ASTM C692-08
(Test Method)Standard Test Method for Evaluating the Influence of Thermal Insulations on External Stress Corrosion Cracking Tendency of Austenitic Stainless Steel
Standard Test Method for Evaluating the Influence of Thermal Insulations on External Stress Corrosion Cracking Tendency of Austenitic Stainless Steel
SIGNIFICANCE AND USE
An inherent characteristic of some alloys of austenitic stainless steel is their tendency to crack at stress points when exposed to certain corrosive environments. The mechanisms of ESCC are complex and not completely understood but are apparently related to certain metallurgical properties. Chloride ions concentrated at a stress point will catalyze crack formation. It has been reported that other halide ions do not promote ESCC to the same degree as does chloride using the test technology of Test Method C 692 (drip test).
Chlorides are common to many environments, so great care shall be taken to protect austenitic stainless steel from chloride contamination.
Most thermal insulations will not, of themselves, cause stress corrosion cracking as shown by qualification tests. When exposed to elevated-temperature (boiling point range), environments containing chlorides, moisture, and oxygen, however, some insulation systems act as collecting media, transmigrating and concentrating chlorides on heated stainless steel surfaces. If moisture is not present, the chloride salts cannot migrate, and stress corrosion cracking because of chloride-contaminated insulation cannot take place.
Insulation materials are available that are specially formulated to inhibit stress corrosion cracking in the presence of chlorides through modifications in basic composition or incorporation of certain chemical additives.
The ability of the 28-day test to measure the corrosion potential of insulation materials is documented by Karnes, whose data appear to have been used for construction of the acceptability curve used in Specification C 795 and other specifications.
The metal for all of the coupons used in this test method (C 692) shall be qualified (see Section 14) to ascertain that under conditions of the test, chloride ions will cause the metal to crack, and deionized water alone will not cause cracks.
SCOPE
1.1 This test method covers two procedures for the laboratory evaluation of thermal insulation materials to determine whether they contribute to external stress corrosion cracking (ESCC) of austenitic stainless steel due to soluble chlorides within the insulation. This laboratory procedure is not intended to cover all of the possible field conditions that contribute to ESCC.
1.2 While the 1977 edition of this test method (Dana test) is applicable only to wicking-type insulations, the procedures in this edition are intended to be applicable to all insulating materials, including cements, some of which disintegrate when tested in accordance with the 1977 edition. Wicking insulations are materials that wet through and through when partially (50 to 75 %) immersed in water for a short period of time (10 min or less).
1.3 These procedures are intended primarily as a preproduction test for qualification of the basic chemical composition of a particular manufacturer's product and are not intended to be routine tests for ongoing quality assurance or production lot compliance. Test Methods C 871, on the other hand, is used for confirmation of acceptable chemical properties of subsequent lots of insulation previously found acceptable by this test method.
1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.5 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.
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Designation: C692 – 08
Standard Test Method for
Evaluating the Influence of Thermal Insulations on External
Stress Corrosion Cracking Tendency of Austenitic Stainless
1
Steel
This standard is issued under the fixed designation C692; 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 priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
1.1 This test method covers two procedures for the labora-
tory evaluation of thermal insulation materials to determine
2. Referenced Documents
whether they contribute to external stress corrosion cracking
2
2.1 ASTM Standards:
(ESCC) of austenitic stainless steel due to soluble chlorides
A240/A240M Specification for Chromium and Chromium-
withintheinsulation.Thislaboratoryprocedureisnotintended
Nickel Stainless Steel Plate, Sheet, and Strip for Pressure
to cover all of the possible field conditions that contribute to
Vessels and for General Applications
ESCC.
A370 Test Methods and Definitions for Mechanical Testing
1.2 Whilethe1977editionofthistestmethod(Danatest)is
of Steel Products
applicable only to wicking-type insulations, the procedures in
C168 Terminology Relating to Thermal Insulation
this edition are intended to be applicable to all insulating
C795 Specification for Thermal Insulation for Use in Con-
materials,includingcements,someofwhichdisintegratewhen
tact with Austenitic Stainless Steel
testedinaccordancewiththe1977edition.Wickinginsulations
C871 Test Methods for Chemical Analysis of Thermal
are materials that wet through and through when partially (50
Insulation Materials for Leachable Chloride, Fluoride,
to 75%) immersed in water for a short period of time (10 min
Silicate, and Sodium Ions
or less).
G30 Practice for Making and Using U-Bend Stress-
1.3 Theseproceduresareintendedprimarilyasapreproduc-
Corrosion Test Specimens
tion test for qualification of the basic chemical composition of
a particular manufacturer’s product and are not intended to be
3. Terminology
routine tests for ongoing quality assurance or production lot
3.1 Definitions:
compliance.Test Methods C871, on the other hand, is used for
Refer to Terminology C168 for definitions relating to insu-
confirmation of acceptable chemical properties of subsequent
lation.
lots of insulation previously found acceptable by this test
method.
4. Summary of Test Method
1.4 The values stated in inch-pound units are to be regarded
4.1 The procedures in this test method consist of using a
as standard. The values given in parentheses are mathematical
specimenofinsulationtoconductdistilled(ordeionized)water
conversions to SI units that are provided for information only
by wicking or dripping to an outside surface, through the
and are not considered standard.
insulation, to a hot inner surface of stressedType 304 stainless
1.5 This standard does not purport to address all of the
steelforaperiodof28days.Ifleachablechloridesarepresent,
safety concerns, if any, associated with its use. It is the
they are carried along with the water and concentrated at the
responsibility of the user of this standard to establish appro-
hot surface by evaporation in much the same way as has been
experienced in actual industrial process situations.
1
ThistestmethodisunderthejurisdictionofASTMCommitteeC16onThermal
InsulationandisthedirectresponsibilityofSubcommitteeC16.31onChemicaland
2
Physical Properties. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Oct. 1, 2008. Published October 2008. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1971. Last previous edition approved 2006 as C692–06. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/C0692-08. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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C692 – 08
4.2 Exposed stainless steel coupons are examined visually, or when heat treatment of a component of the insulation (such
and under 10 to 303 magnification, if necessary, to detect as an attached exterior jacket material) exceeds the manufac-
ESCC after the prescribed period of exposure. turer’s recommended maximum temperature for the exterior
1
component, then the 1 ⁄2-in. (38-mm) wide test specimen is
5. Significance and Use
3
sliced into two ⁄4-in. (19-mm) thick segments.The two halves
5.1 An inherent characteristic of some alloys of austenitic are held together with wire, pins, or a rubber band
...
This document is not anASTM standard and is intended only to provide the user of anASTM 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:C692–06 Designation: C 692 – 08
Standard Test Method for
Evaluating the Influence of Thermal Insulations on External
Stress Corrosion Cracking Tendency of Austenitic Stainless
1
Steel
This standard is issued under the fixed designation C692; 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
1.1 This test method covers two procedures for the laboratory evaluation of thermal insulation materials to determine whether
they contribute to external stress corrosion cracking (ESCC) of austenitic stainless steel due to soluble chlorides within the
insulation. This laboratory procedure is not intended to cover all of the possible field conditions that contribute to ESCC.
1.2 While the 1977 edition of this test method (Dana test) is applicable only to wicking-type insulations, the procedures in this
edition are intended to be applicable to all insulating materials, including cements, some of which disintegrate when tested in
accordance with the 1977 edition. Wicking insulations are materials that wet through and through when partially (50 to 75%)
immersed in water for a short period of time (10 min or less).
1.3 These procedures are intended primarily as a preproduction test for qualification of the basic chemical composition of a
particular manufacturer’s product and are not intended to be routine tests for ongoing quality assurance or production lot
compliance.Test Methods C871, on the other hand, is used for confirmation of acceptable chemical properties of subsequent lots
of insulation previously found acceptable by this test method.
1.4The values stated in inch-pound units are to be regarded as the standard.The values given in parentheses are for information
only.
1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
1.5 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.
2. Referenced Documents
2
2.1 ASTM Standards:
A240/A240M Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels
and for General Applications
A370 Test Methods and Definitions for Mechanical Testing of Steel Products
C168 Terminology Relating to Thermal Insulation
C795 Specification for Thermal Insulation for Use in Contact with Austenitic Stainless Steel
C871 Test Methods for Chemical Analysis of Thermal Insulation Materials for Leachable Chloride, Fluoride, Silicate, and
Sodium Ions
G30 Practice for Making and Using U-Bend Stress-Corrosion Test Specimens
3. Summary of Test Method
3.1The procedures in this test method consist of using a specimen of insulation to conduct distilled (or deionized) water by
wicking or dripping to an outside surface, through the insulation, to a hot inner surface of stressed Type 304 stainless steel for a
period of 28 days. If leachable chlorides are present, they are carried along with the water and concentrated at the hot surface by
evaporation in much the same way as has been experienced in actual industrial process situations.
3.2Exposedstainlesssteelcouponsareexaminedvisually,andunder10to303magnification,ifnecessary,todetectESCCafter
1
This test method is under the jurisdiction of ASTM Committee C16 on Thermal Insulation and is the direct responsibility of Subcommittee C16.31 on Chemical and
Physical Properties.
Current edition approved AprilOct. 1, 2006.2008. Published May 2006.October 2008. Originally approved in 1971. Last previous edition approved 20052006 as
C692–056.
2
ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatservice@astm.org.For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
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C692–08
the prescribed period of exposure. Terminology
3.1 Definitions:
Refer to Terminology C168 for definitions re
...
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