Bsi bs en 00439 1994 (1999)

00345670 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 UDC 621 791 04 403[.]

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 621.791.04-403:621.791.754

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:

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

Switzerland Association suisse de normalisation United Kingdom British Standards Institution

Amendments issued since publication

BS EN 439:1994

Contents

Page

National annex NA (informative) Committees responsible Inside back cover

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

UDC 621.791.04-403:621.791.754

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

Ref No EN 439:1994 E

© 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

Figure 1 — Cylinder pressure-temperature diagram for argon (II) at constant cylinder 6

Table 2 — Classification of shielding gases

Table 3 — Identification numbers for gases in

Table 4 — Purities and dew points of gases

EN 439:1994

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

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:

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;

— F: unreactive gas or reducing gas 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

a Sublimation temperature (solid to gas transition temperature).

b The behaviour of nitrogen varies with different materials Possible negative influences shall be considered.

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

Group Identification

No. CO2Oxidizing O2 Ar Inert He Reducing H2 Unreactive N2

welding, plasma arc cutting, back shielding

welding, back shielding

)

)

)

)

)

)

)

)

)

oxidation

> 0 to 50

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.

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 %

Groupa Purity Dew point

at 1,013 bar Moisture

% by vol min °C max p.p.m max.

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

Welding Manufacturers’ Association (BEAMA Ltd.)

389 Chiswick High Road

London

W4 4AL

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