Overbygning/Aluminiotermisk sveiseprosess

1 Purpose / Scope

This specification applies to consumables and equipment supplied for aluminothermic welding of rail joints on Bane NOR lines. This specification sets out objective requirements concerning the product to be supplied, to enable suppliers to design, produce, inspect and deliver welding consumables and equipment that meets the expectations of Bane NOR.

2 Functional requirements

The welding method must comply with the functional requirements specified below.

2.1 Preheating

This specification applies to welding processes with short and long preheating time.

  • A mixture of oxygen and propane must be used to preheat the rails.
  • The preheating system must be capable of use at temperatures as low as 0°C without any reduction in the throughflow of gas.
  • The preheating system must be capable of use at temperatures as low as -5°C without any reduction in the throughflow of gas when suitable gas or bottle heating system is used.
  • Preheating time must not exceed 5 minutes, for welding process with short preheating time, irrespective of rail profile and grade.
  • Preheating time must not exceed 10 minutes, for welding process with long preheating time, irrespective of rail profile and grade.

2.2 Welding moulds

The welding moulds must be prefabricated to fit the following rail profiles, in accordance with EN 13674-1:

  • 49E1
  • 54E2
  • 54E3 / 54E4
  • 60E1 / 60E2

For all the above profiles, it must be possible to seal the moulds sufficiently to allow rails with up to 15 mm wear at the side and 14 mm wear at the top to be welded satisfactorily.

It must be possible to weld together the following combinations of different rail profiles using transition moulds:

  • 49E1 to 54E3/54E4
  • 54E3 to 60E1/60E2

The welding method must work satisfactorily on track with a cant of up to 150 mm.

2.3 Welding portion

The welding portion must be ready mixed and ready for use. The welding portion must be suitable for use with the following grades of rail, in accordance with EN 13674-1:

  • R200
  • R260Mn
  • R320Cr
  • R350HT
  • R370CrHT
  • R400HT

2.4 Axle loads

  • Welding processes for welding of rails with grade R200, R260Mn, R320Cr and R350HT shall be suitable for use in tracks with axle loads up to 25 ton.
  • Welding processes for welding of rails with grade R370CrHT and R400Ht shall be suitable for use in tracks with axle loads up to 30 ton.

2.5 Crucible

  • The crucible must be of a light type designed for single use.
  • The weight of the crucible minus the welding portion must not exceed 12 kg.
  • The crucible must be able to be placed in a stable position and must prevent overflow on track with a cant of up to 150 mm.
  • Crucibles must have a built-in plug for automatic tapping.

2.6 Tolerances for welding work

The welding method must be capable of accommodating the following discrepancies/tolerances while still complying with the quality requirements specified in EN 14730-1:

Tolerance for welding gap ± 2 mm
Tolerance for positioning of welding moulds ± 2 mm in longitudinal direction of rail
Tolerance for height of blowpipe ± 3 mm

2.7 Welding in tunnels

For welding in tunnels, the welding process must be adapted for use with a filter system to remove most of the welding fume during the reaction.

3 Qualification of welding process

Qualification of welding process shall be in accordance with EN 14730-1. The supplier shall provide all necessary documentation of the qualification tests. For established welding processes which are previous accepted by Bane NOR and have been in use on the Bane NOR network for a longer period, new qualification tests are not necessary provided that no change in the approved welding process has happened.


3.1 Information given from Bane NOR according to EN 14730-1

3.1.1 Preheating (EN 14730-1 - 4.a)

See Preheating

3.1.2 Numbers / dimensions of slag and sand inclusions on the as cast weld surface (EN 14730-1 – 4.b)

The maximum number and dimensions of slag and sand inclusions shall be in accordance with EN 14730-1 ch. 7.1.1

3.1.3 Weld collar geometry affected by riser removal (EN 14730-1 – 4.c)

The fracture surface left under the removed risers shall not contain any remaining shrinkage cavities or other impressions.

3.1.4 Rejection level for ultrasonic testing (EN 14730 – 4.d)

The rejection level for ultrasonic testing is FBH 5 mm for all tests in EN 14730-1, annex C.

3.1.5 Width of heat affected zone (EN 14730-1 – 4.f)

The width of the heat affected zone, according to EN 14730-1, kap. 7.1.3, shall not exceed 40 mm for non heat treated rails and 60 mm for heat treated rails respectively

3.1.6 Minimum fracture load for R320Cr rail grade (EN 14730 – 4.g)

The minimum fracture load for 3-point bending test of R320 Cr rail grade shall not be less than 0,0032 x S, where S [mm3] is the section modulus for the base of the rail.

3.1.7 Width of heat-softened zone (EN 14730 – 4.i)

The width of the heat-softened zone, as defined in EN 14730 annex J, shall not exceed 30 mm.

3.1.8 Fatigue requirements (EN 14730 – 4.j)

The fatigue strength should be determined from the “staircase” testing method according to EN 14730-1, annex K.

The minimum accepted fatigue strength is 210 N/mm2 with 5 million cycles. Standard deviation is maximum 15 N/mm2

3.2 3 point bending test

EN 14730-1 requires 3-point bending test (EN 14730, kap.7.3 and appendix F). In addition to fracture load, Bane NOR requires the deflection to be recorded. Min. deflections are given in Tabell 1

Tabell 1: min. deflection - 3-point bending test

Rail grade Min deflection
R200, R260Mn, R350HT 12 mm
R320CR, R370CrHT, R400HT 10 mm

3.3 Welding process for rail grade R370CrHT and R400HT

The requirements for acceptance of welding process for rail grade R370CrHT and R400HT is the same as the requirements for acceptance of welding process for R350HT with the following exceptions:

Tabell 2: Requirements for rail grade R370CrHT and R400HT

Requirement R370CrHT R400HT
Surface hardness on the weld centreline: 370 HB ± 30 HB 390 HB ± 30 HB
Fatigue strength:

(max standard deviation 15 N/mm2)

min. 230 N/mm2 min. 230 N/mm2

4 Production, testing and acceptance

A quality plan including all quality documents in relation with the acceptance of materials and manufacturing of the consumables shall be established and approved by Bane NOR. The quality plan shall include:

  • description of test for each consumable (welding portion, mould, crucible, luting material and igniter)
  • frequency of testing
  • procedure used to increase the testing frequency when defects or irregularities are identified
  • actions to be taken in the case of defects or irregularities being found to ensure remedial works and recheck for compliance or not acceptance for delivery
  • document control system that ensures control, status and traceability of documents

5 Welding procedure / manual

The supplier must draw up a written work manual and welding procedure for the welding process to be performed. The work manual and welding procedure must include all welding parameters and must describe all operations in the welding process, from cutting the welding gap to straightening and final grinding.

The supplier should provide translation of the work manual and welding procedure to Norwegian.

6 Labelling and packaging of consumables

6.1 Moulds

The moulds must be packed in a way that protects them from impacts and dampness.

The packaging must be labelled with the following information:

  • Date of manufacture
  • Serial number
  • Welding process
  • Rail profile
  • Rail grade

6.2 Welding portions

The welding portions must be packed either in watertight plastic packaging or included in the crucible.

The packaging/crucible must be labelled with the following information:

  • Date of manufacture
  • Serial number
  • Welding method
  • Rail profile
  • Rail grade

6.3 Igniters

Igniters must be packed in separate watertight packaging well apart from the welding portions.

6.4 Crucibles

The crucibles must be packed in a way that protects them from impacts and dampness.

The packaging must be labelled with the following information:

  • Date of manufacture
  • Serial number
  • Welding process
  • Rail profile (in case of portion included in crucible)
  • Rail grade (in case of portion included in crucible)

7 Transport and storage

  • All consumables must be stored and transported frostfree
  • All consumables must be stored and transported protected from any moisture that can cause degradation of the material.

8 Reference documents

  1. EN 13674-1 (2011) Railway applications – Track – Rail – part 1: Flat bottom symmetrical railway rails 46kg/m and above
  2. EN 14730-1 (2006) Railway applications – Track – Aluminiothermic welding of rails – part 1: Approval of welding processes

9 Compliance list

10 Change log

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