AWS C4.2/C4.2M:2017

An American National Standard

Recommended Practices for Oxyfuel Gas Cutting

Torch Operation

AWS C4.2/C4.2M:2017

An American National Standard

Approved by the American National Standards Institute

March 2, 2017

Recommended Practices for Oxyfuel Gas Cutting

Torch Operation

3rd Edition

Supersedes AWS C4.2/C4.2M:2009

Prepared by the American Welding Society (AWS) C4 Committee on Oxyfuel Gas Welding and Cutting

Under the Direction of the AWS Technical Activities Committee

Approved by the AWS Board of Directors

Abstract

These recommended practices for oxyfuel gas cutting include the latest procedures to be used in conjunction with oxyfuel gas cutting equipment and the latest safety recommendations. Complete lists of equipment are available from individual manufacturers.

AWS C4.2/C4.2M:2017

ISBN: 978-0-87171-909-6

© 2017 by American Welding Society

All rights reserved Printed in the United States of America

Photocopy Rights. No portion of this standard may be reproduced, stored in a retrieval system, or transmitted in any form, including mechanical, photocopying, recording, or otherwise, without the prior written permission of the copyright owner.

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Statement on the Use of American Welding Society Standards

All standards (codes, specifications, recommended practices, methods, classifications, and guides) of the American 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 American National 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 governmen- tal 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.

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 special, indirect, consequential, or compensatory, directly or indirectly resulting from the publication, use of, or reliance on this standard. AWS also makes no guarantee or warranty as to the accuracy or completeness of any information published herein.

In issuing and making this standard available, AWS is neither 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. It is assumed that the use of this standard and its provisions is entrusted to appropriately qualified and competent personnel.

This standard may be superseded by new editions. This standard may also be corrected through publication of amend- ments or errata, or supplemented by publication of addenda. Information on the latest editions of AWS standards includ- ing amendments, errata, and addenda is posted on the AWS web page (www.aws.org). Users should ensure that they have the latest edition, amendments, errata, and addenda.

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Official interpretations of any of the technical requirements of this standard may only be obtained by sending a request, in writing, to the appropriate technical committee. Such requests should be addressed to the American Welding Society, Attention: Managing Director, Standards Development, 8669 NW 36 St, # 130, Miami, FL 33166 (see Annex D). With regard to technical inquiries made concerning AWS standards, oral opinions on AWS standards may be rendered. These opinions are offered solely as a convenience to users of this standard, and they do not constitute professional advice. 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 interpretations 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 C4 Committee on Oxyfuel Gas Welding and Cutting. It must be reviewed every five years, and if not revised, it must be either reaffirmed or withdrawn. Comments (recommendations, additions, or deletions) and any pertinent data that may be of use in improving this standard are requested and should be addressed to AWS Headquarters. Such comments will receive careful consideration by the AWS C4 Committee on Oxyfuel Gas Welding and Cutting and the author of the comments will be informed of the Committee’s response to the comments. Guests are invited to attend all meetings of the AWS C4 Committee on Oxyfuel Gas Welding and Cutting to express their comments verbally. Procedures for appeal of an adverse decision concerning all such comments are pro- vided in the Rules of Operation of the Technical Activities Committee. A copy of these rules can be obtained from the American Welding Society, 8669 NW 36 St, # 130, Miami, FL 33166.

AWS C4.2/C4.2M:2017

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Personnel

AWS C4 Committee on Oxyfuel Gas Welding and Cutting

L. L. Liston, Chair Consultant

1. F. Johnson, Vice Chair Miller Electric Manufacturing Company

   1. Naumann, Secretary American Welding Society

J. F. Henderson Victor Technologies, Incorporated

M. J. Hogan The Harris Products Group, A Lincoln Electric Company

R. K. Langford Victor Technologies, Incorporated

1. R. McGowan McGowan Technical Services, Incorporated

2. B. Overvaag Miller Electric Manufacturing Company

J. C. Papritan The Ohio State University

A. T. Sheppard The DuRoss Group

Advisors to the AWS C4 Committee on Oxyfuel Gas Welding and Cutting

J. D. Compton J. C. & Associates

M. E. Owens Columbus State Community College

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Foreword

This foreword is not part of this standard but is included for information purposes only.

This Recommended Practices standard is intended for use by the oxyfuel gas cutter (operator). It describes the oxyfuel gas cutting process, including information relating to equipment, safety, and operating procedures. Although many refer- ences are made to safe practice throughout this standard, it is strongly recommended that all operators become thoroughly familiar with all aspects of safe operation. A suggested standard is ANSI Z49.1, Safety in Welding, Cutting, and Allied Processes, available from the American Welding Society. Much of the information in this standard is necessarily general in nature due to the large number of variations in equipment produced by various manufacturers. The manufacturer’s manual should be consulted for details on safe installation and use of all equipment. When equipment or parts of equip- ment need repair, the work shall be performed by skilled mechanics who have been properly instructed.

A vertical line in the margin or underlined text in clauses, tables, or figures indicates an editorial or technical change from the 2009 edition.

Comments and suggestions for the improvement of this standard are welcome. They should be sent to the Secretary, AWS C4 Committee on Oxyfuel Gas Welding and Cutting, American Welding Society, 8669 NW 36 St, # 130, Miami, FL 33166.

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Table of Contents

Page No.

Personnel v

Foreword vii

List of Tables xi

List of Figures xi

1. General Requirements 1

   1. Scope 1

   2. Units of Measure 1

   3. Safety 1

2. Normative References 1

3. Terms and Definitions 2

4. Process and Operation 3

   1. Oxyfuel Gas Cutting Process 3

   2. Principles of Operation 3

5. Equipment and Supplies 4

   1. Oxygen Supply 4

   2. Fuel Supply 4

   3. Maximum Acetylene Pressure 5

   4. Pressure Regulators 5

   5. Hoses and Fittings 7

   6. Cutting Torches 8

   7. Cutting Tips 10

   8. Personal Protective Equipment (PPE) 13

   9. Cutting Machines 13

   10. Safe Use, Handling, and Storage of Gas Cylinders 13

   11. Safe Working Environment 14

6. Startup and Shutdown Procedure 14

   1. Setting Up Equipment 15

   2. Lighting the Torch 16

   3. Equipment Shutdown 17

7. Flame Adjustment 18

   1. Types of Flames 18

   2. Backfire, Sustained Backfire, and Flashback Safety Note 18

8. Cutting Procedures—Hand Torches 19

   1. Starting Methods 19

   2. Torch Position and Motion 19

   3. Piercing 20

   4. Oxygen Lancing 21

   5. Gouging, Washing, and Special Applications 22

9. Machine Oxygen Cutting 23

   1. Cutting Charts 23

   2. Operating Techniques 23

   3. Bevel Cutting 24

      AWS C4.2/C4.2M:2017

10. Hints for Best Selection of Tips, Speeds, and Pressures 24

    1. Correct Cutting Techniques 25

    2. Common Cutting Faults 25

    3. Tip Distance 25

    4. Gas Adjustment 25

    5. Bevel Cutting 25

11. Flashback Arrestors and Check Valves 26

    1. Flashback Arrestors 26

    2. Check Valves 26

    3. What to Do in the Event of a Flashback 26

    4. Flashback Prevention 26

Annex A (Informative)—Reference Documents 27

Annex B (Informative)—Fuel Gas Withdrawal Rates 29

Annex C (Informative)—Fuel Gases 31

Annex D (Informative)—Requesting an Official Interpretation on an AWS Standard 33

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List of AWS Documents on Oxyfuel Gas Welding and Cutting 35

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List of Tables

Table Page No.

1. Acetylene Withdrawal 29

2. Propylene Withdrawal 30

3. Propane Withdrawal 30

List of Figures

Figure Page No.

1. Description of Oxyfuel Gas Cutting 3

2. Oxygen Cylinder 5

3. Typical Fuel Gas Cylinders 6

4. Pressure Regulators 6

5. Hoses and Fittings 7

6. Manual Oxygen Cutting Torch 9

7. Combination Torch 9

8. Three Hose Machine Torch 9

9. Torches Classified According to Method of Mixing 10

10. Oxyfuel Gas Cutting Tips 11

11. Oxyfuel Gas Cutting Tips—One- and Two-Piece Designs 11

12. Carburizing Flame 18

13. Neutral Flame 18

14. Oxidizing Flame 19

15. Cutting Torch Starting a Cut and in Action 20

16. Lead Torch Angle for Straight Line Cutting 20

17. Oxygen Lance 21

18. Special Application Tips 22

19. Oxygen Orifice Design for Washing Tips 22

20. Bevel Cutting 24

AWS C4.2/C4.2M:2017

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Recommended Practices for Oxyfuel Gas Cutting Torch Operation

1. General Requirements

   1. Scope. This standard describes the equipment, procedures, and safe practices for the oxyfuel cutting of steel. It is for the operators of both hand and machine torches and is recommended for management personnel associated with the oxyfuel cutting process.

      Oxyfuel gas cutting is a process whereby a metal (usually an iron base alloy) is heated to its kindling temperature (well below the melting point) by an oxyfuel gas flame and then burned rapidly by a regulated jet of oxygen. A cutting torch is used for this operation. Although this recommended practice is not written with mandatory requirements, mandatory language, such as the use of “shall,” will be found in those portions of the document where failure to follow the instruc- tions or procedures could produce inferior, misleading, or unsafe results.

   2. Units of Measure. This standard makes use of both U.S. Customary Units and the International System of Units (SI). The latter are shown within brackets ([ ]) or in appropriate columns in tables and figures. The measurements may not be exact equivalents; therefore, each system must be used independently.

   3. Safety. Safety issues and concerns are addressed in this standard although health issues and concerns are beyond the scope of this standard. Safety and health information is available from the following sources:

      American Welding Society:

      1. ANSI Z49.1, Safety in Welding, Cutting, and Allied Processes

      2. AWS Safety and Health Fact Sheets

      3. Other safety and health information on the AWS website Material or Equipment Manufacturers:

         (1) Safety Data Sheets supplied by materials manufacturers (2) Operating Manuals supplied by equipment manufacturers

         Applicable Regulatory Agencies

         Work performed in accordance with this standard may involve the use of materials that have been deemed hazardous, and may involve operations or equipment that may cause injury or death. This standard does not purport to address all safety and health risks that may be encountered. The user of this standard should establish an appropriate safety program to address such risks as well as to meet applicable regulatory requirements. ANSI Z49.1 should be considered when devel- oping the safety program.

         
         

2. Normative References

The documents listed below are referenced within this publication and are mandatory to the extent specified herein. For undated references, the latest edition of the referenced standard shall apply. For dated references, subsequent amend- ments to, or revisions of, any of these publications do not apply.