ASTM A923-14

Standard Test Methods for Detecting Detrimental Intermetallic Phase in Duplex Austenitic/Ferritic Stainless Steels

ABSTRACT
These test methods cover the detection of detrimental intermetallic phase in duplex austenitic/ferritic stainless steel to the extent that toughness and corrosion resistance is affected significantly. These test methods will not necessarily detect losses of toughness or corrosion resistance attributable to other causes. Test method A-sodium hydroxide etch test, test method B-Charpy impact test, and test method C-ferric chloride corrosion test shall be made for classification of structures of duplex stainless steels.
SCOPE
1.1 The purpose of these test methods is to allow detection of the presence of intermetallic phases in duplex stainless steels to the extent that toughness or corrosion resistance is affected significantly. These test methods will not necessarily detect losses of toughness or corrosion resistance attributable to other causes.  
1.2 Duplex (austenitic-ferritic) stainless steels are susceptible to the formation of intermetallic compounds during exposures in the temperature range from approximately 600 to 1750°F (320 to 955°C). The speed of these precipitation reactions is a function of composition and thermal or thermomechanical history of each individual piece. The presence of these phases is detrimental to toughness and corrosion resistance.  
1.3 Correct heat treatment of duplex stainless steels can eliminate these detrimental phases. Rapid cooling of the product provides the maximum resistance to formation of detrimental phases by subsequent thermal exposures.  
1.4 Compliance with the chemical and mechanical requirements for the applicable product specification does not necessarily indicate the absence of detrimental phases in the product.  
1.5 These test methods include the following:  
1.5.1 Test Method A—Sodium Hydroxide Etch Test for Classification of Etch Structures of Duplex Stainless Steels (Sections 3 – 7).  
1.5.2 Test Method B—Charpy Impact Test for Classification of Structures of Duplex Stainless Steels (Sections 8 – 13).  
1.5.3 Test Method C—Ferric Chloride Corrosion Test for Classification of Structures of Duplex Stainless Steels (Sections 14 – 20).  
1.6 The presence of detrimental intermetallic phases is readily detected in all three tests, provided that a sample of appropriate location and orientation is selected. Because the occurrence of intermetallic phases is a function of temperature and cooling rate, it is essential that the tests be applied to the region of the material experiencing the conditions most likely to promote the formation of an intermetallic phase. In the case of common heat treatment, this region will be that which cooled most slowly. Except for rapidly cooled material, it may be necessary to sample from a location determined to be the most slowly cooled for the material piece to be characterized.  
1.7 The tests do not determine the precise nature of the detrimental phase but rather the presence or absence of an intermetallic phase to the extent that it is detrimental to the toughness and corrosion resistance of the material.  
1.8 Examples of the correlation of thermal exposures, the occurrence of intermetallic phases, and the degradation of toughness and corrosion resistance are given in Appendix X1 and Appendix X2.  
1.9 The values stated in either inch-pound or SI units are to be regarded as the standard. The values given in parentheses are for information only.  
1.10 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 appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 28-Feb-2014
• ICS: 77.040.99 - Other methods of testing of metals
• Technical Committee: A01 - Steel, Stainless Steel and Related Alloys
• Drafting Committee: A01.14 - Methods of Corrosion Testing

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: A923 − 14
Standard Test Methods for
Detecting Detrimental Intermetallic Phase in Duplex
1
Austenitic/Ferritic Stainless Steels
This standard is issued under the fixed designation A923; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* 1.6 The presence of detrimental intermetallic phases is
readily detected in all three tests, provided that a sample of
1.1 The purpose of these test methods is to allow detection
appropriate location and orientation is selected. Because the
ofthepresenceofintermetallicphasesinduplexstainlesssteels
occurrence of intermetallic phases is a function of temperature
to the extent that toughness or corrosion resistance is affected
and cooling rate, it is essential that the tests be applied to the
significantly. These test methods will not necessarily detect
region of the material experiencing the conditions most likely
lossesoftoughnessorcorrosionresistanceattributabletoother
to promote the formation of an intermetallic phase. In the case
causes.
of common heat treatment, this region will be that which
1.2 Duplex (austenitic-ferritic) stainless steels are suscep-
cooled most slowly. Except for rapidly cooled material, it may
tible to the formation of intermetallic compounds during
be necessary to sample from a location determined to be the
exposures in the temperature range from approximately 600 to
most slowly cooled for the material piece to be characterized.
1750°F (320 to 955°C). The speed of these precipitation
1.7 The tests do not determine the precise nature of the
reactions is a function of composition and thermal or thermo-
detrimental phase but rather the presence or absence of an
mechanical history of each individual piece. The presence of
intermetallic phase to the extent that it is detrimental to the
these phases is detrimental to toughness and corrosion resis-
toughness and corrosion resistance of the material.
tance.
1.8 Examples of the correlation of thermal exposures, the
1.3 Correct heat treatment of duplex stainless steels can
occurrence of intermetallic phases, and the degradation of
eliminate these detrimental phases. Rapid cooling of the
toughness and corrosion resistance are given in Appendix X1
product provides the maximum resistance to formation of
and Appendix X2.
detrimental phases by subsequent thermal exposures.
1.9 The values stated in either inch-pound or SI units are to
1.4 Compliance with the chemical and mechanical require-
be regarded as the standard. The values given in parentheses
ments for the applicable product specification does not neces-
are for information only.
sarilyindicatetheabsenceofdetrimentalphasesintheproduct.
1.10 This standard does not purport to address all of the
1.5 These test methods include the following:
safety concerns, if any, associated with its use. It is the
1.5.1 Test Method A—Sodium Hydroxide Etch Test for
responsibility of the user of this standard to establish appro-
Classification of Etch Structures of Duplex Stainless Steels
priate safety and health practices and determine the applica-
(Sections3–7).
bility of regulatory limitations prior to use.
1.5.2 Test Method B—Charpy Impact Test for Classification
of Structures of Duplex Stainless Steels (Sections8–13).
2. Referenced Documents
1.5.3 Test Method C—Ferric Chloride Corrosion Test for
2
2.1 ASTM Standards:
Classification of Structures of Duplex Stainless Steels (Sec-
A370Test Methods and Definitions for Mechanical Testing
tions14–20).
of Steel Products
1
These test methods are under the jurisdiction of ASTM Committee A01 on
Steel, Stainless Steel and Related Alloysand are the direct responsibility of
2
Subcommittee A01.14 on Methods of Corrosion Testing. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved March 1, 2014. Published March 2014. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1994. Last previous edition approved in 2008 as A923–08. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/A0923-14. the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
A923 − 14
G48Test Methods for Pitting and Crevice Corrosion Resis- 4.6 Metallurgical Microscope, for examination of etched
tance of Stainless Steels and Related Alloys by Use of microstructures to 400 to 500 diameters.
Ferric Chloride Solution
4.7 Electr
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: A923 − 08 A923 − 14
Standard Test Methods for
Detecting Detrimental Intermetallic Phase in Duplex
1
Austenitic/Ferritic Stainless Steels
This standard is issued under the fixed designation A923; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 The purpose of these test methods is to allow detection of the presence of intermetallic phases in duplex stainless steels to
the extent that toughness or corrosion resistance is affected significantly. These test methods will not necessarily detect losses of
toughness or corrosion resistance attributable to other causes.
1.2 Duplex (austenitic-ferritic) stainless steels are susceptible to the formation of intermetallic compounds during exposures in
the temperature range from approximately 600 to 1750°F (320 to 955°C). The speed of these precipitation reactions is a function
of composition and thermal or thermomechanical history of each individual piece. The presence of these phases is detrimental to
toughness and corrosion resistance.
1.3 Correct heat treatment of duplex stainless steels can eliminate these detrimental phases. Rapid cooling of the product
provides the maximum resistance to formation of detrimental phases by subsequent thermal exposures.
1.4 Compliance with the chemical and mechanical requirements for the applicable product specification does not necessarily
indicate the absence of detrimental phases in the product.
1.5 These test methods include the following:
1.5.1 Test Method A—Sodium Hydroxide Etch Test for Classification of Etch Structures of Duplex Stainless Steels (Sections 3
– 7).
1.5.2 Test Method B—Charpy Impact Test for Classification of Structures of Duplex Stainless Steels (Sections 8 – 13).
1.5.3 Test Method C—Ferric Chloride Corrosion Test for Classification of Structures of Duplex Stainless Steels (Sections 14 –
20).
1.6 The presence of detrimental intermetallic phases is readily detected in all three tests, provided that a sample of appropriate
location and orientation is selected. Because the occurrence of intermetallic phases is a function of temperature and cooling rate,
it is essential that the tests be applied to the region of the material experiencing the conditions most likely to promote the formation
of an intermetallic phase. In the case of common heat treatment, this region will be that which cooled most slowly. Except for
rapidly cooled material, it may be necessary to sample from a location determined to be the most slowly cooled for the material
piece to be characterized.
1.7 The tests do not determine the precise nature of the detrimental phase but rather the presence or absence of an intermetallic
phase to the extent that it is detrimental to the toughness and corrosion resistance of the material.
1.8 Examples of the correlation of thermal exposures, the occurrence of intermetallic phases, and the degradation of toughness
and corrosion resistance are given in Appendix X1 and Appendix X2.
1.9 The values stated in either inch-pound or SI units are to be regarded as the standard. The values given in parentheses are
for information only.
1.10 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 appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
1
These test methods are under the jurisdiction of ASTM Committee A01 on Steel, Stainless Steel and Related Alloysand are the direct responsibility of Subcommittee
A01.14 on Methods of Corrosion Testing.
Current edition approved Oct. 1, 2008March 1, 2014. Published October 2008March 2014. Originally approved in 1994. Last previous edition approved in 20062008 as
A923 – 06.A923 – 08. DOI: 10.1520/A0923-08.10.1520/A0923-14.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
A923 − 14
2. Referenced Documents
2
2.1 ASTM Standards:
A370 Test Methods and Definitions for Mechanical Testing of Steel Products
G48 Test Methods for Pitting and Crevice Corrosion Resistance of Stainless Steels and Related Alloys by Use of Ferric Chl
...