prEN ISO 18595

SLOVENSKI STANDARD
oSIST prEN ISO 18595:2020
01-marec-2020

Uporovno varjenje - Točkovno varjenje aluminija in aluminijevih zlitin - Varivost,

Resistance welding - Spot welding of aluminium and aluminium alloys - Weldability,

Soudage par résistance - Soudage par points de l'aluminium et des alliages d'aluminium

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

Soudage par résistance — Soudage par points de l'aluminium et des alliages d'aluminium — Soudabilité,

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

Foreword ........................................................................................................................................................................................................................................iv

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 2

4 Material .......................................................................................................................................................................................................................... 2

4.1 Form ................................................................................................................................................................................................................. 2

4.2 Types of aluminium alloys ............................................................................................................................................................ 2

5 Surface conditions .............................................................................................................................................................................................. 2

6 Edge distance, edge conditions, form of component and weld spacing ......................................................3

7 Electrodes .................................................................................................................................................................................................................... 3

7.1 Materials ....................................................................................................................................................................................................... 3

7.2 Dimensions ................................................................................................................................................................................................. 3

7.3 Cooling electrodes ................................................................................................................................................................................ 4

8 Qualification of welds ...................................................................................................................................................................................... 4

8.1 General ........................................................................................................................................................................................................... 4

8.2 Pre-production tests .......................................................................................................................................................................... 4

8.3 Routine tests ............................................................................................................................................................................................. 4

8.3.1 Type of tests ......................................................................................................................................................................... 4

8.3.2 Frequency of testing ..................................................................................................................................................... 4

9 Weld quality requirements ........................................................................................................................................................................ 5

9.1 Weld diameter ......................................................................................................................................................................................... 5

9.2 Weld dimensions ................................................................................................................................................................................... 5

9.3 Weld fracture mode ............................................................................................................................................................................ 5

9.4 Weld strength ........................................................................................................................................................................................... 5

9.5 Weld appearance — Surface condition .............................................................................................................................. 7

10 Multi-weld arrays ................................................................................................................................................................................................. 7

Annex A (informative) Recommendations for spot welding equipment .....................................................................10

Annex B (informative) Typical spot welding conditions ...............................................................................................................11

Annex C (informative) Non-exhaustive list of aluminium alloyscovered by this International

Standard .....................................................................................................................................................................................................................12

Annex D (informative) Typical information to appear on a welding procedure sheet for spot

welding ........................................................................................................................................................................................................................14

Annex E (informative) Examples of minimum strength requirements .........................................................................16

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

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any patent rights identified during the development of the document will be in the Introduction and/or

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expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following

This document was prepared by Technical Committee ISO/TC 44, Welding and allied processes,

This second edition cancels and replaces the first edition (ISO 18595:2007), which has been technically

— inclusion of an informative Annex E “Examples of minimum strength requirements”.

Any feedback or questions on this document should be directed to the user’s national standards body. A

This International Standard specifies requirements for resistance spot welding in the fabrication

of assemblies of aluminium sheet, extrusions (both work- and age-hardening alloys) and/or cast

material comprising two or three thicknesses of metal, where the maximum single (sheet) thickness of

This International Standard is applicable to the welding of sheets or plates of dissimilar thickness

where the thickness ratio is less than or equal to 3 : 1. It applies to the welding of three thicknesses

Welding with the following types of machines is within the scope of this International Standard:

— automatic welding equipment where the components are fed by robots or automatic feeding

Information on appropriate welding equipment is given in Annex A and on spot welding conditions in

Annex B. The latter are for guidance only and may require modification depending on service conditions

of the fabrication, type of welding equipment, characteristics of the secondary circuit, electrode

The welding of coated material, e.g. zinc-coated or anodised material, is not within the scope of this

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 669, Resistance welding — Resistance welding equipment — Mechanical and electrical requirements

ISO 3522, Aluminium and aluminium alloys — Castings — Chemical composition and mechanical properties

ISO 10447, Resistance welding — Testing of welds — Peel and chisel testing of resistance spot and

ISO 14273, Resistance welding — Destructive testing of welds — Specimen dimensions and procedure for

ISO 15614-12, Specification and qualification of welding procedures for metallic materials — Welding

ISO 17677-1, Resistance welding — Vocabulary — Part 1: Spot, projection and seam welding

ISO 18278-2, Resistance welding — Weldability — Part 2: Evaluation procedures for weldability in

ISO 18594, Resistance spot-, projection- and seam-welding — Method for determining the transition

For the purposes of this document, the terms and definitions given in ISO 669 and ISO 17677-1 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

Prior to welding, all surfaces shall be checked for their suitability for spot welding. The surfaces should

preferably be free from oil, grease, lubricant, visible oxidation, paint, dirt, or excessive scratches. If

necessary, appropriate surface treatment, e.g. chemical etching, shall be carried out. Unless specifically

developed for spot welding, mill-finish surfaces are generally not suitable for spot welding and may need

pre-treatment. Die-cast material shall be free from excessive surface roughness and imperfections,

e.g. as caused by washing out of the die material. Aluminium manufacturers and component suppliers

can produce surface-treated material suitable for spot welding, e.g. with TiZr conversion coating.

In addition, coated material can be supplied with chromate or phosphate passivation. Phosphated

aluminium may be used in certain applications. Excessive quantities of dissolved gases in die-cast

material shall be avoided. These materials can be spot welded, although adjustment of the welding

In all cases the surface condition and any surface treatment shall be recorded in the testing

The stability of surface condition can be evaluated by measuring the transition resistance in accordance

The components to be welded shall be free from burrs or other defects, which may, in any way, interfere

The shape of the component shall be such that there is satisfactory interfacial contact in the area where

welds are to be made. The distance from the edge of the component to the centre of the weld (edge

distance) shall be not less than 1,25d (see Figure 3), where d is the target weld diameter as defined

in 8.2. The use of edge distances smaller than the recommended values will adversely influence weld

quality. Edge distances smaller than the recommended values should be used only when expressly

specified. In this case the nominal weld diameter specified may be less than that given in 8.2, and

The electrode materials shall be copper alloy and should possess high thermal and electrical conductivity

and shall comply with, and be used in accordance with ISO 5182. If other electrode materials are used

The welding electrodes shall be of sufficient cross-sectional area and strength to carry the welding

current and electrode force without overheating, excessive deformation, or excessive deflection. If

possible, from the point of accessibility, electrodes with a minimum diameter, D, of 20 mm should be

used. If other electrode diameters are used then these shall be recorded in the testing documentation.

The electrode dimensions shall, where practicable, conform to ISO 5184 for straight electrodes,

ISO 5821 for female electrode caps, or ISO 5830 for male electrode caps, as applicable. In cases where

these standards do not apply, the dimensions of the electrode shall be specified such that welds

It is recommended to employ either radiused electrodes or electrodes with a tip diameter greater than

When welding two sheets of dissimilar thickness, the electrode dimensions and the required weld

diameter should be specified with reference to the thickness of the thinner sheet. In the case of three

thicknesses, the thinner sheet of each combination should be used as the reference.

The electrode tip geometry and target weld diameter requirement shall be recorded in the testing

During normal production, electrodes tend to wear, leading to an increase in electrode tip diameter and

damage to the tip surface geometry. The condition of at least one of the electrodes should not be allowed

to deteriorate to a level that results in a reduction in weld diameter to less than the acceptable minimum,

e.g. 4 t . When this diameter has been reached (if not earlier), the electrode shall be replaced or

A common method to control process deterioration is to measure the increase in electrode tip geometry

(or contact rea on the sheet surface), where electrode tips of different diameters are in contact with the

piece to be welded, the permissible increase over the initial diameter shall apply to the smaller of the

A greater increase in the diameter of the electrode(s) is permissible only if tests prove that the strength

of the weld does not fall below the desired requirements, and only by specification.

In cases where adaptive control or automatic weld current increase (i.e. stepper controls), or other

forms of process control are used, a greater deterioration in electrode tip condition can be tolerated.