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Engineering Specification

Track

L1-CHE-SPE-063

Flash Butt Welding

Version: 1

Issued: September 2015

Owner: Engineering Group

Approved By:

Gordon Djurdjevic

Track Engineering Manager

ENGINEERING SPECIFICATION

FLASH BUTT WELDING

L1-CHE-SPE-063 Version: 1 Effective from: 21st September 2015

Approving Manager: Head Engineer Track & Structures Approval Date: 21/09/2015 Next Review Date: 21/09/2018

PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION of 15

Approval

Amendment Record

Approval Date Version Description

21/09/2015 1 Initial Release. Supersedes PTC TM 36 - Joining of Rails by Flash Butt Welding


FLASH BUTT WELDING




Table of Contents

1 Purpose ........................................................................................................................... 5

2 Scope ............................................................................................................................... 5

3 Abbreviations .................................................................................................................. 5

4 Definitions ....................................................................................................................... 5

5 References & Legislations ............................................................................................. 6

6 Responsibilities .............................................................................................................. 6

7 Safety & Environmental .................................................................................................. 6

8 Requirements .................................................................................................................. 6

8.1 Pre-Qualification of the Welding Procedure ........................................................................ 6

8.2 Welder Qualification ............................................................................................................ 7

8.3 Rail Inspection..................................................................................................................... 7

8.4 Rail End Preparation ........................................................................................................... 8

Cleaning and Drying ............................................................................................................ 8 8.4.1

Cutting ................................................................................................................................. 8 8.4.2

Rail End Alignment .............................................................................................................. 8 8.4.3

8.5 Welding Restrictions ........................................................................................................... 8

8.6 Welding Operation .............................................................................................................. 9

8.7 Data Recording and Weld Identification ............................................................................. 9

8.8 Heat Treatment of Rail ...................................................................................................... 10

Plain Carbon Rail ............................................................................................................... 10 8.8.1

Head Hardened Rails ........................................................................................................ 10 8.8.2

8.9 Weld Grinding ................................................................................................................... 10

8.10 Production Weld Testing ................................................................................................... 10

Visual Inspection ............................................................................................................... 10 8.10.1

Weld Alignment ................................................................................................................. 11 8.10.2

Weld Collar ........................................................................................................................ 11 8.10.3

Ultrasonic Testing .............................................................................................................. 12 8.10.4

8.11 Qualification Weld Tests ................................................................................................... 12

Hardness Test ................................................................................................................... 12 8.11.1

Macroscopic Testing .......................................................................................................... 12 8.11.2

Microscopic Testing ........................................................................................................... 13 8.11.3

Slow bend test ................................................................................................................... 13 8.11.4


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Inspection and Additional Tests by Superintendent ........................................................... 13 8.11.5

8.12 Defective Welds ................................................................................................................ 13

8.13 Rail Ends of Long Welded Rails ....................................................................................... 13

Squareness ....................................................................................................................... 13 8.13.1

Cutting of Rails .................................................................................................................. 13 8.13.2

Rail End Drilling ................................................................................................................. 14 8.13.3

8.14 Quality Assurance ............................................................................................................. 14

General .............................................................................................................................. 14 8.14.1

Quality System .................................................................................................................. 14 8.14.2

8.15 Storage, Handling and Transport of Long Welded Rail .................................................... 14

8.16 Defective Welds during the Defects Liability Period ......................................................... 14

9 Related Documents ...................................................................................................... 15

10 Records ......................................................................................................................... 15

11 Appendices ................................................................................................................... 15


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1 Purpose

This specification sets out the supply, manufacturing, testing and documentation required for joining of rails by the flash butt welding process.

2 Scope

This specification will cover the requirements for the systems and procedures relating to the welding of new rail, which is completed at John Holland’s Spotswood depot using the Rectifier Rail Welding Machine – GAas 80/590 (SCHLATTER) in a stationary configuration.

3 Abbreviations

MTM Metro Trains Melbourne

LWR Long Welded Rail

FBW Flash Butt Weld

QA Quality Assurance

4 Definitions

Flash Butt Weld Fusion welding of rail ends by electric arc heating and contact under high pressure.

Primary Rail Un-welded rail, comprising prime length and approved short length rails as supplied by the manufacturer.

Prime Lengths Standard or common length supplied by the manufacturer, normally 13.72m or 27.4m.

Short Lengths Rails shorter than prime lengths. Minimum acceptable short length for welding into long welded rail is 9m.

Long Welded Rail Primary rails which have been welded together to form any length equal to or greater than 82m.

Individual LWR Report

A QA document which shall capture the details of each completed weld.

Non Head Hardened Rail

Plain Carbon Rail typically used by railways. It contains carbon in the order of 0.65-0.82% and manganese in the order of 0.7-1.25%

Head hardened Rail

Superintendent

Rail in which controlled quenching has been carried out on the head during manufacture to significantly increase the hardness of the rail surfaces.

Technical Representative nominated by the Chief Engineer’s Office.

Upset The stage during flash butt welding, after heating, when the two rail ends are forged together.


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5 References & Legislations

AS1085.1 – 2002 (R2013) Railway Track Materials – Part 1: Steel Rails

AS1085.20 - 2012 Railway Track Materials – Part 20: Welding of Steel Rail

PTC TM36 - 1997 Joining of Rails by Flash Butt Welding

MTPR 033000-10 Welded Track Management Manual – Chapter 10 Closure Rails

6 Responsibilities

The Contractor shall be responsible for conformance to this document.

The MTM Technical Representative nominated by the Chief Engineer’s Office shall be responsible for the management of the technical requirements and shall ensure compliance in accordance with the MTM documented processes relevant to this specification.

7 Safety & Environmental

The general requirements in relation to safety are included in MTM’s Safety Management System Manual (L0-SQE-MAN-002).

L0-SQE-PRO-014 Safety and Environmental Requirements for Contractors Working on MTM Premises outline the requirements of contractors operating within MTM’s premises.

8 Requirements

8.1 Pre-Qualification of the Welding Procedure

Prior to the commencement of production welding, the FBW procedure shall be pre-qualified to AS1085.20 Appendix M.

All records of pre-qualification shall be submitted to the Superintendent for acceptance.

Re-qualification is required when any aspect of the pre-qualified procedure is modified. This includes, but is not limited to changes to the rail profile, material grade, pre-heating, rail supplier or when changes to any of the welding parameters (cycle time, duration of flashing, voltage, amps and similar) exceeds 10%.

Test certificates shall be provided to prove conformance of the following aspects, as a minimum:

Surface Examination

o Visual (Section 8.10.1)

o Surface alignment (Section 8.10.2)

o Weld collar tests (Section 8.10.3)

Ultrasonic Tests (Section 8.10.4)

Hardness Traverse (Section 8.11.1)


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Macrostructure test (Section 8.11.2)

Microstructure test (Section 8.11.3)

Slow Bend test (Section 8.11.4)

The number of welds to be tested for qualifying the welding procedure shall be in accordance with AS1085.20 Table M1

Following Pre-qualification of the welding procedure, regular testing of welds shall be carried out on production welds as per Section 8.10.

8.2 Welder Qualification

Rail welding shall be carried out by suitably trained and qualified welders who have been approved by the Superintendent and may be included on the MTM database for competent rail workers.

Each welder operator who will be engaged to undertake the FBW process shall prepare two test welds, each passing the requirements of Production Weld testing as per section 8.10. The Contractor shall record the names of the competent FBW operator for QA and audit purposes.

The cost of production, handling, testing and certification of the test welds shall be met by the Contractor.

The results of each test and the certification shall be submitted to the Superintendent for review and approval of the welding procedures and welders, prior to commencement of production welding.

Rails for practice welds or for repeats of failed approval tests shall be supplied by the Contractor, or by the Superintendent at the cost of the Contractor.

Flash butt welder operators shall re-qualify every 2 years or where less than 500 welds have been performed within a 12 month period.

The Contractor shall follow their FBW and QA procedures and these shall align with AS 1085.20. The FBW procedure shall be subject to regular quality assurance audits with frequencies to be nominated by MTM.

8.3 Rail Inspection

Primary rail shall comply to AS 1085.1 or other approved standard as specified.

The Contractor shall examine each rail prior to welding. Rails containing abnormal corrosion, head, web or foot defects, or bending shall be rejected.

The straightness at the end 1.5m of each rail shall be checked for conformance to AS1085.1.

End squareness shall also be within the tolerances set out in AS1085.1.

Prime lengths shall be 13.72 m minimum, unless otherwise specified. Longer prime lengths are preferred.

Prime rails shall be welded into long lengths of 82 m (3 x 27.4m or 6 x 13.72m), 110 m (4 X 27.4m or 8 x 13.72m) or intermediate lengths as specified.

The minimum acceptable short length of primary rail for welding into long welded rail is 9m.


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Short rails or combinations of short and prime lengths rails shall be welded into lengths as near as practical, but not greater than the long welded rail length as specified. Prime rails shall nominally constitute a minimum of 90% of each long welded length.

Special length long welded rails may be required as directed by the Superintendent. Such special lengths shall not exceed 165m and may be made up of suitable combinations of prime and short length rails.

Localised defects in new rail may be removed by straightening or cropping subject to minimum requirements for short lengths of rail.

Long welded lengths shall not contain drilled holes, unless approved by the Superintendent.

8.4 Rail End Preparation

Cleaning and Drying 8.4.1

Rail ends and electrode contact areas shall be scrubbed to ensure that good contact can be made by the flash butt welder onto the rail. The surfaces must be cleaned of all scale, grease and other contaminants and dried prior to welding.

Abrasive removal of scale may be required depending on the type of rail.

A visual inspection shall be completed to ensure the rail has been adequately cleaned. Mirrors shall be used to inspect the underside of the rail.

Each rail shall be inspected following the cleaning and drying phase and shall be recorded on the Individual LWR Report.

Cutting 8.4.2

Rails shall be cut using a friction saw and may not be flame cut unless approved by the Superintendent.

The Contractor shall supply details of rail saws to be used to the Superintendent for review.

Any cracks or rail defects detected during a cutting operation shall be removed.

Rail End Alignment 8.4.3

Alignment of rails in the welding machine shall be set at the head of the rail.

Welding is to be performed with a slight upward peak to ensure that the production of dipped welds is mitigated

Vertical alignment shall provide for a flat running surface.

Horizontal alignment shall be established such differences (if any) in rail head widths is equally divided on either side.

8.5 Welding Restrictions

The use of flash butt welding for rail junctions is not permitted.


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8.6 Welding Operation

Prior to welding, the flash butt operator shall visually inspect the rail to confirm that the ends of the rails have been cleaned as per Section 8.4.1. If the flash butt operator is unsatisfied with the cleaning of the rail end or electrode contact area, appropriate measures shall be taken to rectify the condition and ensure adequate contact can be made between the rail and the electrodes. Any further cleaning required shall be noted on the Individual LWR Report.

All welds shall be forged to permit plastic deformation of the rail ends and shall have a minimum upset of 12 mm. The upset distance shall be inspected during the FBW operation and any anomalies or deviations form acceptable outputs shall be noted and referenced on the individual LWR report for closer inspection and testing. Refer to section 8.7

If, during the welding process, flashing is interrupted with less than 12 mm of flashing distance remaining, rails shall be re-clamped and flashing re-initiated.

The flash butt welder shall visually inspect the electrode contact area to ensure that there are no electrode burns present. A mirror shall be utilised to inspect the underside of the rail. If electrode burns are discovered, the weld shall be considered defective and removed. An electrode burn is considered to exist where the metal has been displaced. Prior to grinding, the rail shall also be visually inspected to confirm that the weld collar is not excessive and that there are no tears, cracks or gouges.

Details of the ‘as welded’ visual inspection, including the inspection of the electrode contact area shall be recorded on the Individual LWR Report.

8.7 Data Recording and Weld Identification

Welding records (cycle time, duration of flashing, voltage and amps) for each day of production welding shall be recorded and stored in a database. Each weld graph shall be reviewed by the Contractors Engineer on duty and compared to the weld graphs from the qualification welds. If any weld is rejected by the Engineer, the weld is to be cut out and the details of the weld recorded on the Individual LWR Report. The Superintendent shall be notified of any welds exhibiting unusual recorded characteristics.

A review of the weld graphs is to be completed by the Contractor and the results detailed in a Report which shall be submitted to the Superintendent.

The accuracy of calibration of the equipment shall be verified before commencement of welding and shall be maintained. Documentary evidence of calibration shall be provided to the Superintendent before commencement of welding

All records shall be clearly marked with a weld identification number. The same number shall be clearly marked on the web of the rail next to the corresponding weld with an indelible marking pen or paint stick. The marking shall be in letters at least 10mm high and shall remain legible for a period of 12 months from the date of welding.


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8.8 Heat Treatment of Rail

Plain Carbon Rail 8.8.1

Welds shall be cooled to ambient temperature naturally, or using a continuous cooling rate consistent with being left in ambient conditions. Grinding shall only occur once the welds are at ambient temperature.

Head Hardened Rails 8.8.2

Flash butt welds and adjacent heat effected rails of head hardened rail shall be treated to ensure equivalent surface hardness and hardness profile to the primary rail as specified in AS 1085.1, Clause 9.1.2 or as otherwise specified.

The Contractor shall provide details of the heat treatment process as part of the qualified welding procedure.

Grinding shall occur once the rail is at or around ambient temperature.

8.9 Weld Grinding

Welds shall be finished, using a rail profile grinder, to a smooth profile free of tears, drag marks or cracks. The sides and top of the rail head shall be finished flush with the parent section.

8.10 Production Weld Testing

All welds produced by the Contractor shall undergo testing as per Section 8.10. Welds used to Pre-Qualify the FBW procedure shall also undergo testing as per Section 8.11.

Visual Inspection 8.10.1

Each weld shall undergo a visual inspection with the results being recorded on the Individual LWR Report.

Visual weld inspection shall cover the entire weld surface and the heat-affected zone adjacent to the weld. All fins on the weld due to grinding and/or shear drag shall be removed prior to visual inspection.

The visual inspection should cover the following, and details should be recorded on the weld Individual LWR Report:

Cracks

Tears

Gouges

Gas porosity

Shrinkage porosity

Slag or sand inclusions

Underfill

Weld shape and contour

Fins


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Electrode burns

Hammer marks

Cold laps

Glazing due to excessive heating of mould surface

Any defects shall be rectified to the satisfaction of the Superintendent. If rectification is not possible, the weld shall be rejected.

Results of the visual inspection shall be recorded on the Individual LWR Report.

Weld Alignment 8.10.2

Each weld shall undergo a weld alignment test and the results recorded on the Individual LWR Report.

Weld straightness in both the horizontal and vertical plane shall be measured using a straight edge or approved modified straight edge over a distance of 500mm from each side of the weld.

The maximum distance from the rail to the straightedge shall be measured in both the horizontal and vertical directions.

The finished rail shall generally comply with the surface alignment tolerances of AS1085.20 Table 2.1 for Tolerance Grade AT2, except that:

Welds with a dip of more than 0mm shall not be accepted by the Superintendent

The maximum slope angle on top of the rail shall be 7 milliradians, measured from a distance of 250mm either side of the weld, at intervals not greater than 50mm.

Tolerances may be reduced subject to the final application of the rail and shall be determined based on the direction of the Superintendent.

Results of alignment inspection, including maximum dip/peak and maximum slope angle values shall be recorded on the Individual LWR Report.

Weld Collar 8.10.3

Each weld shall undergo a weld collar inspection and the results recorded on the Individual LWR Report.

The outstand of metal at the collar shall be tested using a gauge specifically designed for testing the deviation of the weld to the desired weld profile.

The weld collar tolerance for the web and upper side of the rail foot shall be -0mm +4mm.

The weld collar tolerance for the underside of the rail foot shall be -0mm + 3mm.

These tolerances are greater than the tolerances specified in AS1085.20 but do not compromise the functionality of the weld or the rail. Details of weld collar measurement testing and any weld collars that do not meet the requirements of AS1085.20 Table 2.1 shall be recorded on the Individual LWR Report. Any variation to this tolerance shall be submitted for approval by the MTM Superintendent


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Ultrasonic Testing 8.10.4

Each weld shall be tested using Phased Array Ultrasonic Testing to be arranged by the Contractor after completion of grinding.

A written procedure, outlining the details of the ultrasonic testing equipment, techniques, calibrations, tester qualifications and surface preparation methods shall be provided to the Superintendent for approval prior to commencement of testing.

The weld method used shall be capable of providing the discontinuity detection requirements described in Appendix F of AS1085.20. Tolerances for acceptance requirements shall be as per AS 1085.20 Table F6.1.

Results in the form of a Pass or Fail of ultrasonic inspections shall be recorded on the weld Individual LWR Report.

Rail testing must be carried out by suitably trained and qualified Ultrasonic weld testers. The qualifications and/or experience of the Ultrasonic weld testers shall be provided by the Contractor to the Superintendent and approval obtained prior to any testing commencing. The Superintendent reserves the right to retest ultrasonic testers.

A review of the raw data associated with the ultrasonic inspections is to be completed by the Contractor and the results detailed in the Ultrasonic Inspection Report and shall be submitted to the Superintendent. Any irregularities and welds operating near to any limits or tolerances shall be reported.

8.11 Qualification Weld Tests

As part of the qualification of the FBW procedure detailed in section 8.1, additional tests must be performed on welds as specified in this section. The tests required for the qualification of the FBW procedure are additional to the production weld tests specified above. Results of each test must be submitted to the Superintendent as part of the acceptance of the FBW procedure.

Hardness Test 8.11.1

A hardness traverse test must be performed on two (2) no. welds used to qualify the flash butt welding procedure.

The hardness test shall be performed according AS1085.20 for flash butt welds. Pass criteria is specified in AS1085.20 Table M2.

Macroscopic Testing 8.11.2

A macroscopic test shall be performed on two (2) no. welds used to qualify the flash butt welding procedure.

The macroscopic test shall be performed in accordance to AS1085.20 with pass criteria specified in AS1085.20 Table M2.


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Microscopic Testing 8.11.3

A microscopic test shall be performed on one (1) weld used to qualify the flash butt welding procedure.

The microscopic test shall be performed in accordance to AS1085.20 with pass criteria specified in AS1085.20 Table M2.

Slow bend test 8.11.4

A slow bend test shall be performed on three (3) welds used to qualify the flash butt welding procedure.

The slow bend test shall be performed in accordance to AS1085.20 with pass criteria specified in AS1085.20 Table M2.

Inspection and Additional Tests by Superintendent 8.11.5

The Superintendent reserves the right to carry out additional testing of production welds. Testing using any of the methods outlined above may need to be performed by the Contractor during the course of production welding.

The cost of any such additional tests, over and above those required to qualify or re-qualify the welding procedure, shall be performed by the Contractor at the Superintendent’s cost.

The Contractor shall afford the Superintendent access at all times to inspect the work site and to undertake quality audits of all welding and testing records.

8.12 Defective Welds

All welds not meeting the criteria defined in this Specification (other than misaligned welds suitable for straightening) shall be rejected, cut out, replaced and new welds retested. A minimum of 40 mm on each side of the affected weld shall be removed.

Cutting out and replacement of rejected welds shall be at the Contractors cost.

8.13 Rail Ends of Long Welded Rails

Squareness 8.13.1

Both ends of each completed length of long welded rail shall be inspected and measured to ensure compliance with AS 1085.1 for rail end squareness and condition.

Rail ends which do not comply shall be cropped, at the Contractors cost, to provide compliance.

Cutting of Rails 8.13.2

Rail ends at each end of a long welded rail may be saw cut only, flame cutting is not permitted.

Any cracks or rail defects detected during a cutting operation shall be removed and the Superintendent notified.

Such cutting or additional cutting shall be at the Contractor’s cost.


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Rail End Drilling 8.13.3

The Contractor shall not drill end holes in rails unless requested or approved by the Superintendent.

8.14 Quality Assurance

General 8.14.1

The Contractor shall develop and maintain a Quality System for the Works. The proposed Quality System shall be submitted to the Superintendent for review and approval prior to the commencement of FBW operations.

Quality System 8.14.2

The Quality System shall include Certificates of Compliance and Individual LWR Reports, in a format approved by the Superintendent, for:

Machine operator and support team ID

Date and time of welding

Rail Section (e.g. 47kg, 53 kg 60kg)

Rail and Weld identification numbers

Weld data recording

Test results (weld data recording, visual, alignment and ultrasonic)

8.15 Storage, Handling and Transport of Long Welded Rail

The Contractor shall provide details, as applicable, including location of the proposed stockpiling, handling and transport of long welded rail to the Superintendent for review prior to work commencing.

For stockpiling and transport, LWR shall be stacked straight with feet abutting and with 13mm thick by 100mm wide steel bearer strips placed between each layer at spacing of not greater than 6m.

The Contractor shall be responsible for provision of bearer strips.

Rails shall be handled and transported in a manner which will not be detrimental to the rails. Damage caused by improper handling shall be rectified, to the satisfaction of the Superintendent, by and at the cost of the Contractor.

8.16 Defective Welds during the Defects Liability Period

During the currency of the Contract or within the defect liability period, as defined in the Contract, any weld provided by the Contractor which does not conform to this specification, shall be cut out and a new portion of rail shall be welded in its place.

The Contractor shall be liable for the cost of providing a section of closure rail, if applicable, the length of which shall be specified by the Superintendent according to MTM’s Welded Track Management Manual Chapter 10 – Closure Rails (MTPR 033000-10). All associated costs to reinstate the rail to the specified condition shall be borne by the Contractor.


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9 Related Documents

N/A

10 Records

A record of all welds and associated tests shall be maintained during all stages of the qualification of the welding procedure and during production welding.

An Inspection and Test Plan shall be completed for every dispatch event.

Documentation in relation to FBW procedures and the associated QA records shall be provided to the Superintendent to demonstrate compliance to AS1085.20. This documentation shall be kept on file by the Contractor at all times.

11 Appendices

N/A