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ICS 25.220.40 ISBN 0-626-15424-3

S A N S 121:2000

Edition 1.1

IS O 1461:1999

Edition 2

Any reference to SABS ISO 1461 is deemed to be a reference to this standard (Government Notice No. 1373 of 8 November 2002)

S O U T H A FR IC A N N A TIO N A L S TA N D A R D

Hot dip galvanized coatings on fabricated iron and steel articles -- Specifications and test methods

This national standard is the identical implementation of ISO 1461:1999 and is adopted with the permission of the International Organization for Standardization.

Published by Standards South Africa 1 dr lategan road groenkloof private bag x191 pretoria 0001 tel: 012 428 7911 fax: 012 344 1568 international code + 27 12 www.stansa.co.za © Standards South Africa

SANS 121:2000 Edition 1.1 ISO 1461:2002 Edition 2

Table of changes Change no. Date

Tech. corr. 1 Nat. am dt 1 1999 2000

Scope

Corrected to insert the SABS certification m ark. Am ended to change the certification m ark to the m ark for specific properties.

In current edition, the certification m ark has been rem oved.

Abstract

Specifies the general properties of and m ethods of test for coatings applied by hot dipping in zinc (containing not m ore than 2 % of other m etals) on fabricated iron and steel articles.

K eyw ords

coatings, definitions, galvanizing, hot-dip galvanizing, iron, m etal coatings, protective coatings, specifications, steels, testing, zinc.

N ational forew ord

This South African standard was approved by National Com m ittee StanSA SC 5120.40B, Hot-dip coatings, in accordance with procedures of Standards South Africa, in com pliance with annex 3 of the W TO /TBT agreem ent. This SANS edition is technically identical to SABS ISO 1461:2000.

IN TE R N ATIO N AL STA N D AR D

ISO 1461

Second edition 1999-02-01

H o t d ip g alvan ized co atin g s o n fab ricated iro n an d steel articles -- S p ecificatio n s an d test m eth o d s

Revêtem ents par galvanisation à chaud sur produits finis ferreux -- Spécifications et m éthodes d'essai

A

Reference number ISO 1461:1999(E)

ISO 1461:1999(E)

Foreword

ISO (the International O rganization for Standardization) is a worldwide federation of national standards bodies (ISO m em ber bodies). The work of preparing International Standards is norm ally carried out through ISO technical com m ittees. Each m em ber body interested in a subject for which a technical com m ittee has been established has the right to be represented on that com m ittee. International organizations, governm ental and nongovernm ental, in liaison with ISO , also take part in the work. ISO collaborates closely w ith the International Electrotechnical Com m ission (IEC) on all m atters of electrotechnical standardization. Draft International Standards adopted by the technical com m ittees are circulated to the m em ber bodies for voting. Publication as an International Standard requires approval by at least 75 % of the m em ber bodies casting a vote. International Standard ISO 1461 was prepared by the European Com m ittee for Standardization (C EN) in collaboration with ISO Technical Com m ittee TC 107, M etallic and other inorganic coatings, Subcom m ittee SC 4, Hot dip coatings (galvanized, etc.), in accordance with the Agreement on technical cooperation between ISO and C EN (Vienna Agreem ent). Throughout the text of this standard, read "...this European Standard..." to m ean "...this International Standard...". This second edition cancels and replaces the first edition (ISO 1461:1973) as well as the first edition of ISO 1459 (ISO 1459:1973), which has been technically revised. Annexes A and B form an integral part of this International Standard. Annexes C to E are for inform ation only. For the purposes of this International Standard, the C EN annex regarding fulfilm ent of European Council Directives has been rem oved.

© ISO 1999 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Organization for Standardization Case postale 56 CH-1211 Genève 20 Switzerland Internet [email protected] Printed in Switzerland

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Contents

P age 1 S co pe ....................................................................................................................... ...................................................................1 . 2 N o r m a tive referen ces ........................................................................................................ .......................................................1 . 3 T erm (s) and d efin itio n (s) ................................................................................................... ......................................................1 . 4 G en eral req u irem en ts............................................................. .................................................................................................3 . . 4 .1 H ot d ip g a lv a n izing b ath .................................................................................................. ............................. ......................... 3 4 .2 In fo r m a tion to b e su p p lied b y the p u rch a ser ............................................................................... ....................................... 3 . 4 .3 S afety ................................................................................................................... . ..................................................................3 . 5 S a m p ling .......................................................................................................... ..........................................................................3 . 6 C o a ting p ro p erties .......................................................................................................... ................................................... ........ 3 6 .1 A p p ea ra n ce ................................................................................................................ ............................................................3 . 6 .2 T h ick n ess ................................................................................................................ . ...............................................................4 . 6 .2.1 G en eral ...................................................................................................... ..........................................................................4 . 6 .2.2 T est m eth o ds ............................................................................................................ ................................................... ......... 4 6 .2.3 R eferen ce a reas ......................................................................................................... ..........................................................4 . 6 .3 R en o v a tion ............................................................................................................................................................................ . .6 6 .4 A d h esion ........................................................................................................... ......................................................................6 . 6 .5 A ccep tan ce criteria ....................................................................................................... ....................................................... 7 ... 7 C ertifica te of co m p lia n ce ................................................................................................... ......................................................7 . A n n ex A ( n o r m a tiv e ) In fo rm ation to b e su p p lied b y th e p u rch aser to th e h ot d ip g alv a n izer ..............................................8 A n n ex B ( n o r m a tiv e ) S afety an d p ro cess req u irem en ts ............................................................................................... .............9 A n n ex C ( in f o r m a ti v e ) P rop erties of th e a rticles to b e co ated th at affect th e resu lts of h ot d ip g alv an izin g .....................1 0 A n n ex D ( in f o r m a tiv e ) D eterm in ation of th ick n ess ........................................................................................ .........................1 3 A n n ex E ( in f o r m a tiv e ) B ib lio g ra p hy .................................................................................................................. ....................... 1 5

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Foreword

T h e te x t o f E N I S O 1 4 6 1 :1 9 9 9 h a s b e e n p r e p a r e d b y T e c h n ic a lC o m m itte e C E N /T C 2 6 2 " M e ta llic a n d o th e r in o r g a n ic c o a tin g s " ,th e s e c r e ta r ia to f w h ic h is h e ld b y B S I, in c o lla b o r a tio nw ith T e c h n ic a lC o m m itte eI S O /T C 1 0 7 " M e ta llic a n d o th e r in o r g a n ic c o a tin g s " . T h is E u r o p e a n S ta n d a r d s h a ll b e g iv e n th e s ta tu s o f a n a tio n a l s ta n d a r d , e ith e r b y p u b lic a tio n o f a n id e n tic a l te x t o r b y e n d o r s e m e n t,a t th e la te s t b y A u g u s t 1 9 9 9 , a n d c o n f lic tin g n a tio n a l s ta n d a r d s s h a ll b e w ith d r a w n a t th e la te s t b y A u g u s t 1 9 9 9 . A c c o r d in g to th e C E N /C E N E L E CI n te r n a l R e g u la tio n s ,th e n a tio n a l s ta n d a r d s o r g a n iz a tio n so f th e f o llo w in g c o u n tr ie s a r e b o u n d to im p le m e n tth is E u r o p e a n S ta n d a r d : A u s tr ia , B e lg iu m , C z e c h R e p u b lic ,D e n m a r k ,F in la n d , F r a n c e , G e r m a n y ,G r e e c e , I c e la n d , I r e la n d , I ta ly , L u x e m b o u r g ,N e th e r la n d s ,N o r w a y , P o rtu g a l, S p a in , S w e d e n , S w itz e r la n da n d th e U n ite d K in g d o m .

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1 Scope

T h is S ta n d a r d s p e c if ie s th e g e n e r a l p r o p e r tie s o f a n d m e th o d s o f te s t f o r c o a tin g s a p p lie d b y h o t d ip p in g in z in c ( c o n ta in in g n o t m o r e th a n 2 % o f o th e r m e ta ls ) o n f a b r ic a te d ir o n a n d s te e l a rtic le s . I t d o e s n o t a p p ly to : a) b) c) s h e e t a n d w ir e th a t a r e c o n tin u o u s lyh o t d ip g a lv a n iz e d ; tu b e a n d p ip e th a t is h ot d ip g a lv a n iz e d in a u to m a tic p la n ts ; h o t d ip g a lv a n iz e d p r o d u c ts f o r w h ic h s p e c if ic s ta n d a r d s e x is t a n d w h ic h m a y in c lu d e a d d itio n a lr e q u ir e m e n tso r r e q u ir e m e n tsd iff e r e n t f r o m th o s e o f th is E u r o p e a n S ta n d a r d .

NOTE Individual product standards can incorporate this standard for the coating by quoting its number, or may incorporate it with modifications specific to the product.

A f te r-tr e a tm e n t/o v e r c o a tin go f h o t d ip g a lv a n iz e d a r tic le s is n o t c o v e r e d b y th is s ta n d a r d .

2 Normative references

T h is S tan d a r d in c o r p o r a te s ,b y d a te d o r u n d a te d r e f e r e n c e ,p r o v is io n s f r o m o th e r p u b lic a tio n s .T h e s e n o r m a tiv e r e f e r e n c e s a r e c ite d a t th e a p p r o p r ia tep la c e s in th e te x t a n d th e p u b lic a tio n sa r e lis te d h e r e a f te r .F o r d a te d r e f e r e n c e s ,s u b s e q u e n ta m e n d me n ts to o r re v is io n s o f a n y o f th e s e p u b lic a tio n sa p p ly to th is I n te r n a tio n a l/E u r o p e a nS ta n d a r d o n ly w h e n in c o r p o r a te din it b y a m e n d m e n to r r e v is io n . F o r u n d a te d r e f e r e n c e s ,th e la te s t e d itio n o f th e p u b lic a tio n r e f e r r e d to a p p lie s . E N 1 1 7 9, Zinc and zinc alloys -- Primary zinc. E N IS O 1 4 6 0 , Metallic coatings -- Hot dip galvanized coatings on ferrous materials -- Gravimetric determination of the mass per unit area (ISO 1460:1992). E N 2 2 0 6 3, Metallic and other inorganic coatings -- Thermal spraying -- Zinc, aluminium and their alloys (ISO 2063:1991) . E N IS O 2 0 6 4 , Metallic and other inorganic coatings -- Definitions and conventions concerning the measurement of thickness (ISO 2064:1980). E N IS O 2 1 7 8 , Non-magnetic coatings on magnetic substrates -- Measurement of coating thickness -- M agnetic method (ISO 2178:1982). IS O 7 5 2 , Zinc ingots. IS O 2 8 5 9-1 , Sampling procedures for inspection by attributes -- Part 1: Sampling plans indexed by acceptable quality level (AQL) for lot-by-lot inspection. I S O 2 8 5 9-3 , Sam pling procedures for inspection by attributes -- Part 3: Skip-lot sam pling procedures. I S O 1 0 4 7 4, Steel and steel products -- Inspection documents.

3 Term(s) and definition(s)

F o r th e p u r p o s e s o f th is s ta n d a r d ,th e f o llo w in g d e f in itio n s a p p ly to g e th e r w ith th o s e g iv e n in E N I S O 2 0 6 4 . 3 .1 h ot d ip g alv an izin g f o r m a tio n o f a c o a tin g o f z in c a n d /o r z in c-ir o n a llo y s o n ir o n a n d s te e l p r o d u c ts b y d ip p in g p r e p a r e d s te e l o r c a s t ir o n in m ol te n z in c . 3 .2 h ot d ip g alv an ized co atin g c o a tin g o b ta in e d b y h o t d ip g a lv a n iz in g

NOTE The term 'hot dip galvanized coating' is subsequently referred to as the 'coating'.

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3 .3 co atin g m ass to ta l m a s s o f z in c a n d /o r z in c-ir o n a llo y s p e r a r e a o f s u rf a c e ( e x p r e s s e d in g r a m s p e r s q u a r e m e tr e , g /m 2 ) 3 .4 co atin g th ick n ess to ta l th ick n e s s o f z in c a n d /o r z in c-ir o n a llo y s ( e x p r e s s e d in m ic r o m e tr e s , m ). 3 .5 sign ifican t su rface th e p a r t o f th e a r tic le c o v e r e d o r to b e c o v e r e d b y th e c o a tin g a n d f o r w h ic h th e c o a tin g is e s s e n tia l f o r s e r v ic e a b ilitya n d /o r ap p earan ce 3 .6 con trol sa m p le th e a r tic le o r g r o u p o f a r tic le s fr o m a lo t th a t is s e le c te d f o r te s tin g 3 .7 referen ce a rea th e a r e a w ith in w h ic h a s p e c if ic n u m b e r o f s in g le m e a s u r e m e n tsh a s to b e m a d e 3 .8 lo cal co atin g th ick n ess th e m e a n v a lu e o f c o a tin g th ic k n e s s o b ta in e d f r o m th e s p e c if ie d n u m b e r o f m e a s u r e m e n tsw ith in a r e f e r e n c e a r e a f o r a m a g n etic te s t o r th e s in g le v a lu e fr o m a g r a v im e tr icte s t 3 .9 m ean co atin g th ick n ess th e a v e r a g e v a lu e o f th e lo c a l th ic k n e s s e se ith e r o n o n e la r g e a r tic le o r o n a ll th e a r tic le s in th e c o n tr o l s a m p le . 3 .1 0 lo cal co atin g m ass th e v a lu e o f c o a tin g m a s s o b ta in ed fr o m a s in g le g r a v im e tr icte s t 3 .1 1 m ean co atin g m a ss th e a v e r a g e v a lu e o f th e c o a tin g m a s s e s d e te r m in e d e ith e r b y u s in g a c o n tr o l s a m p le s e le c te d in a c c o r d a n c e w ith c la u s e 5 u s in g te s ts in a c c o r d a n c ew ith E N I S O 1 4 6 0 o r b y c o n v e r s io n o f th e m e a n c o a ting th ic k n e s s ( s e e 3 .9 ) 3 .1 2 m in im um v alu e w ith in a r e f e r e n c e a r e a , th e lo w e s t sin g le m e a s u r e m e n tin a g r a v im e tr icte s t o r th e lo w e s t m e a n o b ta in e d fr o m th e s p e c if ie d n u m b e r o f m e a s u r e m e n tsin a m a g n e tic te s t 3 .1 3 in sp ection lot s in g le o r d e r o r s in g le d e liv e r y lo a d 3 .1 4 a ccep tan ce in sp ection in s p e c tio n o f a n in s p e c tio n lo t a t th e h o t d ip g a lv a n iz e r'sw o r k s ( u n le s s o th e r w is e s p e c if ie d ) 3 .1 5 u n co ated a rea s a r e a s o n th e ir o n o r s te e l a r tic le s th a t d o n o t r e a c t w ith th e m o lte n z in c

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4 General requirements

NOTE 1 The chemical composition and the surface condition (finish or roughness) of the basis metal, the mass of the parts and the galvanizing conditions affect the appearance, the thickness, the texture and physical/mechanical properties of the coating. This Standard does not define any requirement regarding these points, but gives some recommendations in annex C. NOTE 2 EN ISO 14713 gives guidance on the selection of hot dip galvanized coatings for iron and steel. EN ISO 12944-5 includes information on paint coatings over hot dip galvanized steel coatings.

4.1 Hot dip galvanizing bath

T h e h o t d ip g a lv a n iz in g b a th s h a ll p r im a r ily c o n ta in m o lte n z in c . T h e to ta l o f im p u r itie s ( o th e r th a n ir o n a n d tin ) in th e m o lte n z in c s h a ll n o t e x c e ed 1 ,5 % b y m a s s , th e s a id im p u r itie s b e in g th o s e d e f in e d in I S O 7 5 2 o r E N 1 1 7 9 . ( S e e a ls o a n n e x C .)

4.2 Information to be supplied by the purchaser

T h e in f o r m a tio n lis te d in a n n e x A s h a ll b e s u p p lie d b y th e p u r c h a s e r .

4.3 Safety

V e n tin g a n d d r a in ing s h a ll b e p r o v id e d f o r in a c c o r d a n c ew ith a n n e x B .

5 Sampling

A c o n tr o l s a m p le f o r th ic k n e s s te s tin g s h a ll b e ta k e n r a n d o m ly fr o m e a c h in s p e c tio n lo t ( s e e 3 .1 3 ) s e le c te d f o r te s tin g . T h e m in im u m n u m b e r o f a rtic le s f r o m e a c h in s p e c tio n lo t th a t f o r m s th e c o n tr o l s a m p le s h a ll b e in a c c o r d a n c e w ith ta b le 1 .

T ab le 1 -- C on trol sa m p le size related to lot size N u m b er of articles in th e lot 1 to 3

4 to 500 501 to 1 200 1 201 to 3 200 3 201 to 10 000 > 10 000

M in im u m n u m b er of articles in th e con trol sa m p le

All 3 5 8 13 20

A c c e p ta n c ein s p e c tio n s h a ll b e u n d e r ta k e n b e f o r e th e p r o d u c ts le a v e th e h o t d ip g a lv a n iz e r 'sc u s to d y , u n le s s o th e r w is e s p e c if ied a t th e tim e o f o r d e r in g b y th e p u r c h a s e r .

6 Coating properties

6.1 Appearance

A t a c c e p ta n c ein s pe c tio n , th e s ig n if ic a n ts u rf a c e ( s ) o f a ll th e h o t d ip g a lv a n iz e d a r tic le ( s ) ,w h e n e x a m in e d b y n o r m a l c o r r e c ted v is io n , s h a ll b e fr e e fr o m n o d u le s , b lis te r s ( i.e ., r a is e d a r e a s w ith o u t s o lid m e ta l b e n e a th ) ,r o u g h n e s s a n d s h a r p p o in ts ( if th e y c a n c a u s e in jur y ) a n d u n c o a te d a r e a s .

NOTE 1 'Roughness' and 'smoothness' are relative terms and the roughness of coatings on articles galvanized after fabrication differs from mechanically wiped products, such as galvanized sheet and wire.

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T h e o c c u r re n c e o f d a r k e r o r lig h te r g r e y a r e a s ( e .g . a c e llu la r p a tte r n o f d a r k g r e y a r e a s ) o r s o m e s u rf a c e u n e v e n n e s ss h a ll n o t b e a c a u s e f o r r e je c tio n ; a ls o w e t s to r a g e s ta in ( w h ite o r d a r k c o r r o s io n p r o d u c ts -- p r im a r ily b a s ic z in c o x id e -- f o r m e d d u r in g s to r a g e in h u m id c o n d itio n s a f te r h o t d ip g a lv a n iz in g )s h a ll n o t b e c a u s e f o r r e je c tio n ,p r o v id in g th e c o a tin g th ic k n e s s r e m a ins a b o v e th e s p e c if ie d m in im u m v a lu e .

NOTE 2 It is not possible to establish a definition of appearance and finish covering all requirements in practice.

F lu x r e s id u e s s h a ll n o t b e p e r m itte d .L u m p s a n d z in c a s h s h a ll n o t b e p e r m itte d w h e r e th e y m a y a f f e c t th e in te n d e d u s e o f th e h o t d ip g a lv a n iz e d a r tic le o r its c o rr o s io n r e s is ta n c e r e q u ir e m e n t. A r tic le s th a t f a il v is u a l in s p e c tio n s h a ll b e r e n o v a te d in a c c o r d a n c e w ith 6 .3 o r r e g a lv a n iz e da n d r e s u b m itte df o r in s p e c tio n . W h e n p a r tic u la r r e q u ir e m e n tse x is t (f o r e x a m p le , w h e n th e g a lv a n iz e d c o a tin g is to b e p a in te d ) , a s a m p le s h a ll b e p r o d u c e d ( s e e A .2 a n d C .1 .4 ) if r e q u ir e d .

6.2 Thickness

6 .2.1 G en eral C o a tin g s a p p lie d b y h o t d ip g a lv a n iz in g a r e d e s ig n e d to p r o te c t th e ir o n a n d s te e l p r o d u c ts a g a in s t c o rr o s io n ( s e e a n n e x C ). T he le n g th o f tim e o f c o rr o s io n p r o te c tio n b y s u c h c o a tin g s ( w h e th e r lig h t o r d a r k g r e y ) is a p p r o x im a te lyp r o p o r tio n a l to th e c o a tin g th ic k n e s s .F o r e x tr e m e ly a g g r e s s iv e c o n d itio n s a n d /o r a n e x c e p tio n a llylo n g s e r v ic e lif e , th ic k e r c o a tin g s th a n th o s e s p e c if ie d h e r e m a y b e r e q u ir e d . T h e s p e c if ic a tio no f th e s e th ic k e r c o a tin g s s h a ll b e s u b je c t to a g r e e m e n tb e tw e e n th e g a lv a n iz e ra n d th e p u r c h a s e r c o n c e r n in g th e m e a n s o f im p le m e n ta tio n( e .g . g r it b la s tin g , s te e l c h e m ic a l c o m p o s itio n ) . 6 .2.2 T est m eth od s I n c a s e o f d is p u te r e g a r d in g th e te s t m e th o d , th e m e th o d o f c a lc u la tin g th e c o a tin g th ic k n e s s s h a ll b e b y d e te r m ina tio n o f th e m e a n m a s s o f h o t d ip g a lv a n iz e d c o a tin g p e r u n it a r e a u s in g th e g r a v im e tr ic m e th o d in a c c o r d a n c e w ith E N I S O 1 4 6 0 a n d th e n o m in a l d e n s ity o f th e c o a tin g ( 7 ,2 g /cm 3 ) . W h e r e le s s th a n 1 0 a r tic le s a r e in v o lv e d , th e p u r c h a s e r s h a ll n o t h a v e to a cc e p t th e g r a v im e tr icte s t if th a t w o u ld in v o lv e d e s tr u c tio n o f a r tic le s a n d u n a c c e p ta b ler e m e d ia l c o s ts to th e p u r c h a s e r .

NOTE Tests (see annex D) are preferably by the magnetic method (EN ISO 2178) or the gravimetric method (possible alternative methods, e.g., electromagnetic method (ISO 2808), coulometric or microscopic cross-section are given in annex D).

T h e E N I S O 2 1 7 8 m e th o d is m o s t a p p r o p r ia tew ith in w o r k s a n d f o r r o u tin e q u a lity c o n tr o l. B e c a u s e th e a r e a o v e r w h ic h e a c h m e a s u r e m e n tis m a d e in th is m e th o d is v e r y s m a ll, in d iv id u a lfig u r e s m a y b e lo w e r th a n th e v a lu e s f o r th e lo c a l o r m e a n c o a tin g th ic k n e s s .I f a s u ff ic ie n tn u m b e r o f m e a s u r e m e n tsa r e m a d e w ith in a r e f e r e n c e a r e a , e f f e c tiv e ly th e s a m e lo c a l th ic k n e s s w ill be d e te r m in e d b y m a g n e tic a s b y g r a v im e tr icm e th o d s . 6 .2.3 R eferen ce a rea s T h e n u m b e r a n d p o s itio n o f r e f e r e n c e a r e a s a n d th e ir s iz e s f o r th e m a g n e tic o r g r a v im e tr icte s t s h a ll b e c h o s e n w ith r e g a r d to th e s h a p e a n d s iz e o f th e a r tic le ( s ) in o r d e r to o b ta in a r e s u lt a s r e p r e s e n ta ti v e a s p o s s ib le o f m e a n c o a tin g th ic k n e s s o r m as s p e r u n it a r e a a s a p p lic a b le .O n a lo n g a r tic le in th e c o n tr o l s a m p le , th e r e f e r e n c e a r e a s s h a ll b e c u t a p p r o x im a te ly1 0 0 m m fr o m e a c h e n d a n d a t th e a p p r o x im a tec e n tr e a n d s h a ll c o m p r is e th e w h o le c r o s s-s e ctio n o f th e a r tic le . T h e n u m b e r o f r e f e r e n c e a r e a s , d e p e n d e n tu p o n th e s iz e o f th e in d iv id u a la r tic le s in th e c o n tr o l s a m p le , s h a ll b e a s f o llo w s . a) F o r a r tic le s w ith s ig n if ic a n ts u rf a c e a r e a g r e a te r th a n 2 m 2 (" la r g e a r tic le s " ) :A t le a s t th r e e r e f e r e nc e a r e a s s h a ll b e ta k e n o n e a c h a r tic le in th e c o n tr o l s a m p le . O n e a c h a r tic le ( ta k e n s e p a r a te ly )in th e c o n tr o l s a m p le th e m e a n c o a tin g th ic k n e s s w ith in th e r e f e r e n c e a r e a s s h a ll b e e q u a l to o r g r e a te r th a n th e m e a n c o a tin g th ic k n e s s v a lu e s g iv e n in ta b le 2 o r ta b le 3 . F o r a r tic le s w ith s ig n if ic a n ts u rf a c e a r e a o v e r 1 0 0 0 0 m m 2 a n d u p to 2 m 2 (in c lu s iv e ) :O n e a c h a r tic le in th e c o n tr o l s a m p le , th e r e s h a ll b e a t le a s t o n e r e f e r e n c e a r e a . F o r a r tic le s w ith s ig n if ic a n ts u rf a c e a r e a b e tw e e n 1 0 0 0 m m 2 a n d 1 0 0 00 m m 2 (in c lu s iv e ) :O n e a c h a r tic le in th e c o n tr o l s a m p le , th e r e s h a ll b e o n e r e f e r e n c e a r e a .

b) c)

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d)

F o r a r tic le s w ith le s s th a n 1 0 0 0 m m 2 s ig n if ic a n ts u r f a c e a r e a : E n o u g h a r tic le s s h a ll b e g r o u p e d to g e th e r to p r o v id e a t le a s t 1 0 00 m m 2 s u r f a c e f o r a n in d iv id u a lr e f e r e n c e a r e a . T h e n u m b e r o f r e f e r e n c e a r e a s s h a ll b e a s g iv e n in th e la s t c o lu m n o f ta b le 1 . H e n c e , th e to ta l n u m b e r o f a r tic le s te s te d e q u a ls th e n u m b e r o f a r tic le s r e q u ir e d to p r o v id e o n e r e f e r e n c e a r e a m u ltip lie d b y the a p p r o p r ia ten u m b e r fr o m th e la s t c o lu m n o f ta b le 1 r e la te d to th e s iz e o f th e lo t ( o r th e to ta l n u m b e r o f a r tic le s g a lv a n iz e d if th a t is le s s ). A lte r n a tiv e ly ,s a m p lin g p r o c e d u r e ss e le c te d f r o m I S O 2 8 5 9 s h a ll b e u s e d .

10 000 mm2 = 100 cm2 1 000 mm2 = 10 cm2 2 m2 is typically 200 cm x 100 cm; 10 000 mm2 is typically 10 cm x 10 cm; 1 000 mm2 is typically 10 cm x 1 cm

NOTE 1

I n c a s e s b ), c ) a n d d ) , th e th ic k n e s s o n e a c h r e f e r e n c e a r e a s h a ll b e e q u a l to o r g r e a te r th a n th e " lo c a l c o a tin g th ic k n e s s " v alu e s g iv e n in ta b le 2 o r 3 a s a p p r o p ria te .T h e m e a n th ic k n e s s o n a ll r e f e r e n c e a r e a s in a s a m p le s h a ll b e e q u a l to o r g r e a te r th a n th e m e a n c o a tin g th ic k n e s s v a lu e s g iv e n in ta b le 2 o r 3 a s a p p r o p ria te . W h e n th e z in c c o a tin g th ic k n e s s is d e te r m in e d b y th e m a g n e tic m e th o d in a c c o r d a n c ew ith E N I S O 2 1 7 8 , th e r e f e r e n c e a r e a s s h a ll b e w ith in a n d r e p r e s e n ta tiv eo f th o s e th a t w o u ld h a v e b e e n c h o s e n f o r th e g r a v im e tr icm e th o d . W h e n m o r e th a n f iv e a r tic le s h a v e to b e ta k e n to m a k e u p a r e f e r e n c e a r e a o f a t le a s t 1 0 0 0 m m 2 , a s in g le m a g n e tic m e a s u r e m e n ts h a ll b e ta k e n o n e a c h a r tic le if a s u ita b le a r e a o f s ig n if ic a n ts u r f a c e e x is ts : if n o t, th e g r a v im e tr icte s t s h a ll b e used. W ith in e a c h r e f e r e n c e a r e a , w h ic h s h o u ld b e a t le a s t 1 0 0 0 m m 2 , a m in im u m o f f iv e m a g n e tic te s t r e a d in g s s h a ll b e ta k e n o n c o a te d a r e a s . If a n y o f th e in d iv id u a l r e a d in g s is lo w e r th a n th e v a lu e s in ta b le s 2 a n d 3 , th is is irr e le v a n t a s o n ly th e m e a n v a lu e o v e r th e w h o le o f e a c h r e f e r e n c e a r e a is r e q u ir e d to b e e q u a l to o r g r e a te r th a n th e lo c a l th ick n e s s g iv e n in th e ta b le . T h e m e a n c o a tin g th ic k n e s s f o r a ll r e f e r e n c e a r e a s s h a ll b e c a lc u la te d in a s im ila r w a y f o r th e m a g n e tic te s t a s f o r th e g r a v im e tr ictes t (EN ISO 1 4 6 0 ). T h ic k n e s s m e a s u r e m e n tss h a ll n o t b e ta k e n o n c u t s u rf a c e s o r a r e a s le s s th a n 1 0 m m fr o m e d g e s , f la m e c u t s u r f a c e s o r c o r n e r s ( s e e C .1 .3 ) . T ab le 2 -- C o atin g m in im u m th ick n esses on sa m p les th at are n ot cen trifu g ed

Article and its thickness Local coating thickness (minimum)a m 70 55 45 35 70 60 Mean coating thickness (minimum)b m Steel Steel Steel 6 mm 85 70 55 45 80 70

3 mm to < 6 mm 1,5 mm to < 3 mm

Steel < 1,5 mm Castings 6 mm

Castings < 6 mm

a b

See 3.8. See 3.9.

NOTE 2 Table 2 is for general use; individual product standards may include different requirements including different categories of thickness. A requirement for thicker coatings or additional requirements can be added without otherwise affecting conformity to this standard.

T h e lo c a l c o a tin g th ic k n e s s in ta b le 2 s h a ll o n ly b e d e te r m in e d in r e la tio n to r e f e r e n c e a r e a s s e le c te d in a c c o r d a n c ew ith 6 .2. 3 .

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T ab le 3 -- C o atin g m in im u m th ick n esses on sa m p les th at are cen trifu g ed A rticle an d its th ick n ess L o cal co atin g th ick n ess (m in im u m )a m A rticle w ith th read s: 2 0 m m d ia m e te r 6 m m to < 2 0 m m d ia m e te r < 6 m m d ia m e te r O th er articles (in clu d in g castin g s): 3 mm < 3 mm

a b

M ea n co atin g th ick n ess (m in im u m )b m

45 35 20

55 45 25

45 35

55 45

S ee 3 .8 . S ee 3 .9 .

NOTE 3 Table 3 is for general use; fastener coating standards and individual product standards may have different requirements; see also annex A.2, g).

T h e lo c a l c o a tin g th ic k n e s s in ta b le 3 s h a ll o n ly b e d e te r m in e d in r e la tio n to r e f e r e n c e a r e a s s e le c te d in a c c o r d a n c ew ith 6 .2. 3 .

6.3 Renovation

T h e to ta l u n c o a te d a r e a s f o r r e n o v a tio n b y th e g a lv a n iz e rs h a ll n o t e x c e e d 0 ,5 % o f th e to ta l s u rf a c e a r e a o f a c o m p o n e n t.E a c h u n c o a te d a r e a f o r r e n o v a tio n s h a ll n o t e x c e e d 1 0 c m 2 . If u n c o a te d a r e a s a r e la r g e r , th e a r tic le c o n ta in in g s u c h a r e a s s h a ll b e r e g a lv a n iz e du n le s s o th e r w is e a g r e e d b e tw e e n th e p u r c h a s e r a n d th e g a lv a n iz e r . R e n o v a tio n s h a ll b e b y z in c th e r m a l s p r a y in g ( E N 2 2 0 6 3 is r e le v a n t) o r b y a s u ita b le z in c r ic h p a in t w ith in th e p r a c tic a l lim its o f s u c h s y s te m s . T h e u s e o f a z in c a llo y s tic k ( s e e a n n e x C .5 ) is a ls o p o s s ib le . T h e p u r c h a s e r o r e n d-u s e r s h a ll b e a d v is e d b y th e g a lv a n iz e ro f th e m e th o d o f r e n o v a tio n . W h e r e a s p e c ia l r e q u ir e m e n tis a d v is e d b y th e p u r c h a s e r ,e .g . a p a in t c o a tin g to b e a p p lie d s u b s e q u e n tly ,th e p r o p o s e d r e n o v a tio n p r o c e d u r e s h a ll b e a d v is e d in a d v a n c e to th e p u r c h a s e r b y th e g a lv a n iz e r . T h e tr e a tm e n ts h a ll in c lu d e r e m o v a l o f a n y s c a le , c le a n in g a n d a n y n e c e s s a r y p r e tr e a tm e n tto e n s u r e a d h e s io n . T h e c o a tin g th ic k n e s s o n th e r e n o v a te d a r e a s s h a ll b e a m in im u m o f 3 0 m m o r e th a n th e lo c a l c o a tin g th ic k n e s s r e q u ir e m e n tin ta b le 2 o r 3 f o r th e r e le v a n t h o t d ip g a lv a n iz e d c o a tin g u n le s s th e p u r c h a s e r a d v is e s th e g a lv a n iz e ro th e r w is e e .g . w h e n th e g a lv a n iz e d s u rf a c e is to b e o v e r c o a te d a n d th e th ic k n e s s f o r r e n o v a te d a r e as is to b e th e s a m e a s f o r th e h o t d ip g a lv a n iz e d c o a tin g . T h e c o a tin g o n th e r e n o v a te d a r e a s s h a ll b e c a p a b le o f g iv in g s a c r if ic ia lp r o te c tio n to th e ste e l to w h ic h it is a p p li e d .

NOTE See also C.5 for advice on repair of damaged areas.

6.4 Adhesion

N o s u ita b le I S O S ta n d a r d s c u r r e n tly e x is t f o r te s tin g th e a d h e s io n o f h o t d ip g a lv a n iz e d c o a tin g s o n f a b r ic a te d ir o n a n d s te e l a r tic le s . S e e a ls o C .6 .

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A d h e s io n b e tw e e n z in c a n d b a s is m e ta l g e n e r a lly d o e s n o t n e e d to b e te s te d a s a d e q ua te b o n d in g is c h a r a c te r is tico f th e g a lv a n iz in gp r o c e s s a n d th e c o a te d w o r k s h o u ld b e a b le to w ith s ta n d -- w ith o u t p e e lin g o r fla k in g -- h a n d lin g c o n s is te n tw ith th e n a tu r e a n d th ic k n e s s o f th e c o a tin g a n d th e n o r m a l u s e o f th e a r tic le . I n g e n e r a l, th ic k e r c o a tin g s r e q u ir e m o r e c a r e f u l h a n d lin g th a n th in n e r c o a tin g s . B e n d in g o r f o r m in g a f te r h o t d ip g a lv a n iz in g a r e n o t c o n s id e r e d to b e n o r m a l h a n d lin g . S h o u ld it b e n e c e s s a r y to te s t th e a d h e s io n ,e .g . in th e c a s e o f w o r k p ie c e sth a t a r e to b e s u b je c te d to h ig h m e c h a n ic a ls tr e s se s , a n y te s t s h a ll o n ly b e o n s ig n if ic a n ts u rf a c e s , i.e . in a r e a s in w h ic h g o o d a d h e s io n is im p o r ta n tf o r th e p r o p o s e d a p p lic a tio n . A c r o s s-h a tc h te s t w ill g iv e s o m e g u id a n c e o n th e m e c h a n ic a lp r o p e r tie s o f th e c o a tin g b u t in s o m e c a s es m a y b e m o r e d e m a n d in g th a n th e a p p lic a tio n r e q u ir e s . O th e r im p in g e m e n tte s ts a n d c u ttin g te s ts m a y a ls o b e d e v e lo p e d f o r h o t d ip g a lv a n iz e d c o a tin g s a n d w ill b e f u rth e r c o n s id e r e d f o r p o s s ib le e v e n tu a l is s u e a s a s e p a r a te d o c u m e n t.

6.5 Acceptance criteria

W h e n te s te d in a c c o r d a n c e w ith 6 .2 .2 f o r th e a p p r o p r ia ten u m b e r o f r e f e r e n c e a r e a s g iv e n in 6 .2 .3 , th e c o a tin g th ic k n e s s s h a ll b e n o t le s s th a n th e v a lu e s g iv e n in ta b le 2 o r ta b le 3 a s a p p r o p r ia te .E x c e p t in th e c a s e o f d is p u te , th e n o n-d e s tr u c tiv ete s t s h a ll b e u s e d u n le s s th e p u r c h a s e r s p e c if ic a lly a c c e p ts th a t h is a r tic le s m a y b e c u t f o r m a s s lo s s d e te r m in a tio n s .W h e r e a r tic le s in c lu d e a n u m b e r o f d iff e r e n t th ic k n e s s e so f s te e l, e a c h th ic k n e s s r a n g e s h a ll b e r e g a r d e d a s a s e p a r a te a r tic le a n d th e r e le v a n t v a lu e s in ta b le s 2 a n d 3 , a s a p p r o p r ia te ,s h a ll a p p ly . If th e th ic k n e s s o f c o a tin g o n a c o n tr o l s a m p le d o e s n o t c o n f o r m to th e s e r e q u ir e m e n ts ,tw ic e th e o r ig in a l n u m b e r o f a rtic le s (o r a ll th e a r tic le s if th a t is th e le s s e r n u m b e r ) s h a ll b e ta k e n fr o m th e lo t a n d te s te d . I f th is la r g e r c o n tr o l s a m p le p a s s e s , the w h o le in s p e c tio n lo t s h a ll b e a c c e p te d . If th e la r g e r c o n tr o l s a m p le d o e s n o t p a s s , th e a r tic le s th a t d o n o t c o n f o r m to th e r e q u ir e me n ts s h a ll e ith e r b e d is c a r d e d o r th e p u r c h a s e r m a y a u tho r iz e th e m to b e r e g a lv a n iz e d .

7 Certificate of compliance

W h e n r e q u ir e d , th e h o t d ip g a lv a n iz e rs h a ll p r o v id e a c e r tif ic a te o f c o m p lia n c e w ith th e r e q u ir e m e n tso f th is s ta n d a r d (I S O 1 0 4 7 4 is r e le v a n t) .

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Annex A (normative) Information to be supplied by the purchaser to the hot dip galvanizer

A.1 Essential information

T h e n u m b e r o f th is s ta n d a r d ,i.e . E N I S O 1 4 6 1 , s h a ll b e s u p p lie d b y th e p u r c h a s e r to th e h o t d ip g a lv a n iz e r .

A.2 Additional information

T h e f o llo w in g in f o r m a tio n m a y b e r e q u ir e d f o r p a r tic u la r p u r p o s e s a n d , if s o , s h a ll b e s u p p lie d o r s p e c if ie d ,a s a p p lic a b le ,b y th e p u rch aser. T h e g a lv a n iz e rs h a ll o n r e q u e s t p r o v id e a n y r e le v a n t in f o r m a tio na v a ila b le to h im in c lu d in g th e m eth o d o f r e n o v a tio n o f u n c o a te d a r e a s . a) b) c) d) e) f) g) h) i) j) T h e c o m p o s itio na n d a n y p r o p e r tie s o f th e b a s is m e ta l ( s e e a n n e x C ) th a t m a y a ff e c t h o t d ip g a lv a n iz in g ; a n id e n tif ic a tio no f s ig n if ic a n ts u rf a c e s , f o r e x a m p le b y d r a w in g s o r b y th e p r o v is io n o f s u ita b ly m a r k e d s a m p le s ; a d r a w in g o r o th e r m e a n s o f id e n tif y in g w h e r e s u rf a c e u n e v e n n e s s ,f o r e x a m p le r o u n d d r o p s o r c o n ta c t m a r k s , w ill m a k e th e c o a te d a r tic le u n a c c e p ta b lef o r its in te n d e d p u r p o s e ; th e p u r c h a s e r s h a ll d is c u s s w ith th e g a lv a n iz e rth e w a y to d e a l w ith s u c h p r o b le m s ; a s a m p le o r o th e r m e a n s o f s h o w in g th e r e q u ir e d f in is h ; a n y s p e c ia l p r e tr e a tm e n tr e q u ir e m e n ts ; a n y s p e c ia l th ic k n e s s o f c o a tin g ( s e e 6 .2 .1 , n o te s 2 a n d 3 to 6 .2 .3 a n d a n n e x C ; th e n e e d f o r , o r th e a c c e p ta b ilityo f, a c e n tr if u g e d c o a tin g th a t is to m e e t th e r e q u ir e m e n tso f ta b le 3 in s te a d o f ta b le 2 ; a n y a f te r-tr e a tm e n ts o r o v e r c o a tin g to b e g iv e n to th e g a lv a n iz e d c o a tin g ( s e e 6 .3 , C .4 a n d C .5 ) ; in s p e c tio n a rr a n g e m e n ts( s e e c la u s e 5 ) ; w h e th e r a c e r tif ic a te o f c o m p lia n c eis r e q u ir e d in a c c o r d a n c ew ith I S O 1 0 4 7 4 .

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Annex B (normative) Safety and process requirements

I n th e a b s e n c e o f n a tio n a l s a f e ty a n d h e a lth r e g u la tio n sc o v e r in g v e n tin g a n d d r a in in g o f c a v itie s , th e p u rc h a s e r s h a ll p r o v id e m e a n s f o r h a n d lin g th e w o r k a n d h o le s o r o th e r m e a n s f o r v e n tin g a n d d r a in in g e n c lo s e d c a v itie s o r g iv e c o n s e n t f o r th e g a lv a n iz e rto p r o v id e s u c h v e n ts a n d d r a in s . T h e s e a r e e s s e n tia l f o r b o th s a f e ty a n d p r o c e s s r e a s o n s . W A R N IN G

NOTE

It is e s s e n tia l to a v o id e n c lo s e d c a v itie s a s th e s e c a n c a u s e e x p lo s io n s d u r in g h o t d ip g a lv a n iz in g .

Further information on venting and draining is given in EN ISO 14713.

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Annex C (informative) Properties of the articles to be coated that affect the results of hot dip galvanizing

C.1 Basis metal

C.1.1 Composition

U n a llo y e d c a r b o n s te e l, lo w-a llo y s te e ls a n d g r e y a n d m a lle a b le c a s t ir o n a r e in g e n e r a l s u ita b le f o r h o t d ip g a lv an iz in g . W h ere o th e r f e rr o u s m e ta ls a r e to b e g a lv a n iz e d ,a d e q u a te in f o r m a tio no r s a m p le s s h o u ld b e p r o v id e d b y th e p u r c h a s e rf o r th e g a lv a n iz e rto d e c id e w h e th e r th e s e s te e ls c a n b e s a tis f a c to r ilyg a lv a n iz e d .S u lf u r-c o n ta in in g f r e e-c u ttin g s te e ls a r e n o r m ally u n s u ita b le .

C.1.2 Surface condition

T h e s u rf a c e o f th e b a s is m e ta l s h o u ld b e c le a n b e f o r e d ip p in g in to th e m o lte n z in c . P ic k lin g in a c id is th e r e c o m m e n d e dm e th o d o f c le a n in g th e s u rf a c e . E x c e s s iv e p ic k lin g s h o u ld b e a v o id e d .S u rf a c e c o n ta m in a n tsth a t c a n n o t b e r e m o v e d b y p ic k lin g , e .g . c a r b o n f ilm s ( s u c h a s r o llin g o il r e s id u e s ) ,o il, g r e a s e , p a in t, w e ld in g s la g a n d s im ila r im p u ritie s s h o u ld b e r e m o v e d p r io r to p ic k lin g . T h e r e s p o n s ib ilityf o r r e m o v a l o f s u c h im p u r itie s s h o u ld b e a g r e e d b e tw e e n th e g a lv a n iz e ra n d th e p u r c h a s e r . C a s tin g s s h o u ld b e a s f r e e a s p o s s ib le f r o m s u rf a c e p o r o s ity a n d s h r in k a g e h o le s a n d s h o u ld b e c le a n e d b y g r it b la s tin g , e le c tr o ly ticp ic k lin g o r b y o th e r m e th o d s s p e c ia lly s u ita b le f o r c a s tin g s .

C.1.3 The influence of steel surface roughness on the hot dip galvanized coating thickness

T h e s u rf a c e r o u g h n e s s o f th e s te e l s u rf a c e h a s a n in flu e n c e o n th e th ic k n e s s a n d th e s tr u c tu r e o f th e c o a tin g . T h e e f f e c t o f s u rf a c e u n e v e n n e s so f th e b a s is m e ta l g e n e r a lly r e m a in s v is ib le a f te r g a lv a n iz in g . A r o u g h s te e l s u r f a c e a s o b ta in e d b y g r it b la s tin g , c o a r s e g r in d in g ,e tc ., p r io r to p ic k lin g g iv e s a th ic k e r c o a tin g th a n a s u r f a c e th a t is o b ta in e d b y p ic k lin g a lo n e . F la m e-c u ttin g c h a n g e s th e s te e l c o m p o s itio na n d s tr u c tu r e in th e f la m e-c u t z o n e , s o th a t th e c o a tin g th ic k n e s s e sg iv e n in 6 .2 , a n d ta b le s 2 a n d 3 , a r e m o r e d iff ic u lt to o b ta in . I n o r d e r to o b ta in th e s e c o a tin g th ic k n e s s e sr e lia b ly , f la m e c u t s u rf a c e s s ho u ld b e g r o u n d o ff b y th e f a b r ic a to r .

C.1.4 The influence of reactive elements in the basis metal on the zinc coating thickness and appearance

M o s t s te e ls c a n b e s a tis f a c to r ilyh o t d ip g a lv a n iz e d .H o w e v e r ,s e v e r a l r e a c tiv e e le m e n ts in th e s te e l c a n a ff e c t h o t d ip g a lv a n iz in g ,f o r e x a m p le , s ilic o n (S i) a n d p h o s p h o r u s(P ). T h e s te e l s u rf a c e c o m p o s itio n h a s a n in f lu e n c e o n th e th ic k n e s s a n d a p p e a r a n c e o f th e z in c c o a tin g . A t c e r ta in c o m p o s itio n le v e ls , s ilic o n a n d p h o s p h o r u s c a n g iv e u n e v e n , b r ig h t a n d /o r d u ll d a r k g r e y c o a tin g s , w h ic h m a y b e b rittle a n d th ic k . F r e n c h S ta n d ar d N F A 3 5-5 0 3 :1 9 9 4 g iv e s s o m e g u id a n c e o n b e h a v io u r a n d o n s te e ls p o s s ib ly s u ita b le f o r h o t d ip g a lv a n iz in g b u t r e s e a r c h o n th e in f lu e n c e o f s p e c if ic e le m e n ts in th e s te e ls is s till in pr o g r e s s ( s ee a lso E N I S O 1 4 7 1 3 ) .

C.1.5 Stresses in the basis metal

S o m e s tr e s s e s in th e b a s is m e ta l w ill b e r e lie v e d d u r in g th e h o t d ip g a lv a n iz in g p r o c e s s a n d th is m a y c a u s e d e f o r m a tio no f th e c o a te d a r tic le . S te e l a r tic le s th a t a r e c o ld w o r k e d ( e .g . b e n t) m a y b e c o m e e m b r ittle d ,d e p e n d in g o n th e ty p e o f s te e l a n d th e d e g r e e o f c o ld w o r k . A s h o t d ip g a lv a n iz in gis a f o r m o f h e a t tr e a tm e n t,it m a y a c c e le r a te th e o n s e t o f s tr a in a g e e m b r ittle m e n tif th e s te e l is a lr e a d y s u s c e p tib le .T o a v o id r is k o f e m b r ittle m e n t,a s te e l w h ic h is n o t s u s c e p tib le to s tr a in a g e-h a r d e n in g c an b e u s e d . I f a s te e l is th o u g h t to b e s u s c e p tib leto s tr a in a g e e m b r ittle m e n t,a v o id s e v e r e c o ld w o r k if p o s s ib le . If s e v e r e c o ld w o r k c a n n o t b e a v o id e d , s tr e s s s h o u ld b e r e lie v e d b y h e a t-tr e a tm e n t b e f o r e p ic k lin g a n d h o t d ip g a lv a n iz in g .

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NOTE Susceptibility to strain age-hardening and the consequent risk of embrittlement is principally caused by the nitrogen content of the steel, which, in turn, is largely dependent on the steelmaking process. As a general guide, the problem does not occur in modern steelmaking practice. Aluminium-killed steels are the least susceptible to strain age-hardening.

H e a t tr e a te d o r c o ld w o r k e d s te e ls m a y b e te m p e r e d b y th e h e a t in th e h o t d ip g a lv a n iz in g b a th a n d lo s e s o m e o f a n y in c r e a s e d s tr e n g th o b ta in e d b y h e a t tr e a tm e n t o r c o ld w o r k in g . H a r d e n e d a n d /o r h ig h te n s ile s te e ls m a y c o n ta in in te r n a l s tr e s s e s o f s u c h a m a g n itu d e th a t p ic k lin g a n d h o t d ip g a lv a n iz in g m a y in c r e a s e th e r is k o f c r a c k in g o f th e s te e l in th e h o t d ip g a lv a n iz in g b a th . T h e r is k o f c r ac k in g m a y b e r e d u c e d b y s tr e s s r e liev in g b e f o r e p ic k lin g a n d h o t d ip g a lv a n iz in g ,b u t s p e c ia lis t a d v ic e s h o u ld b e s o u g h t w h e n h o t d ip g a lv a n iz in g s u c h s te e ls . S tr u c tu r a ls te e ls a r e n o t n o r m a lly e m b r ittle d b y th e a b s o r p tio n o f h y d r o g e n d u r in g p ic k lin g , a n d h y d r o g e n r e m a in in g ( if a n y ) d o e s n o t in g e n e r a l a f f e c t s tr u c tu r a ls te e ls . W ith s tr u c tu r a ls te e ls , a b s o r b e d h y d r o g e n is d is c h a r g e d d u r in g h o t d ip g a lv a n iz in g . If s te e ls a r e h a r d e r th a n a p p r o x im a te ly3 4 H R C , 3 4 0 H V o r 3 2 5 H B ( s e e I S O 4 9 6 4 ) , c a r e is n e c e s s a ry to m in im iz e h y d r o g e n a b s o r b tio n d u r in g s u rf a c e p r e p a r a tio n . W h e r e e x p e r ie n c e s h o w s th a t s p e c if ic s te e ls , p r e tr e a tm e n ts ,th e r m a l a n d m e c h a n ic a ltr e a tm e n ts ,p ic k lin g a n d h o t d ip g a lv a n iz in gp r o c e d u r e sh a v e b e e n s a tis f a c to r y ,th e in f o r m a tio ns e r v e s a s a n in d ic a tio n th a t a n e m b r ittle m e n tp r o b le m is n o t to b e e x p e c te d f o r th e s a m e c o m b in a tio no f s te e ls , p r e tr e a tm e n ts ,th e r m a l a n d m e c h a n ic a ltr e a tm e n ts a n d g a lv a n iz in g p r o c e d u r e s .

C.1.6 Large objects or thick steels

L o n g e r h a n d lin g tim e s a r e n e e d e d in th e g a lv a n iz in g b a th f o r la r g e a r tic le s a n d th is , a s w e ll a s th e m e ta llu r g ic a lp r o p e r tie s of th ic k s te e ls d u e to n o r m a l m a n u f a c tu r in gm e th o d s ,m a y c a u s e th ic k c o a tin g s to f o r m .

C.1.7 Hot dip galvanizing practice

V e r y s m a ll a m o u n ts o f a llo y in g e le m e n ts m a y b e a d d e d to th e g a lv a n iz in g b a th ( s u b je c t to th e r e q u ir e m e n tso f 4 .1 ) a s p a r t o f th e p r o c e s s in g te c h n iq u e o f g a lv a n iz e r s ,n o ta b ly to r e d u c e th e a d v e r s e e f f e c ts o f s ilic o n a n d p h o s p h o r u s( s e e C .1 .4 ) o r to m o d if y th e s u r f a c e a p p e a r a n c e o f th e g a lv a n iz e d c o a tin g . S u c h p o s s ib le a d d itio n s d o n o t a f f e c t th e g e n e r a l q u a lity o r lo n g-te r m c o r r o s io n r e s is ta n c e o f th e g a lv a n iz e d c o a tin g o r th e m e c h a n ic a lp r o p e r tie s o f th e g a lv a n iz e d p r o d u c t a n d a r e n o t r e q u ir e d to be s ta n d a r d iz e d .

C.2 Design

C.2.1 General

T h e d es ig n o f th e a r tic le s to b e h o t d ip g a lv a n iz e d s h o u ld b e a p p r o p r ia tef o r th e p r o c e s s o f h o t d ip g a lv a n iz in g .T h e p u r c h a s e r s h o u ld s e e k th e a d v ic e o f th e h o t d ip g a lv a n iz e rb e f o r e d e s ig n in g o r m a k in g a p r o d u c t th a t is s u b s e q u e n tlyto b e h o t d ip g a lv a n iz e d ,as it m a y b e n e c e s s a r y to a d a p t th e c o n s tr u c tio no f th e a r tic le f o r th e h o t d ip g a lv a n iz in g p r o c e s s ( s e e a n n e x B ).

C.2.2 Dimensional tolerances on mating threads

T h e r e a r e tw o d if f e r e n t w a y s to m a k e a llo w a n c e s-- e ith e r b y u n d e r c u ttin gth e m a le th r e a d o r b y o v e r c u ttin g th e f e m a le th r e a d . F o r f a s te n e r s ,s e e th e r e le v a n t f a s te n e r d o c u m e n ts .I n g e n e r a l, a llo w a n c e ss h o u ld b e m a d e o n m a tin g th r e a d s to a c c o m m o d a te th e th ic k n e s s o f th e c o a tin g . T h e r e a r e n o c o a tin g r e q u ir e m e n tsf o r in te r n a l th r e a d s w h ic h a r e th re a d e d o r r e-th r e a d e d a f te r h o t d ip g a lv a n iz in g . T h e c o a tin g th ic k n e s s e sg iv e n f o r th r e a d e d c o m p o n e n tsr e la te to c o m p o n e n tsth a t r e q u ir e c e n tr if u g in gim m e d ia te lya f te r g a lv a n iz in gto e n s u r e c le a n th r e a d s .

NOTE 1 The coating on external screw threads galvanically protects the internal threads in an assembly. Therefore, no zinc coating is required on the internal threads. NOTE 2 The coated threads should have strength adequate to meet the design requirement.

C.2.3 Effect of process heat

M a te r ia ls th a t w ill b e a d v e r s e ly a f f e c te d b y th e h e a t o f th e h o t d ip g a lv a n iz in g b a th s h o u ld n o t b e h o t d ip g a lv a n iz e d .

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C.3 The hot dip galvanizing bath

Where there is a special requirement, levels of additions or impurities in the bath or in the coating may be specified by the purchaser. In particular, where boilers (i.e., tanks and cylinders) are hot dip galvanized and specified for use with hot dip galvanized tubes in potable water systems, the purchaser may require that their coating conforms to the same compositional requirements as for tube in EN 10240.

C.4 After-treatment

N o r m a lly a r tic le s s h o u ld n o t b e s ta c k e d to g e th e r w h ile h o t o r w e t. S m a ll a rtic le s d ip p e d in b u lk in b a s k e ts o r o n jig s m a y b e c e n tr if u g e d im m e d ia te lya f te r w ith d r a w a lfr o m th e z in c to r e m o v e a n y s u r p lu s m e ta l ( s e e A .2 , g )) . T o r e ta r d th e p o s s ib le f o r m a tio n o f w e t s to r a g e s ta in o n th e s u rf a c e , a r tic le s th a t a r e n o t to b e p a in te d c a n b e g iv e n a s u itable s u rf a c e tr e a tm e n ta f te r h o t d ip g a lv a n iz in g . If th e a r tic le s a r e to b e p a in te d o r p o w d e r c o a te d a f te r g a lv a n iz in g ,th e p u r c h a s e r s h o u ld in f o r m th e g a lv a n iz e rb e f o r e th e a rt ic le is g a lv a n iz e d .

C.5 Renovation of uncoated or damaged areas

W h e r e th e h o t d ip g a lv a n iz e ris a d v is e d th a t a n o v e r c o a tin g is to b e s p e c if ie d ,th e p u r c h a s e r s h o u ld b e in f o r m e d th a t r e p a ir o f d a m a g e d a r e a s is p e r m itte d a n d in f o r m e d a b o u t th e p r o p o s e d m e th o d s a n d m a te r ia ls u s e d f o r r e p a ir o f u n c o a te d o r d a m a g e d a r e a s . P u r c h a s e r s a n d a p p lic a to r so f s u b s e q u e n tc o a tin g s s h o u ld a s s u r e th e m s e lv e sth a t s u c h a s u b s e q u e n tc o a tin g s y s te m is c o m p a tib le w ith th e m e th o d s a n d m a te r ia ls u s e d . 6 .3 c o v e r s th e th ic k n e s s o f c o a tin g r e q u ir e d b y th e r e n o v a tio n p r o c e d u r e a t a c c e p ta n c e in s p e c tio n .T h e s a m e te c h n iq u e s a r e u s e d f o r o n-s ite r e p a ir s to d a m a g e d a r e a s . T h e s iz e o f a r e a s a c c e p ta b le f o r tr e a tm e n t s h o u ld b e s im ila r to th o s e a c c e p ta b le f o r u n c o a te d a r e a s .

C.6 Adhesion testing

A n y p r o p o s e d te s t s h o u ld b e a g r e e d a n d r e la te d to th e lik e ly c o n s tr a in ts in s e r v ic e .

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Annex D (informative) Determination of thickness

D.1 General

T h e m o s t g e n e r a l n o n-d e s tr u c tiv e m e th o d o f d e te r m in in gth ic k n e s s is th e m a g n e tic m e th o d ( s e e 6 .2 a n d E N I S O 2 1 7 8 ) . O th e r m e th o d s m a y h o w e v e r b e u s e d (s e e , f o r e x a m p le , I S O 2 8 0 8 , th e e le c tr o m a g ne tic m e th o d ) . D e s tr u c tiv em e th o d s in c lu d e th e d e te r m in a tio no f m a s s p e r a r e a b y th e g r a v im e tr icm e th o d c o n v e r te d to th ic k n e s s ( m ic r o n s )b y d iv id in g th e g r a m s p e r s q u a r e m e tr e f ig u r e b y 7 ,2 ( s e e D .3 ) , th e c o u lo m e tr icm e th o d ( s e e E N I S O 2 1 7 7 ) , a n d th e m ic r os c o p ic c r o s s-s e c tio n m e th o d ( s e e D .2 ) . C a r e f u l s tu d y s h o u ld b e m a d e o f th e d e f in itio n sin c la u s e 3 ; in p a r tic u la r ,th e r e la tio n s h ip b e tw e e n lo c a l a n d m e a n th ic k n e s s s h o u ld b e g iv e n w h e n th e m a g n e tic m e th o d is u s e d a n d th e r e s u lts a r e c o m p a r e d w ith th o s e fr o m th e g r a v im e tr icte s t o f E N I S O 1 4 6 0 u s e d in c a s e s o f d is p u te .

D.2 Microscopic cross-section method

T h e m ic r o s c o p ic c r o s s-s e c tio n m e th o d ( s e e E N I S O 1 4 6 3 ) m a y a ls o b e u s e d . H o w e v e r , it is in a p p r o p r ia tef o r r o u tin e u s e o n la r g e o r e x p e n s iv e a r tic le s a s it is a d e s tr u c tiv e m e th o d a n d r e la te s o n ly to a s in g le lin e . It g iv e s a s im p le v is u a l p ic tu r e of th e lin e e x a m in e d .

D.3 Calculation of thickness from mass per area (reference method)

T h e E N I S O 1 4 6 0 m e th o d g iv e s th e c o a tin g m a s s p e r u n it a r e a e x p r es s e d in g r a m s p e r s q u a r e m e tr e . T h is c a n b e c o n v e r te d to lo c a l th ic k n e s s ( m ic r o n s ) b y d iv id in g b y th e n o m in a l d e n s ity o f th e c o a tin g ( 7 ,2 g /c m 3 ) . T h e a p p r o x im a tec o a tin g m a s s e s c o r r e s p o n d in gto th e th ic k n e s s e sg iv e n in ta b le s 2 a n d 3 a r e g iv e n in ta b le s D .1 a n d D .2 . T ab le D .1 -- C o atin g m in im u m m asses (related to th ick n esses) on sa m p les th at a re n o t cen trifu g ed a A rticle an d its th ick n ess L o cal co atin g (m in im u m) b g /m 2 S te e l S te e l S te e l 6 mm 505 395 325 2 50 505 4 30 m 70 55 45 35 70 60 M ea n co atin g (m in im u m )c g /m 2 610 505 395 3 25 575 5 05 m 85 70 55 45 80 70

3 m m to < 6 m m 1 ,5 m m to < 3 m m

S te e l < 1 ,5 m m C a s tin g s 6 m m C a s tin gs < 6 m m

a b c

S ee n o te 2 to 6 .2 .3 . S ee 3 .1 0 . S ee 3 .1 1 .

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T ab le D .2 -- C o atin g m in im u m m asses (related to th ick n esses) on sa m p les th at a re cen trifu g ed a A rticle an d its th ick n ess L o cal co atin g (m in im u m ) b g /m 2 A rticles w ith th read s: 2 0 m m d ia m e te r 6 m m to < 2 0 m m d ia m e te r < 6 m m d ia m e te r O th er a rticles (in clu d in g castin g s): 3 mm < 3 mm

a b c

M ea n co atin g (m in im u m ) c g /m 2 m

m

325 250 145

45 35 20

395 325 180

55 45 25

325 250

45 35

395 325

55 45

S ee n o te 3 to 6 .2 .3 . S ee 3 .1 0 . S ee 3 .1 1 .

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Annex E (informative) Bibliography

E N I S O 1 4 6 3 :1 9 9 4, M etallic and oxide coatings -- M easurement of coating thickness -- M icroscopical method (ISO 1463:1982). E N I S O 2 1 7 7 :1 9 9 4, M etallic coatings -- M easurement of coating thickness -- Coulometric method by anodic dissolution (ISO 2177:1985). I S O 2 8 0 8 :1 9 9 7, Paints and varnishes -- Determination of film thickness. I S O 4 9 6 4 :1 9 8 4, Steel -- Hardness conversions. E N IS O 1 2 9 4 4-4 , Paints and varnishes -- Corrosion protection of steel structures by protective paint systems -- Part 4: Types of surface and surface preparation (ISO 12944-4:1998). E N IS O 1 2 9 4 4-5 , Paints and varnishes -- Corrosion protection of steel structures by protective paint systems -- Part 5: Protective paint systems (ISO 12944-5:1998). E N I S O 1 4 7 1 3, Protection against corrosion of iron and steel in structures -- Zinc and aluminium coatings -- Guidelines (ISO 14713:1999). E N 1 0 2 40 Internal and/or external protective coatings for steel tubes -- Specification for hot dip galvanized coatings applied in automatic plants. N F A 3 5-5 0 3 :1 9 9 4 ,Iron and steel -- Steel for hot dip galvanizing.

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