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AWS C4.4/C4.4M:2007 Recommended Practices for Heat Shaping and Straightening with Oxyfuel Gas Heating Torches
standard by American Welding Society, 2007
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AWS C4.4/C4.4M:2007
An American National Standard
Approved by the American National Standards Institute
September 11, 2007
2nd Edition
Supersedes AWS C4.4/C4.4M:2004
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
This second edition of Recommended Practices for Heat Shaping and Straightening covers the shaping of metal products by prudent use of heat to obtain a desired configuration. The text reviews the theory and analytical calculations that explain how heat shaping and straightening occurs. Sample calculations and tables are presented for typical materials. General heating patterns and heat shaping and straightening techniques are discussed. Specific heating applications are illustrated for various sections.
550 N.W. LeJeune Road, Miami, FL 33126
International Standard Book Number: 978-0-87171-079-6
American Welding Society 550 N.W. LeJeune Road, Miami, FL 33126
© 2007 by American Welding Society
All rights reserved Printed in the United States of America
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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 govern- mental 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 the AWS administers the process and establishes rules to promote fairness in the development of consensus, it does not independently test, evalu- ate, 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 are entrusted to appropriately qualified and competent personnel.
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 or trade name. Users of this standard accept any and all liabilities for infringement of any patent or trade name items. AWS disclaims liability for the infringement of any patent or product trade name resulting from the use of this standard.
Finally, the 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 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, Technical Services Division, 550 N.W. LeJeune Road, Miami, FL 33126 (see Annex C). 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 required 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 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.
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AWS C4 Committee on Oxyfuel Gas Welding and Cutting
A. T. Sheppard, Chair The DuRoss Group
M. J. Hogan, 1st Vice Chair The Harris Products Group, A Lincoln Electric Company
B. Overvaag, 2nd Vice Chair Smith Equipment Company, Division of ITW
M. Alonso, Secretary American Welding Society
J. D. Compton JD & Associates
J. D. Karow American General Corporation
L. L. Liston, Jr. Consultant
R. McGowan McGowan Technical Services
Mirgliotta Forest City Erectors, Incorporated
D. A. Pryor Thermadyne Industries, Incorporated
R. A. Smith Compressed Gas Association
Advisors to the AWS C4 Committee on Oxyfuel Gas Welding and Cutting
J. G. Dawson, Jr. Consultant
D. Hambleton Smith Equipment Company, Division of ITW
C. M. Hightower BMS, Incorporated
R. E. Holt Retired
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This foreword is not part of AWS C4.4/C4.4M:2007, Recommended Practices for Heat Shaping and Straightening with Oxyfuel Gas Heating Torches, but is included for informational purposes only.
The shaping of metals by the use of heat has a long history of successful applications. This shaping has been used to curve, camber, or otherwise shape a product as well as to correct members that have become distorted or damaged by accident or fire.
This second edition of Recommended Practices for Heat Shaping and Straightening with Oxyfuel Gas Heating Torches presents methods and techniques used by engineers and technicians to shape and straighten metal parts by careful appli- cation of heat.
All revisions to the 2004 edition are identified by a vertical line in the margin next to the text.
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, 550 N.W. LeJeune Road, Miami, FL 33126.
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Page No.
Personnel v
Foreword vii
List of Tables xi
List of Figures xi
Scope 1
Normative References 1
Terms and Definitions 2
Theory of Heat Shaping 2
Distortion 6
Fundamentals and Precautions 7
Equipment and Supplies 8
Standard Equipment. 8
Special Equipment 8
Oxygen Supply 8
Fuel Supply 8
Maximum Acetylene Pressure 9
Pressure Regulators 9
Hoses and Fittings 11
Heating Torches 12
Heating Tip/Head. 12
Maintenance of Heating Tips or Heads 12
Personal Protective Equipment (PPE) 13
Safe Use, Handling, and Storage of Gas Cylinders 14
Startup and Shutdown Procedure 15
Setting Up Equipment 15
Lighting the Torch 16
Equipment Shutdown 17
Equipment Not in Use 17
Reuse of Equipment Already Connected 17
Flame Adjustment 17
Types of Flames 17
Flashback Arrestors and Check Valves 18
General Technique 19
Procedures for General Applications 20
Mechanically Restrained Structures 20
Freestanding Unrestrained Members 21
Shaping of Plate 23
Flattening Plates 23
Plate Tightening 23
Page No.
Procedures for Specific Applications 23
Bending of Flat Bar, V Heat 23
Bending of Channel, V Heat 26
Bending of Beams. 26
Bending of Angle 27
Bending of T Sections 27
Bending of Plate 30
Pipe 30
Line Heating and Flame Bending in Shipyards 30
Background 30
Basic Concepts. 32
Planning and Methods 32
Recommended Practices 33
Code Compliance. 33
Conclusions 33
Safety and Health 33
Annex A (Informative)—Informative References 35
Annex B (Informative)—Fuel Gas Withdrawal Rates 39
Annex C (Informative)—Guidelines for the Preparation of Technical Inquiries 41
List of AWS Documents on Oxyfuel Gas Welding and Cutting 43
Table Page No.
Acetylene Withdrawal 39
Methylacetylene-Propadiene Stabilized (MPS) Withdrawal 39
Propylene Withdrawal 40
Propane Withdrawal 40
Figure Page No.
Shortening of Bar from Application of Heat 3
Variation in Yield Strength and Modulus of Elasticity with Respect to Temperature for
ASTM A 36 Steel 4
Imperceptible Welding Distortion of a Thick Steel Plate 5
Welding Distortion of a Thin Steel Plate 7
Oxygen Cylinder 9
Typical Fuel Gas Cylinders 9
Pressure Regulators 10
Hoses and Fittings 11
Manual Heating Torch 12
Multi-Flame Heating Heads 13
Water-Cooled Flame Hardening Head 13
Carburizing Flame 18
Neutral Flame 18
Oxidizing Flame 18
Basic Heating Patterns 20
Externally Restrained Plate 21
Externally Restrained Beam 21
V Shape Heat Pattern for Straightening or Shaping a Flat Bar 22
Dimensions for Calculating Upset 23
Behavior of ASTM A 36 Steel Perfectly Confined in One Axis as a Function of Temperature 24
Heat Patterns in Rolled Shapes 25
Spot Heat Repair of Dent in Plate 25
Spot Heat Repair (Tightening) on Irregular Plate 26
Application of V Shape Heat Pattern and Direction of Movement 26
Bending of Channel Toward Flange 27
Bending of Channel Toward Web 27
Bending of Channel Toward Open Side 27
Bending of Beam Toward Open Side 28
Bending of Beam Toward Flange 28
Bending of Angle Toward Face of Leg 28
Bending of Angle Toward Edge of Leg 29
Bending of T Section Toward Web 29
Figure Page No.
Bending of T Section Toward Flange 29
Bending of Plate 29
Bending of Plate (More Movement) 30
Decreasing Diameter of Heavy Wall Pipe 31
Straightening of Pipe or Round 31
Straightening Pipe or Round Stock—V Shape Heating with Serpentine Path 31
Straightening Pipe or Round Stock—V Shape Heating with Line Heating Pattern 32
Scope
This publication describes some causes of distortion and corrective actions through the use of heat. It also describes some heat shaping techniques and the direction of movement expected in the heated metal. Equations are provided to aid in estimating the amount of movement for a given heating technique. The methods discussed are specifically applicable to ferrous metals, but many of the methods can be applied to nonferrous metals as well. For a more comprehensive description of specific applica- tions, see Annex A, Informative References.
Heat has been used to shape and straighten structural ele- ments in bridges, buildings, and marine constructions for over a hundred years. Since the late 1930s, the use of oxyfuel gas torches to do this work has become more prevalent. This publication is a recommended practice for using the torch process for work on bridges and buildings, and to some extent, shipbuilding.
Mechanical forces in fabrication and erection, forces occurring in service, accidental impacts from external forces, fire, and explosion, all cause stress in a structural member or a part of a member. If that stress exceeds the elastic limit of the material, distortion will occur, and the member will not conform to its desired shape. Heat shap- ing and straightening is an economical method to pro- duce the desired movement to bring the member into conformance.
The shipbuilding industry throughout the world has taken heat shaping to new heights in shaping technology. Particularly, the use of line heating to shape complex curves in hull structures has become an integral part of a group technology in shipbuilding which also includes product work packages and accuracy control.
Basically, straightening and shaping involves controlled thermal expansion and contraction of a structural ele- ment. The method, location, and shape of the heat appli- cation are covered briefly in this publication. This
recommended practice is limited to fundamentals and sim- ple applications (see Annex A for additional information).
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 equiva- lents; therefore, each system must be used independently.
Safety and health issues may not be fully addressed by this standard. Users of this standard should consult ANSI Z49.1, Safety in Welding, Cutting, and Allied Processes, applicable federal, state, and local regulations and other relevant documents concerning safety and health issues not addressed herein.
Normative References
The following standard contains provisions, which, through reference in this text, constitute mandatory pro- visions of this AWS standard. For undated references, the latest edition of the referenced standard shall apply. For dated references, subsequent amendments to, or revi- sions of, any of these publications do not apply.
AWS documents:1
AWS A3.0, Standard Welding Terms and Definitions, Including Terms for Adhesive Bonding, Brazing, Solder- ing, Thermal Cutting, and Thermal Spraying; and
AWS F4.1, Recommended Safe Practices for Prepara- tion for Welding and Cutting of Containers and Piping.
Other documents:
ANSI Z49.1, Safety in Welding, Cutting, and Allied Processes;2
1 AWS standards are published by the American Welding Society, 550 N.W. LeJeune Road, Miami, FL 33126.
2 ANSI Z49.1 is published by the American Welding Society, 550 N.W. LeJeune Road, Miami, FL 33126.