ASTM C692-13(2023)
(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
5.1 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 and fluoride ions have the potential to induce stress corrosion cracking in the absence of inhibiting ions.3
5.2 Chlorides are common to many environments, so great care shall be taken to protect austenitic stainless steel from chloride contamination.
5.3 Most thermal insulations will not, of themselves, cause stress corrosion cracking. Preproduction qualification tests are used to evaluate that under the conditions of the laboratory test that specific thermal insulation materials do not cause cracking of sensitized austenitic stainless steel. Insulation systems have the potential to act as collecting media by means of transmigration and concentration of corrosive ions on heated stainless steel surfaces. Exposure to elevated temperature results in evaporation of water and increased chemical reaction rates. Environments containing corrosive ions, moisture, and oxygen will increase the chance for stress corrosion cracking.
5.4 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.
5.5 The ability of the 28-day test to measure the corrosion potential of insulation materials is documented by Karnes,4 whose data appear to have been used for construction of the acceptability curve used in Specification C795 and other specifications.
5.6 The metal for all of the coupons used in this test method (C692) 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 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.
1.4 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Dev...
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Standards Content (Sample)
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: C692 − 13 (Reapproved 2023)
Standard Test Method for
Evaluating the Influence of Thermal Insulations on External
Stress Corrosion Cracking Tendency of Austenitic Stainless
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. 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 1.6 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.1 This test method covers two procedures for the labora-
ization established in the Decision on Principles for the
tory evaluation of thermal insulation materials to determine
Development of International Standards, Guides and Recom-
whether they contribute to external stress corrosion cracking
mendations issued by the World Trade Organization Technical
(ESCC) of austenitic stainless steel due to soluble chlorides
Barriers to Trade (TBT) Committee.
within the insulation. This laboratory procedure is not intended
to cover all of the possible field conditions that contribute to
2. Referenced Documents
ESCC.
2.1 ASTM Standards:
1.2 While the 1977 edition of this test method (Dana test) is
A240/A240M Specification for Chromium and Chromium-
applicable only to wicking-type insulations, the procedures in
Nickel Stainless Steel Plate, Sheet, and Strip for Pressure
this edition are intended to be applicable to all insulating
Vessels and for General Applications
materials, including cements, some of which disintegrate when
A370 Test Methods and Definitions for Mechanical Testing
tested in accordance with the 1977 edition. Wicking insulations
of Steel Products
are materials that wet through and through when partially
C168 Terminology Relating to Thermal Insulation
(50 % to 75 %) immersed in water for a short period of time
C795 Specification for Thermal Insulation for Use in Con-
(10 min or less).
tact with Austenitic Stainless Steel
1.3 These procedures are intended primarily as a preproduc-
C871 Test Methods for Chemical Analysis of Thermal Insu-
tion test for qualification of the basic chemical composition of
lation Materials for Leachable Chloride, Fluoride, Silicate,
a particular manufacturer’s product and are not intended to be
and Sodium Ions
routine tests for ongoing quality assurance or production lot
G30 Practice for Making and Using U-Bend Stress-
compliance. Test Methods C871, on the other hand, is used for
Corrosion Test Specimens
confirmation of acceptable chemical properties of subsequent
3. Terminology
lots of insulation previously found acceptable by this test
method.
3.1 Definitions: Refer to Terminology C168 for definitions
relating to insulation.
1.4 The values stated in inch-pound units are to be regarded
as standard. The values given in parentheses are mathematical
4. Summary of Test Method
conversions to SI units that are provided for information only
and are not considered standard.
4.1 The procedures in this test method consist of using a
specimen of insulation to conduct distilled (or deionized) water
1.5 This standard does not purport to address all of the
by wicking or dripping to an outside surface, through the
safety concerns, if any, associated with its use. It is the
insulation, to a hot inner surface of stressed Type 304 stainless
responsibility of the user of this standard to establish appro-
steel for a period of 28 days. If leachable chlorides are present,
priate safety, health, and environmental practices and deter-
they are carried along with the water and concentrated at the
mine the applicability of regulatory limitations prior to use.
hot surface by evaporation in much the same way as has been
experienced in actual industrial process situations.
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. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved May 1, 2023. Published June 2023. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1971. Last previous edition approved 2018 as C692 – 13 (2018). DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/C0692-13R23. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C692 − 13 (2023)
4.2 Exposed stainless steel coupons are examined visually, sometimes necessary to make the insulating material “wick,”
and under 10× to 30× magnification, if necessary, to detect and thus testable by either insulation test procedure (see
ESCC after the prescribed period of exposure. Sections 12 and 13).
6.3 If the test insulation cannot be made to wick in any way
5. Significance and Use
(such as in the case of organic or inorganic closed-cell foams),
or when heat treatment of a component of the insulation (such
5.1 An inherent characteristic of some alloys of austenitic
stainless steel is their tendency to crack at stress points when as an attached exterior jacket material) exceeds the manufac-
turer’s recommended maximum temperature for the exterior
exposed to certain corrosive environments. The mechanisms of
ESCC are complex and not completely understood but are component, then the 1 ⁄2 in. (38 mm) wide test specimen is
sliced into two ⁄4 in. (19 mm) thick segments. The two halves
apparently related to certain metallurgical properties. Chloride
and fluoride ions have the potential to induce stress corrosion are held together with wire, pins, or a rubber band, and are
tested by dripping into the crack between the two halves, thus
cracking in the absence of inhibiting ions.
simulating the situation where water penetrates the junction
5.2 Chlorides are common to many environments, so great
between two sections of insulation. Wetting the mating faces
care shall be taken to protect austenitic stainless steel from
on the two half sections facilitates water wicking down to the
chloride contamination.
coupon surface.
5.3 Most thermal insulations will not, of themselves, cause
6.4 Adhesives are tested by gluing together a test block of
stress corrosion cracking. Preproduction qualification tests are
the insulation material to be used with the adhesive. The
used to evaluate that under the conditions of the laboratory test
adhesive joint must come into contact with the stainless steel
that specific thermal insulation materials do not cause cracking
test coupon.
of sensitized austenitic stainless steel. Insulation systems have
6.5 Cements with a clay binder are tested by casting a
the potential to act as collecting media by means of transmi-
1 ⁄2 in. (38 mm) thick slab, drying, and using the drip proce-
gration and concentration of corrosive ions on heated stainless
dure. Such a sample will disintegrate in the Dana test proce-
steel surfaces. Exposure to elevated temperature results in
dure.
evaporation of water and increased chemical reaction rates.
Environments containing corrosive ions, moisture, and oxygen
6.6 The drip procedure has the potential to be used for the
will increase the chance for stress corrosion cracking.
testing of coatings applied to the coupon prior to test. The
corrosive liquids dripped into such a system are limited only by
5.4 Insulation materials are available that are specially
the imagination of the researcher.
formulated to inhibit stress corrosion cracking in the presence
of chlorides through modifications in basic composition or
7. Apparatus for Dana Test Procedure
incorporation of certain chemical additives.
7.1 Enclosure—In dusty environments, it is permissible for
5.5 The ability of the 28-day test to measure the corrosion
the test apparatus to be located in a cabinet or other closed
potential of insulation materials is documented by Karnes,
structure provided with a blower to maintain a positive internal
whose data appear to have been used for construction of the
pressure, and equipped with a filter for intake air to minimize
acceptability curve used in Specification C795 and other
dust or other contamination. The test apparatus is normally
specifications.
housed in any suitable clean environment not subject to
5.6 The metal for all of the coupons used in this test method chloride contamination. The enclosure shall not be so tight as
to exclude oxygen from the system, since oxygen is necessary
(C692) shall be qualified (see Section 14) to ascertain that
under conditions of the test, chloride ions will cause the metal for ESCC to occur.
to crack, and deionized water alone will not cause cracks.
7.2 Pyrex Glass Wool.
7.3 “Cookie Cutter,” made from 1 ⁄4 in. (32 mm) thin wall
6. Applicability (see also 11.2)
electrical conduit (inside diameter 1.38 in. (35 mm)) to cut a
6.1 While the original test procedure for the 1977 edition of 3
1 ⁄8 in. (35 mm) diameter plug from 2 in. (51 mm) Pyrex Glass
this test method (Dana Test) was limited to “wicking-type
Wool.
insulations,” the “drip test procedure” given in this edition is
7.4 Specimen Holder, as shown in Fig. 1, or equivalent.
applicable to all insulations when cut or formed into the
7.5 Precision Bender, see Practice G30.
required test specimen.
7.6 Wet-Grinding Belt Grinder, 80-grit.
6.2 Heat treatment at some temperature (as recommended
by the manufacturer) up to the maximum use temperature is
7.7 Copper Lugs, commercial 2/0–4/0 solderless, or 2 in. by
1 1
⁄2 in. by ⁄8 in. (51 mm by 13 mm by 3.2 mm) copper tabs.
7.8 Silver Solder, and chloride-free flux for use with stain-
Whorlow, Kenneth M., Woolridge, Edward and Hutto, Francis B., Jr., “Effect
less steel.
of Halogens and Inhibitors on the External Stress Corrosion Cracking of Type 304
7.9 Torch, acetylene or propane.
Austenitic Stainless Steel”; STP 1320 Insulation Materials: Testing and
Applications, Third Volume, Ronald S. Graves and Robert R. Zarr, editors , ASTM
7.10 Bolt, stainless steel, ⁄16 in. (5 mm) in diameter and
West Conshohocken, PA, 1997 page 485
2 ⁄2 in. (65 mm) long with insulating washer and nut for
Karnes, H. F., “The Corrosion Potential of Wetted Thermal Insulation,” AICHE,
57th National Meeting, Minneapolis, MN, September 26 through 29, 1965. electrically insulating the bolt from the U-bend specimen.
C692 − 13 (2023)
8.3 I.V. Bottles, 1 L or equivalent, to individually supply
each test specimen with test liquid.
8.4 Specimen Holder, for grinding. See Fig. 1.
8.5 Precision Bender, see Fig. 2 in the 1979 edition of
Practice G30.
8.6 Wet-Sanding Belt Sander, with 80-grit belt.
3 1
8.7 Bolt, stainless steel, ⁄16 in. (5 mm) in diameter by 2 ⁄2 in.
(65 mm) long with nut.
8.8 Hole Saw, 2 in. (51 mm) outside diameter.
FIG. 1 Suction Cup Coupon Holder
8.9 Band Saw.
8.10 Thermocouple, 28 gauge or smaller.
7.11 Hand-Held Magnifier, 10× or 30× binocular
8.11 Heat Transfer Grease, chloride free.
microscope, or both.
8.12 Kimwipe Tissue, chloride free.
7.12 Band Saw.
7.13 Hole Saw, 2 in. (51 mm) outside diameter (optional).
9. Reagents and Materials
7.14 Crystallizing Dish, of borosilicate glass, 7 ⁄2 in.
9.1 Distilled or Deionized Water, containing less than
(190 mm) in diameter by 4 in. (100 mm) in depth, or stainless
0.1 ppm chloride ions.
1 1
steel pan 9 ⁄2 in. by 5 ⁄2 in. by 4 in. (41 mm by 140 mm by 102
9.2 Distilled or Deionized Water, containing 1500 ppm
mm) deep.
chloride ion (2.473 g NaCl/L).
7.15 Electrical Transformer, isolation-type. (approximately
9.3 Type 304 Stainless Steel Sheet—16 gauge, meeting the
150 mV/150 AMP).
composition requirements of Specification A240/A240M. Cer-
7.16 Thermocouple, 28 gauge or smaller.
tificates of chemical composition and mechanical properties,
including ultimate tensile strength and yield strength by the
7.17 Epoxy Adhesive, aluminum filled.
0.2 % offset method are required. Type 304 stainless steel
7.18 Drill Bit, ⁄32 in. (7 mm), cobalt steel preferred.
meeting Specification A240/A240M shall have a carbon con-
7.19 Dye Penetrant and Developer, available at most weld-
tent in the range of 0.05 %–0.06 % and shall be solution-
ing supply houses.
annealed.
8. Apparatus for Drip Test Procedure
10. Test Coupons
8.1 Steam Heated Pipe—A 5 ft (1.5 m) section of 1 ⁄2 in. 10.1 Shear 2 in. by 7 in. (51 mm by 178 mm) coupons from
IPS pipe (inconel or other corrosion-resistant material), is
16 gauge Type 304 stainless sheet, as specified in 9.3, with the
heated either by a small self-contained steam boiler or by long dimension parallel to the long dimension of the sheet.
regulated house steam.
(Long dimension parallel to sheet-rolling direction.)
8.2 Peristaltic Pump—A multichannel peristaltic pump is 10.2 Clean coupons with chloride-free liquid soap and water
used to supply 250 (625) mL/day to each specimen.
to remove any grease or other contamination.
10.3 Sensitize all coupons before bending by heating at
1200 °F (649 °C) in an argon (inert) or air (oxidizing) atmo-
sphere for three hours. Let cool in the furnace after the
sensitizing period. Temperature of the coupons must be
measured in the stack of coupons, not in the furnace itself, as
the coupon temperatures “lag” the furnace temperature by at
least 50 °F to 100 °F (28 °C to 56 °C).
10.4 A suggestion for sensitizing in an inert atmosphere is to
use a stainless steel box with a tight-fitting cover to contain the
argon around the coupons during sensitization.
10.5 Grip coupon with suction cup holder (see Fig. 1) or
other means to facilitate wet grinding on an 80-grit belt grinder.
Grind parallel to the long dimension of the coupon using an
Kimwipe is a trademarked product of Kimberly-Clark Corp., Roswell, GA.
For a discussion of the effect of sensitizing stainless steel and its susceptibility
to stress corrosion, refer to “Stress-Corrosion Cracking of Sensitized Stainless Steel
FIG. 2 Typical External Stress Corrosion Cracks (5× Magnifica- in Oxygenated High Temperature Water,” Batelle Columbus Laboratories, Report
tion) No. BMI 1927, June 1972.
C692 − 13 (2023)
80-grit wet belt with just enough pressure to remove the dull 10.11 Obtain the value of the yield strength and the modulus
finish and leave the metal bright. Do not overgrind. The of elasticity from the certified statement of mechanical prop-
beltground face is the test surface
...
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