SIST EN ISO 10683:2018

SLOVENSKI STANDARD
01-december-2018
1DGRPHãþD
SIST EN ISO 10683:2014
Vezni elementi - Cinkova lamelna prevleka, ki ni izdelana z elektrolizo (ISO
10683:2018)
Fasteners - Non-electrolytically applied zinc flake coating systems (ISO 10683:2018)
Verbindungselemente - Nichtelektrolytisch aufgebrachte Zinklamellenüberzugsysteme
(ISO 10683:2018)
Fixations - Systèmes de revêtements non électrolytiques de zinc lamellaire (ISO
10683:2018)
Ta slovenski standard je istoveten z: EN ISO 10683:2018
ICS:
21.060.01 Vezni elementi na splošno Fasteners in general
25.220.40 Kovinske prevleke Metallic coatings
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 10683
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2018
EUROPÄISCHE NORM
ICS 21.060.01; 25.220.40 Supersedes EN ISO 10683:2014
English Version
Fasteners - Non-electrolytically applied zinc flake coatings
(ISO 10683:2018)
Fixations - Systèmes de revêtements non Verbindungselemente - Nichtelektrolytisch
électrolytiques de zinc lamellaire (ISO 10683:2018) aufgebrachte Zinklamellenüberzüge (ISO 10683:2018)
This European Standard was approved by CEN on 10 August 2018.

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 CEN-CENELEC Management Centre 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 CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 10683:2018 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 10683:2018) has been prepared by Technical Committee ISO/TC 2 "Fasteners"
in collaboration with Technical Committee CEN/TC 185 “Fasteners” the secretariat of which is held by
BSI.
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 March 2019, and conflicting national standards shall
be withdrawn at the latest by March 2019.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 10683:2014.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 10683:2018 has been approved by CEN as EN ISO 10683:2018 without any modification.
INTERNATIONAL ISO
STANDARD 10683
Third edition
2018-08
Fasteners — Non-electrolytically
applied zinc flake coating systems
Fixations — Systèmes de revêtements non électrolytiques de zinc
lamellaire
Reference number
ISO 10683:2018(E)
©
ISO 2018
ISO 10683:2018(E)
© ISO 2018
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
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved

ISO 10683:2018(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General characteristics of the coating . 2
4.1 Zinc flake coating systems . 2
4.2 Composition of the systems . 2
4.3 Mechanical and physical properties and curing. 2
4.4 Avoidance of internal hydrogen embrittlement . 3
4.5 Coating systems and coating processes. 3
5 Corrosion protection and testing . 3
5.1 General . 3
5.2 Neutral salt spray test . 3
5.3 Sulfur dioxide test (Kesternich test) . 4
5.4 Bulk handling, automatic processes such as feeding and/or sorting, storage and
transport . . 4
6 Dimensional requirements and testing . 4
6.1 General . 4
6.2 Fasteners with ISO metric thread . 4
6.2.1 Coating thickness . 4
6.2.2 Gaugeability and assemblability . 5
6.3 Other fasteners . 6
7 Mechanical and physical properties and testing . 6
7.1 Appearance . 6
7.2 Corrosion resistance related to temperature . 6
7.3 Test methods for thickness or coating weight determination . 6
7.4 Ductility . 7
7.5 Adhesion/cohesion . 8
7.6 Sacrificial cathodic protection . 8
7.7 Torque/clamp force relationship . 8
7.8 Determination of hexavalent chromium . 8
8 Applicability of tests . 8
8.1 General . 8
8.2 Tests mandatory for each lot . 8
8.3 Tests for in-process control. 9
8.4 Tests to be performed when specified by the purchaser . 9
9 Designation . 9
9.1 Designation of zinc flake coating systems for the order . 9
9.2 Designation of zinc flake coating systems for labelling .10
10 Ordering requirements .10
Annex A (informative) Design aspects and assembly of coated fasteners .12
Annex B (informative) Coating thickness and thread clearance for ISO metric screw threads .16
Annex C (informative) Coating systems tested in accordance with ISO 9227, NSS —
Evaluation of cabinet corrosivity for the neutral salt spray test .23
Bibliography .31
ISO 10683:2018(E)
Foreword
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
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
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
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
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
URL: www .iso .org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 2, Fasteners, SC 14, Surface coatings.
This third edition cancels and replaces the second edition (ISO 10683:2014), which has been technically
revised. The main changes compared to the previous edition are as follows:
— the normative references have been updated;
nd
— the restriction of gauging to external threads in the 2 paragraph of 6.2.2 has been removed;
— the last column in Table B.2 with maximum clearance for tolerance position e has been removed;
— Annex C has been revised completely.
iv © ISO 2018 – All rights reserved

INTERNATIONAL STANDARD ISO 10683:2018(E)
Fasteners — Non-electrolytically applied zinc flake
coating systems
1 Scope
This document specifies requirements for non-electrolytically applied zinc flake coating systems for
steel fasteners. It is applicable to coatings:
— with or without hexavalent chromium;
— with or without top coat;
— with or without lubricant (integral lubricant and/or subsequently added lubricant).
It is applicable to bolts, screws, studs and nuts with ISO metric thread, to fasteners with non-ISO metric
thread, and to non-threaded fasteners such as washers, pins, clips, etc.
This document does not specify requirements for such fastener properties as weldability or paintability.
It is not applicable to mechanically applied zinc coatings.
NOTE Coatings in accordance with this document are especially used for high strength fasteners
(≥ 1 000 MPa) to avoid risk of internal hydrogen embrittlement (IHE — see 4.4).
Information for design and assembly of coated fasteners is given in Annex A.
2 Normative references
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 1463, Metallic and oxide coatings — Measurement of coating thickness — Microscopical method
ISO 1502, ISO general-purpose metric screw threads — Gauges and gauging
ISO 1891-2, Fasteners — Terminology — Part 2: Vocabulary and definitions for coatings
ISO 3613:2010, Metallic and other inorganic coatings — Chromate conversion coatings on zinc, cadmium,
aluminium-zinc alloys and zinc-aluminium alloys — Test methods
ISO 6988, Metallic and other non organic coatings — Sulfur dioxide test with general condensation of
moisture
ISO 8991, Designation system for fasteners
ISO 9227, Corrosion tests in artificial atmospheres — Salt spray tests
ISO 16047, Fasteners — Torque/clamp force testing
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 1891-2 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
ISO 10683:2018(E)
— IEC Electropedia: available at www .electropedia .org
4 General characteristics of the coating
4.1 Zinc flake coating systems
Zinc flake coating systems are produced by applying a zinc flake dispersion to the surface of a steel
fastener, usually with the addition of aluminium flakes, in a suitable medium. Under the influence
of heat (curing), a bonding amongst flakes and also between flakes and substrate is generated, thus
forming an inorganic surface coating sufficiently electrically conducting to ensure cathodic protection.
The coating system can contain hexavalent chromium, Cr(VI).
Special techniques can be necessary to avoid excessive or insufficient coating thickness.
Special techniques can be necessary to prevent lightweight and/or flat fasteners from sticking together
(e.g. washers, clips, fasteners with captive washer, flanged nuts).
An additional top coat can be applied to increase corrosion resistance and/or to achieve specific
properties (e.g. torque/clamp force properties, chemical resistance, aspect, colour, electrical insulation/
conductivity — see A.2).
4.2 Composition of the systems
There are four basic zinc flake coating systems, as shown in Figure 1.
Key
1 only base coat
2 base coat + lubricant
3 base coat + top coat
4 base coat + top coat + lubricant
Figure 1 — Basic zinc flake coating systems
Base coat and top coat can be with integral lubricant; see detailed possible combinations in A.1.2.
4.3 Mechanical and physical properties and curing
The coating process shall not adversely influence the mechanical and physical properties of the
fasteners.
NOTE Distributors who coat non-coated fasteners are considered as alteration distributors in accordance
with ISO 1891-4.
Depending on the zinc flake coating system, the curing temperatures can be up to 320 °C. The curing
temperature shall not be above the tempering temperature of quenched and tempered fasteners.
WARNING — The curing process (especially with higher temperature and/or longer duration)
can affect the fatigue limit of fasteners with thread rolled after heat treatment. See also A.1.3 for
other possible effects of curing.
2 © ISO 2018 – All rights reserved

ISO 10683:2018(E)
4.4 Avoidance of internal hydrogen embrittlement
A characteristic of zinc flake coating systems is that hydrogen is not generated during the deposition
process.
Pre-treatment processes using alkaline/solvent cleaner followed by mechanical cleaning do not
generate hydrogen, thus eliminating all risk of internal hydrogen embrittlement (IHE).
When mechanical cleaning is not suitable for functional reasons (e.g. for fasteners with captive
washers, fasteners with internal threads, fasteners to be rack coated), chemical cleaning (pickling) may
be applied, provided that acid with suitable inhibitor and minimum cleaning cycle time are used to
minimize the risk of internal hydrogen embrittlement. Fasteners with hardness greater than 390 HV
or property class 12.9 and above shall not be subjected to acid cleaning. The duration between cleaning
and coating shall be as short as possible.
A phosphating process is permitted as an alternative to mechanical cleaning (hydrogen may be
generated during this pre-treatment process, however the curing process allows outward diffusion).
The duration between phosphating and coating shall be as short as possible.
Cathodic cleaning processes are not permitted.
NOTE Zinc flake coatings have a high permeability for hydrogen which, during the curing process, allows
outward diffusion of hydrogen that could have been absorbed during the pre-treatment process.
4.5 Coating systems and coating processes
The type and geometry of the fasteners shall be considered when selecting a coating system and the
related coating process; see A.2.
5 Corrosion protection and testing
5.1 General
Corrosion resistance in accelerated corrosion tests cannot be directly related to corrosion protection
behaviour in particular service environments. However, accelerated tests are used to evaluate the
corrosion resistance of the coating.
5.2 Neutral salt spray test
The neutral salt spray test (NSS) in accordance with ISO 9227 shall be used to evaluate the corrosion
resistance of the coating systems.
When evaluation of the cabinet corrosivity is requested, it should be performed in accordance with
Annex C.
The neutral salt spray test shall be carried out on fasteners alone, no sooner than 24 h after coating in
the “as-coated” condition, i.e. before sorting, packaging and/or assembling.
After the neutral salt spray test using a test duration of Table 1, there shall be no visible basis metal
corrosion (red rust).
The contact points of fasteners with a holding fixture shall not be considered in the evaluation of
corrosion protection.
NOTE Guidance for the selection of coating thickness in relation to corrosion protection is given in Annex B.
ISO 10683:2018(E)
Table 1 — Standard categories for neutral salt spray test
Neutral salt spray test duration Reference thickness
a
(without red rust) of the coating system
h µm
240 4
480 5
600 6
720 8
960 10
a
The reference thickness includes base coat(s) and top coat(s), if any, with or without Cr(VI). The corrosion resistance
shall be decisive for acceptance; the reference thickness is given for guidance only.
The composition of the system (base coat only, base coat + top coat, etc.) shall be specified at the time of the order.
5.3 Sulfur dioxide test (Kesternich test)
This test is only intended for outdoor building fasteners.
The sulfur dioxide test with general condensation of moisture in accordance with ISO 6988 shall be
used to evaluate the corrosion resistance of the coating systems; for outdoor building fasteners, the
test shall be carried out with two litres of SO .
The sulfur dioxide test shall be carried out on fasteners alone, no sooner than 24 h after coating in the
“as-coated” condition, i.e. before sorting, packaging and/or assembling.
The minimum number of cycles shall be agreed between the supplier and the purchaser at the time of
the order, i.e. 2 cycles, 3, 5, 8, 10, 12, 15 cycles, etc.
The contact points of fasteners with a holding fixture shall not be considered in the evaluation of
corrosion protection.
5.4 Bulk handling, automatic processes such as feeding and/or sorting, storage and
transport
Bulk handling, automatic processes such as feeding and/or sorting, storage and transport can cause a
significant reduction of corrosion protection depending on the coating system and type and geometry
of the fasteners. This can especially occur for Cr(VI)-free coating systems where less self-healing effect
takes place and/or where top coats are sensitive to impact damage and/or abrasion.
When necessary, an agreement should be reached between the supplier and the purchaser, e.g. by
reducing the minimum duration of neutral salt spray test and/or by increasing the thickness of the
coating system.
6 Dimensional requirements and testing
6.1 General
Before coating, fasteners shall be within the specified dimensions. For ISO metric threads, special
requirements may apply; see 6.2.2, B.4 and B.5.
6.2 Fasteners with ISO metric thread
6.2.1 Coating thickness
When considering the coating thickness related to the desired corrosion resistance, the dispersion of
the thickness of the coating system shall be taken into account; see B.3.
4 © ISO 2018 – All rights reserved

ISO 10683:2018(E)
Coating thickness has a significant influence on gaugeability and assemblability, therefore thread
tolerance and clearance in the thread shall be taken into account. The coating shall not cause the zero
line (basic size) to be exceeded in the case of external threads, nor shall it fall below in the case of
internal threads; see B.4.
NOTE For standard bolts, screws, studs and nuts not specifically manufactured to accommodate zinc flake
coatings, see B.4 and B.5.
6.2.2 Gaugeability and assemblability
Coated ISO metric screw threads shall be gauged with a GO-gauge, in accordance with ISO 1502, of
tolerance position h for external threads and H for internal threads.
When gauging coated threads of bolts, screws and studs, a maximum torque of 0,001 d (Nm) on a
length of 1d, beginning from thread end, is acceptable. When gauging coated internal threads of nuts, a
maximum torque of 0,001 D (Nm) is acceptable. See Table 2.
Table 2 — Maximum torque for gauging of coated ISO metric threads
a
Nominal thread diameter Maximum torque for gauging
d or D
mm Nm
3 0,03
4 0,06
5 0,13
6 0,22
8 0,51
10 1,0
12 1,7
14 2,7
16 4,1
18 5,8
20 8,0
22 11
24 14
27 20
30 27
33 36
36 47
39 59
a 3
For other diameters, the torque shall be calculated in accordance with 0,001 d or
0,001 D (Nm) and rounded to 2 significant figures.
Acceptance procedures for assemblability may be applied by agreement between supplier and
purchaser:
— for external thread, use of a suitable nut or the original mating fastener;
— for internal thread, use of a suitable mandrel (e.g. the mandrel specified for proof load in accordance
with ISO 898-2) or the original mating fastener.
ISO 10683:2018(E)
6.3 Other fasteners
After coating, there is no dimensional requirement for fasteners with non-ISO metric thread and for
non-threaded fasteners specified in this document. For additional information, see A.3.
7 Mechanical and physical properties and testing
7.1 Appearance
The colour of a zinc flake coating is originally silver-grey. Other colours can be obtained by using a top
coat. Variation in colour shall not be cause of rejection unless otherwise agreed; see Clause 10 g) and h).
The coated fastener shall be free from blisters and uncoated areas which can adversely affect the
corrosion protection. Local excess of coating shall not impair functional properties (see Clause 6 and A.2).
7.2 Corrosion resistance related to temperature
Elevated temperature can affect the corrosion protection of the coated fasteners. This test is specified
for in-process control; it is not intended to check the behaviour of the coated fasteners together with
the assembled parts.
After heating the coated fasteners for 3 h at 150 °C (part temperature) the corrosion resistance
requirements as specified in Clause 5 shall still be met.
Other specifications may be agreed at the time of the order.
7.3 Test methods for thickness or coating weight determination
Coating thickness or coating weight shall be determined using one of the following test methods:
— magnetic inductive techniques (determination of the total local thickness, on measuring areas);
— X-ray techniques (this method is only capable to determine the local thickness of the base coat, on
measuring areas);
— chemical or mechanical removal of the coating system (determination of the average total coating
weight of the fastener);
— microscopic method in accordance with ISO 1463 (determination of the total local thickness, on any
area(s) of the fastener).
In case of dispute, the microscopic method in accordance with ISO 1463 shall be used. The thickness
shall be measured on the reference areas specified in Figure 2, unless otherwise agreed.
6 © ISO 2018 – All rights reserved

ISO 10683:2018(E)
a) Reference areas for threaded fasteners
b) Reference areas for captive washers
c) Reference areas for non-threaded fasteners (examples)
Key
1 reference area for local coating thickness determination
Figure 2 — Reference areas for fasteners
7.4 Ductility
Zinc flake coating systems are generally not very ductile, i.e. corrosion performance can be affected
when deformation occurs after coating. Ductility shall be compatible with the elastic deformation
occurring during assembly of the fastener, e.g. tightening of threaded fasteners, flattening for conical
washers, bending for clips during installation.
The ability of the zinc flake coating system to deform should not cause impairment of the performance
of the fastener, e.g. corrosion resistance, torque/clamp force relationship when specified. Therefore,
suitable tests for particular applications shall be agreed between the purchaser and the supplier.
NOTE Lack of ductility can generate cracks/chips of the coating thus impairing corrosion resistance.
ISO 10683:2018(E)
7.5 Adhesion/cohesion
This test may be carried out at each step of the application process.
When an adhesive tape with 25 mm width with an adhesive strength of (7 ± 1) N is firmly pressed by
hand on to the surface and is subsequently pulled off rapidly and perpendicularly to the surface, the
coating shall not be peeled off the basis metal. Small amounts of the coating material left sticking to the
tape are acceptable.
NOTE Coating material visible on both surfaces of the fastener and adhesive tape usually results from lack
of cohesion. Visible basis metal and coating material on the adhesive tape usually result from lack of adhesion.
7.6 Sacrificial cathodic protection
The sacrificial cathodic protection ability of the coating may be tested as follows:
— the fastener shall be scratched down to the basis metal, using a tool with a nominal width of 0,5 mm;
— after a neutral salt spray test of 72 h duration in accordance with Clause 5, there shall be no red rust
in the scratched area.
7.7 Torque/clamp force relationship
When specified, the torque/clamp force relationship may be determined for fasteners with external ISO
metric thread and nuts with zinc flake coating systems including integral lubricant and/or subsequently
added lubricant.
The test method shall be agreed between the supplier and the purchaser, in accordance with ISO 16047
or other relevant technical specifications.
The requirements for torque/clamp force relationship shall be agreed between the supplier and the
purchaser. See A.2 for information.
Storage conditions shall not impair the torque/clamp force performance of the coated fasteners (see A.4).
7.8 Determination of hexavalent chromium
The presence or absence of Cr(VI) may be determined. In this case, the determination shall be done in
accordance with ISO 3613:2010, 5.5.2.
8 Applicability of tests
8.1 General
All requirements specified in Clauses 5, 6 and 7 apply as far as they are general characteristics of the
coating or are separately specified by the purchaser.
8.2 Tests mandatory for each lot
The following tests shall be carried out for each lot of fasteners (see ISO 3269).
— Gauging of thread (see 6.2.2).
— Appearance (see 7.1).
8 © ISO 2018 – All rights reserved

ISO 10683:2018(E)
8.3 Tests for in-process control
The following tests are not intended to be applied for each fastener lot, but shall be used for in-process
control (see ISO 16426), when relevant.
— Corrosion resistance: neutral salt spray test (see 5.2) or, alternatively and only when specifically
required, sulfur dioxide test (see 5.3).
— Temperature resistance (see 7.2).
— Coating thickness or coating weight (see 7.3).
— Adhesion/cohesion (see 7.5).
8.4 Tests to be performed when specified by the purchaser
The following tests are performed when specifically required by the purchaser; see ISO 3269. In-
process test results for that lot (see 8.3) may be used to supply test results to the purchaser.
— Corrosion resistance: neutral salt spray test (see 5.2) or, alternatively and only when specifically
required, sulfur dioxide test (see 5.3). Significant areas may be specified for the evaluation of the
corrosion resistance.
— Coating thickness or coating weight (see 7.3).
— Torque/clamp force relationship (see 7.7 and Table 3).
— Ductility (see 7.4).
— Cathodic protection (see 7.6).
— Presence or absence of Cr(VI) (see 7.8).
9 Designation
9.1 Designation of zinc flake coating systems for the order
The designation of the coating shall be added to the fastener designation in accordance with the
designation system specified in ISO 8991. The zinc flake coating system shall be designated in
accordance with Table 3 and in the same order. A slash (/) shall be used to separate data fields in the
coating designation.
Table 3 — Designation for zinc flake coating systems for the order
Zinc flake coating system Neutral salt Torque/clamp
spray test force require-
Base coat Hexavalent chromium Organic or inor- Additional
duration ment, if any
Cr(VI) ganic top coat lubricant, if
(red rust)
any
No specification: may
be delivered with or With integral
Without inte-
without Cr(VI) at the lubricant in the top
gral lubricant =
choice of the supplier coat = TL
flZn
a
or
or L e.g. 480 h C
or
With Cr(VI) = yc Without integral
With integral lu-
lubricant in the top
bricant = flZnL or
coat = Tn
Without Cr(VI) = nc
a
Range of µ or K values to be specified at the time of the order, see also A.2.1.
ISO 10683:2018(E)
Examples 1 to 4 provide examples of coating designation for the order:
EXAMPLE 1 Fastener with a non-electrolytically applied zinc flake coating (flZn), with a required minimum
corrosion resistance (neutral salt spray test) of 240 h is designated as follows:
[fastener designation] – flZn/240h
EXAMPLE 2 Fastener with a non-electrolytically applied zinc flake coating with integral lubricant (flZnL),
without Cr(VI) (nc), without top coat, with a required minimum corrosion resistance (neutral salt spray test) of
480 h, lubricated but without specific torque/clamp force requirement is designated as follows:
[fastener designation] – flZnL/nc/480h
EXAMPLE 3 Fastener with a non-electrolytically applied zinc flake coating (flZn) with Cr(VI) (yc), with a top
coat with integral lubricant (TL), with a required minimum corrosion resistance (neutral salt spray test) of 720 h,
and with a coefficient of friction µ within the range of [0,10 to 0,20] (C) is designated as follows:
[fastener designation] – flZn/yc/TL/720h/C
EXAMPLE 4 Fastener with a non-electrolytically applied zinc flake coating (flZn) without Cr(VI) (nc), without
integral lubricant, with a top coat without integral lubricant (Tn), with additional lubricant (L), with a required
minimum corrosion resistance (neutral salt spray test) of 960 h, and with a coefficient of friction µ equal to
0,17 ± 0,03 (C) is designated as follows:
[fastener designation] – flZn/nc/Tn/L/960h/C
9.2 Designation of zinc flake coating systems for labelling
At least the following information shall be added on the label, separated by a slash (/):
— flZn for the zinc flake coating (base coat);
— yc for coating with Cr(VI), or nc for Cr(VI) free coating;
— minimum duration of corrosion resistance (neutral salt spray) in hours.
Examples 1 to 3 provide examples for labelling.
EXAMPLE 1 Hexagon head bolt ISO 4014 – M12×80 – 10.9 – flZn/nc/720h
EXAMPLE 2 Hexagon regular nut ISO 4032 – M12 – 10 – flZn/yc/480h
EXAMPLE 3 Plain washer ISO 7089 – 12 – 300HV – flZn/nc/240h
10 Ordering requirements
When ordering a zinc flake coating system for fasteners in accordance with this document, the following
information shall be supplied:
a) reference to this document;
b) the coating designation (see Clause 9);
c) the material properties of the fastener that may be influenced by the coating process, e.g. tempering
temperature, hardness or other properties;
d) torque/clamp force requirements, if any, including specification and related test method (e.g.
ISO 16047);
e) other requirements, if any (e.g. resistance to chemicals, suitability for adhesives, electrical
conductivity/insulation);
f) tests to be carried out, if any (see Clause 8);
10 © ISO 2018 – All rights reserved

ISO 10683:2018(E)
g) sampling;
h) colour if different from silver-grey;
i) cosmetic appearance, if any.
ISO 10683:2018(E)
Annex A
(informative)
Design aspects and assembly of coated fasteners
A.1 Design
A.1.1 General
Before selecting a coating system, all functions and conditions of the assembly should be considered and
not just the fastener; see A.2.2. The purchaser should consult the supplier to determine the appropriate
choices for a given application.
A.1.2 Description of zinc flake coating systems
Figure A.1 shows typical zinc flake coating systems.
Figure A.1 — Typical zinc flake coating systems
An integral lubricant may be chosen to achieve torque/clamp force properties.
An additional top coat may be chosen to increase corrosion resistance and to achieve other specific
properties (e.g. torque/clamp force properties, resistance to chemicals, mechanical resistance, aspect,
colour, thermal resistance, electrical insulation/conductivity, UV resistance).
The selection of the nature of the top coat should be based on desired additional properties:
— organic top coat: electrical insulation, high resistance to chemicals or colouring possibilities, etc.;
— inorganic top coat: impact/abrasion resistance or thermal resistance, etc.
An additional lubricant may be chosen to adjust torque/clamp force relationship.
12 © ISO 2018 – All rights reserved

ISO 10683:2018(E)
A.1.3 Coating process
Zinc flake coating systems can be applied in bulk or rack process using dip-spin or spray process.
Zinc flake coating is generally a mass process. When lots of small quantities have to be coated, a
suitable coating line and/or process can be necessary in order to achieve the required properties and
performances for the coated fasteners. For fasteners of large size or mass or when the risk of thread
damage has to be reduced, rack instead of bulk process may be considered.
Curing process (especially with higher temperature and/or longer duration) can have an effect on the
properties/performances of fasteners:
— when the curing temperature is above the tempering temperature, reduction of hardness can affect
the performances of case hardened or nitrocarburised fasteners (e.g. for thread forming or self-
drilling screws), or elastic and plastic deformation (e.g. for clips);
— for cold worked fasteners or fasteners with thread rolled after heat treatment, residual stresses
may be reduced.
A.2 Functional properties
A.2.1 Assemblability and mountability
Clearance between assembly components (e.g. clearance hole), dimensional tolerances of the functional
parts of the fasteners, tool gripping (e.g. for retaining rings), tool insertion (e.g. for recess and internal
drives) and driving should not be impaired.
For dimensional requirements after coating for threaded fasteners, see 6.2 and Annex B.
The compatibility of the coating system with the tightening process, especially when high speed
tightening is foreseen (risk of overheating, stick/slip, etc.) should be considered.
The compatibility of the coated fasteners with the clamped parts, e.g. tapped holes, clamped parts
in aluminium, magnesium, stainless steel, electrophoreticaly coated parts, hot dip galvanized parts,
plastic, wood should be considered.
To achieve a specific clamp force and a consistent torque/clamp force relationship for fasteners with
ISO metric thread, at least one of the mating threaded fasteners should be lubricated. Zinc flake coating
systems provide lubricated solutions (see A.1.2). Torque/clamp force relationship can be determined in
accordance with ISO 16047 and expressed as a coefficient of friction µ (or by K-factor).
A.2.2 Other properties of the assembly with coated fasteners
A.2.2.1 Chemical resistance
Organic top coats applied on zinc flake base coats are more resistant to acidic and alkaline chemicals
than inorganic top coats.
A.2.2.2 Electrical conductivity
The electrical conductivity of zinc flake base coats with inorganic top coat is generally suitable for
application of electrophoretic coatings and antistatic purposes. Zinc flake coating systems are not
suitable for electrical grounding.
A.2.2.3 Galvanic corrosion
In order to reduce the risk of galvanic corrosion, all of the parts of the assembly should be considered
(coated fasteners and clamped parts). A direct metal contact with non-coated clamped parts should be
ISO 10683:2018(E)
avoided, especially e.g. for stainless steel, magnesium, copper or copper alloys. Due to their insulating
effect, organic top coats improve the resistance against galvanic corrosion.
The items listed in A.2.2 are not exhaustive. All the specific service conditions should be considered
when selecting a coating system.
A.2.2.4 Cleanliness
For cleanliness require
...