ASTM D807-2018 Standard Practice for Assessing the Tendency of Industrial Boiler Waters to Cause Embrittlement (USBM Embrittlement Detector Method).pdf

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1、Designation: D807 14D807 18Standard Practice forAssessing the Tendency of Industrial Boiler Waters toCause Embrittlement (USBM Embrittlement DetectorMethod)1,2This standard is issued under the fixed designation D807; the number immediately following the designation indicates the year oforiginal adop

2、tion 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. Scope1.1 This practice,3 known as the embrittlement-detector method, covers the a

3、pparatus and procedure for determining theembrittling or nonembrittling characteristics of the water in an operating boiler. The interpretation of the results shall be restrictedto the limits set forth in 8.6.NOTE 1The embrittlement detector was designed to reproduce closely the conditions existing

4、in an actual boiler seam. It is considered probable thatthe individual conditions of leakage, concentration, and stress in the boiler seam can equal those in the detector. The essential difference between thedetector and the boiler is that the former is so constructed and operated that these three m

5、ajor factors act simultaneously, continuously, and under the mostfavorable circumstances to produce cracking; whereas, in the boiler the three factors are brought together only under unique circumstances. Furthermore,in the detector any cracking is produced in a small test surface that can be inspec

6、ted thoroughly, while the susceptible areas in a boiler are large and canbe inspected only with difficulty. In these respects the embrittlement detector provides an accelerated test of the fourth condition necessary forembrittlement, the embrittling nature of the boiler water.NOTE 1Cracks in a speci

7、men after being subjected to this test indicate that the boiler water can cause embrittlement cracking, but not that the boilerin question necessarily has cracked or will crack.1.2 The effectiveness of treatment to prevent cracking, as well as an indication of whether an unsafe condition exists, are

8、 shownby this practice. Such treatments are evaluated in terms of method specimen resistance to failure.1.3 The practice may be applied to embrittlement resistance testing of steels other than boiler plate, provided that a duplicate,unexposed specimen does not crack when bent 90 on a 2-in. (51-mm) r

9、adius.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 to address all of the safety concerns, if

10、any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability ofregulatory limitations prior to use.1.6 This international standard was developed in accordance with international

11、ly recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:5A108 Specificat

12、ion for Steel Bar, Carbon and Alloy, Cold-FinishedA515/A515M Specification for Pressure Vessel Plates, Carbon Steel, for Intermediate- and Higher-Temperature ServiceD1129 Terminology Relating to Water1 This test method is under the jurisdiction of ASTM Committee D19 on Water and is the direct respon

13、sibility of Subcommittee D19.03 on Sampling Water andWater-Formed Deposits, Analysis of Water for Power Generation and Process Use, On-Line Water Analysis, and Surveillance of Water.Current edition approved Jan. 1, 2014Oct. 15, 2018. Published January 2014October 2018. Originally approved in 1944. L

14、ast previous edition approved in 20092014 asD807 05 (2009).D807 14. DOI: 10.1520/D0807-14.10.1520/D0807-18.2 United States Bureau of Mines.3 This test method was developed during an investigation conducted under a cooperative agreement between the Joint Research Committee on Boiler Feedwater Studies

15、and the United States Bureau of Mines. For information on the development of this test method reference may be made to the following: Schroeder and Berk, 1941 (1);4Schroeder, Berk, and Stoddard, 1941 (2); Transactions of the American Society of Mechanical Engineers, 1942 (3); Whirl and Purcell, 1942

16、 (4); and Berk and Schroeder,1943 (5).5 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standardsstandards Document Summary page on the ASTM website.This document

17、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 depict all changes accurately, ASTM recommends that users consult prior editions as appro

18、priate. 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, PA 19428-2959. United States1D1193 Specification for Reagent WaterE3 Guide for Preparation

19、of Metallographic SpecimensE883 Guide for ReflectedLight PhotomicrographyE1351 Practice for Production and Evaluation of Field Metallographic Replicas3. Terminology3.1 DefinitionsDefinitions:For3.1.1 For definitions of terms used in this standard, refer to Terminology D1129. definitions of other ter

20、ms used in this practice,refer to Terminology D1129.D807 1823.2 Definitions of Terms Specific to This Standard:3.2.1 embrittlement cracking, na form of metal failure that occurs in steam boilers at riveted joints and at tube ends, thecracking being predominantly intercrystalline.3.2.1.1 DiscussionTh

21、is form of cracking, which has been known as “caustic embrittlement,” is believed to result from the action of certainconstituents of concentrated boiler water upon steel under stress. For a detailed discussion as to what cracking should be consideredsignificant for the purpose of this practice, see

22、 8.6.4. Summary of Practice4.1 For embrittlement cracking of the boiler metal to be possible, the boiler water must concentrate a thousand times or morein contact with the metal under high residual or applied tensile stress. In a boiler such concentration may take place in riveted seamsor in annular

23、 spaces at tube ends, and the steel at such locations may be highly stressed when the boiler is constructed or maybecome highly stressed when it is operated. If the chemicals in the boiler water concentrate in the seams to develop an embrittlingsolution, cracking may occur.4.2 In the embrittlement d

24、etector (Fig. 1), the conditions of concentration and stress are provided by the design of the unit.Boiler water is permitted to seep slowly from the small hole through the restricted space between the contact surfaces of the testspecimen and the groove in the block. As this extremely slow flow take

25、s place toward atmospheric pressure, the heat in the metaland in the liquid causes progressive evaporation to produce an increasingly concentrated solution. When the detector is properlyadjusted, concentrated boiler water is in contact with the stressed test surface of the specimen, thus providing t

26、he necessary factorto determine whether the boiler water can cause embrittlement cracking.5. Significance and Use5.1 Embrittlement is a form of intercrystalline cracking that is associated with the exposure of boiler steel to a combination ofphysical and chemical factors. For embrittlement of boiler

27、 metal to occur, the metal must be under stress, it must be at the site ofa leak, and it must be exposed to the concentrated boiler water. In addition, the boiler water must be embrittling in nature. Thein. mm in. mm18 3.17 1 25.412 12.7 138 3534 19 234 702732 21.43FIG. 1 Cross-Section of Embrittlem

28、ent DetectorD807 183precise chemical causes of the embrittling nature of some waters are not well understood. Experience has shown that certain watersexhibit an embrittling characteristic while others do not.5.2 Because embrittlement is a form of cracking, it is nearly impossible to detect in an ope

29、rating boiler until a failure hasoccurred. In general, cracking failures tend to be sudden, and often with serious consequences. This practice offers a way todetermine whether a particular water is embrittling or not. It also makes it possible to determine if specific treatment actions haverendered

30、the water nonembrittling.5.3 The embrittlement detector was designed to reproduce closely the conditions existing in an actual boiler seam. It isconsidered probable that the individual conditions of leakage, concentration, and stress in the boiler seam can equal those in thedetector. The essential d

31、ifference between the detector and the boiler is that the former is so constructed and operated that thesethree major factors act simultaneously, continuously, and under the most favorable circumstances to produce cracking; whereas,in the boiler the three factors are brought together only under uniq

32、ue circumstances. Furthermore, in the detector any cracking isproduced in a small test surface that can be inspected thoroughly, while the susceptible areas in a boiler are large and can beinspected only with difficulty. In these respects the embrittlement detector provides an accelerated test of th

33、e fourth conditionnecessary for embrittlement, the embrittling nature of the boiler water.6. Apparatus6.1 Embrittlement DetectorThe embrittlement detector shall consist of the unit, complete with steel specimen, as shownassembled in cross section in Fig. 1 and as the installed unit in Fig. 2. The pr

34、incipal parts consist of a rectangular block basethrough which the water circulates and in which a groove has been machined to receive the test specimen, a test specimen, anda clamping plate which fits over four stud bolts in the block. When the nuts on the stud bolts are tightened, the pressure of

35、theclamping plate molds the test specimen to the contour of the groove, thus stressing in tension the surface of the specimen. Workingdrawings showing the dimensions of all the machined parts are shown in Figs. 3-5.Accurate machining of the groove with respectto the small hole through which the boil

36、er water is brought to the test surface of the specimen is especially important.6.2 WrenchesAn extra-heavy box-type wrench of 1116-in. (27-mm) opening is recommended for assembling and adjusting theunit. A lighter box-type wrench of 34-in. (19-mm) opening is recommended for the hexagonal head of the

37、 adjusting screw in theend of the specimen.6.3 Jig for Bending SpecimenA jig as shown in Fig. 6, or its equivalent, is recommended for bending the specimen with ahydraulic press at the end of the test to reveal cracks that may have been formed but are too fine to be visible without additionalstressi

38、ng of the steel surface. Other devices may be substituted to affect the same purpose of bending the specimen uniformly inthe proper place without injuring the surface to be studied (Note 32). A vise and sledge hammer shall not be used.FIG. 2 Embrittlement Detector InstalledD807 184in. mm in. mm in.

39、mm in. mm164 0.39 1116 17.46 1316 30 214 5718 3.17 2332 18.25 114 31.7 238 60316 4.76 34 19 11116 42.8 212 63.5516 7.93 1316 20.63 134 44.4 2916 6538 9.52 78 22.22 11316 46 318 792764 10.71 1 25.4 178 47.6 312 8912 12.7 118 28.6 2 50.8 5 12758 15.87FIG. 3 Dimensional Details of Base Block of Embritt

40、lement Detectorin. mm in. mm18 3.17 38 22.22516 7.93 1 25.458 15.87 138 3534 19 178 47.61316 20.63 312 89FIG. 4 Dimensional Details of Clamping Plate of EmbrittlementDetectorin. mm in. mmin. mm in. mm0.010 0.25 34 190.010364120.251.1912.734519127364 1.19 5 12712 12.7FIG. 5 Dimensional Details of Tes

41、t SpecimenD807 185NOTE 2The surface to be studied is the stressed area, which starts 14 in. (6 mm) above the spot corresponding to the opening in the test block andextends about 1 in. (25 mm) toward the adjusting screw.6.4 Grinding/polishing equipment.6.5 Magnifying glass, for inspecting for crack7.

42、 Reagents and Materials7.1 Purity of ReagentsUnless otherwise indicated, references to water shall be understood to mean reagent water conformingto Type IV of Specification D1193.7.2 Kerosine, commercial grade.7.3 Lubricating oil, commercial grade for thread lubrication.7.4 Graphite, commercial grad

43、e for thread lubrication.8. Procedure8.1 Test Specimens:8.1.1 Cut test specimens 12 by 34 by 5 in. (13 by 19 by 127 mm) from 12 by 34-in. (13 by 19-mm) cold-finished bar stock (Note43 and Note 54) conforming to Grade 1020 of Specification A108.NOTE 3Where specimens of cold-rolled steel have been cra

44、cked, similar specimens machined from boiler plate conforming to SpecificationA515/A515M, or hot-rolled steel of comparable composition may be tested to determine the severity of the embrittling condition. Hot-rolled steel hasproved less susceptible to cracking than cold-rolled steel.NOTE 4Alloy ste

45、els are often more susceptible for cracking than the standard cold-rolled steel specified for test specimens. Where the water testedis used in alloy-steel boilers, it is desirable that the test specimen be prepared from the same material or from bars of similar composition and physicalproperties.8.1

46、.2 Finish the test surface of the specimen by either grinding with a surface grinder to a finish comparable to that producedby No. 2 metallographic polishing paper, or milling to remove surface imperfections and smoothing with No. 2 metallographicpaper to remove the cutter marks. Grind and polish al

47、ong the length of the specimen. If the specimen surface still shows visibleflaws, such as holes, oxide, or rolling marks, after 0.01 in. (0.2 mm) has been removed, discard the specimen and prepare anotherone.8.1.3 Bevel the edges of the test surface 5, as shown in Fig. 5.8.1.4 Center the threaded ho

48、le in the specimen for the adjusting screw and tap as specified in Fig. 5 so that the cap screw isperpendicular to the surface. The adjusting screw shall be sufficiently free so that it can be turned easily with the fingers.NOTE 5Specimens that have been prepared in accordance with the directions gi

49、ven in Section 8 may be obtained from the major water-treatingcompanies.8.2 Assembly of Specimen and Detector:8.2.1 When a new specimen is to be installed in the detector (Note 76), clean the block, especially the surface of the groove,with hot water to dissolve soluble solids, and scrape lightly to remove less soluble incrustations. Polish the groove with fine emerycloth. Finally open the inlet valve for an instant to make sure that the small leakage hole is cleaned out, then wipe the groove clean.Trea