SIST EN 10179:2024

SLOVENSKI STANDARD
01-september-2024
Jekla - Določevanje dušika (v sledeh) v jeklih - Spektrofotometrična metoda
Steels - Determination of nitrogen (trace amounts) - Spectrophotometric method
Stähle - Bestimmung von Stickstoff (Spurengehalte) - Photometrisches Verfahren
Aciers - Détermination de l'azote (à l'état de traces) - Méthode spectrophotométrique
Ta slovenski standard je istoveten z: EN 10179:2024
ICS:
77.040.30 Kemijska analiza kovin Chemical analysis of metals
77.080.20 Jekla Steels
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 10179
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2024
EUROPÄISCHE NORM
ICS 77.040.30 Supersedes EN 10179:1989
English Version
Steels - Determination of nitrogen (trace amounts) -
Spectrophotometric method
Aciers - Détermination de l'azote (à l'état de traces) - Stähle - Bestimmung von Stickstoff (Spurengehalte) -
Méthode spectrophotométrique Photometrisches Verfahren
This European Standard was approved by CEN on 29 April 2024.

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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye 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
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 10179:2024 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Principle . 4
5 Reagents . 4
6 Apparatus . 7
7 Sampling . 12
8 Procedure . 12
8.1 Test portion . 12
8.2 Blank test . 12
8.3 Preparation of the steam distillation apparatus . 12
8.4 Determination . 13
8.4.1 Preparation of the test solution . 13
8.4.2 Distillation . 13
8.4.3 Development of the colour . 13
8.4.4 Spectrophotometric measurements . 14
8.5 Establishment of the calibration curve . 14
8.5.1 Preparation of the calibration solutions . 14
8.5.2 Spectrophotometric measurements . 14
8.5.3 Plotting the calibration curve . 15
9 Expression of results . 15
10 Test report . 15
Annex A (informative) Precision data . 16
Bibliography . 17

European foreword
This document (EN 10179:2024) has been prepared by Technical Committee CEN/TC 459/SC 2
“Methods of chemical analysis for iron and steel”, the secretariat of which is held by SIS.
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 December 2024, and conflicting national standards
shall be withdrawn at the latest by December 2024.
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 10179:1989.
In comparison with the previous edition, the following technical modifications have been made:
— normative references: updated;
— Clause 3; Terms and definitions: added;
— references 5.10, 5.11, 5.14, 5.17 and 5.18: added;
— Clause 10: updated;
— Bibliography: added.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,
Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye
and the United Kingdom.
1 Scope
This document specifies a spectrophotometric method for the determination of nitrogen in steels.
The method is primarily intended for the determination of total nitrogen in very low contents in non-
alloy steels.
It can be used, however, for any low nitrogen ferrous alloy that is soluble in hydrochloric acid provided
that the acid-resistant form of silicon nitride is not present. These highly resistant nitrides have been
found only in samples of silicon steels manufactured without aluminium addition and then only in
sheet material.
The method is applicable to nitrogen contents from 0,000 5 % (by mass) to 0,005 % (by mass).
The precision data of the present method are 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.
EN ISO 648, Laboratory glassware — Single-volume pipettes (ISO 648)
EN ISO 1042, Laboratory glassware — One-mark volumetric flasks (ISO 1042)
EN ISO 14284, Steel and iron — Sampling and preparation of samples for the determination of chemical
composition (ISO 14284)
3 Terms and definitions
No terms and definitions are listed in this document.
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 https://www.electropedia.org/
4 Principle
Dissolution of the test portion with hydrochloric acid and separation of the acid-insoluble residue by
centrifugation.
Decomposition of the acid-insoluble residue by intense fuming with sulphuric acid and addition of the
extract to the solution of the test portion containing the acid-soluble nitrogen.
Recovery of the total nitrogen as ammonia by steam distillation over sodium hydroxide.
Spectrophotometric measurement of the coloured complex produced by a reaction with indophenol
blue.
5 Reagents
During the analysis use only reagents of recognized analytical grade and which are known to give a
very low nitrogen bank. The same batch of each reagent shall be used for every test solution and blank
determination in a given series of analysis.
All references to “water” relate to ammonia-free water. Ammonia-free water shall be prepared by
passing distilled water through a cation exchange column (6.2). It is essential that the resin column
+
shall be acid washed before use to ensure its conversion to the hydrogen form, H . This is most
conveniently done by passing 2 l of a solution of hydrochloric acid (5.2), diluted 1 + 9, through the
column and then washing with water until freed from acid.
5.1 High purity iron or steel with a very low nitrogen content
High purity iron powder or very low nitrogen content mild steel [<0,001 % (by mass) nitrogen] may
be used for this purpose. It should be cleaned in the same way as the sample.
5.2 Hydrochloric acid, ρ 1,19 g/ml approximately
5.3 Sulphuric acid, ρ 1,84 g/ml approximately
Sulphuric acid supplied shall be tested individually and selected for a low content of combined
nitrogen in any form (less than 0,5 µg/g). Nitrogen as ammonia will usually be the major source of
contamination and this may be tested by normal methods, but nitrates may also be present and should
be detected by using the method described below.
Add 6 ml of sulphuric acid (5.3) to 2 ml of water and cool to 60 °C. Add one drop of hydrochloric
acid (5.2) and one drop of diphenylamine (5.8). No blue colour should appear.
NOTE Less than 0,1 µg/g can be detected by this test.
5.4 Sulphuric acid, solution 1 + 4
Carefully add 40 ml of sulphuric acid (5.3) to 160 ml of water.
Allow to cool and mix.
5.5 Sodium hydroxide, 400 g/l
Dissolve 400 g of sodium hydroxide in water, dilute to 1 000 ml and mix.
This solution should be prepared in a polyethylene beaker (water-cooled if necessary) and stored in a
polyethylene bottle.
5.6 Barium chloride, 100 g/l
Dissolve 100 g of barium chloride (BaCl · 2H 0) in water, dilute to 1 000 ml and mix.
2 2
5.7 Chromic-sulphuric acid
Dissolve 2 g of chromium trioxide (CrO ) in 50 ml of water and slowly add 100 ml of sulphuric
acid (5.3) with constant stirring.
5.8 Diphenylamine, 1 g/l
To 25 ml of water, whilst stirring, cautiously add 75 ml of sulphuric acid (5.3) then add 0,1 g of
diphenylamine, stir until dissolved and allow to cool.
5.9 Phenol, 50 g/l
Dissolve 50 g of phenol in water, transfer into a 1 000 ml volumetric flask, dilute to the mark with
water and mix.
Store this solution out of direct sunlight in an amber coloured bottle.
5.10 Potassium iodide (KI)
5.11 Glacial acetic acid, ρ 1,05 g/ml approximately
5.12 Sodium hydroxide - sodium hypochlorite solution
5.12.1 Determination of chlorine in commercial sodium hypochlorite solution
Transfer 10 ml of the sodium hypochlorite solution to be tested into a 250 ml volumetric flask, dilute
to the mark with water and mix.
Transfer, 10 ml of this solution into a 100 ml conical beaker, add 2 g of potassium iodide (5.10) and
10 ml of glacial acetic acid (5.11). Titrate the liberated iodine using sodium thiosulphate (5.15) until
the colour has almost disappeared. Add 2 ml of starch solution (5.16) and continue the titration until
the blue colour has disappeared.
The chlorine content (w ) in per cent (m/v) is given by Formula (1):
Cl
w = 0,886 × V (1)
Cl 1
where
V is the volume in millilitres of sodium thiosulphate (5.15) used in the titration.
5.12.2 Calculation
The volume, V , expressed in millilitres, of sodium hypochlorite solution necessary for the preparation
of 1 l of sodium hydroxide - sodium hypochlorite solution (5.12) is given by Formula (2):
2,1××100 70,,91 225 7
V (2)
0,,886××V 74 44 V
1 1
This volume is equivalent to 2,1 g of chlorine.
5.12.3 Preparation of the solution 5.12
Dissolve 25 g of sodium hydroxide in about 400 ml of water. Exactly add the calculated volume of
sodium hypochlorite solution (5.12.2), dilute t
...