CR 10320:2004
(Main)Optical emission analysis of low alloy steels (routine method) - Method for determination of C, Si, S, P, Mn, Cr, Ni and Cu
Optical emission analysis of low alloy steels (routine method) - Method for determination of C, Si, S, P, Mn, Cr, Ni and Cu
This document specifies an optical emission spectrometry spark source routine standard method for multi-element analysis of unalloyed steel and iron.
Optische Emissionsanalyse von niedriglegierten Stählen (Reihenanalyse) - Verfahren zur Bestimmung von C, Si, S, P, Mn, Cr, Ni und Cu
Analyse des aciers faiblement alliés par spectrométrié d´émission optique (méthode de routine) - Méthode de détermination de C, Si, S, P, Mn, Cr, Ni et Cu
Optična emisijska analiza malolegiranih jekel (rutinska metoda) – Metoda za določevanje C, Si, S, P, Mn, Cr, Ni in Cu
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-december-2004
2SWLþQDHPLVLMVNDDQDOL]DPDOROHJLUDQLKMHNHO UXWLQVNDPHWRGD ±0HWRGD]D
GRORþHYDQMH&6L630Q&U1LLQ&X
Optical emission analysis of low alloy steels (routine method) - Method for determination
of C, Si, S, P, Mn, Cr, Ni and Cu
Optische Emissionsanalyse von niedriglegierten Stählen (Reihenanalyse) - Verfahren zur
Bestimmung von C, Si, S, P, Mn, Cr, Ni und Cu
Analyse des aciers faiblement alliés par spectrométrié d´émission optique (méthode de
routine) - Méthode de détermination de C, Si, S, P, Mn, Cr, Ni et Cu
Ta slovenski standard je istoveten z: CR 10320:2004
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.
CEN REPORT
CR 10320
RAPPORT CEN
CEN BERICHT
September 2004
ICS 77.040.20; 77.140.20
English version
Optical emission analysis of low alloy steels (routine method) -
Method for determination of C, Si, S, P, Mn, Cr, Ni and Cu
Analyse des aciers faiblement alliés par spectrométrié Optische Emissionsanalyse von niedriglegierten Stählen
d´émission optique (méthode de routine) - Méthode de (Reihenanalyse) - Verfahren zur Bestimmung von C, Si, S,
détermination de C, Si, S, P, Mn, Cr, Ni et Cu P, Mn, Cr, Ni und Cu
This CEN Report was approved by CEN on 3 June 2001. It has been drawn up by the Technical Committee ECISS/TC 20.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2004 CEN All rights of exploitation in any form and by any means reserved Ref. No. CR 10320:2004: E
worldwide for CEN national Members.
Contents page
Foreword.3
1 Scope .4
2 Test sample preparation .4
3 Calibration of the instrument.4
3.1 Determination of calibration curve .4
3.2 Linear correlation.5
3.3 Quadratic correlation .6
3.4 Confidence limit (Syc) and standard error (Syx) in a linear correlation .7
3.5 Confidence limit (Syc) and standard error (Syx) in a quadratic correlation.7
3.6 Correlation accuracy .8
4 Calculation of interferences .8
4.1 Spectral interferences .8
4.2 Matrix interferences.10
4.3 Calculation of an interfered element due to either matrix effect or spectral interference.10
5 Determination of performance criteria .11
5.1 Determination of background equivalent concentration BEC .11
5.2 Determination of detection limit DL.11
5.3 Determination of repeatability as relative standard deviation RSD .13
5.4 Determination of accuracy SEA .13
6 Performing analysis .13
7 Ordinary maintenance.14
8 Quality control.14
8.1 Control chart .14
8.2 Calibration curve control .15
9 Examples .15
9.1 Determination of calibration curve .15
9.2 Calculation of interferences .20
9.3 Determination of background equivalent concentration.25
9.4 Determination of detection limit.26
9.5 Determination of repeatability.27
9.6 Determination of accuracy.29
9.7 Ordinary maintenance.31
9.8 Control CHART.31
9.9 Calibration curve control .34
10 Statistical results .35
Annex A Optical emission spectrometry.37
Bibliography .60
Foreword
This document (CR 10320:2004) has been prepared by ECISS /TC 20, "Methods of chemical analysis of ferrous
products".
1 Scope
This document specifies an optical emission spectrometry spark source routine standard method for multi-
element analysis of unalloyed steel and iron.
2 Test sample preparation
Prepare reference materials, test samples and setting up samples, by grinding to provide a uniform flat surface.
It is recommended a surface grinder with aluminium oxide, or zirconium oxide, abrasive to be employed with a
coarse grit of 60 - 100.
3 Calibration of the instrument
3.1 Determination of calibration curve
Analyse a series of reference materials (min. 5) for the element intensity/matrix intensity ratio according to the
pattern shown in Figure 1.
Calculate the average intensity for each reference material.
NOTE In (Figure 1) the first group values into parentheses refers to odd ns.
Correlate the average intensity ratio with the concentration of test element.
n
i
(1)
cA%= I
∑
i
i=0
where:
A means correlation constants;
i
i
I means unknown values (intensity ratio).
Figure 1
3.2 Linear correlation
For linear correlations, constants are calculated in the following way:
Ay=−Ax
(2)
01mm
()xy
∑
A = (3)
()x
∑
where:
x and y are average values (Σi /n);
m m m
n number of points;
x and y are intensity ratio readouts and concentrations, respectively, of test samples.
Besides correlation parameters, calculate the following:
[]n xy− x y
∑∑∑
r =
(4)
2 2
2 2
[]n ()x −()x ×[]n ()y −()y
∑∑ ∑∑
where r is the correlation coefficient.
A and A may also be calculated by single values according to the following equations:
0 1
yx − xy x
() ( )
∑∑ ∑ ∑
A = (5)
nx − x
()
()
∑ ∑
yA− ()x
∑∑1
A = (6)
n
nxy − x y
()
∑ ∑∑
A =
(7)
nx − x
()
()
∑ ∑
3.3 Quadratic correlation
Calculate constants in the following way, by resolving the system:
2 3 42
Ax++A x A x= xy (8)
() () () ()( )
∑ ∑ ∑ ∑
0 1 2
2 3
Ax++A ()x A (x)= (xy) (9)
∑ ∑ ∑ ∑
01 2
An++A x A ()x= y (10)
∑ ∑ ∑
01 2
where:
n is the number of tests.
cc−
()
∑ it ic
r =−1 (11)
()cc−
∑
it a
where:
c is the true value of the reference material i;
it
c is the value of the reference material i read on the calibration curve;
ic
c is the average concentration of all the c
a ic
3.4 Confidence limit (Syc) and standard error (Syx) in a linear correlation
Confidence limit indicates the area where the true value of y for a given x lies at 95 % of probability. In other
words, it indicates the area including the regression range. The slope error is an evidence of the method
sensitivity, in fact the wider x range the lower the slope error. The standard error in a correlation is the extent of
the deviation around the regression line. Calculate the standard error in a linear correlation by the following
formula:
yA−−yA xy
() ( )
∑ ∑∑
Syx = (12)
n− 2
and the confidence limit:
()x −x
i m
Syc=Syx× +
(13)
n
()x
∑
Calculate the slope error (Sb) as follows:
Syx
Sb= (14)
()x
∑
3.5 Confidence limit (Syc) and standard error (Syx) in a quadratic correlation
Calculate the standard error in a quadratic correlation by the following formula:
yA−−yA xy−A ()xy
() ( )
∑ 01∑∑∑ 2
Syx= (15)
n−2
and the confidence limit:
1()x −x
i m
Syc Syx
= × +
(16)
n
()x
∑
Calculate the slope error (Sb) as follows:
Syx
Sb= (17)
x
()
∑
3.6 Correlation accuracy
Among reference standards, either secondary or tertiary, select a low, a medium and a high standard and
determine their repeatability both in concentration and intensity ratio. The resulting values indicate the method
accuracy index at the specific concentration (intensity ratio).
If RSD is correlated with concentration, a change in repeatability is obtained with respect to concentration.
4 Calculation of interferences
4.1 Spectral interferences
In the line intensity/matrix ratio, analyse at least 5 reference materials on the interference line with a variable
concentration of the interfering element but possibly free from the interfered element. Analyses should be
repeated at least four times after performing the drift correction, according to the Figure 2 scheme. Calculate the
average intensity ratio for each reference material and compute the corresponding concentration of interfered
element.
Figure 2
Correlate the resulting concentrations to the concentration of the interfering element by the method of least
squares. The following equation is obtained:
n
i
cA% = c (18)
∑ ii
i=0
where:
c% is the concentration of the interfered element;
c is the concentration of the interfering element;
i
A is the correlation constants (it is advisable to calculate a straight line).
i
The angle coefficient of the straight line (A ) is the factor of spectral interference of the element interfering over
the analyte.
This factor is nonlinear only rarely and for wide concentration ranges of the interfering and/or interfered
elements. In this case it is advisable to work with analyte families and limit concentration ranges.
The following equation calculates the analyte concentration:
n k
i
cA%=+I fc (19)
∑∑i jj
i==00j
where:
f means the factor of spectral interference of element j over the analyte;
j
c means its concentration.
j
It is possible to calculate interference factors in intensity. In this case correlations must be made with intensities.
The following formula is used to calculate f easier and when only one interfering element has been detected:
j
n
i
cA%=+Ifc (20)
∑ i 11
i=0
n
i
cA%− I
∑ i
i=0
f = (21)
c
Suitable reference materials must be selected that have a variable concentration of the
...
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