BS EN 439-94.pdf

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

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 effect on

15 December 1994 © BSI 02-1999

The following BSI references relate to the work on this standard:

Committee reference WEE/39 Draft for comment 91/70924 DC

ISBN 0 580 23240 9

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 Oesterreichisches Normungsinstitut

Belgium Institut belge de normalisation

Denmark Dansk Standard

Finland Suomen Standardisoimisliito, r.y.

France Association française de normalisation

Germany Deutsches Institut für Normung e.V.

Greece Hellenic Organization for Standardization

Iceland Technological Institute of Iceland

Ireland National Standards Authority of Ireland

Italy Ente Nazionale Italiano di Unificazione

Luxembourg Inspection du Travail et des Mines Netherlands Nederlands Normalisatie-instituut

Norway Norges Standardiseringsforbund

Portugal Instituto Portuguès da Qualidade

Spain Asociación Española de Normalización y Certificación

Sweden Standardiseringskommissionen i Sverige

Switzerland Association suisse de normalisation United Kingdom British Standards Institution

Amendments issued since publication

BS EN 439:1994

© BSI 02-1999 i

Contents

Page

Cooperating organizations Inside front cover

National foreword ii

Foreword 2

Text of EN 439 3

ii © BSI 02-1999

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.

EUROPEAN STANDARD

NORME EUROPÉENNE

EUROPÄISCHE NORM

EN 439

August l994

Descriptors: Welding, arc welding, gas shielded gases, gas mixtures, classifications, designation, chemical properties

English version

Welding consumables

Shielding gases for arc welding and cutting

Produits consommables pour le soudage —

Gaz de protection pour le soudage et le

coupage à l’arc

Schweißzusätze — Schutzgase zum

Lichtbogenschweißen und Schneiden

This European Standard was approved by CEN on 1994-08-17. 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

© BSI 02-1999

2

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 1995. 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 3

7.1 Gas cylinders 4

7.2 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

EN 439:1994

© BSI 02-1999 3

1 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

component/composition combinations of shielding gases according to their reaction behaviour. The symbols used for classification groups are:

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 439 — 13

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 containing 10 %

carbon dioxide, 3 % oxygen and balance argon, designation M24, but also containing 2,5 % neon is designated:

Shielding gas EN 439 — S M24 + 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 between 5 % 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.

— 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;

4 © BSI 02-1999

7.1 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.

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”.

Table 1 — Properties of gases

Type of gas Chemical

symbol Specified at 0 °C and 1,013 bar (0,101 MPa) Boiling point at 1,013 bar Reaction behaviour during welding Density

(air = 1,293) Relative density to air

kg/m3 _°C

Argon Ar 1,784 1,380 – 185,9 Inert

Helium He 0,178 0,138 – 268,9 Inert

Carbon dioxide CO₂ 1,977 1,529 – 78,5a _Oxidizing

Oxygen O₂ 1,429 1,105 – 183,0 Oxidizing

Nitrogen N₂ 1,251 0,968 – 195,8 Unreactiveb

Hydrogen H2 0,090 0,070 – 252,8 Reducing

a _{Sublimation temperature (solid to gas transition temperature).}

E

N

4

39

:1

99

4

Table 2 — Classification of shielding gases for arc welding and cutting

Symbola _{Components in percent volume Typical applications Remarks}

Group Identification

No. CO2Oxidizing O2 Ar Inert He ReducingH2 UnreactiveN2

R 1 Balance2

) > 0 to 15 TIG plasma arc _{welding, plasma arc}

cutting, back shielding

2 Balance2

) > 15 to 35 Reducing

I 1 100 MIG, TIG, plasma arc

welding, back shielding

2 100 Inert 3 Balance > to 95 M1 1 > 0 to 5 Balance2 ) > 0 to 5 Slightly oxidizing 2 > 0 to 5 Balance2 ) 3 > 0 to 3 Balance2 ) 4 > 0 to 5 > 0 to 3 Balance2 ) M2 1 > 5 to 25 Balance2 ) MAG 2 > 3 to 10 Balance2 ) 3 > 0 to 5 > 3 to 10 Balance2 ) 4 > 5 to 25 > 0 to 8 Balance2 ) M3 1 > 25 to 50 Balance2 ) 2 > 10 to 15 Balance2 ) 3 > 5 to 50 > 8 to 15 Balance2 ) C 1 100 More pronounced oxidation 2 Balance > 0 to 30

F 1 100 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.

6 © BSI 02-1999

Table 3 — Identification numbers for gases in

groups R and M containing helium Table 4 — Purities and dew points of gases and gas mixtures

Identification number Helium content in volume %

(1) > 0 to 33

(2) > 33 to 66

(3) > 66 to 95

Groupa Purity Dew point

at 1,013 bar Moisture

% by vol min. °C max. p.p.m. max.

R 99,95 – 50 40 I 99,99 – 50 40 M1 99,70 – 50 40 M2 99,70 – 44 80 M3 99,70 – 40 120 C 99,70 – 35 200 F 99,50 – 50 40 Oxygen 99,50 – 35 200 Hydrogen 99,50 – 50 40

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

BS EN 439:1994

© BSI 02-1999

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

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