ASTM C692-2013 Standard Test Method for Evaluating the Influence of Thermal Insulations on External Stress Corrosion Cracking Tendency of Austenitic Stainless Steel《评定奥氏体钢热绝缘材料对外应力.pdf
《ASTM C692-2013 Standard Test Method for Evaluating the Influence of Thermal Insulations on External Stress Corrosion Cracking Tendency of Austenitic Stainless Steel《评定奥氏体钢热绝缘材料对外应力.pdf》由会员分享,可在线阅读,更多相关《ASTM C692-2013 Standard Test Method for Evaluating the Influence of Thermal Insulations on External Stress Corrosion Cracking Tendency of Austenitic Stainless Steel《评定奥氏体钢热绝缘材料对外应力.pdf(9页珍藏版)》请在麦多课文档分享上搜索。
1、Designation: C692 081C692 13Standard Test Method forEvaluating the Influence of Thermal Insulations on ExternalStress Corrosion Cracking Tendency of Austenitic StainlessSteel1This standard is issued under the fixed designation C692; the number immediately following the designation indicates the year
2、 oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1 NOTEFig. 4 was editorially corrected in December 2010.1. Scope1.1
3、This test method covers two procedures for the laboratory evaluation of thermal insulation materials to determine whetherthey contribute to external stress corrosion cracking (ESCC) of austenitic stainless steel due to soluble chlorides within theinsulation. This laboratory procedure is not intended
4、 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 thisedition are intended to be applicable to all insulating materials, including cements, some of which
5、disintegrate when tested inaccordance 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 o
6、f the basic chemical composition of aparticular manufacturers product and are not intended to be routine tests for ongoing quality assurance or production lotcompliance. Test Methods C871, on the other hand, is used for confirmation of acceptable chemical properties of subsequent lotsof insulation p
7、reviously 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 mathematicalconversions to SI units that are provided for information only and are not considered standard.1.5 This standard does not purport t
8、o address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A240/A240M
9、 Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels andfor General ApplicationsA370 Test Methods and Definitions for Mechanical Testing of Steel ProductsC168 Terminology Relating to Thermal InsulationC795 Specification for Thermal Insulation f
10、or Use in Contact with Austenitic Stainless SteelC871 Test Methods for Chemical Analysis of Thermal Insulation Materials for Leachable Chloride, Fluoride, Silicate, andSodium IonsG30 Practice for Making and Using U-Bend Stress-Corrosion Test Specimens3. Terminology3.1 Definitions: Refer to Terminolo
11、gy C168 for definitions relating to insulation.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 andPhysical Properties.Current edition approved Oct. 1, 2008May 1, 2013. Published October 2008M
12、ay 2013. Originally approved in 1971. Last previous edition approved 20062008 asC692 06.C692 081. DOI: 10.1520/C0692-08.10.1520/C0692-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume in
13、formation, refer to the standards Document Summary page on the ASTM website.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. Becauseit may not be technically possible to adequately
14、 depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, P
15、A 19428-2959. United States14. Summary of Test Method4.1 The procedures in this test method consist of using a specimen of insulation to conduct distilled (or deionized) water bywicking or dripping to an outside surface, through the insulation, to a hot inner surface of stressed Type 304 stainless s
16、teel for aperiod of 28 days. If leachable chlorides are present, they are carried along with the water and concentrated at the hot surface byevaporation in much the same way as has been experienced in actual industrial process situations.4.2 Exposed stainless steel coupons are examined visually, and
17、 under 10 to 30 magnification, if necessary, to detect ESCC afterthe prescribed period of exposure.5. Significance and Use5.1 An inherent characteristic of some alloys of austenitic stainless steel is their tendency to crack at stress points when exposedto certain corrosive environments.The mechanis
18、ms of ESCC are complex and not completely understood but are apparently relatedto certain metallurgical properties. Chloride ions concentrated at a stress point will catalyze crack formation. It has been reportedthat other halide ions do not promote ESCC to the same degree as does chloride using the
19、 test technology of Test Method andfluoride ions have the potential to induce stress corrosion cracking in the absence of inhibiting ions.C692 (drip test).35.2 Chlorides are common to many environments, so great care shall be taken to protect austenitic stainless steel from chloridecontamination.5.3
20、 Most thermal insulations will not, of themselves, cause stress corrosion cracking as shown by qualification tests. Whenexposed to elevated-temperature (boiling point range), environments containing chlorides, moisture, and oxygen, however, someinsulation systems cracking. Preproduction qualificatio
21、n tests are used to evaluate that under the conditions of the laboratory testthat specific thermal insulation materials do not cause cracking of sensitized austenitic stainless steel. Insulation systems have thepotential to act as collecting media, transmigrating and concentrating chlorides media by
22、 means of transmigration andconcentration of corrosive ions on heated stainless steel surfaces. If moisture is not present, the chloride salts cannot migrate, andstress corrosion cracking because of chloride-contaminated insulation cannot take place.Exposure to elevated temperature resultsin evapora
23、tion of water and increased chemical reaction rates. Environments containing corrosive ions, moisture, and oxygen willincrease the chance for stress corrosion cracking.5.4 Insulation materials are available that are specially formulated to inhibit stress corrosion cracking in the presence ofchloride
24、s 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 whosedata appear to have been used for construction of the acceptability curve used in S
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