schweißprozesses unter den spezifischen Bedingungen von Oberbau und Betrieb.
Die Norm berücksichtigt keine Schweißungen unterschiedlicher Schienenquerschnitte, unterschiedlich abgenutzter Schienen und unterschiedlicher Stahlsorten.
Zusätzlich zu den in dieser Norm festgelegten Anforderungen sind gleichfalls die in Abschnitt 4 aufgeführten Angaben zu dokumentieren. Für die Konformität mit dieser Norm ist es wichtig, sowohl die festgelegten Anforderungen als auch die Dokumentation der Angaben zu erfüllen.

Applications ferroviaires - Infrastructures - Soudage par aluminothermie des rails à gorge

La présente norme définit les essais de laboratoire et les exigences pour l’approbation d’un procédé de soudage des rails par aluminothermie effectués dans des conditions opératoires d’atelier.
Elle s'applique à l'assemblage de rails à gorge neufs, tels que décrits dans l'EN 14811, de même profil et de même nuance d'acier. Elle ne traite pas du soudage des profils de construction et des profils usinés.
La conformité aux exigences de la présente norme n’assure pas par elle-même l’aptitude à l’emploi d’un procédé de soudage dans des conditions spécifiques de voie ferrée et de trafic.
La présente norme ne s'applique pas au soudage des rails de profils, d'usures ou de nuances différentes.
Outre les exigences définitives, la présente norme exige également que les éléments détaillés à l'Article 4 soient documentés. Pour être conforme à la présente norme, il est important que les exigences définitives ainsi que les éléments à documenter soient remplis.

Železniške naprave - Infrastruktura - Aluminotermično varjenje tirnice z žlebom

Ta standard opredeljuje laboratorijske preskuse in zahteve za odobritev postopka aluminotermičnega varjenja z uporabo zvarov, izdelanih v delavnici.
Uporablja se za združevanje novih tirnic z žlebom, kot je opisano v standardu EN 14811, istega profila in razreda jekla. Varjenje konstrukcijskih in strojnih profilov ni obravnavano v tem standardu.
Skladnost z zahtevami iz tega standarda sama po sebi še ne zagotavlja ustreznosti postopka varjenja za določene pogoje glede proge in prometa.
Standard ne obravnava zvarov, izdelanih iz različnih delov tirnic, obrabljenih tirnic ali različnih razredov tirnic.
Poleg dokončnih zahtev ta standard zahteva tudi, da so postavke, opredeljene v točki 4, dokumentirane. Za skladnost s tem standardom je pomembno, da so izpolnjene tako dokončne zahteve kot dokumentirane postavke.

General Information

• Status: Published
• Publication Date: 08-Nov-2016
• ICS: 25.160.10 - Welding processes
• ICS: 93.100 - Construction of railways
• Technical Committee: CEN/TC 256 - Railway applications
• Drafting Committee: CEN/TC 256/SC 1/WG 4 - Rails
• Current Stage: 9093 - Decision to confirm - Review Enquiry
• Start Date: 13-Jun-2022
• Completion Date: 14-Apr-2025
• Ref Project: SIST EN 16771:2017 - Railway applications - Infrastructure - Aluminothermic welding of grooved rails

Overview - EN 16771:2016 (CEN)

EN 16771:2016 specifies the laboratory tests and approval requirements for aluminothermic welding of grooved rails (welds produced in workshop conditions). Prepared by CEN/TC 256, it applies to joining new grooved rails of the same profile and steel grade (as described in EN 14811). The standard defines the approval procedure for a single welding process (process identification, documentation, and laboratory testing) but does not cover construction or machined profiles, welds between different rail sections, worn rails, or welding between different rail grades. Compliance with EN 16771 provides laboratory evidence of weld quality but does not automatically guarantee suitability for specific track or traffic conditions.

Key topics and technical requirements

• Scope & limitations: Applies only to new grooved rails of identical profile/grade; excludes worn or mixed-grade welds.
• Process identification & documentation: Requires a detailed process manual and drawings covering pouring/casting system, mould geometry, riser configuration, consumables, critical timings, safety and storage conditions.
• Mandatory documented items (Clause 4): Railway authority must specify items such as required heat‑softened zone width and pre‑heat limitations.
• Laboratory tests and acceptance criteria:
  • Visual surface examination (as-cast and ground)
  • Running-surface hardness testing (Brinell/Vickers references)
  • Slow bend (fracture) testing
  • Internal examination: weld soundness, fusion zone shape & dimensions
  • Microscopic examination of fusion zone and HAZ
  • Measurement of heat‑softened zone width (hardness distribution)
  • Chemical analysis of weld/rail materials
  • Ultrasonic inspection procedures (Annex G) and other normative annexes for test methods
• Approval workflow: Initial compliance testing (category 1/2 schemes), possible extensions to other profile groups, and re‑approval after process changes.

Practical applications

• Establishes a laboratory-based approval route for aluminothermic welding processes used to fabricate grooved-rail welds in workshops or near-track environments.
• Useful for ensuring consistent weld quality before field trials or trackside implementation.
• Helps railway authorities, infrastructure managers, and contractors assess whether a supplier’s aluminothermic welding process meets defined metallurgical and mechanical criteria.

Who should use this standard

• Railway authorities and infrastructure owners (for specifying approval requirements)
• Welding process suppliers and manufacturers (to obtain process approval)
• Accredited testing laboratories and NDT personnel (to perform required laboratory tests)
• Track maintenance contractors and quality assurance teams

Related standards

• EN 14811 (grooved rail profiles)
• EN ISO 6506‑1 (Brinell hardness)
• EN ISO 6507‑1 (Vickers hardness)
• EN ISO 9712 (NDT personnel qualification)

Keywords: EN 16771, aluminothermic welding, grooved rails, railway infrastructure, weld approval, laboratory tests, fusion zone, heat‑softened zone, process manual.

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Bahnanwendungen - Infrastruktur - Aluminiothermisches Schweißen von RillenschienenApplications ferroviaires - Infrastructures - Soudage par aluminothermie des rails à gorgeRailway applications - Infrastructure - Aluminothermic welding of grooved rails45.080Rails and railway components25.160.10Varilni postopki in varjenjeWelding processesICS:Ta slovenski standard je istoveten z:EN 16771:2016SIST EN 16771:2017en,fr,de01-januar-2017SIST EN 16771:2017SLOVENSKI
STANDARD
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 16771
November
t r s x ICS
t wä s x rä s râ
{ uä s r r English Version
Railway applications æ Infrastructure æ Aluminothermic welding of grooved rails Applications ferroviaires æ Infrastructures æ Soudage par aluminothermie des rails à gorge
Bahnanwendungen æ Infrastruktur æ Aluminothermisches Schweißen von Rillenschienen This European Standard was approved by CEN on
s w July
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egulations which stipulate the conditions for giving this European Standard the status of a national standard without any alterationä Upætoædate lists and bibliographical references concerning such national standards may be obtained on application to the CENæCENELEC Management Centre or to any CEN memberä
translation under the responsibility of a CEN member into its own language and notified to the CENæCENELEC Management Centre has the same status as the official versionsä
CEN members are the national standards bodies of Austriaá Belgiumá Bulgariaá Croatiaá Cyprusá Czech Republicá Denmarká Estoniaá Finlandá Former Yugoslav Republic of Macedoniaá Franceá Germanyá Greeceá Hungaryá Icelandá Irelandá Italyá Latviaá Lithuaniaá Luxembourgá Maltaá Netherlandsá Norwayá Polandá Portugalá Romaniaá Slovakiaá Sloveniaá Spainá Swedená Switzerlandá Turkey and United Kingdomä
EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre:
Avenue Marnix 17,
B-1000 Brussels
t r s x CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Membersä Refä Noä EN
s x y y sã t r s x ESIST EN 16771:2017

Steps in approval . 22 Annex B (informative)
Suggested sequence of laboratory tests . 24 Annex C (informative)
Procedure for FRY etching . 25 Annex D (normative)
Procedure for measurement of surface hardness . 26 Annex E (normative)
Procedure for slow bend test . 27 Annex F (normative)
Procedure for recording test weld fracture face defects . 29 Annex G (normative)
Ultrasonic inspection procedure on aluminothermic welds to be sectioned . 30 G.1 Principle . 30 G.2 Apparatus . 30 G.3 Preparation of samples . 30 G.4 Calibration . 30 SIST EN 16771:2017

Procedure for microscopic examination of the visible heat affected zone and fusion zone of welds . 32 Annex I (normative)
Procedure for measurement of the heat softened zone width . 33 I.1 Measurement of hardness . 33 I.2 Evaluation of hardness data . 34 Bibliography . 36
¶ 30 mm gap and ± 3 mm for > 30 mm to 50 mm gaps and ± 5 mm for > 50 mm gaps; f) preheating details; g) range of ignition to tap times for the portions; h) critical process timings; i) time (or temperature) before trains can pass; j) safety information. 5.4.2 Drawing with the required measurements. A drawing, as illustrated in Figure 1, which provides the measurements listed below: a) weld collar width (W1). The development of the weld collar shall be fully dimensioned around the weld; b) maximum depth of collar at section B-B (D1 and D2); c) minimum depth of collar at section B-B (d1 and d2); d) riser cross section at foot; SIST EN 16771:2017

Key 1 figure showing the width of the weld collar around the weld 2 riser cross section on the neutral axis mm2 3 25 % of the foot width 4 riser cross section at the foot mm2 5 longitudinal axis under the rail foot Figure 1 — Dimensions taken from mould pattern 5.4.3 Chemical analysis ranges and tolerances. The chemical analysis ranges and tolerances shall be in accordance with 7.5.1. 5.5 Initial compliance testing a) For the purposes of approval the standard, rail profiles (see EN 14811) shall be grouped as follows. SIST EN 16771:2017

Hardness test 7.2 6 5 B
Surface examination – Visual 7.1.1 7.1.2 6 5 C
Slow Bend Test 7.3 6 3 D
Ultrasonic inspection – Annex G 7.4.1.1 2 Nil E
Weld soundness 7.4.1 7.3 2 (2) Nil F
Fusion Zone – Shape and Dimensions 7.4.2 2 Nil G
Chemical analysis 7.5 3 3 H
Heat softened zone – Hardness distribution 7.4.4 2 2 I
Structure – Fusion Zone – Heat affected zone 7.4.3.3 7.4.3.2 2 2 1 1 NOTE () indicates weld soundness evaluation of the fracture face of the slow bend test specimens. a Category 1 Initial tests to be conducted using not heat treated grade on one rail profile from group 1 or 2 (Table 1 or 2). b Category 2 Tests required extending approval for heat treated grades. Tests on one rail profile cover all profile groups approved in categories 1 and 2. 5.6 Extension of initial compliance testing Initial compliance can be extended as follows: The relevant railway authority requirements defined in Clause 4 shall be met for each of the items below: a) to other group of rail profiles listed in Table 1 or 2 [5.5, a)], by doing the tests given in Table 3 category 1 [5.5, b)] on one profile of the appropriate group. Failure of any test shall cause non-compliance for the group of rail profiles being tested; b) to other rail grade by doing the tests given in Table 3 category 2 [5.5, b)]. Failure of any test shall cause non-compliance for that rail grade. Tests on one rail profile cover all profiles in group 1 or 2. 5.7 Preparation and allocation of test welds a) Welds required for the tests shall be produced in accordance with the process manual (5.4.1) under the supervision of the approving authority. Rails to be used for the production of test SIST EN 16771:2017
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