Welding consumables Shielding gases for arc welding and cutting

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1 BRITISH STANDARD BS EN 439:1994 Welding consumables Shielding gases for arc welding and cutting The European Standard EN 439:1994 has the status of a British Standard UDC :

2 BSEN 439:1994 Cooperating organizations The European Committee for Standardization (CEN, under whose supervision this European Standard was prepared, comprises the national standards organizations of the following countries: Austria Belgium Denmark Finland France Germany Greece Iceland Ireland Italy Luxembourg Netherlands Norway Portugal Spain Sweden Switzerland United Kingdom Oesterreichisches Normungsinstitut Institut belge de normalisation Dansk Standard Suomen Standardisoimisliito, r.y. Association française de normalisation Deutsches Institut für Normung e.v. Hellenic Organization for Standardization Technological Institute of Iceland National Standards Authority of Ireland Ente Nazionale Italiano di Unificazione Inspection du Travail et des Mines Nederlands Normalisatie-instituut Norges Standardiseringsforbund Instituto Portuguès da Qualidade Asociación Española de Normalización y Certificación Standardiseringskommissionen i Sverige Association suisse de normalisation British Standards Institution This British Standard, having been prepared under the direction of the Welding Standards Policy Committee, was published under the authority of the Standards Board and comes into effecton 15 December 1994 BSI Amendments issued since publication Amd. No. Date Comments The following BSI references relate to the work on this standard: Committee reference WEE/39 Draft for comment 91/70924 DC ISBN

3 BSEN 439:1994 Contents Page Cooperating organizations Inside front cover National foreword ii Foreword 2 Text of EN National annex NA (informative Committees responsible Inside back cover BSI i

4 BSEN 439:1994 National foreword This British Standard has been prepared under the direction of the Welding Standards Policy Committee and is the English language version of EN 439:1994 Welding consumables Shielding gases for arc welding and cutting, published by the European Committee for Standardization (CEN. National annex NA gives the constitution of the committees responsible for UK participation in the preparation of this standard. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the EN title page, pages 2 to 6, an inside back cover and a back cover. This standard has been updated (see copyright date and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. ii BSI

5 EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM EN 439 August l994 UDC : Descriptors: Welding, arc welding, gas shielded gases, gas mixtures, classifications, designation, chemical properties English version Welding consumables Shieldinggasesforarcweldingand cutting Produits consommables pour le soudage Gazde protection pour le soudage et le coupage à l arc Schweißzusätze Schutzgase zum Lichtbogenschweißen und Schneiden This European Standard was approved by CEN on CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German. A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comité Européen de Normalisation Europäisches Komitee für Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1994 Copyright reserved to CEN members Ref. No. EN 439:1994 E

6 EN 439:1994 Foreword This European Standard was prepared by the Technical Committee CEN/TC 121, Welding, the secretariat of which is held by DS. This European Standard shall be given the status of a National Standard, either by publication of an identical text or by endorsement, at the latest by February 1995, and conflicting national standards shall be withdrawn at the latest by February According to the Common CEN/CENELEC Internal Regulations, the following countries are bound to implement this European Standard. Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. Contents Page Foreword 2 1 Scope 3 2 Properties of gases 3 3 Classification of shielding gases 3 4 Designation 3 5 Tolerances of mixtures 3 6 Purities and dew point 3 7 Forms of supply Gas cylinders Liquid 4 8 Shielding gas identification 4 Figure 1 Cylinder pressure-temperature diagram for argon (II at constant cylinder 6 Table 1 Properties of gases 4 Table 2 Classification of shielding gases for are welding and cutting 5 Table 3 Identification numbers for gases in groups R and M containing helium 6 Table 4 Purities and dew points of gases and gas mixtures 6 2 BSI

7 EN 439: Scope This standard is applicable to gas shielded arc welding and cutting processes with gases and gas mixtures defined within. Applications include, but are not limited to: tungsten inert gas (TIG welding; metal active gas (MAG welding; metal inert gas (MIG welding; plasma arc welding (PAW; plasma arc cutting (PAC; back shielding. The purpose of this standard is to classify shielding gases in accordance to their chemical properties as a base for the approval of shielding gas and filler wire combinations. Gas purities and mixing tolerances are also specified. 2 Properties of gases The physical and chemical properties are listed in Table 1. 3 Classification of shielding gases Table 2 classifies into groups the various component/composition combinations of shielding gases according to their reaction behaviour. The symbols used for classification groups are: R: reducing gas mixtures; I: inert gases and inert mixtures; M: oxidizing mixtures containing oxygen, carbon dioxide or both; C: highly oxidizing gas and highly oxidizing mixtures; F: unreactive gas or reducing gas mixtures. Where components not listed in Table 2 are added to one of these classifications it is designated as a special gas mixture and carries the prefix S. Details of the S designation are given in clause 4. 4 Designation Shielding gases are designated by the term shielding gases, the number of this standard, group and identification number according to Table 2. Example 1: A gas mixture containing 30% helium, and balance argon is designated: Shielding gas EN Example 2: A gas mixture containing 10% carbon dioxide, 3% oxygen and balance argon is designated: Shielding gas EN 439 M24 If argon is partly replaced by helium, the helium content is designated by an additional identification number, see Table 3. This identification number is added in brackets as a suffix. Example 3: A gas mixture M21 containing 25 % helium is designated: Shielding gas EN 439 M21(1 Special gases shall be designated by the prefix S followed by the base gas or mixture symbol as in Table 2, followed by the percent concentration by volume and chemical formula of the additional gases. S (designation + % chemical symbol Example 4: A special gas mixture containing10% carbon dioxide, 3% oxygen and balance argon, designation M24, but also containing 2,5% neon is designated: Shielding gas EN 439 SM24 + 2,5Ne 5 Tolerances of mixtures For component concentrations up to 5% by volume the permissible deviation shall not exceed ± 0,5% by volume from the specified value. For component concentrations of between5% by volume and 50% by volume the concentration shall not vary by more than ± 10% of the specified value. 6 Purities and dew point The minimum purities and maximum dew points of gases as delivered in cylinders or insulated tanks, are specified in Table 4 according to their classifications in Table 2. Purities and dew points for special gas mixtures shall correspond to the base gases or gas mixtures used, as specified in Table 4. For some materials, e.g. titanium and tantalum, gases of higher purities may be required and specifications can be agreed between the user and the supplier. The user s gas supply system should be designed and maintained such that the purity as delivered is maintained up to the point of use. 7 Forms of supply Shielding gases are supplied in the gaseous or liquid state either as single gas or gas mixture. Where gas mixtures are prepared on site from individual gases, the mixing system shall be designed and maintained such that the tolerance and the purity specified in clauses 5 and 6 can be achieved and maintained. BSI

8 EN 439: Gas cylinders With the exception of carbon dioxide, all the gases and gas mixtures listed in Table 2 are fully in the gaseous state when supplied in gas cylinders. The gas cylinders for the gases listed in Table 2 are filled to a stated volume and pressure as indicated by the supplier. The actual pressure will vary with the ambient temperature, e.g. the pressure of argon (I1 will vary as in Figure 1. Suitable regulators shall be fitted to the gas cylinder before use. 7.2 Liquid Liquefied gases will be supplied as low temperature (cryogenic liquids in insulated tanks or, in the case of carbon dioxide, as a liquid at ambient temperature in gas cylinders. Before use liquified gases supplies have to be converted into the gaseous state. Type of gas Chemical symbol Table 1 Properties of gases Specified at 0 C and 1,013 bar (0,101 MPa Density (air = 1,293 In order to produce gas mixtures from liquified gases, the liquids have to be converted to the gaseous state prior to mixing. Argon-oxygen mixtures can also be stored pre-mixed as a liquid without using a mixer for the supply. NOTE In plasma arc cutting, gas mixing can take place inside the machine from individual gases or gas mixtures. 8 Shielding gas identification The designation of the shielding gas according to clause 4 has to be provided with or without the term shielding gases. Relative density to air Boiling point at 1,013 bar kg/m 3 C Argon Ar 1,784 1, ,9 Inert Helium He 0,178 0, ,9 Inert Carbon dioxide CO 2 1,977 1,529 78,5 a Oxidizing Oxygen O 2 1,429 1, ,0 Oxidizing Reaction behaviour during welding Nitrogen N 2 1,251 0, ,8 Unreactive b Hydrogen H 2 0,090 0, ,8 Reducing a Sublimation temperature (solid to gas transition temperature. b The behaviour of nitrogen varies with different materials. Possible negative influences shall be considered. 4 BSI

9 BSI Group Table 2 Classification of shielding gases for arc welding and cutting Symbol a Components in percent volume Typical applications Remarks Identification Oxidizing Inert Reducing Unreactive No. CO 2 O 2 Ar He H 2 N 2 R 1 Balance 2 2 Balance 2 > 0 to 15 TIG plasma arc welding, plasma arc cutting, back shielding > 15 to 35 Reducing I MIG, TIG, plasma arc welding, back shielding Inert 3 Balance > to 95 M1 1 > 0 to 5 Balance 2 > 0 to 5 Slightly oxidizing 2 > 0 to 5 Balance 2 3 > 0 to 3 Balance 2 4 > 0 to 5 > 0 to 3 Balance 2 M2 1 > 5 to 25 Balance 2 2 > 3 to 10 Balance 2 3 > 0 to 5 > 3 to 10 Balance 2 4 > 5 to 25 > 0 to 8 Balance 2 M3 1 > 25 to 50 Balance 2 2 > 10 to 15 Balance 2 3 > 5 to 50 > 8 to 15 Balance 2 C More pronounced 2 Balance > 0 to 30 oxidation F Plasma arc cutting, back shielding Unreactive > 0 to 50 2 Balance Reducing a Where components not listed are added to one of the groups in this table, the gas mixture is designated as special gas mixture and carries the prefix S. Details of the S designation are given in clause 4. 2 Argon may be replaced by up to 95 % helium. The helium content is designated by an additional identification number, see clause 4, and is given in Table 3. MAG EN 439:1994

10 EN 439:1994 Table 3 Identification numbers for gases in groups R and M containing helium Identification number Helium content in volume % (1 >0 to 33 (2 >33 to 66 (3 >66 to 95 Table 4 Purities and dew points of gasesand gasmixtures Group a Purity Dew point at 1,013 bar Moisture % by vol min. C max. p.p.m. max. R 99, I 99, M1 99, M2 99, M3 99, C 99, F 99, Oxygen 99, Hydrogen 99, a Data for oxygen and hydrogen have been included in this table. Figure 1 Cylinder pressure-temperature diagram for argon (I1 at constant cylinder content 6 BSI

11 BS EN 439:1994 National annex NA (informative Committees responsible The United Kingdom participation in the preparation of this European Standard was entrusted by the Welding Standards Policy Committee (WEE/- to Technical Committee WEE/39 upon which the following bodies were represented: Aluminium Federation Associated Offices Technical Committee Association of Welding Distributors British Association for Brazing and Soldering British Compressed Gases Association British Constructional Steelwork Association Ltd. British Steel Industry Electricity Association Engineering Equipment and Materials Users Association Lloyd s Register of Shipping Magnesium Industry Council Power Generation Contractors Association [PGCA (BEAMA Ltd.] Process Plant Association Stainless Steel Wire Industry Association Suffolk Lawn Mowers Ltd. Welding Institute Welding Manufacturers Association (BEAMA Ltd. BSI

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