ASTM E1086-22 2022

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This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the

Development of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.

Designation:E1086-22

Standard Test Method for

Analysis of Austenitic Stainless Steel by Spark Atomic

Emission Spectrometry¹

This standard is issued under the fixed designation E1086;the number immediately following the designation indicates the year of

original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A

superscript epsilon(ε)indicates an editorial change since the last revision or reapproval.

1. Scope

1.1 This test method²covers the analysis of austenitic

stainless steel by spark atomic emission spectrometry for the

following elements in the ranges shown

Element Composition Range,%

Chromium 17.0 to 23.0

Nickel 7.5 to 13.0

Molybdenum 0.01 to 3.0

Manganese 0.01 to 2.0

Silicon 0.01 to 0.90

Copper 0.01 to 0.30

Carbon 0.005 to 0.25

Phosphorus 0.003 to 0.15

Sulfur 0.003 to 0.065

1.2 This test method is designed for the analysis of chill-cast

disks or inspection testing of stainless steel samples that have

a flat surface of at least 13 mm(0.5 in.)in diameter.The

samples must be sufficiently massive to prevent overheating

during the discharge and of a similar metallurgical condition

and composition as the reference materials.

1.3 One or more of the reference materials must closely

approximate the composition of the specimen.The technique

of analyzing reference materials with unknowns and perform-

ing the indicated mathematical corrections (typically referred

to as type standardization)may also be used to correct for

interference effects and to compensate for errors resulting from

instrument drift.A variety of such systems are commonly used.

Any of these that will achieve analytical accuracy equivalent to

that reported for this test method are acceptable.

1.4 This standard does not purport to address all of the

safety concerns,if any,associated with its use.It is the

responsibility of the user of this standard to establish appro-

priate safety,health,and environmental practices and deter-

mine the applicability of regulatory limitations prior to use.

!This test method is under the jurisdiction of ASTM Committee E01 on

Analytica Chemistry for Metals,Ores,and Related Materials and s the direct

responsibility of Subcommitte E01.01 on Iron,Steel ,and Ferroalloys.

Current edition approved Aug.15,2022.Published September 2022.Originally

approved in 1985.Last previous edition approved in 2014 as E1086-14.DOI:

²Supporting data have been filed at ASTM International Headquarters and may

be obtained by requesting Research Report RR:E02-1023.Contact ASTM Customer

Service at service@astm.org.

1.5 This international standard was developed in accor-

dance with internationally recognized principles on standard-

ization established in the Decision on Principles for the

Development of International Standards,Guides and Recom-

mendations issued by the World Trade Organization Technical

Barriers to Trade(TBT)Committee.

2.Referenced Documents

2.1 ASTMStandards:³

E29 Practice for Using Significant Digits in Test Data to

Determine Conformance with Specifications

E135 Terminology Relating to Analytical Chemistry for

Metals,Ores,and Related Materials

E305 Practice for Establishing and Controlling Spark

Atomic Emission Spectrochemical Analytical Curves

E406 Practice for Using Controlled Atmospheres in Atomic

Emission Spectrometry

E1060 Practice for Interlaboratory Testing of Spectrochemi-

cal Methods of Analysis (Withdrawn 1997)⁴

E1329 Practice for Verification and Use of Control Charts in

Spectrochemical Analysis (Withdrawn 2019)⁴

E1806 Practice for Sampling Steel and Iron for Determina-

tion of Chemical Composition

2.2 Other ASTMDocuments:

MNL7 Manual on Presentation of Data and Control Chart

Analysis⁵

3.Terminology

3.1 Definitions—For definitions ofterms used in this test

method,refer to Terminology E135.

4.Summary of Test Method

4.1 A controlled discharge is produced between the flat

surface of the specimen and the counter electrode.The radiant

³For referenced ASTM standards,visit the ASTM website,www.astm.org,or

contact ASTM Customer Service at service@astm.org.For Annual Book ofASTM

Standards volume information,refer to the standard's Document Summary page on

the ASTM website.

4The last approved version of this historical standard is referenced on

www.astm.org.

5ASTM Manual Series,ASTM International,9th edition,2018.

10.1520/E1086-22.

interference from manganese 322.809 can be used as an internal standard line

with any of the listed analytical lines.Iron 271.441 is not appropriate for tungsten

energies of selected analytical lines are converted into electri-

cal energies by photomultiplier tubes and stored on capacitors.

The discharge is terminated at a predetermined level of

accumulated radiant energy from the internal standard iron line

or after a fixed integration time.At the end of the integration

period,the charge on each capacitor is measured,and displayed

or recorded as a relative energy or mass fraction %.

5.Significance and Use

5.1 The chemical composition of stainless steels must be

determined accurately to ensure the desired metallurgical

properties.This test method is suitable for manufacturing

control and inspection testing.

6.Apparatus

6.1 Sampling and Sample Preparation Equipment:

6.1.1 Refer to Practice E1806 for devices and practices to

sample liquid and solid steel.

6.1.2 Abrasive Grinder; a suitable belt grinder,horizontal

disk grinder,or similar grinding apparatus.The resulting

surface should be uniformly plane and free of defects.These

may be either wet or dry grinding devices.Grinding materials

with grit sizes ranging from 60 to 180 have been found

satisfactory.

6.2 Excitation Source,with parameters capable of produc-

ing a usable spectrum in accordance with 11.1.

6.3 Excitation Stand,suitable for mounting in optical

alignment,a flat surface of the specimen in opposition to a

counter electrode.The stand shall provide an atmosphere of

argon and may be water cooled.Counter electrodes and argon

are described in 7.1 and 7.2.

6.4 Spectrometer; having sufficient resolving power and

linear dispersion to separate clearly the analytical lines from

other lines in the spectrum of a specimen in the spectral region

170.0 nm to 500.0 nm.Spectrometer characteristics for two of

the instruments used in this test method are described as having

dispersion of 0.697 nm/mm(first order),and a focal length of

1m.Spectral lines are listed in Table 1.

6.5 Measuring System, consisting of photomultiplier tubes

having individual voltage adjustment,capacitors on which the

output of each photomultiplier tube is stored and an electronic

system to measure voltages on the capacitors either directly or

indirectly,and the necessary switching arrangements to pro-

vide the desired sequence of operation.

6.6 Readout, capable of indicating the ratio of the analytical

lines to the internal standard line with sufficient precision to

produce the accuracy of analysis desired.

6.7 Vacuum Pump, capable of maintaining a vacuum of 25

μm Hg or less.

6.8 Gas System,consisting of an argon supply with pressure

and flow regulation.Automatic sequencing shall be provided to

actuate the flow at a given rate for a specific time interval.The

flow rate may be manually or automatically controlled.The

argon system shall be in accordance with Practice E406.

NoTE 1—It is not within the scope ofthis test method to prescribe all

details of equipment to be used.Equipment varies among manufacturers.

TABLE 1 Analytical and Internal Standard Lines

Element

Wavelength,nm

Mass Fraction%

Switch Over

Points

Chromium

298.919

Nickel

243.789

227.021

218.549

216.910

202.030

<1%

Molybdenum

281.615

308.561

369.265

>1%

Manganese

293.306

Silicon

251.612A

288.158

Copper

327.396

224.699

<0.10%

>0.10%

Carbon

193.092

Phosphorus

178.287A

Sulfur

180.731

IronB

271.441

322.775

A Silicon 251.612 can have a small but significant interference from molybdenum

251.611.Phosphorus 178.287 may show small but significant interferences from

unlisted lines or background due to molybdenum,chromium,and manganese.

Interference corrections will not be necessary if:separate slicon and phosphorus

curves are used for 316 and 317 alloys;the manganese content varies only

between 0.7%and 1.5%;and the chromium content is held between 17%and

20%.

BEither iron line 271.441 or 322.775 with narrow entrance and exit slits to avoid

tool steels or super alloys with high cobalt because of interference from cobalt

271.442.

7. Reagents and Materials

7.1 Argon,must be of sufficient purity(gas or liquid supply)

to permit proper excitation of the analytical lines of interest.

Argon of 99.998%purity has been found satisfactory.Refer to

Practice E406.

7.2 Counter Electrodes,can vary in diameter from 1.5 mm

to 6.5 mm(depending on the instrument manufacturer)and

typically are machined to a 90°or 120°angled tip.Silver or

tungsten rods are typically used.Other material may be used

provided it can be shown experimentally that equivalent

precision and accuracy are obtained.

8.Reference Materials

8.1 Certified Reference Materials(CRMs)are available

from NIST⁶and other international metrology organizations.

8.2 Reference Materials(RMs)with matrices similar to that

of the test specimen and containing varying amounts of the

elements to be determined may be used provided they have

been chemically analyzed in accordance with ASTM E01

standard test methods.These reference materials shall be

homogeneous,and free of voids or porosity.

8.3 The reference materials shall cover the ranges of the

elements being sought.A minimum of three reference materials

shall be used for each element.

⁶Available from National Institute of Standards and Technology(NIST),100

Bureau Dr.,Stop 1070,Gaithersburg,MD 20899-1070,http://www.nist.gov.

9.Preparation of Samples

9.1 The specimens and reference materials must be prepared

in the same manner.A specimen cut from a large sample

section must be of sufficient size and thickness for preparation

and to properly fit the spectrometer stand.

9.2 Ensure the specimens are homogenous and free from

voids and pits in the region to be excited.Grind the surface

with an abrasive belt or disc.Refer to 6.1.2.Perform the final

grind with a dry abrasive belt or disc.

10.Preparation of Apparatus

10.1 Follow the manufacturer's instructions for verifying

the optical alignment of the entrance slit and programming the

appropriate wavelengths(Table 1).

11. Excitation and Integration

11.1 Electrical Parameters—Two different types of sources

were employed in the interlaboratory study (ILS)of this test

method.

11.1.1 Directional Self-Initiating Capacitor Discharge

Source:

Capacitance,μF 0.015

Inductance,L₁,μH 310

Inductance,L₂,μH 20

Resistance,Qresidual

Potential,V 13500

Peak Current,A 90

First Valley Current,A 60

Current pulse duration,μs 120

Number of discharges/s 240

11.1.1.1 Excitation Conditions:

Flush,s

Preburn,s

Integration,s

11.1.2 Triggered Capacitor Discharge Source:

Pulse Output:

Capacitance,μF(d-c charged)

Inductance,μH

Resistance,Ω

Potential,V

Peak Current,A

Current pulse duration,μs

Number of discharges/s

Trigger:

Capacitance(d-c charged),μF

Inductance,μH

Resistance, Q

Potential,V

Preburn

7.5

residual

950

275

250

120

1.2

residual

425

Integration

2.5

residual

950

100

130

120

11.1.2.1 Excitation Conditions:

Argon Flow 0.56 m³/h

Argon Flow 0.56m³/h

12.Calibration,Drift Correction (Standardization),and

Verification

12.1 Calibration—Using the conditions given in 11.1,excite

each calibration RM and drift correction sample two to four

times and bracket these with similar excitations ofany verifi-

ers.A verifier may be used as a calibration RM even though it

is sparked only as a verifier.There shall be at least three

calibration RMs for each element,spanning the required mass

fraction range.If the spectrometer system and software

permits,perform random excitations of each calibration RM

and drift correction sample and repeat with different random

sequences at least four times.Follow the spectrometer manu-

facturer's software procedures to convert sample intensities

into mass fraction %.Using the averages ofthe data for each

point,determine calibration curves in accordance with Practice

E305.

12.2 Drift Correction(Standardization)—Following the

manufacturer's recommendations,drift correct on an initial

setup or anytime that it is known or suspected that readings

have shifted.Make the necessary corrections.Drift correction

will be done anytime verification indicates that readings have

gone out of statistical control.

12.3 Verification—Analyze verifiers in replicate to confirm

that they read within the expected confidence interval,as

directed in 12.4.

12.3.1 Each laboratory should determine the frequency of

verification necessary based on statistical analysis.Typically,

every 4h to 8h is practical and adequate (or if the instrument

has been idle for more than 1h).If the results are not within the

control limits established in 12.4, perform a drift correction and

then repeat verification.Repeat drift correction as necessary so

verifications are within control limits or investigate further for

instrument problems.

12.4 The confidence interval will be established from ob-

servations ofthe repeatability ofthe verifiers by utilizing the

upper and lower limit of a control chart in accordance with

Practice E1329 or ASTM Manual MNL 7.

13. Procedure for Excitation and Radiation Measurement

13.1 Produce and record the intensities using the conditions

in 11.1.

13.2 Replicate Excitation—Make duplicate excitations of

each specimen and report the average.Place the freshly

surfaced specimen on the excitation stand to effect a gas-tight

seal and adequate argon flushing.Position the specimen so

there will be a uniform pattern of excitations around its face.

For example,a disk-shaped specimen should have a ring of

excitation marks around its outer edge and approximately 6

mm(0.25 in.)from the edge.Avoid the center of cast

specimens because of possible quench cracks and segregation.

Make a good electrical ground.If required,cool the specimen

after two excitations to prevent overheating.Examine the

specimen after each excitation to evaluate the quality of

excitation.Cracks,voids,pits,moisture,or inclusions will limit

the sampling and the accuracy of a determination.Successive

excitations shall be sufficiently separated so that the discharge

patterns do not overlap.

14.Calculation of Results

14.1 Average the readings obtained for each specimen.Use

the spectrometer software and the calibration curves to convert

the intensities obtained to mass fraction %.

14.2 Rounding of test results obtained using this test method

shall be performed in accordance with Practice E29,Rounding

Method,unless an alternative rounding method is specified by

the customer or applicable material specification.

Argon Flow 0.42m³/h

Argon Flow 0.42 m³/h

Flush,s

Preburn,s

Integration,s

10 or 15

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1ThisinternationalstandardwasdevelopedinaccordancewithinternationallyrecognizedprinciplesonstandardizationestablishedintheDecisiononPrinciplesfortheDevelopmentofInternationalStandards,GuidesandRecommendationsissuedbytheWorldTradeOrganizationTechnicalBarrierstoTrade(TBT)Committee.Designation:E1086-22...

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