Specification for Welding Shielding Gases

1 ANSI/AWS American National StandardSpecification forWelding ShieldingGases550 LeJeune Road, Miami, Florida 33126 ANSI/AWS American National StandardApproved byAmerican National Standards InstituteDecember 8, 1997 Specification forWelding Shielding GasesPrepared byAWS Committee on Filler MetalsUnder the Direction ofAWS Technical Activities CommitteeApproved byAWS Board of DirectorsAbstractThis Specification for Welding Shielding Gases specifies minimum requirements for the composition and purity of themost popular single-component Shielding Gases . Classification designators for both single and multicomponent Gases areintroduced. Other topics include testing procedures, package marking, and general application Specification makes use of both Customary Units and the International System of Units (SI). Since these arenot equivalent, each system must be used independently of the Words Argon, carbon dioxide, helium, hydrogen, nitrogen, oxygen, Shielding Gases , Welding gasesviTable of ContentsPage iiiForeword.

2 VList of Tables ..viiList of Figures ..vii1. Scope .. 1 Part A General Requirements2. Normative References .. 13. 14. Acceptance .. 15. Certification .. 26. Units of Measure and Rounding-Off Procedure .. 2 Part B Tests, Procedures, and Requirements7. Summary of 28. 29. Chemical Analysis .. 310. Dew Point 3 Part C Manufacture, Packaging, and Identification11. Method of Manufacture .. 312. Packaging .. 313. Identification .. 314. Marking of High-Pressure Cylinders, Liquid Containers, and Bulk 6 Annex Guide to AWS Specification for Welding Shielding System .. During Welding .. Considerations .. and Intended Use of the Shielding Safety References .. 15 AWS Filler Metal Specifications by Material and Welding 17 AWS Filler Metal Specifications and Related Documents .. 19viiList of TablesTa blePage Type, Purity, and Dew Point Requirements for Shielding Gas 22 Tests Required for Classification.

3 33 Dew Point Conversion Chart .. 44 AWS Classifications for Typical Gas Mixtures .. 5A1 Additional Information .. 16 List of FiguresFigurePage System for a Single Gas .. 52 Classification System for Multicomponent Shielding 53 Classification System for Special Multicomponent Shielding Gases .. 54 Classification System for X Designator Shielding Gases .. 511. ScopeThis Specification prescribes requirements for theclassification of Shielding Gases . Gases may be suppliedin either gaseous or liquid form, but when used in weld -ing, the Shielding is always in the gaseous form. Gasshielded arc Welding processes include, but are not lim-ited to: manual, semiautomatic, mechanized, and auto-matic gas tungsten arc Welding (GTAW), gas metal arcwelding (GMAW), flux cored arc Welding (FCAW),electrogas Welding (EGW), and plasma arc Welding (PAW).Part AGeneral Requirements2. Normative ASTM Standards1E29, Standard Practice for Using Significant Digits inTest Data to Determine Conformance with SpecificationsE260, Standard Practice for Packed Column CGA , Commodity Specification for , Commodity Specification for , Commodity Specification for Carbon Dioxide1.

4 ASTM standards can be obtained from ASTM, 100 BarrHarbor Drive, West Conshohocken, PA CGA publications can be obtained from Compressed GasAssociation, Inc., 1725 Jefferson Davis Highway, Suite 1004,Arlington, VA , Commodity Specification for , Commodity Specification for , Commodity Specification for ArgonP-15, Filling of Industrial and Medical NonflammableCompressed Gas Cylinders3. Shielding Gases covered by the are classified using a system that is inde-pendent of Customary Units and the InternationalSystem of Units (SI). Classification is according tochemical composition of the Shielding gas as specified classified under one classification shall not beclassified under any other classification in this specifica-tion. Individual Gases shall meet or exceed the require-ments of Table Gases classified under this Specification are in-tended for use with the gas shielded arc Welding pro-cesses listed in the Scope. This does not prohibit theiruse with any other process for which they are AcceptanceAcceptance3 of the Gases by the user shall be in accor-dance with the tests and requirements of Parts B and C ofthis See Section A3 (in the Annex) for more for Welding Shielding Gases25.

5 CertificationBy affixing the AWS Specification and classificationdesignations on the packaging enclosing the product, thesupplier (manufacturer) certifies that the product meetsall of the requirements of the Units of Measure and Rounding-Off Specification uses Customary Units and theSI Units. The measurements are not exact equivalents;therefore each system must be used independently of theother without combining values in any way. The specifi-cation with the designation of uses the Cus-tomary Units. The Specification with the designation uses SI Units. The latter are shown in appropriatecolumns in tables and in figures, and within brackets [ ]when used in the the purpose of determining conformance withthis Specification , values shall be rounded to the nearestunit in accordance with the rounding-off method given inASTM E29, Standard Practice for Using SignificantDigits in Test Data to Determine Conformance BTests, Procedures, and Requirements7.

6 Summary of TestsCompositional analysis of the Shielding gas is theonly test required for classification of a product underthis Specification . Tests required for each single gas arespecified in Table 2. The purpose of these tests is to de-termine the purity and dew point of the Shielding RetestIf any gas fails to meet its requirements, that test shallbe repeated twice. The results of both retests shall meetthe requirement of this See Section A4 (in the Annex) for further information con-cerning certification and the testing called for to meet 1 Gas Type, Purity, and Dew Point Requirements for Shielding Gas ComponentsGasAWSC lassificationProductStateMinimumPurity(% )MaximumMoisturea(ppm)Dew PointMaximum Moisture at 1 AtmosphereCGA Class F 76 60 Type Grade 76 60 Type Grade CCarbon 60 Grade 60 Grade 71 57 Type Grade 71 57 Type Grade 60 51 Type Grade 60 51 Type Grade 60 51 Type Grade 90 68 Type Grade Applicable 54 48 Type Grade Applicable 82 63 Type Grade BNotes:a.

7 Moisture specifications are guaranteed at full cylinder pressure, at which the cylinder is Including Including the results of one or both retests fail to meet the re-quirement, the gas being tested shall be considered as notmeeting the requirements of this Specification for the event that appropriate procedures were not fol-lowed in preparing the test sample(s) or in conductingthe tests, the test shall be considered invalid, without re-gard to whether the test was actually completed, orwhether test results met or failed to meet the require-ment. In this case, the requirement for two retests of thegas sample does not Chemical AnalysisSamples of gas(es) for chemical analysis shall bedrawn from an individual cylinder, vessel or from the gasoutlet source. The sample shall be analyzed by accept-able methods. Results of chemical analysis of a specificgas(es) shall comply with the requirements of Table 1 forthe gas being analyzed. The referee method for chemicalanalysis of Gases shall be ASTM E 260, Standard Prac-tice for Packed Column Gas Chromatography.

8 Whenmixed Gases are being analyzed, the volumetric percent-age of minor components shall be within 10 percent rel-ative to the nominal percentage of the minor componentof the classification. See and for Dew Point DeterminationSample Gases for dew point analysis shall be drawnfrom the individual cylinder, vessel, or gas outlet standard dew point measurement method may beused. Dew point may be expressed in F at one atmo-sphere pressure ( psia), [ C at 760 mm of mercury],or in ppm. The Dew Point Conversion Chart, see Table 3,may be used to convert dew point measurements to orfrom F, C, or ppm. Results of the dew point test shallmeet, or exceed, the requirements of Table 1 for thegases being CManufacture, Packaging, and Identification11. Method of ManufactureShielding Gases classified according to this specifica-tion may be manufactured by any method that will pro-duce gas or gas mixtures that meet the requirements ofthis Cylinder Residual Gases .

9 All gas containers shalleither be evacuated or, if not evacuated, residual gasesshall be analyzed for composition and purity prior PackagingGases and gas mixtures shall be packaged in accor-dance with Department of Transportation (DOT) regula-tions for protection during shipment and normal Cylinder sizes shall be as agreed upon be-tween purchaser and supplier. Cylinders shall be labeledin accordance with Sections 13 and Individual gas components are identified by the fol-lowing codes:A ArgonC Carbon DioxideHe HeliumH HydrogenN NitrogenO Oxygen5. CGA P-15, Filling of Industrial and Medical NonflammableCompressed Gas Cylinders, can be obtained from the Com-pressed Gas Association, Inc., 1725 Jefferson Davis Highway,Suite 1004, Arlington, VA DOT regulations can be obtained from the Department ofTransportation, NASSIF Building, 400 7th Street , Wash-ington, DC 2 Tests Required for ClassificationGasPurityDewPointMixture CompositionSingle gasMulticomponent gasSpecial gas RequiredNotes:a.

10 Each gas of a multicomponent mixture shall be tested for and meetthe purity requirements of that specific gas (see Section 9 andTable 1).b. The multicomponent gas mixture shall meet the dew point require-ment not greater than the highest dewpoint of the individual Gases inthe mixture (see Section 10 and Table 1).c. Individually filled cylinders or one cylinder from each filling mani-fold group, shall be tested for and meet the requirements of Part B,Tests, Procedures, and Requirements for the mixture These Gases are classified as SG-B-G.