1、Recommended Practices for Oxyfuel Gas Cutting Torch OperationAWS C4.2/C4.2M:2017An American National StandardAWS C4.2/C4.2M:2017An American National StandardApproved by theAmerican National Standards InstituteMarch 2, 2017Recommended Practices for Oxyfuel Gas Cutting Torch Operation3rd EditionSupers
2、edes AWS C4.2/C4.2M:2009Prepared by theAmerican Welding Society (AWS) C4 Committee on Oxyfuel Gas Welding and CuttingUnder the Direction of theAWS Technical Activities CommitteeApproved by theAWS Board of DirectorsAbstractThese recommended practices for oxyfuel gas cutting include the latest procedu
3、res 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:2017iiISBN: 978-0-87171-909-6 2017 by American Welding SocietyAll rights reservedPrinted in the United States
4、 of AmericaPhotocopy 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.Authorization to photocopy items for internal
5、, 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 provided that the appropri-ate fee is paid to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, tel: (978) 75
6、0-8400; Internet: .AWS C4.2/C4.2M:2017iiiStatement on the Use of American Welding Society StandardsAll standards (codes, specifications, recommended practices, methods, classifications, and guides) of the American Welding Society (AWS) are voluntary consensus standards that have been developed in ac
7、cordance 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 carr
8、y 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 contra
9、ct 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
10、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
11、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 relia
12、nce 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
13、 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
14、 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. I
15、nformation 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.Publication of this standard does not authorize infringement of any patent
16、 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.AWS does not monitor, police, or enforce compliance with
17、this standard, nor does it have the power to do so.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, Attentio
18、n: 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 d
19、o 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 opin
20、ions 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. Co
21、mments (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
22、 of the comments will be informed of the Committees 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-vid
23、ed 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:2017ivThis page is intentionally blank.AWS C4.2/C4.2M:2017vPersonnelAWS C4 Committee on Oxyfuel Gas Weldin
24、g and CuttingL. L. Liston, Chair ConsultantB. F. Johnson, Vice Chair Miller Electric Manufacturing CompanyA. Naumann, Secretary American Welding SocietyJ. F. Henderson Victor Technologies, IncorporatedM. J. Hogan The Harris Products Group, A Lincoln Electric CompanyR. K. Langford Victor Technologies
25、, IncorporatedC. R. McGowan McGowan Technical Services, IncorporatedD. B. Overvaag Miller Electric Manufacturing CompanyJ. C. Papritan The Ohio State UniversityA. T. Sheppard The DuRoss GroupAdvisors to the AWS C4 Committee on Oxyfuel Gas Welding and CuttingJ. D. Compton J. C. therefore, each system
26、 must be used independently.1.3 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 Weldin
27、g, Cutting, and Allied Processes(2) AWS Safety and Health Fact Sheets(3) Other safety and health information on the AWS websiteMaterial or Equipment Manufacturers:(1) Safety Data Sheets supplied by materials manufacturers(2) Operating Manuals supplied by equipment manufacturersApplicable Regulatory
28、AgenciesWork 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
29、 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 ReferencesThe documents listed below are referenced within this publication and
30、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.AWS C4.2/C4.2M:20172American Welding Society (AWS) standards:1AWS
31、A3.0M/A3.0, Standard Welding Terms and Definitions, Including Terms for Adhesive Bonding, Brazing, Soldering, Thermal Cutting, and Thermal Spraying; andAWS F4.1, Recommended Safe Practices for Preparation for Welding and Cutting of Containers and Piping.American National Standards Institute (ANSI) s
32、tandard:2ANSI Z49.1, Safety in Welding, Cutting, and Allied ProcessesCode of Federal Regulations (CFR):329 CFR 1910, Occupational Safety and Health Standards; and29 CFR 1926, Safety and Health Regulations for Construction.Compressed Gas Association (CGA) standard:4CGA E-1, Standard for Rubber Weldin
33、g Hose and Hose Connections for Gas Welding, Cutting, and Allied Processes.National Fire Protection Association (NFPA) standards:5NFPA 51: 2013, Standard for the Design and Installation of Oxygen-Fuel Gas Systems for Welding, Cutting, and Allied Processes, Quincy, MA: National Fire Protection Associ
34、ation; andNFPA 55, Standard for the Storage, Use, and Handling of Compressed Gases and Cryogenic Fluids in Portable and Stationary Containers, Cylinders, and Tanks.Rubber Manufacturers Association (RMA) standard:6RMA IP-7, Specifications for Rubber Welding Hose, Washington, DC: Rubber Manufacturers
35、Association.3. Terms and DefinitionsAWS A3.0M/A3.0, Standard Welding Terms and Definitions, provides the basis for terms and definitions used herein. However, the following terms and definitions are included to accommodate usage specific to this document.backfire. The momentary recession of the flam
36、e into the torch, potentially causing a flashback or sustained backfire. It is usually signaled by a popping sound, after which the flame may either extinguish or reignite at the end of the tip. See also flashback and sustained backfire.flashback. The recession of the flame through the torch and int
37、o the hose, regulator, and/or cylinder, potentially causing an explosion. See also backfire and sustained backfire.sustained backfire. The recession of the flame into the torch body with continued burning characterized by an initial popping sound followed by a squealing or hissing sound, potentially
38、 burning through inside the torch body. See also backfire and flashback.These terms describe potentially hazardous events that can occur when using oxyfuel gas equipment. Operators and their employers should understand these events and the terms that are associated with them. See 7.2.1AWS standards
39、are published by the American Welding Society, 8669 NW 36 St, # 130, Miami, FL 33166.2This ANSI standard is published by the American Welding Society, 8669 NW 36 St, # 130, Miami, FL 33166.3CFR standards are published by the United States Department of Labor, 200 Constitution Ave., NW, Washington DC
40、 20210.4CGA standards are published by the Compressed Gas Association, 14501 George Carter Way, Suite 103, Chantilly, VA 20151.5NFPA standards are published by the National Fire Protection Association, 1 Batterymarch Park, Quincy, MA 02169.6RMA standards are published by the Rubber Manufacturers Ass
41、ociation, 1400 K Street, NW, Suite 900, Washington DC 20005.AWS C4.2/C4.2M:201734. Process and Operation4.1 Oxyfuel Gas Cutting Process. The process is a series of chemical reactions between iron and oxygen. It is based on the ability of high-purity oxygen to combine rapidly with iron when the iron
42、is heated to its ignition temperature, above 1600F 870C. The iron is quickly oxidized by the high-purity oxygen, and heat is liberated when iron is quickly oxidized by the high-purity oxygen. As the iron oxidizes (burns), it produces a mixture of molten oxides called slag. During the cutting, a narr
43、ow slot called a kerf is formed as a result of the removal of some of the metal by the stream of cutting oxygen (see Figure 1).Oxyfuel gas cutting of steel has been used on material ranging in thickness from 1/32 in 0.8 mm to thicknesses in excess of 100 in 2500 mm. The majority of cutting is done o
44、n steel from 1/4 in to 2 in 6 mm to 50 mm in thickness. A skilled oxyfuel gas cutting torch operator, using a mechanically guided torch, can easily maintain tolerances as close as 1/32 in 0.8 mm on materials up to 2 in 50 mm thick.Oxyfuel cutting offers advantages over machining methods in terms of
45、speed, versatility, and cost. Cutting speeds of 20 in/min 500 mm/min on 1 in 25 mm steel are not uncommon. Almost any two-dimensional shape can be produced by oxyfuel gas cutting. Much of the versatility is due to the nature of the oxygen cutting jet, as it will operate in any axis with equal facili
46、ty.4.2 Principles of Operation. The oxyfuel gas cutting process employs a torch with a tip (nozzle). The torch cutting tip is designed with a number of preheating flame ports and a center passage for the cutting oxygen. The functions of the torch and tip are to mix the fuel gas and the oxygen in the
47、 correct proportions, to produce preheat flames, and to supply a concentrated stream of high-purity oxygen to the reaction zone. The oxygen oxidizes the hot metal and blows the molten reaction products away from the cut.The preheat flames serve to heat the metal to a temperature at which the metal w
48、ill react with the cutting oxygen. The oxygen jet rapidly oxidizes most of the metal in a narrow section to make the cut. Metal oxides and molten metal are expelled from the cut by the kinetic energy of the oxygen stream. Moving the torch across the workpiece at the proper rate produces a continuous
49、 cutting action. The torch may be moved manually or by means of a mechanism or automated carriage.Figure 1Description of Oxyfuel Gas CuttingAWS C4.2/C4.2M:20174The accuracy of a manual operation depends largely on the skill of the operator. The accuracy and speed of the cut and the finish of the cut surface are usually improved when mechanized or automated cutting operations are used. Several torches may be used on one machine. Automated operations can be programmed to perform a series of complex cuts with a high level of accuracy.75. Equipment and SuppliesTo perform oxyfu
