Metallic and other inorganic coatings - Electrodeposited coatings of chromium for engineering purposes (ISO 6158:2018)

This document specifies requirements for electroplated coatings of metallic chromium, with or without undercoats, on ferrous and non-ferrous metals for engineering purposes. The coating designation provides a means of specifying the thickness of chromium appropriate for typical engineering applications.

Metallische und andere anorganische Überzüge - Galvanische Chromüberzüge für technische Zwecke (ISO 6158:2018)

Revêtements métalliques et autres revêtements inorganiques - Dépôts électrolytiques de chrome pour usages industriels (ISO 6158:2018)

Le présent document spécifie les exigences relatives aux dépôts électrolytiques de chrome métallique, avec ou sans sous-couches, sur des métaux de base ferreux et non ferreux pour usages industriels. La désignation des revêtements permet de spécifier l'épaisseur de chrome appropriée pour les applications industrielles courantes.

Kovinske in druge anorganske prevleke - Galvanske prevleke kroma za tehnično uporabo (ISO 6158:2018)

Ta dokument določa zahteve za galvanske prevleke kovinskega kroma, s spodnjim premazom ali brez, na železnih in neželeznih kovinah za tehnično uporabo. Oznaka prevleke omogoča način določanja debeline kroma, ki je primerna za običajno tehnično uporabo.

General Information

Status
Published
Publication Date
11-Dec-2018
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
12-Dec-2018
Completion Date
12-Dec-2018

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SLOVENSKI STANDARD
SIST EN ISO 6158:2019
01-marec-2019
1DGRPHãþD
SIST EN ISO 6158:2011
.RYLQVNHLQGUXJHDQRUJDQVNHSUHYOHNH*DOYDQVNHSUHYOHNHNURPD]DWHKQLþQR
XSRUDER ,62

Metallic and other inorganic coatings - Electrodeposited coatings of chromium for

engineering purposes (ISO 6158:2018)
Metallische und andere anorganische Überzüge - Galvanische Chromüberzüge für
technische Zwecke (ISO 6158:2018)

Revêtements métalliques et autres revêtements inorganiques - Dépôts électrolytiques de

chrome pour usages industriels (ISO 6158:2018)
Ta slovenski standard je istoveten z: EN ISO 6158:2018
ICS:
25.220.40 Kovinske prevleke Metallic coatings
SIST EN ISO 6158:2019 en

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

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SIST EN ISO 6158:2019
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SIST EN ISO 6158:2019
EN ISO 6158
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2018
EUROPÄISCHE NORM
ICS 25.220.40 Supersedes EN ISO 6158:2011
English Version
Metallic and other inorganic coatings - Electrodeposited
coatings of chromium for engineering purposes (ISO
6158:2018)

Revêtements métalliques et autres revêtements Metallische und andere anorganische Überzüge -

inorganiques - Dépôts électrolytiques de chrome pour Galvanische Chromüberzüge für technische Zwecke

usages industriels (ISO 6158:2018) (ISO 6158:2018)
This European Standard was approved by CEN on 12 November 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 6158:2018 E

worldwide for CEN national Members.
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SIST EN ISO 6158:2019
EN ISO 6158:2018 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 6158:2019
EN ISO 6158:2018 (E)
European foreword

This document (EN ISO 6158:2018) has been prepared by Technical Committee ISO/TC 107 "Metallic

and other inorganic coatings" in collaboration with Technical Committee CEN/TC 262 “Metallic and

other inorganic coatings, including for corrosion protection and corrosion testing of metals and alloys”

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 June 2019, and conflicting national standards shall be

withdrawn at the latest by June 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 6158:2011.

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 6158:2018 has been approved by CEN as EN ISO 6158:2018 without any modification.

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SIST EN ISO 6158:2019
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SIST EN ISO 6158:2019
INTERNATIONAL ISO
STANDARD 6158
Fourth edition
2018-11
Metallic and other inorganic
coatings — Electrodeposited coatings
of chromium for engineering purposes
Revêtements métalliques et autres revêtements inorganiques —
Dépôts électrolytiques de chrome pour usages industriels
Reference number
ISO 6158:2018(E)
ISO 2018
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SIST EN ISO 6158:2019
ISO 6158:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© 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
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SIST EN ISO 6158:2019
ISO 6158:2018(E)
Contents Page

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

Introduction ..................................................................................................................................................................................................................................v

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

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

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

4 Information to be supplied by the purchaser to the processor ........................................................................... 2

5 Designation ................................................................................................................................................................................................................ 3

5.1 General ........................................................................................................................................................................................................... 3

5.2 Designation specification ............................................................................................................................................................... 3

5.3 Designation of basis metal ............................................................................................................................................................ 3

5.4 Designation of heat treatment requirements ............................................................................................................... 4

5.5 Designation of type and thickness of metal coating ............................................................................................... 4

5.6 Examples of designations .............................................................................................................................................................. 5

6 Requirements .......................................................................................................................................................................................................... 5

6.1 Special test specimens ...................................................................................................................................................................... 5

6.2 Appearance ................................................................................................................................................................................................ 5

6.3 Surface finish ............................................................................................................................................................................................ 6

6.4 Thickness ..................................................................................................................................................................................................... 6

6.5 Hardness ....................................................................................................................................................................................................... 6

6.6 Adhesion ....................................................................................................................................................................................................... 6

6.7 Porosity ......................................................................................................................................................................................................... 7

6.8 Stress relief heat treatment prior to coating ................................................................................................................. 7

6.9 Hydrogen-embrittlement-relief heat treatment ........................................................................................................ 7

6.10 Peening of metal parts ...................................................................................................................................................................... 7

6.11 Use of undercoats ................................................................................................................................................................................. 8

6.12 Stripping ....................................................................................................................................................................................................... 8

6.13 Corrosion resistance/multilayer chromium plating .............................................................................................. 8

6.14 Surface roughness of electroplated metallic chromium coating .................................................................. 8

7 Sampling ........................................................................................................................................................................................................................ 8

Annex A (informative) Typical thickness of metallic chromium coatings specified in

engineering applications ............................................................................................................................................................................. 9

Annex B (normative) Thickness test methods for electroplated metallic chromium and

other metallic coatings ...............................................................................................................................................................................10

Annex C (normative) Determination of cracks and pores in metallic chromium coatings.......................11

Annex D (normative) Classification of different quality/grate of roughness of

electrodeposited metallic chromium coatings ..................................................................................................................12

Bibliography .............................................................................................................................................................................................................................13

© ISO 2018 – All rights reserved iii
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SIST EN ISO 6158:2019
ISO 6158:2018(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 of 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 www .iso

.org/iso/foreword .html.

This document was prepared by Technical Committee ISO/TC 107, Metallic and other inorganic coatings,

Subcommittee SC 3, Electrodeposited coatings and related finishes.

This fourth edition cancels and replaces the third edition (ISO 6158:2011), which has been technically

revised. The main changes compared with the previous edition are as follows:
— the Scope has been corrected;

— in Clause 4, additional required information on special technical and engineering (surface) purposes

for the electrodeposited metallic chromium coating has been added;

— in 5.2, additional information on surface roughness grate/quality for designation has been added;

— in 5.2, additional information for the description of the necessary final surface roughness of the

complete finished parts given by the purchaser has been added;
— in 5.6, object temperature during heat treatment has been added;

— in 5.6, an example of designation with additional information on the final surface roughness of the

completed parts has been added;

— in 6.1, important information for receiving reliable test results has been added;

— in 6.11, important information for the pretreatment of chromium plating has been added;

— in 6.13, information for corrosion resistance has been added;

— in 6.14 and Annex D, information on surface roughness and structure has been added.

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

complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2018 – All rights reserved
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SIST EN ISO 6158:2019
ISO 6158:2018(E)
Introduction

Electrodeposited chromium coatings are frequently deposited from hexavalent chromium solutions

similar to those used for electroplating. Engineering chromium coatings, however, are generally thicker

than decorative ones. Regular or conventional chromium is the type most frequently specified, but

microporous, microcracked or specially profiled surfaces and duplex chromium are also applied to

achieve oil-retaining or non-sticking surfaces, or to improve corrosion resistance. These properties

are the main reason for using metallic chromium coatings for engineering purposes. Summarized

electrodeposited coatings of metallic chromium for engineering purposes have in total more than 35

coating and process properties simultaneously.

Electrodeposited chromium coatings for engineering applications are most often applied directly to the

basis metal to increase wear and abrasion resistance, to increase fretting resistance, to reduce static

and kinetic friction, to reduce galling and seizing, to increase corrosion resistance, and to build up

undersize or worn parts. For protection against severe corrosion, nickel or other metallic undercoats

may be applied prior to the electrodeposition of chromium, or the corrosion resistance of the chromium

coating may be increased by alloying, e.g. with molybdenum.
© ISO 2018 – All rights reserved v
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SIST EN ISO 6158:2019
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SIST EN ISO 6158:2019
INTERNATIONAL STANDARD ISO 6158:2018(E)
Metallic and other inorganic coatings — Electrodeposited
coatings of chromium for engineering purposes

WARNING — This document calls for the use of substances and/or procedures that may

be injurious to health if adequate safety measures are not taken. This document does not

address any health hazards, safety or environmental matters associated with its use. It is

the responsibility of the user of this document to establish appropriate health, safety and

environmentally acceptable practices.
1 Scope

This document specifies requirements for electroplated coatings of metallic chromium, with or without

undercoats, on ferrous and non-ferrous metals for engineering purposes. The coating designation

provides a means of specifying the thickness of chromium appropriate for typical engineering

applications.
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 2064, Metallic and other inorganic coatings — Definitions and conventions concerning the measurement

of thickness

ISO 2080, Metallic and other inorganic coatings — Surface treatment, metallic and other inorganic

coatings — Vocabulary

ISO 3497, Metallic coatings — Measurement of coating thickness — X-ray spectrometric methods

ISO 3543, Metallic and non-metallic coatings — Measurement of thickness — Beta backscatter method

ISO 3882, Metallic and other inorganic coatings — Review of methods of measurement of thickness

ISO 4516, Metallic and other inorganic coatings — Vickers and Knoop microhardness tests

ISO 4519, Electrodeposited metallic coatings and related finishes — Sampling procedures for inspection by

attributes

ISO 4526, Metallic coatings — Electroplated coatings of nickel for engineering purposes

ISO 9227, Corrosion tests in artificial atmospheres — Salt spray tests

ISO 9587, Metallic and other inorganic coatings — Pretreatment of iron or steel to reduce the risk of

hydrogen embrittlement

ISO 9588, Metallic and other inorganic coatings — Post-coating treatments of iron or steel to reduce the

risk of hydrogen embrittlement
ISO 10309, Metallic coatings — Porosity tests — Ferroxyl test

ISO 10587, Metallic and other inorganic coatings — Test for residual embrittlement in both metallic-coated

and uncoated externally-threaded articles and rods — Inclined wedge method
© ISO 2018 – All rights reserved 1
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SIST EN ISO 6158:2019
ISO 6158:2018(E)

ISO 12686, Metallic and other inorganic coatings — Automated controlled shot-peening of metallic articles

prior to nickel, autocatalytic nickel or chromium plating, or as a final finish

ISO 15724, Metallic and other inorganic coatings — Electrochemical measurement of diffusible hydrogen in

steels — Barnacle electrode method
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 2064, ISO 2080, ISO 3882,

ISO 9587, ISO 9588 and ISO 12686 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
— IEC Electropedia: available at http: //www .electropedia .org/
4 Information to be supplied by the purchaser to the processor

When ordering articles to be processed in accordance with this document, the purchaser shall provide

the following essential information in writing, for example, in the contract or purchase order, or on the

engineering drawings:
a) the designation (see Clause 5);

b) the nominal composition or specification, and metallurgical condition of the basis metal including

hardness (see 5.3); in the case of reclaimed articles, it may not be possible to supply this information,

and it may, therefore, be difficult to guarantee the quality of the coating;

c) the nature, condition and finish of the basis metal if they are likely to affect the serviceability and/

or appearance of the coating (see 6.3);

d) the significant surface, indicated by drawings of the articles or by suitably marked samples

(see 6.2);
e) the requirements for special test specimens (see 6.1);

f) the appearance and surface finish of the metallic chromium coating, e.g. as-plated, ground or

machined (see 6.2 and 6.3); alternatively, samples showing the appearance and required finish

shall be supplied or approved by the purchaser, and used for comparison purposes (see 6.2);

g) the necessity for any treatment to induce compressive stress, e.g. peening before or after

electroplating (see 6.10);

h) any special requirements for, or restrictions on, pretreatment, e.g. vapour blasting instead of acid

pretreatment;

i) positions, where unavoidable, contact marks and the type, size and number of other defects that

are acceptable (see 6.2) per unit area to be mentioned;
j) requirements for undercoats (see 5.5 and 6.11) and stripping (see 6.12);

k) the test method to be used to measure thickness (see 6.4) and additional segments of the surface

where minimum thickness requirements apply;

l) the adhesion and porosity requirements, and test methods (see 6.6 and 6.7, respectively);

m) the tensile strength of parts and the requirement for stress-relief heat treatment before

electroplating (see 6.8);
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SIST EN ISO 6158:2019
ISO 6158:2018(E)

n) requirements for any embrittlement-relief heat treatment after electroplating, and for hydrogen

embrittlement testing (see 6.9);
o) the sampling plan and acceptance levels (see Clause 7);

p) any additional information, e.g. any special requirements for adhesion (see 6.6);

q) additional information belonging to the required surface roughness and structure (for special

technical and engineering purposes (see 6.14 and Annex D).
5 Designation
5.1 General

The designation shall appear on engineering drawings, in the purchase order, the contract or in the

detailed product specification.

The designation specifies, in the order given, the basis metal, the specific alloy (optional), stress relief

requirements, the type and thickness of undercoats, the type and thickness of the electroplated metallic

chromium coating, and post-treatments such as heat treatment to reduce susceptibility to hydrogen

embrittlement.
5.2 Designation specification
The designation shall comprise the following:
a) the term “Electrodeposited coating”;
b) the number of this document, i.e. ISO 6158;
c) a hyphen;
d) the chemical symbol of the basis metal (see 5.3), e.g. Fe (iron or steel);
e) a solidus (/);
f) stress relief (SR) designation (see 5.4);
g) a solidus (/);

h) chemical symbols for the metallic chromium coating, as well as coatings applied prior to chromium

electroplating, separated by solidi for each stage in the coating sequence in the order of application;

double solidi or separators (//) to be used to indicate that a step has been omitted or is not a

requirement;

i) a number indicating the minimum thickness, in micrometres, of the coating(s) followed by a

solidus (/);

j) hydrogen-embrittlement-relief (ER) designation (see 5.4), followed by a solidus (/);

k) a number indicating the quality/grate of the final surface roughness (see 6.14).

See 5.6 for examples of designations.
5.3 Designation of basis metal

The basis metal shall be designated by its chemical symbol, or its principal constituent if it is an alloy.

For example:
a) Fe for iron and steel;
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SIST EN ISO 6158:2019
ISO 6158:2018(E)
b) Zn for zinc alloys;
c) Cu for copper and copper alloys;
d) Al for aluminium and aluminium alloys.

To ensure proper surface preparation and hence adherence of the coating to the substrate, it is essential

to identify the specific alloy and its metallurgical condition (tempered, nitrided, etc.).

It is recommended that the specific alloy be identified by its standard designation following the

chemical symbol of the basis metal; for example, its UNS number, or the national or regional equivalent,

may be placed between the symbols < > (see Bibliography).
EXAMPLE Fe is the UNS designation for a high-strength steel.
5.4 Designation of heat treatment requirements
The heat treatment requirements shall be in brackets and designated as follows:

a) the letters SR for heat treatment for stress relief purposes; the letters ER for heat treatment for the

purpose of reducing susceptibility to hydrogen embrittlement; the letters HT for heat treatment for

other purposes;
b) in parenthesis, the minimum temperature, in degrees Celsius;
c) the duration of the heat treatment, in hours;

EXAMPLE [SR(210)1] designates stress relief heat treatment at 210 °C for 1 h (temperature of the plated

object).

d) when heat treatment prior to or after electrodeposition is specified, the requirements shall be

included in the designation (see 5.6).
5.5 Designation of type and thickness of metal coating

The electrodeposited metallic chromium coating shall be designated by the symbols given in Table 1

placed after a number giving the specified minimum local thickness of the coating, in micrometres.

Annex A provides information on the typical thickness of metallic chromium specified in engineering

applications.
EXAMPLE Cr50hr designates a regular hard chromium coating that is 50 µm thick.
Table 1 — Symbols for different types of chromium
Type of chromium Symbol
Regular hard chromium hr
Hard chromium from mixed acid solutions hm
Microcracked hard chromium hc
Microporous hard chromium hp
Duplex chromium hd
Special types of chromium hs

Nickel undercoats shall be designated in accordance with ISO 4526, i.e. the symbol sf for sulfur-free

nickel coatings, sc for sulfur-containing nickel coatings, or pd for sulfur-free nickel coatings containing

submicron particles dispersed throughout the nickel matrix shall be used to designate the type of

nickel undercoat by placing the appropriate symbol after the number giving the specified minimum

local thickness of the coating, in micrometres.

EXAMPLE Ni10sf designates an electrodeposited nickel undercoat 10 µm thick prepared from a solution that

does not introduce sulfur into the deposit.
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SIST EN ISO 6158:2019
ISO 6158:2018(E)
5.6 Examples of designations

The examples of designations below describe the heat treatment and electroplating steps in the order

that they are performed. The standard designation of the basis material is placed immediately after the

chemical symbol for steel, Fe. It is especially important to know the standard designation of a metal or

alloy that is difficult to prepare for electroplating and that is susceptible to hydrogen embrittlement.

For ordering purposes, the detailed product specification shall not only comprise the designation, but

shall also include clear written statements of other requirements that are essential for the serviceability

of a particular product (see Clause 4).

An example of an electrodeposited coating of regular hard chromium 50 µm thick (Cr50hr) deposited

on mild steel (Fe), ignoring omissi
...

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