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\4m~ Designation:B 154- 95

Standard Test MethodlorMercurous Nitrate Test f~)fCopper and Copper Alfoys1 1 6 O 8This standard is issued under tbe fixed designation B 154; tbe number immediate1y foUowing tbe designation indicates tbe year oforiginal adoption or, in tbe case of revision, tbe year of 1ast revision. A number in parentbeses indicates tbe year of 1ast reapproval. Asuperscript epsiIon (E)indicates an editorial change sinee tbe last revision or reapproval. "

This test method has been approvedfor use by agencies ofthe Department ofDefense to replace Method 831 ofFederal Test MethodStandard No. 151 b. Consult the DaD lndex of Specificmions and Standards for the specific year 01 issue that has been adopted by theDepartment of Delense.

1. Scope1.1 Tbis test metbod describes tbe tecbnique for con-

ducting tbe mercurous nitrate test for residual stress inwrougbt copper and cast or wrougbt copper-base alloyproducts. This test metbod is intended to cover tbe mercu-rous nitrate test of certain copper-alloy products supplied inaccordance witb ASTM specifications prepared by Com-mittee B-5. This test metbod is not intended to be used onassembled parts.

NOTEI-For any particularcopperalloy,referenceshouldbe madeto the materialspecification.

1.2 Tbe values stated in SI units are to be regarded as tbestandard. Tbe values given in parentbeses are for informa-tion only.

1.3 This standard does not purport to address all of thesafety concems, if any, associated with its use. lt is theresponsibilityof the user of this standard to establish appro-priate safety and health practices and determine the applica-"bility of regulatory limitations prior to use. For specificprecautionary and bazard statements seeNotes 2, 3, 4, 5, and6 and Sections 1, 4, 5, and 7.

NOTE2: Warning-Mercury is a definite hea1th hazard in use anddisposal.

2. Terminology2.1 Dejinitions:2.1.1 stress co"osion crack-spontaneous failure of metals

by cracking under combined action of corrosion and stress,residual or applied.

2.1.2 residual stress-stresses tbat remain witbin a bodyas tbe result of plastic deformation or casting.

3. Significanceand Use3.1 Tbis test metbod is an accelerated test for detecting

tbe presenceof residual (internal) stresseswhicb migbt resultin failure of individual parts in storage or in service due tostress corrosion cracking. Tbis test metbod is not intendedfor assembliesunder applied stress. If used for tbat purpose itsballbe for information only and not a cause for rejection oftbe assembly, its component parts, or tbe original miliproducto

I This test metbod is under tbe jurisdiction of ASTMCommitteeB-5 onCopper and Copper Alloys and is tbe direct responsibility ofSubcommittee 805.06on Metbods ofTest.

Currentedition approved Sept. 10, 1995. Published November 1995. Origina1lypublished as B 154 - 41 T. Last previous edition B 154 - 92.

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4. Mercurous Nitrate Solution

4.1 Concentration- Tbe solution sball be an aqueousmercurous nitrate solution containing 10g of HgN03 and 10mL of HN03 (sp gr 1.42)per litre of solution.

4.2 Preparation- Tbe aqueous mercurous nitrate solutionshall be prepared by eitber of tbe followingprocedures, A orB. Used solutions may be replenisbed as described in 4.3.

4.2.1 ProcedureA-Dissolve 11.4 g of HgN03.2H20 or10.7 g of HgN03 .H20 in approximately 40 roL of distilledwater acidified witb 10 mL of HN03 (sp gr 1.42).After tbecrystals are completely dissolved, dilute tbe solution witbdistilled water to 1000 mL.

NOTE3: Wamlng- The mercurous nitrate crystaIs are obtainable inboth the monohydrate and dihydrate form and should be bandled withcaution because of their highIy toxic effects.

NOTE4: Caution-When weighingcrystaIs, the weight ofthe water ofcrystallization should be taken into consideration. The mercurousnitrate crystals are photosensitive and when they have turned yellow aredifficult to dissolve.

NOTE5: Precaution-Care should be exercised when mixing chemi-caJs. Mixing should only be done by qualified personnel using appro-priate chemicallaboratory techniques.

4.2.2 ProcedureB-Dissolve 76 g of mercury in 114 mLof diluted HN03 (1 part water to 1part HN03) (sp gr 1.42).Carefully dilute witb distilled water to 1000 mL. Thisprovides a concentration of 100 g of HgN03 after a sligbt10ssdue 10 beating. Add tbe water in small portions whilestirring to prevent local overdilution. Tbis gradual dilution,togetber witb tbe excess acid, will prevent precipitation ofbasic salts ofmercury. Dilute 100mL oftbis solution (10 %)witb 7 mL ofHN03 (sp gr 1.42)and 893 mL ofwater.

NOTE6: Warning-Mercury is a definite hea1thhazard and thereforeequipment for the detection and removal of mercury vapor produced involatilization is recommended. The use of rubber gloves in testing isadvisable.

4.3 Replenishment of Solution- Tbe spent solution maybe reclaimed by replenishing tbe mercurous nitrate solution,to a 1 % concentration, as follows:

4.3.1 Measure as accurately as possible in a small gradu-ated cylinder 50 "mLof tbe spent HgN03 solution.

4.3.2 Transfer to an Erlenmeyer flask, and add 10 mL ofHN03 (1 + 1).

4.3.3 Add slowly KMn04 solution (1 %) from a buretwitb a constant shaking until tbere is an excess as indicatedby tbe pink color, whicb persists for several minutes.

4.3.4 Add FeS04 crystalsuntil tbe solution, wben shaken,becomes clear. Tben titrate tbe solution witb 0.1 N KCNSsolution to the appearance of a reddish brown color. Repeat

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4~ B 154

TABLE 1 Replenlshment of Spent Mercurous Nltrate Solution to1 '" Concentratlon

NOTe-X= 111.1(1 - R)where:R = fractlon of mercury remainlng in soIution (determined by titration). andX = number of millilltres of mercurous nitrate soIutlon (10 %) to be added to 1 L ofspent mercurous nitrate solution to raise the concentration of mercurous nitrate to1 %.

this procedure with 50 mL of a standard HgN03 solution(1 %).

4.3.5 The ratio, R. of the number of millilitres of KCNSsolution required to titrate the spent solution, to the numberof millilitres required to titrate the standard solution, deter-mines the number of millilitres, X, of 10 % HgN03 in 3 %HN03 solution required to replenish 1 L of spent solution.Values of R and X for a litre volume are given in Table 1.

s. Hazards5.1 Warning-Mercury is a definite health hazard in use

and disposal.5.2 Suggested Mercurous Nitrate Disposa/:5.2.1 To mercurous nitrate solutions add sodium hy-

droxide to pH 10 to 11.5.2.2 Filter precipitated mercury and other heavy metals.5.2.3 Though the filtrate is low in free mercurous or

mercuric ions, it must be further treated before disposal.5.2.4 To each litre of filtrate, add two drops (0.1 cm3) of

24 % ammonium sulfide.5.2.5 After the second fi1tering,the filtrate may be dis-

carded.

NOTE7-If heating is used in either of the previous procedures, thecontainer should be covered with a watch glass to prevent 10ssof HN03

5.2.5.1 Monitor the filtrate to assure it meets appropriatehealth safety standards, or is disposed of properly.

5.2.6 The precipitates should be collected and stored withthe mercury contaminated test samples and sold to a licensedmercury disposal service.

6. Test Specimen6.1 The test specimen shall be prescribed in the specifica-

tion for the material being tested. In the event that a testspecimen size is not prescribed in a given rod, wire, or tubespecification, a full cross-section length of 6 in. (152 mm)shall be tested.

6.2 The presence of burrs on the test specimen maycontribute to acceleration of stress corrosion cracking if notremoved prior to the mercurous nitrate test. The burrs shallbe removed by fine fileor abrasivepaper to facilitatethis test.

7. Procedure7.1 Degrease the specimen in a suitable a1ka1inedegreas-

ing solution or organic solventoIfnecessary, totally immersethe specimen in an aqueous solution of sulfuric acid (15volume %) or nitric acid (40 volume %) until all oxides arecompletely removed from its surface or pickle in such solu-tions as may be prescribed in the specification for the mate-rial being tested. Remove the specimen from the. picklingsolution and wash it immediately in running water. Drainthe specimen free of excess water and totally immerse it atroom temperature in the mercurous nitrate solution pre-pared in accordance with 4.2. Use at least 10 mL of mercu-rous nitrate solution per square inch of exposed surface ofthe test specimen.

7.2 After 30 min remove the specimen from the mercu-rous nitrate solution and wash it in running water. Wipe offany excess mercury from the surface of the specimen.Immediately examine it visually for cracks unless a timelimitation is provided in the product specification.

7.2.1 Tested specimens are mercury contaminated andmust be disposed of properly. They may not be includedwith retums for remelting or machined into producto

7.2.2 Make sure that rinse water and wiping material aremonitored to ensure that they meet appropriate hea1thsafetystandards, or are disposedof properly.

7.3 Do not reuse the solution unless it is replenished to1 % in accordance with the procedure in 4.3.

8. Precision and Bias8.1 No statement is made about the precision or bias of

this test method since the procedure is directed at a subjec-tive visual interpretation of condition of the specimen and itsrelation to an applicableproduct specification.

9. Keywords9.1 mercurous nitrate; residual stress; stress corrosion

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R X R X

0.10 100.0 0.56 48.90.12 97.8 0.58 46.7

0.14 95.5 0.60 44.40.16 93.3 0.62 42.20.18 91.1 0.64 40.0

0.20 88.9 0.66 37.80.22 86.7 0.68 35.60.24 84.4 0.70 33.30.26 82.2 0.72 31.10.28 80.0 0.74 28.9

0.30 77.8 0.76 26.70.32 75.5 0.78 24.40.34 73.3 0.80 22.20.36 71.1 0.82 20.00.38 68.9 0.84 17.8

0.40 66.7 0.86 15.60.42 64.4 0.88 13.30.44 62.2 0.90 11.10.46 60.0 0.92 8.90.48 57.8 0.94 6.7

0.50 55.6 0.96 4.40.52 53.3 0.98 2.20.54 51.1

41 B 154

The American Soclely far Testlng and Materlals talees no pasltlon respectlng the vaJldlty of any patent rlghts esserted In connectlonwlth any Item mentioned In thls standard. Users of thls standard are expressly edvised that determlnatlon of the vaJldlty of any such

patent rlghts, and the risk of Infrlngement of such rlghts, are entlrely thelr own responsibillty.

Thls standard is subject to revislon at any time by the 'responslble technlcaJ commlttee and must be revlewed evlll)' five yeatS andif not revised, elther respproved ar wlthdrawn. Your comments are Invlted elther far revislon of thls standard ar far addltlonal standardsand should be addressed lo ASTM Heedquarters, Your comments wlll rece/ve careful conslderatlon at a meeting of the responsibletechnlcal commlttee. whlch you may attend. If you feel that your comments have not recelved a falr haarlng you should malee yourviews known to the ASTM Commlttee on Standards, 1916 Race St., Phlladelphla, PA 19103. .

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