IEC 60974-7:2013

IEC 60974-7


®


Edition 3.0 2013-01



INTERNATIONAL



STANDARD



NORME
INTERNATIONALE


Arc welding equipment –
Part 7: Torches

Matériel de soudage à l'arc –
Partie 7: Torches


IEC 60974-7:2013

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IEC 60974-7



®



Edition 3.0 2013-01







INTERNATIONAL





STANDARD







NORME



INTERNATIONALE











Arc welding equipment –

Part 7: Torches




Matériel de soudage à l'arc –

Partie 7: Torches

















INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE

PRICE CODE
INTERNATIONALE

CODE PRIX U


ICS 25.160 ISBN 978-2-83220-573-0



Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

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– 2 – 60974-7  IEC:2013



CONTENTS

FOREWORD . 4


1 Scope . 6

2 Normative references . 6

3 Terms and definitions . 6


4 Environmental conditions . 9

5 Classification . 9

5.1 General . 9

5.2 Process . 9
5.3 Guidance . 9
5.4 Cooling . 9
5.5 Main arc striking for plasma processes . 10
6 Test conditions . 10
6.1 General . 10
6.2 Type tests . 10
6.3 Routine tests . 10
7 Protection against electric shock . 10
7.1 Voltage rating . 10
7.2 Insulation resistance . 11
7.3 Dielectric strength . 12
7.3.1 General requirement . 12
7.3.2 Additional requirements for plasma cutting torches . 12
7.3.3 Additional requirements for striking and stabilizing voltage rating . 12
7.4 Protection against electric shock in normal service (direct contact) . 13
7.4.1 Degree of protection requirements . 13
7.4.2 Additional requirements for plasma cutting torches . 13
8 Thermal rating . 13
8.1 General . 13
8.2 Temperature rise . 13
8.3 Heating test . 14
8.3.1 General . 14
8.3.2 Metal inert/active gas (MIG/MAG) or self-shielded flux-cored arc
welding torch . 14

8.3.3 Tungsten inert gas (TIG) and plasma arc welding torch . 16
8.3.4 Plasma cutting torch . 17
8.3.5 Submerged arc welding torch . 18
9 Pressure of the liquid cooling system . 18
10 Resistance to hot objects . 18
11 Mechanical provisions . 19
11.1 Impact resistance . 19
11.2 Accessible parts . 20
11.3 Handle material . 20
12 Marking . 20
13 Instructions for use . 21
Annex A (informative) Additional terminology . 22
Annex B (normative) Position of the welding torches for the heating test. 25

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60974-7  IEC:2013 – 3 –


Annex C (informative) Cooled copper block . 26

Annex D (informative) Copper block with a hole . 27


Annex E (informative) Copper bars with a slot . 28

Bibliography . 29




Figure 1 – Device for testing the resistance to hot objects . 19

Figure 2 – Device for the impact test . 20

Figure A.1 – Torch for metal inert/active gas (MIG/MAG) or self-shielded flux-cored arc

welding . 23

Figure A.2 – Gun for metal inert/active gas (MIG/MAG) or self-shielded flux-cored arc
welding . 23
Figure A.3 – Torch for tungsten inert gas arc welding . 23
Figure A.4 – Torch for plasma arc welding . 23
Figure A.5 – Torch for plasma cutting . 23
Figure A.6 – Supply unit . 23
Figure A.7 – Mechanically guided plasma torch . 24
Figure B.1 – MIG/MAG torches . 25
Figure B.2 – TIG torches . 25
Figure B.3 – Plasma welding torches . 25
Figure C.1 – Water-cooled copper block – Example . 26
Figure D.1 – Water-cooled copper block with a hole – Example . 27
Figure E.1 – Water-cooled copper bars with a slot – Example . 28

Table 1 – Voltage rating of torches . 11
Table 2 – Test values for metal inert gas arc welding (MIG) of aluminium alloys . 15
Table 3 – Test values for metal active gas arc welding (MAG) of mild steel . 15
Table 4 – Test values for metal active gas arc welding (MAG) with flux-cored wire . 16
Table 5 – Test values for self-shielded flux-cored arc welding of mild steel . 16
Table 6 – Test values for tungsten inert gas arc welding (TIG) . 17
Table 7 – Test values for plasma arc welding . 17
Table A.1 – List of terms . 22

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INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________




ARC WELDING EQUIPMENT –



Part 7: Torches



FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
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6) All users should ensure that they have the latest edition of this publication.
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 60974-7 has been prepared by IEC technical committee 26:
Electric welding.
This third edition cancels and replaces the second edition published in 2005 and constitutes a
technical revision. The significant changes with respect to the previous edition are listed
below:
• new requirement for degree of protection of torch coupling device (see Table 1);
• scope is extended to cable-hose assembly connected between a power source and
ancillary equipment (see Clause 1);
• torch parts, as recommended by the manufacturer, are included in the safe plasma cutting
system design (see 7.4.2);
• new flammability requirement for handle material (see 11.3).

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60974-7  IEC:2013 – 5 –


The text of this standard is based on the following documents:

FDIS Report on voting


26/492/FDIS 26/495/RVD



Full information on the voting for the approval of this standard can be found in the report on

voting indicated in the above table.


This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.


This part of IEC 60974 is to be used in conjunction with IEC 60974-1.
A list of all parts of the IEC 60974 series can be found, under the general title Arc welding
equipment, on the IEC website.
In this standard, the following print types are used:
– conformity statements: in italic type.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

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ARC WELDING EQUIPMENT –



Part 7: Torches








1 Scope


This part of IEC 60974 specifies safety and construction requirements for torches for arc

welding and allied processes. This part of IEC 60974 is applicable to manual, mechanically
guided, air-cooled, liquid-cooled, motorized, spool-on and fume extraction torches.
In this part of IEC 60974, a torch consists of the torch body, the cable-hose assembly and
other components.
This part of IEC 60974 is also applicable to a cable-hose assembly connected between a
power source and ancillary equipment.
This part of IEC 60974 is not applicable to electrode holders for manual metal arc welding or
air-arc cutting/gouging.
NOTE 1 Typical allied processes are electric arc cutting and arc spraying.
NOTE 2 Other components are listed in Table A.1.
NOTE 3 In this part of IEC 60974, the terms "torch" and "gun" are interchangeable. For convenience "torch" has
been used in the following text.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60050 (all parts), International Electrotechnical Vocabulary (available at
)
IEC 60529, Degrees of protection provided by enclosures (IP Code)

IEC 60664-1, Insulation coordination for equipment within low-voltage systems – Part 1:
Principles, requirements and tests
IEC 60695-11-10, Fire hazard testing – Part 11-10: Test flames – 50 W horizontal and vertical
flame test methods
IEC 60974-1:2012, Arc welding equipment – Part 1: Welding power sources
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60050,
IEC 60664-1, and IEC 60974-1, as well as the following, apply.
NOTE Additional terminology is given in Annex A.

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60974-7  IEC:2013 – 7 –


3.1

torch

device that conveys all services necessary to the arc for welding, cutting or allied processes

(for example, current, gas, coolant, wire electrode)


3.2

gun

torch with a handle substantially perpendicular to the torch body


3.3

torch body

main component to which the cable-hose assembly and other components are connected
3.4
handle
part designed to be held in the operator's hand
3.5
gas nozzle
component at the exit end of the torch directing the shielding gas around the arc and over the
weld pool
3.6
non-consumable electrode
arc welding electrode which does not provide filler metal
3.7
wire electrode
solid or tubular filler wire which conducts welding current
3.8
contact tip
replaceable metal component fixed at the front end of the torch, which transfers the welding
current to, and guides, the wire electrode
3.9
cable-hose assembly
flexible assembly of cables and hoses, and their connecting elements, that delivers supplies
to the torch body or ancillary equipment
3.10

manual torch
torch held and guided by the operator's hand during its operation
3.11
mechanically guided torch
torch fixed to, and guided by, a mechanical device during its operation
3.12
air-cooled torch
torch cooled by the ambient air and, where appropriate, by the shielding gas
3.13
liquid-cooled torch
torch cooled by the circulation of a cooling liquid

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3.14

motorized torch

torch incorporating means to supply motion to the wire electrode


3.15

spool-on torch

motorized torch incorporating a filler wire supply


3.16

arc striking and stabilizing voltage

voltage superimposed on the welding circuit to initiate or maintain the arc or both

3.17
filler metal
metal added during welding or allied processes
[SOURCE: IEC 60050-851:2008, 851-14-43]
3.18
filler wire
filler metal in solid or tubular wire form which may or may not be part of the welding circuit
3.19
plasma tip
component that provides the constricting orifice through which the plasma arc passes
3.20
visual inspection
inspection by eye to verify that there are no apparent discrepancies with respect to the
provisions of the standard concerned
[SOURCE: IEC 60974-1:2012, 3.7]
3.21
plasma cutting system
combination of power source, torch, and associated safety devices for plasma cutting/gouging
3.22
plasma cutting power source
equipment for supplying current and voltage and having the required characteristics suitable
for plasma cutting/gouging and which may supply gas and cooling liquid

Note 1 to entry: A plasma cutting power source may also supply services to other equipment and auxiliaries, for
example auxiliary power, cooling liquid, and gas.
[SOURCE: IEC 60974-1:2012, 3.55]
3.23
torch coupling device
part of torch connecting the cable-hose assembly to the welding equipment
Note 1 to entry: A torch coupling device may include several connecting parts.
3.24
fume extraction torch
torch that incorporates means to capture the welding fumes

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60974-7  IEC:2013 – 9 –


4 Environmental conditions


Torches shall be capable of operation when the following environmental conditions prevail:


a) range of ambient air temperature:

during operation: –10 °C to +40 °C;


b) relative humidity of the air:

up to 50 % at 40 °C;

up to 90 % at 20 °C.


Torches shall withstand storage and transport at an ambient air temperature of –20 °C to
+55 °C without any damage to function and performance.
NOTE Different environmental conditions may be agreed upon between the manufacturer and the purchaser.
Examples of these conditions are: high humidity, unusually corrosive fumes, steam, excessive oil vapour, abnormal
vibration or shock, excessive dust, severe weather conditions, unusual coastal or shipboard conditions, vermin
infestation and atmospheres conducive to the growth of mold.
5 Classification
5.1 General
Torches shall be classified in accordance with:
a) the process for which they are designed, see 5.2;
b) the method by which they are guided, see 5.3;
c) the type of cooling, see 5.4;
d) the method of striking the main arc for plasma processes, see 5.5.
5.2 Process
Torches can be designed for:
a) MIG/MAG welding;
b) self-shielded flux-cored arc welding;
c) TIG welding;
d) plasma welding;
e) submerged arc welding;
f) plasma cutting/gouging.

5.3 Guidance
Methods of torch guidance:
a) manual;
b) mechanical.
5.4 Cooling
Type of torch cooling method:
a) ambient air or shielding gas, see 3.12;
b) liquid, see 3.13.

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5.5 Main arc striking for plasma processes


Methods for striking the main arc:

a) by an arc striking voltage;

b) by a pilot arc;

c) by contact.


6 Test conditions


6.1 General

All tests shall be carried out on the same new and completely assembled torch, fitted with the
cable-hose assembly normally supplied.
All tests shall be carried out at any ambient air temperature given in Clause 4, item a).
The accuracy of measuring instruments shall be:
a) electrical measuring instruments: class 1 (± 1 % of full-scale reading), except for the
measurement of insulation resistance and dielectric strength where the accuracy of the
instruments is not specified, but shall be taken into account for the measurement;
b) temperature measuring device: ± 2 K.
6.2 Type tests
All type tests given below shall be carried out on the same sample and in the following
sequence:
a) general visual inspection;
b) insulation resistance without humidity treatment (preliminary check), see 7.2;
c) impact resistance, see 11.1;
d) resistance to hot objects, see Clause 10;
e) protection against direct contact, see 7.4;
f) insulation resistance, see 7.2;
g) dielectric strength, see 7.3;
h) general visual inspection.
The heating test in accordance with 8.3 may be carried out on a separate sample and shall be

followed by the coolant leakage test in accordance with Clause 9. The other tests included in
this standard and not listed here may be carried out in any convenient sequence.
6.3 Routine tests
The following routine tests shall be carried out on each torch in the following sequence:
a) general visual inspection;
b) functional test as specified by the manufacturer, for example, leaks of fluid or gas, trigger
operation.
7 Protection against electric shock
7.1 Voltage rating
Torches shall be rated according to the classification and use as given in Table 1.

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60974-7  IEC:2013 – 11 –


Table 1 – Voltage rating of torches


Voltage Insulation Dielectric Degree of protection in

rating resistance strength accordance with IEC 60529
V V r.m.s.
MΩ
peak
Classification
Nozzle Handle Torch Other

b, c

orifice coupling parts
a
device


Manually guided torches 113 1 1 000 IP0X IP3X IP2X IP3X
except for plasma

cutting

Mechanically guided 141 1 1 000 IP0X Not IPXX IP2X

torches except for applicable

plasma cutting and
submerged arc welding
Mechanically guided 141 1 1 000 IP0X Not IPXX IPXX
submerged arc welding applicable
torches
Manually guided plasma 500 2,5 2 100 Plasma IP4X IP3X IP3X
cutting torches tip, see
7.4.2
Mechanically guided 500 2,5 2 100 IP0X Not IP2X IP2X
plasma cutting torches applicable
a
Degree of protection for torch coupling device is tested while coupled.
b
Other parts are, for example, gas nozzle, neck.
c
Wire drive systems of motorized torches that are accessible to touch are not considered as other parts: IPXX.

7.2 Insulation resistance
The insulation resistance of a new torch shall, after the humidity treatment, be not less than
...