AWS D15.2

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Practices for

the Welding of

Rails and Related

Rail Components

for Use by Rail

Vehicles

Copyright American Welding Society

Provided by IHS under license with AWS Licensee=ConocoPhillips WAN/5919206100

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Approved by

American National Standards Institute

October 7, 2003

Recommended Practices

for the Welding of Rails

and Related Rail Components

for Use by Rail Vehicles

Supersedes ANSI/AWS D15.2-94

Prepared by AWS D15 Committee on Railroad Welding Under the Direction of AWS Technical Activities Committee Approved by AWS Board of Directors

Abstract

This document recommends minimum standards for the maintenance welding of rails and related rail components used by rail vehicles. Repair procedures for rails and austenitic manganese steel components are covered. Thermite welding and electric flash welding guidelines are discussed. Procedure qualification, welder qualification, and general welding safety procedures are addressed.

oxyfuel welding, procedure

qualification, railroad safety, railroad welding, rails, switch points, thermite welding, track, welder qualification

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--`,,``,``,`,``,```,```,,````,`-`-`,,`,,`,`,,`---Welding Society (AWS) are voluntary consensus standards that have been developed in accordance with the rules of the American National Standards Institute (ANSI). When AWS standards are either incorporated in, or made part of, documents that are included in federal or state laws and regulations, or the regulations of other governmental bodies, their provisions carry the full legal authority of the statute. In such cases, any changes in those AWS standards must be approved by the governmental body having statutory jurisdiction before they can become a part of those laws and regulations. In all cases, these standards carry the full legal authority of the contract or other document that invokes the AWS standards. Where this contractual relationship exists, changes in or deviations from requirements of an AWS standard must be by agreement between the contracting parties.

International Standard Book Number: 0-87171-717-4 American Welding Society, 550 N.W. LeJeune Road, Miami, FL 33126 © 2004 by American Welding Society. All rights reserved Printed in the United States of America AWS American National Standards are developed through a consensus standards development process that brings together volunteers representing varied viewpoints and interests to achieve consensus. While AWS administers the process and establishes rules to promote fairness in the development of consensus, it does not independently test, evaluate, or verify the accuracy of any information or the soundness of any judgments contained in its standards.

AWS disclaims liability for any injury to persons or to property, or other damages of any nature whatsoever, whether spe-cial, indirect, consequential or compensatory, directly or indirectly resulting from the publication, use of, or reliance on this standard. AWS also makes no guaranty or warranty as to the accuracy or completeness of any information published herein. In issuing and making this standard available, AWS is not undertaking to render professional or other services for or on behalf of any person or entity. Nor is AWS undertaking to perform any duty owed by any person or entity to someone else. Anyone using these documents should rely on his or her own independent judgment or, as appropriate, seek the advice of a competent professional in determining the exercise of reasonable care in any given circumstances.

This standard may be superseded by the issuance of new editions. Users should ensure that they have the latest edition. Publication of this standard does not authorize infringement of any patent. AWS disclaims liability for the infringement of any patent resulting from the use or reliance on this standard.

Finally, AWS does not monitor, police, or enforce compliance with this standard, nor does it have the power to do so. On occasion, text, tables, or figures are printed incorrectly, constituting errata. Such errata, when discovered, are posted on the AWS web page (www.aws.org).

Official interpretations of any of the technical requirements of this standard may be obtained by sending a request, in writing, to the Managing Director, Technical Services Division, American Welding Society, 550 N.W. LeJeune Road, Miami, FL 33126 (see Annex F). With regard to technical inquiries made concerning AWS standards, oral opinions on AWS standards may be rendered. However, such opinions represent only the personal opinions of the particular individuals giving them. These individuals do not speak on behalf of AWS, nor do these oral opinions constitute official or unofficial opinions or inter-pretations of AWS. In addition, oral opinions are informal and should not be used as a substitute for an official interpretation. This standard is subject to revision at any time by the AWS D15 Committee on Railroad Welding. It must be reviewed every five years, and if not revised, it must be either reapproved or withdrawn. Comments (recommendations, additions, or deletions) and any pertinent data that may be of use in improving this standard are required and should be addressed to AWS Headquarters. Such comments will receive careful consideration by the AWS D15 Committee on Railroad Welding and the author of the comments will be informed of the Committee’s response to the comments. Guests are in-vited to attend all meetings of the AWS D15 Committee on Railroad Welding to express their comments verbally. Pro-cedures for appeal of an adverse decision concerning all such comments are provided in the Rules of Operation of the Technical Activities Committee. A copy of these Rules can be obtained from the American Welding Society, 550 N.W. LeJeune Road, Miami, FL 33126.

Photocopy Rights

Authorization to photocopy items for internal, personal, or educational classroom use only, or the internal, personal, or educational classroom use only of specific clients, is granted by the American Welding Society (AWS) provided that the appropriate fee is paid to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, Tel: 978-750-8400; online: http://www.copyright.com.

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AWS D15 Committee on Railroad Welding

R. W. Dawson, Chair TTX Company

M. R. Untermeyer, Vice Chair Union Tank Car Company E. F. Mitchell, Secretary American Welding Society

B. C. Blackwell Standard Car Truck Company

*J. L. Bobo Consultant

C. Boulden Trinity Rail Group N. S. Brown Canadian Pacific Railway

T. Bruno Johnstown America

J. Cooley J. C. & Associates, Incorporated S. A. Coughlin Welding Metallurgical Engineering R. T. Easterman Trinity Rail Group

T. Y. Gehr, Jr. Esco Equipment Service Company *P. B. Heideman Portland General Electric

*W. Jaxa-Rozen Bombardier Transportation * P. G. Kinnecom Association of American Railroads

*G. A. Lycan G. A. Gage Company

M. J. Markase Taussig Materials Testing S. E. Markis Norfolk Southern

*C. C. Menzemer The University of Akron M. T. Merlo Select Arc, Incorporated *M. A. Miller Consolidated Rail Corporation

*J. P. Moffet GE Transportation Systems J. B. Pearson, Jr. LTK Engineering Services

*K. R. Rollins Norfolk Southern

*J. Sun Association of American Railroads *J. A. Stewart Ideal Consulting Services

L. H. Strouse G.E. Rail Services

J. Tolene CNIC Railroad

S. W. Tribble Track-Weld Ind., Incorporated R. A. Watson Miner Enterprises, Incorporated M. A. Wheeland Union Pacific Railroad

J. B. Wheeler American Rail Car Industries P. H. Williams Victoria Mechanical Services

R. A. Wolbert Progress Rail Services Corporation *D. A. Wright, Sr. Zephyr Welding

*Advisor

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T. Y. Gehr, Jr., Vice Chair Esco Equipment Service Company E. F. Mitchell, Secretary American Welding Society

T. L. Baxley Norfolk Southern

R. L Bell BNSF Railroad

D. Bjork CNUS

D. N. Blowatt CNR

M. J. Boos Union Pacific Railroad W. C. Bragg Orgo-Thermit, Incorporated

N. Brown Canadian Pacific Railroad

G. K. Clem GKC Consulting Company

G. Copeland Consultant

*R. W. Dawson TTX Company

M. A. Gilstrap CSX

J. C. Handley Elgin Joliet & Eastern Railway

B. F. Hansen Rail Maintenance

J. R. Hornaday, Jr. Alpha Gamma Transform, Incorporated C. Jackson Long Island Railroad

R. S. Koblinski METRA

R. Kral Holland Company

P. J. Lawless BNSF

M. J. Markase Bodycoate

*D. G. McCord Union Pacific Railroad B. A. Meade The Lincoln Electric Company

*J. B. Pearson LTK

A. R. Pierson Norfolk Southern

R. Roper CSX Transportation

S. Scharnweber DMER RR

*J. Sun Association of American Railroads S. W. Tribble Track-Weld Industries

J. G. Wallin Stoody Company

M. A. Wheeland Union Pacific Railroad J. S. Wiederhott Burlington Northern

M. Wilson CSX Transportation

*Advisor

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(This Foreword is not a part of AWS D15.2:2003, Recommended Practices for the Welding of Rails and Related Rail Components for Use by Rail Vehicles, but is included for informational purposes only.)

This recommended practice establishes standards for the joining, repair, maintenance and inspection of rail welds and the welding of related rail components. It was developed and is maintained by the Subcommittee on Track Welding within the AWS Committee on Railroad Welding.

The welding of rails and related rail components for use by rail vehicles is vital to the safe and economical operation of American railroads. This subcommittee has endeavored to develop these recommended practices to serve as a guide-line for the railroad and related industries in the establishment of track welding specifications. The subcommittee is made up of individuals from all segments of the railroad industry, both users and suppliers, and representatives of both the Association of American Railroads and the American Railway Engineering and Maintenance of Way Association.

The purpose of this document is to provide a single comprehensive source of information that will be used throughout the railroad industry. It should act as a guideline towards improving welding quality through the economical joining and repair of rail and rail components.

The first edition of D15.2 was published in 1994.

Comments and suggestions for the improvement of this standard are welcome. They should be sent to the Secretary, AWS D15 Committee on Railroad Welding, American Welding Society, 550 N.W. LeJeune Road, Miami, FL 33126.

Official interpretations of any of the technical requirements of this standard may be obtained by sending a request, in writing, to the Managing Director, Technical Services Division, American Welding Society. A formal reply will be issued after it has been reviewed by the appropriate personnel following established procedures.

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Page No.

Personnel... iii

Foreword ...v

List of Tables ...ix

List of Figures...ix

List of Forms...ix

1. Scope ...1

2. Referenced Documents ...1

3. Rail, Rail Components Manufactured from Rail, and Their Repair ...2

3.1 Specific Items ...2

3.2 Welding Processes ...2

3.3 Railroad Rail Welding ...2

3.4 Repair of Battered Rail Ends and Wheel Burns (Carbon Steel or Premium Steel Rail) ...2

3.5 Repair of Rail-Type Switch Points and Switch Point Protectors ...3

3.6 Frogs, Crossings, and Other Components Made From Rail Steel...4

3.7 Miscellaneous Carbon Steel and Low Alloy Steel Components ...4

4. Repair or Fabrication of Components Manufactured from Austenitic Manganese Steel ...4

4.1 Metallurgical Background ...4

4.2 Components ...4

4.3 Welding Processes ...4

4.4 Filler Metals...4

4.5 Preparation for Welding ...4

4.6 Welding Recommendations—General ...5

4.7 Welding Recommendations—Frogs and Crossings in Track...6

5. Recommended Practices for Joining of Rails by Thermite Welding (TW) ...6

5.1 General Description ...6

5.2 Application ...6

5.3 Preparation of Final Gap for Welding ...6

5.4 Welding Procedure ...6

5.5 Care of Thermite Materials...7

5.6 Procedure Qualification ...8

5.7 Welder Qualification ...8

5.8 Thermite Welding Safety Precautions ...8

6. Flash Welding (FW) of Rail...8

6.1 General Process Description...8

6.2 Rail Preparation ...8

6.3 Rail Welding...9

6.4 Finishing Operations...9

6.5 Continuous Welded Rail Storage...9

7. Procedure Qualification—Arc Welding Processes ...9

7.1 Prequalified Procedures ...9

7.2 Welding Procedures...9

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8.1 Procedure Qualification ...9

8.2 Workmanship Samples ...13

8.3 Results of the Workmanship Samples ...13

9. Nondestructive Testing ...13

9.1 Geometry Inspection (Rail Weld Alignment)...13

9.2 Magnetic Particle Inspection ...13

9.3 Ultrasonic Inspection ...13

9.4 Radiography...13

9.5 Dye Penetrant Inspection...13

Nonmandatory Annexes...15

Annex A—Welding Processes...15

Annex B—Welding of Austenitic Manganese Steel ...21

Annex C—Flash Welding Guidance...25

Annex D—AREMA Tests for Continuous Welded Rail...27

Annex E—Safe Practices ...31

Annex F—Guidelines for Preparation of Technical Inquiries for AWS Technical Committees ...35

List of AWS Documents on Railroad Welding...37

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Table Page No.

D1 Processes for Carbon and Alloy Steel Rail Components...2

D2 Minimum Performance Specifications for New Flash and Thermite Welded Rail ...7

D1 Wheel Loads for Rolling Load Test...27

List of Figures

Figure Page No. A1 Typical Weld Pattern for Rail End Repair ...3

A2 Skip Welding Repair Made in 5 in. (125 mm) Long Increments ...5

A3 Layout of Hardness Survey on Rail Head...10

A4 Layout of Transverse Hardness Survey ...11

A1 Shielded Metal Arc Welding (SMAW) ...16

A2 Gas Metal Arc Welding (GMAW)...16

A3 Flux Cored Arc Welding (FCAW)...17

A4 Section Through a Thermite Mold and Crucible ...18

A5 Automatic Hydraulically Operated Flash Welding Machine with Horizontal Clamping...18

A6 Rail Welding Production Line ...19

A7 Oxyfuel Gas Welding (OFW) ...19

D1 Loading Arrangement for the 12 in. Stroke Rolling Load Machine...28

D2 Load Arrangement for the Slow Bend Test and Formula for Deriving the Modulus of Rupture...29

List of Forms

Form Page No. 1 Typical Welding Procedure Qualification Test Record...12

2 Typical Welder Qualification Test Record ...14

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1. Scope

This document recommends standards for the joining, repair, maintenance, inspection of rail welds, and related rail components. For the purposes of this document, rails include railroad rails, crane rails, guard rails, electri-cal contact rails, girder rails, and retarder rails. Classifica-tion of rails is based on the American Railway Engineering and Maintenance of Way Association (AREMA) specifica-tions governing the manufacture of rails.

Related rail components include rail crossings and turnouts which further include switch points, stock rails, switch point guards, spacer blocks, connecting rods, switch rods, plates, frogs, and frog components.

The use of track components reconditioned by welding is a decision of the rail owner outside the scope of this document. This document does not include road bed maintenance except where it affects the expected life of the repair. Safety precautions shall conform to Code of Federal Regulations (CFR), Title 49, Part 214, Railroad Workplace Safety. Safety and health issues and concerns are beyond the scope of this standard, and therefore are not fully addressed herein. Safety and health information is available from other sources, including, but not limited to, ANSI Z49.1, Safety in Welding, Cutting, and Allied Processes, and applicable federal and state regulations (see also Annex E, Safe Practices).

Welding processes include shielded metal arc welding (SMAW), gas metal arc welding (GMAW), flux cored arc welding (FCAW), flash welding (FW), thermite welding (TW), and oxyfuel gas welding (OFW). See Annex A and Volume 2, Eighth Edition, Welding Handbook for details. This standard makes use of the U.S. Customary Units. Approximate mathematical equivalents in the International System of Units (SI) are provided for comparison in paren-theses ( ) or in appropriate columns in tables and figures.

2. Referenced Documents

The following standards contain provisions which, through reference in this text, constitute provisions of

this AWS standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this AWS standard are encouraged to investigate the pos-sibility of applying the most recent editions of the docu-ments shown below. For undated references, the latest edition of the standard referred to applies.

(1) ANSI Z49.1, Safety in Welding, Cutting, and Allied Processes, Volume 2, Eighth Edition, Welding Handbook1

(2) AREMA Chapter 4, Rail2

(3) ASTM E 140, Hardness Conversion Tables for Metals (Relationship Among Brinell Hardness, Vickers Hardness, Rockwell Hardness, Rockwell Superficial Hardness, Knoop Hardness, and Scleroscope Hardness)3

(4) ASTM E 164-97, Standard Practice for Ultra-sonic Contact Examination of Weldments

(5) ASTM E 1417-99, Standard Practice for Liquid Penetrant Examination

(6) ASTM E 709-01, Standard Guide for Magnetic Particle Examination

(7) AWS A5.13, Specification for Surfacing Elec-trodes for Shielded Metal Arc Welding2

(8) AWS A5.21, Specification for Composite Surfac-ing WeldSurfac-ing Rods and Electrodes

(9) Code of Federal Regulation, Title 49, Volume 4, Parts 200–299, revised October 1, 2000.4

1. ANSI Z49.1 and AWS documents are available from Global Engineering, 15 Inverness Way East, Englewood, CO 80112-5776; telephones: (800) 854-7179, (303) 397-7956; fax (303) 397-2740; Internet: www.global.ihs.com.

2. AREMA documents are available from the American Rail-way Engineering and Maintenance of Way Association, 8201 Corporate Drive, Suite 1125, Landover, MD 20785-2230. 3. ASTM documents are available from the American Society for Testing and Materials, 100 Barr Harbor Drive, West Con-shohocken, PA 19428.

4. Federal regulations are available from the U.S. Government Bookstore, Wells Fargo Building, 201 West 8th, Pueblo, CO 81003, or http://www.gpo.gov/.

Recommended Practices for the Welding of Rails and

Related Rail Components for Use by Rail Vehicles

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3. Rail, Rail Components

Manufactured from Rail, and

Their Repair

It is essential to identify the track material to attain optimum results in selecting the welding procedure. 3.1 Specific Items. These recommendations apply to, but are not limited to, the items listed in Section 1.

3.2 Welding Processes. Welding processes include shielded metal arc welding (SMAW), gas metal arc weld-ing (GMAW), flux cored arc weldweld-ing (FCAW), flash welding (FW), thermite welding (TW), and oxyfuel gas welding (OFW).

3.3 Railroad Rail Welding 3.3.1 Railroad Rail Grades

3.3.1.1 Carbon steel rail having a minimum hard-ness of 240 HB.

3.3.1.2 Premium steel rail has a nominal hardness exceeding 341 HB. This hardness may be the result of alloy composition (nonheat treated) or heat treatment process. Heat treated rail and other variations may re-quire special welding procedures as recommended by the rail manufacturer or filler metal producer, or both.

3.3.1.3 Electrical contact rails are low-carbon steel rails without hardness requirements.

3.3.2 Procedure Requirements for Arc Welding of Carbon Steel and Premium Steel Rail

3.3.2.1 Preheating the weld areas to 800°F–1000°F (425°C–540°C), as measured immediately before weld-ing, is recommended to equalize temperature in the workpiece to prevent breakout of material.

3.3.2.2 Interpass temperature should be within the same range as the preheat temperature to maintain tem-perature in the workpiece.

3.3.2.3 Filler metal should provide weld metal hav-ing a nominal surface hardness compatible with the ex-isting base metal to eliminate breakout of the weld.

3.3.2.4 Postweld heat treatment is recommended, to prevent hardening and cracking when a part is cooled too rapidly through the transformation range, but is not required unless dictated by past experience or by ap-proved railroad welding procedures.

3.3.3 Procedure Requirements for Arc Welding of Premium Steel Rail

3.3.3.1 A preheating temperature of 800°F–1000°F (425°C–540°C) is recommended for premium steel rail. There are two reasons this is done:

(1) To equalize temperature in the workpiece.

(2) To prevent hardening and cracking when a part is cooled too rapidly through the transformation range.

3.3.3.2 The required cooling rate depends on rail size and chemical composition, filler metal, and ambient welding temperature.

3.4 Repair of Battered Rail Ends and Wheel Burns (Carbon Steel or Premium Steel Rail)

3.4.1 Carbon steel or premium steel rail may be re-paired using a process selected from 3.2 and Table 1.

3.4.2 Rail Preparation

3.4.2.1 Visually inspect the rail to determine re-pairability in accordance with the rail owner’s policy.

3.4.2.2 Defective material should be removed to sound base metal. Soundness may be checked using dye penetrant or magnetic particle testing (see Section 9).

3.4.3 Welding Procedure

3.4.3.1 As outlined in 3.3.2 or 3.3.3, preheat the repair area plus 4 in.–6 in. (100 mm–150 mm) longitudinally beyond the weld area in both directions.

3.4.3.2 Interpass temperature should be within the same range as the preheat temperature to maintain tem-perature in the workpiece.

3.4.3.3 All the above recommended temperatures are dependent on the base metal composition, the filler metal used, ambient temperature, weather conditions, and the manufacturer’s recommendations.

3.4.3.4 Weld beads should be made primarily in the longitudinal direction for proper heat distribution.

3.4.3.5 Diagonal or chevron weld bead patterns are preferred, see Figure 1 for typical chevron pattern.

Table 1

Processes for Carbon and

Alloy Steel Rail Components

Component Material Processes

Carbon steel Shielded metal arc welding (SMAW) Gas metal arc welding (GMAW) Flux cored arc welding (FCAW) Oxyfuel gas welding (OFW) Flash welding (FW) Thermite welding (TW)

Premium steel Shielded metal arc welding (SMAW) Gas metal arc welding (GMAW) Flux cored arc welding (FCAW) Flash welding (FW)

Thermite welding (TW)

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--`,,``,``,`,``,```,```,,````,`-`-`,,`,,`,`,,`---3 3.4.3.6 Provisions must be made to prevent perma-nent distortion of the weld area.

3.4.3.7 All weld craters shall be filled.

3.4.3.8 Arc strikes shall not be permitted outside the preheated repair area. Accidental arc strikes outside the repair area shall be repaired in accordance with the provisions of 3.4.

3.4.4 Finish Grinding

3.4.4.1 Welds should be finish ground according to approved procedures on the same work day the rail is welded to minimize impact loading and prevent weld deformation.

3.4.4.2 Finished surface of the weld should be smooth and uniform to match the existing rail contour.

3.5 Repair of Rail-Type Switch Points and Switch Point Protectors

3.5.1 Repair of austenitic manganese switch points is not recommended because the heat input cannot be con-trolled properly to control distortion.

3.5.2 Carbon steel and premium steel rail components may be welded by the processes shown in Table 1.

3.5.3 Visually inspect the switch point or switch point protector to determine the reparability in accordance with the rail owner’s policy.

3.5.4 Defective material should be removed to sound base metal. Soundness may be determined by dye pene-trant or magnetic particle testing (see Section 9).

3.5.5 Temperature control is extremely critical be-cause of variations in thickness and the need to minimize distortion. In order to minimize distortion of the switch point and stock rail during cooling, pre-and post heating should be balanced over the base/web intersection and the repair area.

3.5.6 Switch Point Repair Procedure

3.5.6.1 Welding the switch point against a stock rail is not recommended because of the possibility of arc strikes on the stock rail. A copper backing plate should be used.

3.5.6.2 Switch point must be protected from traffic movement during welding, cooling, and finish grinding.

3.5.6.3 When using arc welding processes, ham-mer shaping of repaired carbon steel, alloy or heat treated rail switch points is not recommended to prevent hot tearing at the grain boundaries of the weld.

3.5.7 Preheat Procedure. Preheat the switchpoint as-sembly in the weld areas, as measured immediately be-fore welding, to 800°F–1000°F (425°C–540°C) unless otherwise recommended by the rail owner. To equalize temperature in the workpiece and prevent breakout of material. If there are differences between the recommen-dations of the rail owner and this document, the rail owner’s recommendation shall prevail.

3.5.8 Interpass temperature shall be in the same range as the preheat temperature.

To maintain temperature in the workpiece. 3.5.9 Application of Filler Metal

3.5.9.1 Longitudinal lineal stringer beads are rec-ommended for carbon steel rail. Slight oscillation result-ing in slower lineal travel speed and increased lineal heat input may be beneficial for premium steel rails to main-tain Interpass temperature. Weld bead pattern shall be in

Figure 1—Typical Weld Pattern

for Rail End Repair

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3.5.9.2 All welds shall be finished to the approved contour.

3.5.9.3 Arc strikes shall not be permitted outside the pre-heated weld repair area because they may cause cracks. Accidental arc strikes outside the repair area shall be re-paired according to 3.5.

3.6 Frogs, Crossings and Other Components Made from Rail Steel. Practices outlined in 3.4 are applicable. 3.7 Miscellaneous Carbon Steel and Low Alloy Steel Components. Practices outlined in 3.4 may be applicable.

4. Repair or Fabrication of

Components Manufactured from

Austenitic Manganese Steel

4.1 Metallurgical Background. For a general discussion of the welding of austenitic manganese steel see Annex B. 4.2 Components. Austenitic manganese steel compo-nents include but are not limited to frogs, crossings, switch point guards, casting inserts, and bridge track components.

If composition of the component is in doubt, a hand magnet should be used for identification purposes. An austenitic manganese steel component will be nonmag-netic, or at the most, have a slightly magnetic skin. The carbon steel or low alloy steel component will be strongly magnetic.

4.3 Welding Processes

4.3.1 Manual welding processes are restricted to shielded metal arc welding electrodes.

4.3.2 Semiautomatic welding processes refer to flux cored arc welding.

4.4 Filler Metals

4.4.1 Austenitic manganese steel shall not be surfaced nor joined using carbon steel or low alloy steel welding electrodes or welding wires.

4.4.2 Austenitic Manganese Welding Electrodes 4.4.2.1 AWS A5.13, Specification for Surfacing Electrodes for Shielded Metal Arc Welding, and AWS A5.21, Specification for Composite Surfacing Welding Rods and Electrodes, detail several basic compositions.

4.4.2.2 AWS A5.13 and AWS A5.21 reflect the va-riety of modifications of the basic austenitic manganese composition currently available. The electrodes generally

deposit undiluted weld metal with manganese content in excess of 14% plus smaller additions, alone or in combi-nation, of nickel, molybdenum, chromium, or vanadium.

4.4.2.3 The range of properties developed by these electrodes enables the user to select the combination best suited for the particular application. For example, an overlay with relatively high yield strength might be used to build up the running surface of frogs whereas an alloy with a yield strength more closely matching that of the base metal might be used to repair a deep crack.

4.4.3 Special nickel-iron and chromium-manganese-nickel-iron austenitic electrodes are accept-able to weld austenitic manganese base metal.

4.5 Preparation for Welding

4.5.1 Austenitic Manganese Steel Castings

4.5.1.1 Grease, rust, and dirt should be removed from the surfaces by appropriate means.

4.5.1.2 The entire casting should be inspected for cracks and other defects. Dye penetrant testing may be used to locate and define the cracks (see Section 9).

4.5.1.3 Cracks shall be removed as completely as practical by grinding or air arc gouging. The latter is the preferred process. Air arc gouging procedures should be as follows:

(1) Locate the end of the crack using a shallow cut. (2) Make a deeper cut moving from the end of the crack towards the edge of the casting.

(3) If the crack does not extend to the edge, air arc gouging should proceed from the ends towards the mid-dle of the crack.

(4) Gouging should be continuous utilizing straight rapid cuts.

(5) Metal and oxides should be eliminated from the cut groove by grinding.

(6) Groove should be kept just wide enough to permit electrode manipulation during welding.

(7) Base metal temperature should not exceed 500°F (260°C) at a point 1 in. (25 mm) from the area being gouged.

4.5.1.4 Worn areas should be located and marked using a straight edge or template.

4.5.1.5 Work hardened (plastically deformed) metal should be removed (this includes weld deposits impacted by traffic during repair).

4.5.1.6 Sharp edges along flangeway surfaces should be rounded slightly.

4.5.2 For Castings to be Welded in Track. Track conditions that may have contributed to the damaged or worn casting shall be corrected prior to welding.

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4.5.3.1 Rail-bound frogs should be stripped before examination for cracks.

4.5.3.2 Distortion control procedures such as pre-or postweld bending should be considered by the repair shop.

4.6 Welding Recommendations—General

The repair of each worn casting tends to be an individ-ual job not subject to rigid definition. Therefore, the rec-ommendations of this section are of a general nature applicable to a wide variety of applications.

4.6.2 When the casting temperature is below 32°F (0°C), it shall be warmed to approximately 70°F (21°C) before any welding or gouging. To prevent embrittlement of the base metal, interpass temperatures should not ex-ceed 500°F (260°C) at a point 1 in. (25 mm) from the area being welded.

4.6.3 Diameter of covered electrodes for SMAW should not exceed 3/16 in. (5 mm).

4.6.4 Diameter of flux cored wire for semiautomatic welding should not exceed 7/64 in. (2.8 mm).

4.6.5 Welding current and travel speed should be ap-propriate to ensure adequate penetration, bead tie-in and lowest thermal input. Excess current should be avoided to prevent heat buildup.

4.6.6 Arc length should be maintained as short as pos-sible while maintaining good arc characteristics.

4.6.7 Weld beads should be slightly crowned and no more than 5/8 in. (16 mm) in width.

4.6.8 Length of individual weld bead should not ex-ceed 10 in. (250 mm) when welding in track. In the shop where precautions can be taken to minimize distortion and heat buildup, longer welds are permitted.

4.6.9 Heat input into the casting should be monitored frequently. Welding should be discontinued in any area where the casting temperature exceeds 500°F (260°C) measured 1 in. (25 mm) from the weld area.

4.6.9.1 Quenching is recommended to prevent over-heating the casting.

4.6.9.2 Skip welding should be used to minimize heat buildup, (see Figure 2).

4.6.10 Carbon blocks or copper plates may be used in the flangeways to maintain proper contour and minimize finish grinding.

4.6.11 Flangeway beads should be deposited first. 4.6.12 Adjacent beads should have tie-in by 35–50%.

4.6.13 The direction of successive beads should be re-versed to minimize stress buildup.

4.6.14 The end of welds should be staggered to fur-ther minimize stress buildup.

4.6.15 Weld beads should not be started or stopped at the edge of the casting to prevent weld undercut.

4.6.16 Weld beads on frog wings, or points should be parallel to the flangeways.

4.6.17 The general procedure for welding frog points is as follows:

4.6.17.1 Welding should start at the lowest point of the repair area gradually building up to the full width of the repair to maintain weld integrity.

4.6.17.2 The arc should be struck about 1/2 in. (13 mm) ahead of the direction of travel where the beads are to begin.

4.6.17.3 Craters should be filled by reversing di-rection and welding back into the bead before breaking the arc.

4.6.18 Successive layers of austenitic manganese may be applied to achieve the desired thickness of buildup.

4.6.19 Individual layers of weld metal should be visu-ally examined prior to proceeding with the next layer.

Figure 2—Skip Welding Repair Made in

5 in. (125 mm) Long Increments

WING RAIL FROG POINT 1 2 1 2 1 2 1 4 3 4 3 4 3 4 5 in. (125 mm) 2 1 2 1 2 4 3 4 3 4 3 4 WING RAIL 1st WELD BEADS 2nd WELD BEADS 3rd WELD BEADS 4th WELD BEADS

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--`,,``,``,`,``,```,```,,````,`-`-`,,`,,`,`,,`---6 Any unacceptable indications should be repaired prior to starting the next layer.

4.6.20 If defect removal requires grinding through the thickness of the casting, a back-up bar of austenitic manganese steel should be used to provide a base for welding.

4.6.21 Specially modified stainless steel may be used as a root pass or initial pass.

4.7 Welding Recommendations—Frogs and Crossings in Track

4.7.1 The general recommendations of 4.6 should apply, as applicable.

4.7.2 Safe movement of trains while frogs are being repaired should be the first priority.

4.7.2.1 Cracks and major break-out areas should be repaired prior to the buildup of worn areas.

4.7.2.2 Large areas to be welded should be sub-divided into sections in such a way that train movement will not be disrupted.

4.7.2.3 The guards of self-guarded frogs shall be rebuilt to their original dimension prior to other repairs. Enough time should be allowed between traffic move-ments to allow complete welding and finish grinding of the raised guard. After the guards have been repaired, the tread portion should be restored.

4.7.2.4 Immediately after completing each bead, peen the bead with the ball end of a two pound ball-peen hammer to stress relive the weld bead. The bead should be struck two to four times per inch of weld using moder-ate blows that produce an indentation of approximmoder-ately 0.040 in. (1.0 mm). Peening should start at the crater and proceed toward the start of the weld. Do not peen the first bead layer, to prevent damage between the bead interface and the parent material. Do not peen the final layer to prevent blemishes in the finished surface.

5. Recommended Practices for

Joining of Rails by Thermite

Welding (TW)

Thermite is defined as a mixture of finely divided alu-minum and iron oxide. When the alualu-minum and iron oxide react, the reaction is called a thermite reaction. Thermite welding is accomplished with the heat pro-duced by the thermite reaction. Filler metal is obtained from the combination of the iron reaction product and pre-alloyed shot in the mixture.

5.1 General Description. Thermite welding is a welding process that joins rail ends by melting them with super-heated liquid metal from a chemical reaction between iron oxide and aluminum. Filler metal is obtained from the liquid metal (see Figure A5).

5.1.1 For a general discussion of the process, see Volume 2, Eighth Edition, Welding Handbook.

5.1.2 Thermite welding supplies are sold under a number of commercial trade names.

5.2 Application

5.2.1 Application includes, but is not limited to, items listed in Section 1.

5.2.2 The thermite welding process may be utilized to weld both carbon steel rail and premium steel rail. pecial procedures may be necessary when welding alloy steel premium rail. to prevent hardening and cracking when the weld is cooled too rapidly through the transformation range.

5.3 Preparation of the Final Gap for Welding

5.3.1 Rail ends should be aligned properly, both laterally and vertically. Rail ends should be secured to prevent movement during the welding process.

5.3.2 The root opening between rails may be oxyfuel gas cut, sawed, or cut with an abrasive disc. Of these, oxyfuel gas cutting is the least desirable.

5.3.2.1 If the final gap is to be prepared by OFC, the rail should be preheated to 700°F (370°C) prior to the oxyfuel gas cut to prevent cracking.

5.3.2.2 Care should be exercised to ensure smooth cut surfaces. An end squareness of ±1/16 in. (±2 mm) both horizontally and vertically is recommended.

5.3.2.3 Ends of oxyfuel gas cut rails should be cleaned thoroughly to remove all residual oxide and must be welded prior to cooling.

5.3.3 The root opening between the rail end faces may vary depending on the specific commercial process.

5.3.4 At least 6 in. (150 mm) on each side of the gap should be free of all moisture and foreign substances such as dirt, grease, loose oxide, burns, fins, and metal flow. In addition, a 6 in. (150 mm) hole free zone is recommended.

5.3.5 Copper material from track circuit bonds shall be removed for at least 2 in. (50 mm) on each side of the weld area.

5.4 Welding Procedure. Welding procedure including preheating techniques, method of ignition, rate of cool-ing, and mold removal will vary somewhat depending on the instructions of the manufacturer of the specific

ther-Copyright American Welding Society

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--`,,``,``,`,``,```,```,,````,`-`-`,,`,,`,`,,`---7 mite kit being employed and the type, size and chemical composition of the specific rail being welded, as well as the local service conditions.

5.4.1 Welds made in accordance with 5.4 should be subjected to the following tests and meet the minimum requirements as specified in Table 2:

(1) Slow bend tests to determine load and deflection (see Annex D)

(2) Hardness tests to evaluate resistance to wear and deformation (see Figure 3)

(3) Rolling load test to determine fatigue life (see Annex D) at the customer’s option

5.5 Care of Thermite Materials

5.5.1 DANGER: INTRODUCTION OF MOIS-TURE TO THE THERMITE WELDING PROCESS MAY CAUSE SERIOUS OR FATAL INJURY. Molten steel and hot slag can cause serious explosion upon com-ing into contact with snow, ice, standcom-ing water, frozen ballast or soil.

Table 2

Minimum Performance Specifications for New Flash and Thermite Welded Rail

Slow Bend Testing

Material

Flash Welding Thermite Welding

Modulus of Rupture(1) _{Deflection Min.} _{Modulus of Rupture(1)} _{Deflection Min.}

Soft Carbon Rail

(248 HB Min.) 100 000 psi(689 MPa) (38 mm)1.5 in. 100 000 psi(689 MPa) (25 mm)1.0 in. Standard Carbon Rail

(300 HB Min.) 120 000 psi(827 MPa) (25 mm)1.0 in. 110 000 psi(758 MPa) (23 mm)0.9 in. Premium Steel Rail

(341 HB Min.) 125 000 psi(862 MPa) (19 mm)0.7 in. 120 000 psi(827 MPa) (15 mm)0.6 in.

Optional Rolling Load Test

Material Loads Cycles All rails See Table D1 2 000 000

Hardness Survey(2)

Flash Welding

Material Deviation from Parent Material, through HAZ Area Standard Carbon Rail

Premium Steel Rail +40 HB/–60 HB to maximum 410 HB+60 HB/–80 HB to maximum 415 HB Thermite Welding

The hardness of the weld metal shall be within ±30 HB points of the manufacturer's specified hardness for the specific welding kit being used.

Macroetch (Flash Welded Rail Only)

Structure Specification Flow-Line Grain turn-out angle

Parallel Heat-Affected Zone 6.350 mm (0.25 in.) maximum deviation35°–75°

Notes:

(1) Modulus of Rupture =

(2) Measurements may be taken in Rockwell Hardness Numbers and converted to Brinell Hardness These conversions be done according to Table 1 in ASTM E 140. Numbers providing a minimum of five Rockwell Hardness readings are obtained, discarding the highest and lowest reading and averaging the remaining readings.

9 Load psi×

( )

Section Modulus

---Copyright American Welding Society

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--`,,``,``,`,``,```,```,,````,`-`-`,,`,,`,`,,`---8 5.5.2 Molds shall be protected from moisture contam-ination and freezing during storage. Charges shall be pro-tected from moisture contamination during storage.

5.5.3 Charges and molds shall be protected from moisture contamination during transportation from stor-age to work site.

5.5.4 Molds and charges shall be used within the shelf-life period recommended by the manufacturer

5.5.5 Crucibles (reaction chambers) shall be clean and dry at all times.

5.5.6 Crucible, mold, charge, and adjacent rail area shall be protected from moisture.

5.5.7 Rail weld geometry shall be checked with a straight edge and taper gauge in accordance with the re-quirements of AREMA 4-2.5, Specification for Quality Assurance of Thermite Welding of Rail, or those selected by the operating authority.

5.5.8 Alignment and Finish Requirements

5.5.8.1 Alignment tolerance of running surfaces should be within the requirement of the individual railroad. 5.5.8.2 Additional grinding to remove surface de-fects should be kept to a minimum.

5.5.8.3 If required, a light grinding of the weld col-lar area to remove sharp corners or surface blemishes is permissible. Care should be exercised to prevent aggres-sive grinding. All grinding of the weld collar should be symmetrical, the as cast geometry should be left intact.

5.5.8.4 Radiography is not recommended for in-spection of thermite welds. Defects are very difficult to detect and interpret.

5.5.8.5 Visual and ultrasonic examinations of fin-ished welds are recommended.

5.6 Procedure Qualification. Procedure tests performed by the thermite manufacturer may be accepted by the user if individual testing is not feasible.

5.7 Welder Qualification

5.7.1 Prior to qualification, welders should receive training from qualified instructors.

5.7.2 In the absence of established welder qualifica-tion tests, the welding supervisor should determine the tests required.

5.7.3 Results of the evaluation of the welder should be made a part of the operator’s permanent record.

5.8 Thermite Welding Safety Precautions

5.8.1 Over tightening the base plate or mold clamp screws may cause cracking of the mold and subsequent leaking of molten metal.

5.8.2 Improper or careless luting (sealing) of the mold may cause leakage of the molten metal.

5.8.3 Avoid all contact with moisture. Molten steel and slag can cause serious explosions when contacted by any form of moisture.

5.8.4 Personnel must wear approved personal safety equipment at all times.

5.8.5 Slag basin should be emptied only after the slag has completely solidified. Solid slag should be disposed of in such a manner as not to pose any hazard to operat-ing personnel.

6. Flash Welding (FW) of Rail

6.1 General Process Description

6.1.1 The automated resistance welding process (see Figures A6 and A7) heats and prepares the rail ends, pro-vides a non-oxidizing environment, and forges the rail ends into a welded joint. Critical flash welding parame-ters are shown in Annex C.

6.1.2 The process and related equipment may contain the following operations: preparation, preheating, flash-ing, forgflash-ing, shearflash-ing, postweld heat treatment, and finishing.

6.1.3 Chapter 4 Part 2 of The American Railway En-gineering and Maintenance of Way Association (AREMA) Manual [4-2.2 Specification for Fabrication of Continuous Welded Rail] provides minimum specifi-cations for rail welding.

6.2 Rail Preparation

6.2.1 Rail ends should be free of rust, dirt, grease, or other foreign material that would impede the start of a low-voltage electric arc.

6.2.2 Electrode contact points should be free from rust, slag, and raised lettering that might provide added resistance to the flow of high electric current and thus cause electrode burns on the rail.

6.2.3 An electrode burn on welded rails shall be de-fined as follows:

(1) Any electrode contact areas which have trans-formed to martensite,

(2) Any electrode contact areas which have been dis-placed during welding, and

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--`,,``,``,`,``,```,```,,````,`-`-`,,`,,`,`,,`---9 (3) Any electrode contact areas which contain trans-ferred electrode copper.

6.2.4 Rails should be presented to the stations of the welding plant in a consistent manner to enhance produc-tion and performance.

6.2.5 Rails should be grouped by length, composition, type, and wear to minimize adjustments required by op-erating personnel.

6.3 Rail Welding

6.3.1 Railroad rails shall be flash butt welded using only the following:

(1) A previously qualified welding procedure. (2) Welding equipment certified as being able to con-sistently reproduce the required welding program.

(3) A qualified operator able to set up the welding program dictated by 6.3.1, calibrate the monitoring equipment, and maintain the machine.

(4) Acceptable welds shall qualify the welding proce-dure, the welding equipment or the welding operator.

6.3.2 Welds made in accordance with 6.3.1 should be subjected to the following tests and meet the minimum requirements as specified in Table 2:

(1) Slow bend tests to determine load and deflection (see Annex D)

(2) Hardness tests to evaluate resistance to wear and deformation (see Figure 3)

(3) Macroetch tests to determine metallurgical sound-ness, forging patterns, and heat-affected zone (HAZ) (see Figure 4)

(4) Rolling load test to determine fatigue life (see Annex D) at the customer’s option

(5) Microetch examination to evaluate metallurgical quality at the customer’s option

6.3.3 Test welds and the results should be evaluated by qualified personnel designated by the engineer in charge and experienced in the flash welding of rail be-fore production welds are made.

6.3.4 Production operations should be monitored by an inspector to ensure compliance with specifications.

6.3.5 Weld parameters for each weld shall be recorded.

6.3.5.1 Recorders should be calibrated daily before use.

6.3.5.2 These permanent records should be re-tained by the verification inspector, operating authority or manufacturer.

6.3.5.3 Records shall be compared with those certi-fied by qualicerti-fied personnel during qualification testing.

6.3.6 Table 2 lists a number of tests that may be used to evaluate the quality of maintenance welds.

6.3.7 Final inspection of the welded rail (see Section 9) shall be done at the last station of the welding plant prior to acceptance for transportation and installation (see Figure A7).

6.4 Finishing Operations

6.4.1 Excess weld material shall be removed.

6.4.2 Finished contour should be as specified by qual-ified personnel. In the absence of specific instructions, the requirements of AREMA Specifications 4-2.2 should apply.

6.5 Continuous Welded Rail Storage

6.5.1 A point person should safely guide and monitor transfer of the welded rail string from the production line into, or onto, the storage rack, ground storage, or contin-uous welded rail (CWR) train.

6.5.2 Care should be exercised to prevent kinking the rail string.

6.5.3 Rail strings should be supported at 25 ft–35 ft (8–11 m) intervals to prevent bending during handling and storage.

7. General Procedure Qualification—

Arc Welding Processes

Each welding process has its own qualification. 7.1 Prequalified Procedures. There are no prequalified procedures for railroad track maintenance welding. 7.2 Welding Procedures. Each operating authority or railroad service company should develop a welding cedure for each specific application, base metal, and pro-cess combination in accordance with the general guidelines of this document. Qualified welding proce-dures may be utilized at any location within the individ-ual authority. Welding procedure should be documented on a form, or forms, equivalent to Form 1. All tests may not be required, but selected tests shall be performed as agreed between the contractor and operating authority.

8. Track Welder Qualification—Arc

Welding Processes

8.1 Procedure Qualification. Any track welder who suc-cessfully performs the procedure qualification shall be qualified to perform the same operations in production.

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Figure 3—Layout of Hardness Survey on Rail Head

SI EQUIVALENTS

in. mm

1/8 3

1/4 6

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Figure 4—Layout of Transverse Hardness Survey

SI EQUIVALENTS

in. mm

1/4 6

5/8 16

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--`,,``,``,`,``,```,```,,````,`-`-`,,`,,`,`,,`---12

Form 1

Typical Welding Procedure Qualification Test Record

PROCEDURE SPECIFICATION HARDNESS GRADIENTS

Base Material Description ________________________ Base Metal Hardness ____________________________ Welding Process _______________________________ Filler Metal Hardness ____________________________ Manual / Semi-Automatic ________________________ HAZ Metal Hardness ____________________________ Position of Welding _____________________________

Filler Metal Description __________________________ Filler Metal Chemical Composition _________________ Filler Metal AWS Classification ____________________

ULTRASONIC EXAMINATION Single or Multiple Pass __________________________

Max/Min Base Metal Temperature _________________ UT Report No. _________________________________ Preheat Temperature ___________________________

Interpass Temperature __________________________ Shielding Gas _________________________________

EXAMINATION METALLOGRAPHY

Post Heat Temperature __________________________ Macroetch Size 1.________________ 2. ___________ Welding Current _______________________________ Microetch detail ________________________________ Welding Voltage _______________________________

Welders Name ________________________________

VISUAL INSPECTION OF WELD All Weld Metal Strength Details

Appearance___________________________________ Tensile Strength (psi) ____________________________ Undercut _____________________________________ Yield Point Strength (psi) _________________________ Porosity ______________________________________ Elongation in 2 in., % ____________________________ Foreign Material Inclusion ________________________ Reduction in Area, % ____________________________

WELDING PROCEDURE

We the undersigned certify that the statements in this record are correct and that the test welds were prepared, welded, and tested in accordance with the requirements of AWS D15.2: (____________) year.

Procedure No. _________________________________ Railroad or Contractor ___________________________ Revision No. __________________________________ Authorized by __________________________________ Date _________________________________________ Pass No. Electrode/ Wire Size Welding Current Amperes/Volts Bead Size Max Bead Length Speed of

Travel WELD DETAIL

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--`,,``,``,`,``,```,```,,````,`-`-`,,`,,`,`,,`---13 8.2 Workmanship Samples. All track welders should prepare one or more workmanship samples or demon-strate on-track welding skill test to verify performance for the welding supervisor. Qualified personnel desig-nated by the engineer in charge may determine the type, size, and number of the workmanship samples.

8.3 Results of the Workmanship Samples. Results of the evaluation of the workmanship samples or on-track skill test should be recorded and made part of the per-manent qualification record of the track welder (see example Form 2).

9. Nondestructive Testing

9.1 Geometry Inspection (Rail Weld Alignment). Rail weld geometry shall be checked with a straight edge and taper gauge in accordance with the requirements of AREMA 4-2.2 or those selected by the operating author-ity. If alignment adjustments are required they shall be performed at a temperature below 900°F (482°C). 9.2 Magnetic Particle Inspection. Magnetic particle in-spection shall be used to inspect for surface defects such as piped rail, shear tears, craters pushed to the surface,

and for the presence of free cementite. Testing shall be in accordance with ASTM E 709, Standard Guide for Mag-netic Particle Examination, and performed below 800°F (427°C). Cementite will not be indicated at a temperature below 400°F (205°C). Results of the inspection shall meet or exceed the requirements of the operating railroad. 9.3 Ultrasonic Inspection. Ultrasonic inspection is best suited for inspection of welds installed in the field. It may be used, with reservations, in the production line. Results of the inspection shall meet or exceed the requirements of the operating railroad. Examination should follow established guidelines of ASTM E 164, Standard Practice for Ultrasonic Contact Examination of Weldments.

9.4 Radiography. Radiography is not recommended for the inspection of rail welds. Defects are very difficult to detect and interpret.

9.5 Dye Penetrant Inspection. Dye penetrant inspection may be used for detection of discontinuities, such as lack of fusion, corrosion, cracks, laps, cold shuts and porosity that are open or connected to the surface. Testing shall be in accordance with ASTM E 1417, Standard Practice for Liquid Penetrant Examination.

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--`,,``,``,`,``,```,```,,````,`-`-`,,`,,`,`,,`---14

Form 2

Typical Welder Qualification Test Record

Welders Name _____________________________________________________ Welders ID No. ________________ Welding Process _________ Manual ________________ Semiautomatic __________ Machine _______________ Position _________________________________________________________________________________________ In Accordance With Procedure Specification No. _________________________________________________________ Material Specification ______________________________________________________________________________ Rail Size ________________________ Switch Point Size __________________ Frog Size ____________________ Description and Size of Other Material _________________________________________________________________

FILLER METAL

Specification No. __________________ Classification _____________________ F No. ________________________ Describe Filler Metal (if not covered by AWS Specification) _________________________________________________ _______________________________________________________________________________________________ Filler Metal Chemical Composition ____________________________________________________________________ Filler Metal Diameter _________________________________________________ Is Backing Plate Used? _________

VISUAL INSPECTION

Appearance______________________ Undercut ________________________ Porosity______________________

ULTRASONIC INSPECTION

HARDNESS GRADIENT

Base Metal Hardness ______________________________________________________________________________ Filler Metal Hardness ______________________________________________________________________________ HAZ Hardness ___________________________________________________________________________________

METALLOGRAPHY EXAMINATION

Macroetch Size 1.__________________ 2.__________________ 3.__________________ 4. ______________ Macroetch Detail __________________________________________________________________________________ Microetch Detail __________________________________________________________________________________ Test Authorized by______________________________ Test Witnessed by ______________________________ Test No. ______________________________________

We the undersigned certify that the statements in this record are correct and that the welds were prepared and tested in accordance with the requirements of the American Welding Society AWS D15.2: (___________) year.

Railroad or Contractor ___________________________ Date _________________________________________ UT Method Transducer Type Result Remarks

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--`,,``,``,`,``,```,```,,````,`-`-`,,`,,`,`,,`---15

A1. Arc Welding

A1.1 Shielded Metal Arc Welding (SMAW) (Stick Welding)

A1.1.1 An arc welding process with an arc between a covered electrode and the weld pool. The process is used with shielding from the decomposition of the electrode covering, without the application of pressure, and with filler metal from the electrode.

A1.1.2 See Figure A1 for a schematic of the process. A1.2 Gas Metal Arc Welding (GMAW)

A1.2.1 An arc welding process that uses an arc be-tween a continuous filler metal electrode and the weld pool. The process is used with shielding from an exter-nally supplied gas and without the application of pressure. A1.2.2 See Figure A2 for a schematic of the process. A1.3 Flux Cored Arc Welding (FCAW)

A1.3.1 An arc welding process that uses an arc be-tween a continuous filler metal and the weld pool. The process is used with a shielding gas from a flux con-tained within the tubular electrode, with or without addi-tional shielding from an externally supplied gas, and without the application of pressure.

A1.3.2 See Figure A3 for a schematic of the process.

A2. Thermite Welding (TW)

A2.1 A welding process that produces coalescence of metals by heating them with superheated liquid metal

from a chemical reaction between a metal oxide and alu-minum, with or without the application of pressure. Filler metal is obtained from the liquid metal.

A2.2 See Figure A4 for a typical thermite installation.

A3. Flash Welding (FW)

A3.1 A resistance welding process that produces a weld at the faying surfaces of a butt joint by a flashing action and by the application of pressure after heating is sub-stantially completed. The flashing action, caused by very high current densities at small contact points between the workpieces, forcibly expels the material from the joint as the workpieces are slowly moved together. The weld is completed by a rapid upsetting of the workpieces. A3.2 In the welding of continuous rail, the flash welding machine (Figure A5) is only one station in the production cycle (Figure A6).

A4. Oxyfuel Gas Welding (OFW)

A4.1 A group of welding processes that produces coales-cence of workpieces by heating them with an oxyfuel gas flame. The processes are used with or without the appli-cation of pressure and with or without the addition of filler metal.

A4.2 See Figure A7 for a schematic of the process. A5. For further discussions of the arc welding processes refer to Volume 2, Eighth Edition, Welding Handbook.

Annex A

Welding Processes

(This Annex is not a part of AWS D15.2-2003, Recommended Practices for the Welding of Rails and Related Rail Components for Rail Vehicles, but is included for informational purposes only.)

Nonmandatory Annexes

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--`,,``,``,`,``,```,```,,````,`-`-`,,`,,`,`,,`---16

Figure A1—Shielded Metal Arc Welding (SMAW)

Figure A2—Gas Metal Arc Welding (GMAW)

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--`,,``,``,`,``,```,```,,````,`-`-`,,`,,`,`,,`---17

Figure A3—Flux Cored Arc Welding (FCAW)

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--`,,``,``,`,``,```,```,,````,`-`-`,,`,,`,`,,`---18

Figure A4—Section Through a Thermite Mold and Crucible

Figure A5—Automatic Hydraulically Operated

Flash Welding Machine with Horizontal Clamping

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--`,,``,``,`,``,```,```,,````,`-`-`,,`,,`,`,,`---19

Figure A6—Rail Welding Production Line

Figure A7—Oxyfuel Gas Welding (OFW)

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--`,,``,``,`,``,```,```,,````,`-`-`,,`,,`,`,,`---21

B1. Introduction

B1.1 Austenitic manganese steel is an extremely tough, nonmagnetic alloy with properties uniquely different from those of most commonly used structural and wear resistant steels. It is the preferred material for a number of trackwork components, with frogs and crossings the most important. It has high strength and durability and resists failure under impact and heavy loading. Its capac-ity for work hardening is a major asset; the surface of the part hardens under impact, undergoing some deforma-tion, while the underlying body retains its original tough-ness. The propagation rate of any cracks that may be initiated is extremely slow. Metal-to-metal wear resis-tance is excellent. Resisresis-tance to abrasive wear is good, compared to that of carbon steel and low alloy steels. B1.2 Austenitic manganese steel is available as castings, which comprise the most tonnage. Rolled plate, bars and wire, as well as electrodes for welding in various forms also are available.

B2. Composition

A number of modifications of the original Hadfield composition are produced commercially as castings; the ASTM A 128, Standard Specification for Steel Castings, Austenitic Manganese, lists ten grades. For trackwork cast-ings the American Railway Engineering and Maintenance of Way Association (AREMA) requires production in con-formance with ASTM A 128, Standard Specification for Steel Castings, Austenitic Manganese, except that the chemical requirements are modified slightly as follows:

Carbon 1.00/1.30% Manganese 12.00% Min Silicon 1.00% Max Phosphorus 0.07% Max

Some lower carbon steel castings alloyed with molyb-denum are used in special applications.

For many purposes, the optimum carbon content is about 1.15%, considering foundry and heat treating problems, casting properties, and economy. The high-manganese con-tent plays a vital role in stabilizing the austenite by retard-ing its transformation to other structures. Silicon is present mainly for deoxidization purposes. Phosphorus is re-stricted because of its tendency to promote hot cracking, both in the foundry and in subsequent welding operations. Composition of filler metals deposited by austenitic manganese electrodes differ from casting analyses to provide the desired austenitic structure with weld cooling rates. Carbon commonly is somewhat reduced and addi-tional alloying elements are added to maintain acceptable mechanical properties. Nickel, molybdenum, chromium, and vanadium, alone or in combinations, are used as added alloying elements in austenitic manganese steel welding electrodes.

B3. Basic Metallurgy

B3.1 At high temperatures, the structure of steel is essen-tially austenitic; most carbon steels and alloy steels trans-form from the austenitic structure to other structures as the metal cools. Large manganese additions effectively suppress the transformation of austenite, so that with suf-ficiently fast cooling an austenitic structure is retained at room temperature.

B3.2 Before heat treatment, manganese steel castings are relatively brittle, as slow cooling in the molds does not provide a fully austenitic structure. Heat treatment in-volves heating to the appropriate austenitizing tempera-ture, usually in the 1850°F–1950°F (1010°C–1065°C) range, holding until the sections are fully austenitic and all carbides dissolved, and quenching in cold, agitated water.

Annex B

Welding of Austenitic Manganese Steel

(This Annex is not a part of AWS D15.2-2003, Recommended Practices for the Welding of Rails and Related Rail Components for Use by Rail Vehicles, but is included for informational purposes only.)