1、Designation: F 945 06Standard Test Method forStress-Corrosion of Titanium Alloys by Aircraft EngineCleaning Materials1This standard is issued under the fixed designation F 945; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye
2、ar of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.INTRODUCTIONChemical solutions and compoun
3、ds used for preinspection cleaning or for preservation of titaniumalloy aircraft turbine engine parts shall be subject to qualification requirements of this test method.1. Scope1.1 This test method establishes a test procedure for deter-mining the propensity of aircraft turbine engine cleaning andma
4、intenance materials for causing stress corrosion cracking oftitanium alloy parts.1.2 The evaluation is conducted on representative titaniumalloys by determining the effect of contact with cleaning andmaintenance materials on tendency of prestressed titaniumalloys to crack when subsequently heated to
5、 elevated tempera-tures.1.3 Test conditions are based upon manufacturers maxi-mum recommended operating solution concentration.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish a
6、ppro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For specificprecautionary statements, see 5.3 and 5.6.2. Referenced Documents2.1 ASTM Standards:2D 740 Specification for Methyl Ethyl KetoneD 841 Specification for Nitration Grade Toluene
7、D 1193 Specification for Reagent Water2.2 SAE Aerospace Material Specifications:AMS 4911 Sheet, Strip and Plate-6AL-4V Annealed3AMS 4916 Sheet, Strip, and Plate-8AL 1MO 1V, DuplexAnnealed33. Significance and Use3.1 Because of the tendency of prestressed titanium alloyparts to crack if heated while i
8、n contact with certain chemicalreagents, it is necessary to ensure that cleaning and mainte-nance materials will not initiate stress corrosion of titaniumalloys under controlled conditions. For test specimens, twocommon titanium alloys are selected, one that is very suscep-tible (AMS 4916) and one t
9、hat is not very susceptible(AMS 4911) to stress corrosion cracking.4. Apparatus4.1 Measuring Device capable of linear measurement witha 60.01-in. (60.25-mm) tolerance.4.2 Press Forming Apparatus4with 0.56-in. (14-mm) di-ameter mandrel capable of producing approximately 65 bendsin 0.050-in. (1.25-mm)
10、 titanium alloy sheet specimens.4.3 Beakers or Small Tanks for containment of cleaning,rinsing, and test solutions, appropriately lined to preventcontamination of the solutions by container materials.4.4 Vise, capable of precise manipulation at jaw opening of0.65 in. (16.5 mm). A standard sheet meta
11、l workers vise witha 3-in. jaw has been found satisfactory.4.5 Air Circulation Furnace capable of operating at 900F(480C) with control to 620F (10C).4.6 Magnifier capable of 20-diameters magnification.4.7 Microscope capable of 500-diameters magnification.4.8 Bolt, stainless steel, 0.25-in. (6-mm) di
12、ameter withstainless steel washers and nut.1This test method is under the jurisdiction of ASTM Committee F07 onAerospace and Aircraft and is the direct responsibility of Subcommittee F07.07 onQualification Testing of Aircraft Cleaning Materials.Current edition approved April 1, 2006. Published April
13、 2006. Originallyapproved in 1985. Last previous edition approved in 2001 as F 945 - 01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summa
14、ry page onthe ASTM website.3Available from Society of Automotive Engineers, 400 Commonwealth Dr.,Warrendale, PA 15096.4The sole source of supply of the apparatus (A laboratory bench hydraulic pressENER PAC Model No. P-39 has been found satisfactory) known to the committeeat this time is Black Hawk I
15、ndustrial Products, Butler, WI 53007. If you are awareof alternative suppliers, please provide this information to ASTM InternationalHeadquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee,1which you may attend.1Copyright ASTM International,
16、100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.9 Test Specimens, AMS 4911 and AMS 4916 TitaniumAlloyswith specimens prepared from the same sheet stockfor each alloy and cut parallel to the rolling direction to thedimensions of Fig. 1. The specimen edges shall n
17、ot be deburredor otherwise relieved before testing.4.10 Cotton Gloves, white.4.11 Volumetric Flask of Low Sodium Glass with GroundGlass Stopper, 1000 and 100 mL.4.12 Volumetric Pipette,10mL.4.13 Volumetric Flask with Ground Glass Stopper, 100 mL.5. Reagents and Materials5.1 Purity of ReagentReagent
18、grade chemicals shall beused in all cases. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.5Other grades may beused, provided it is first
19、ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of analysis.5.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water conformingto Specification D 1193 Type IV.5.3 Cleaning Solution, mix 35 v
20、olume % nitric acid (42Be8)(WarningSee Annex A1.2) and 3 volume % hydrofluoric acid (70 %) (WarningSee Annex A1.3) with reagentwater.5.4 2Propanol (Isopropanol), HPLC grade.5.5 Salt Solutions:5.5.1 100ppm sodium chloride solution in 2propanol.5.5.1.1 Preparation of 1000ppm NaCl in 2Propanol StockSol
21、ution (Shelf Life Three Months in Flask, see 4.11)Weigh1.000g NaCl 6 0.001 g into a 1000mLvolumetric flask.Add250- 6 25-mL reagent water and stir to dissolve. Fill to themark with 2propanol and mix.5.5.1.2 Preparation of 100ppm NaCl Test Solution (ShelfLife Seven Days in Flask, see 4.11)Pipette 10 m
22、L of thestock solution into a 100mL volumetric flask. Fill to the markwith 2-propanol and mix.5.5.2 Preparation of 3 Weight % Sodium Chloride in 2Pro-panol (Shelf Life Three Months)Weight 3.00g NaCl into a100mL volumetric flask (see 4.13). Add about 50 mL ofreagent water and stir to dissolve. Fill t
23、o the mark with2propanol and mix.5.6 Solvent, toluene conforming to Specification D 841 ormethyl ethyl ketone conforming to Specification D 740.(WarningSee Annex A1.1).NOTE 1The use of 2propanol is important to ensure an evendistribution of the salt by evaporating quickly. This decreases the effect
24、ofa “drop” at the bottom of the specimens.6. Precleaning Test Specimens6.1 Handling contamination and shop soils shall be removedby washing in a solvent. Dry thoroughly.7. Specimen Fabrication7.1 With the short specimen axis as the bend axis, pressform the specimen around an approximately 0.45-in. (
25、14-mm)diameter mandrel in one operation so that an unrestrainedpreform angle of approximately 65 is obtained. See Fig. 2.7.2 Clean the specimen preform by immersing in cleaningsolution of 5.3 for 15 6 5 s. Rinse in clean water, then inreagent water. Air dry with the bend zone up. Use white cottonglo
26、ves when handling specimens and do not touch the bendzone after cleaning.7.3 Final U-bend configuration shall be accomplished bybending the free ends of the preform together in a vise until thedistance between the free ends is reduced to 0.65 in. 6 0.05(16.5 6 1 mm).7.4 Restrain the test specimen wi
27、th sides approximatelyparallel by fastening the ends with a clean 0.25-in. (6-mm)diameter stainless steel bolt with washers. Unplated stainlesssteel nuts may be used. See Fig. 3.7.5 Load the specimen by tightening the bolt until the legsare 0.535 6 0.005 in. (13.6 6 0.10 mm) apart. See Fig. 3.NOTE 2
28、Before acquiring titanium alloy sheet for the fabrication oftest panels, notably AMS 4916, it is recommended to establish thatsusceptibility for SCC is present according to Section 8, using theappropriate salt solutions. If no cracking is exhibited, the test must berepeated using another lot of AMS
29、4916 titanium alloy.5Reagent Chemicals, American Chemical Society Specifications , AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the Uni
30、ted States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.FIG. 1 U-Bend Specimen DimensionsF9450628. Procedure (See Fig. 4.)8.1 Test a minimum of nine specimens of each alloy usingthe following procedure.8.1.1 To establish acceptability of the titanium a
31、lloy sheetmaterials for use in these tests, test three restrained testspecimens of each alloy without contacting any test solutionafter acid cleaning.8.1.2 To establish sensitivity of the titanium alloy sheetmaterials to stress corrosion attack, wet three restrained testspecimens of AMS 4916 alloy b
32、y immersing in the 100ppmsodium chloride solution and three restrained test specimens ofAMS 4911 alloy by immersing in the solution of 3 weight %sodium chloride. Hang to dry with the bend zone down.Remove and test as in 8.2.NOTE 3Control specimens must be included in each actual test toensure proper
33、 materials, technique, and examination.8.1.3 To evaluate the effect of the candidate solution, wetthree restrained test specimens of each alloy by immersing inthe candidate solution at the maximum recommended concen-tration. Hang to dry with the bend zone down and test as in 8.2.8.2 Heat the restrai
34、ned specimens in an air circulationfurnace in accordance with method(s) to be specified by thepurchaser as follows:8.2.1 Method AHeat at 900 6 20F (480 6 10C) for 8 60.2 h.8.2.2 Method BHeat at 500 6 20F (260 6 10C) for 1686 4h.8.2.3 After heating, remove the specimens from the furnace,allow to cool
35、, and inspect for cracks.8.3 Preliminary EvaluationInspect all of the restrainedspecimens visually using 20-diameters magnification.8.3.1 If cracks are found on the untreated (control) speci-mens, repeat the entire stress corrosion test using acceptabletitanium alloy sheet material.8.3.2 If cracks a
36、re found on all candidate-solution-treatedspecimens, this shall be cause for rejection of the candidatecleaning material.8.3.3 All restrained specimens not found to be crackedduring visual inspection at 20-diameters magnification preparefor further inspection as follows:8.3.3.1 Remove the bolt restr
37、aints.8.3.3.2 Rinse in warm tap water; do not permit to dry.8.3.3.3 While wet, immerse in acid cleaning solution of 5.3for 15 6 5s.8.3.3.4 Rinse in tap water and air dry.8.3.3.5 Inspect metallographically as in 8.4.1.8.4 Metallographic Inspection.8.4.1 Make a cross section of each specimen at the be
38、ndnormal to the bend axis (parallel to the test panel long axis).Cut the specimens using a fine-tooth hacksaw or other appa-ratus capable of producing a smooth cut with minimal distur-bance of specimen edges. Make the cut approximately at thecenter axis in line with the holes. The metallographic spe
39、cimenshall encompass material from the bend to a point approxi-mately 0.5 in. (13 mm) from the bend. Examine the cut surfaceover the 0.5-in. (13-mm) distance on both sides of the bendFIG. 2 Brake Formed U-Bend SpecimenFIG. 3 Loaded U-Bend SpecimenPreliminary Examination20XExamine Control Specimens:I
40、f any are cracked, repeat entire test.If none are cracked proceed to examine candidate-solution-treated specimens.Hold uncracked NaCl-solution-treated specimens for metallographic examination.Examine Candidate-Solution-Treated Specimens:If all are cracked, candidate cleaning compound is rejected.If
41、some or none are cracked, proceed to clean specimens and perform metallographic examination.Metallographic Examination500XExamine Control Specimens:If any are cracked, repeat entire test.If none are cracked, proceed to examine NaCl- and candidate-solution-treated specimens.Examine NaCl-Solution-Trea
42、ted Specimens:If not all are cracked, repeat entire test procedure.If all are cracked, proceed to examine candidate-solution-treated specimens.Examine Candidate-Solution-Treated Specimens:If none are cracked, candidate cleaning compound is accepted.If all are cracked, candidate cleaning compound is
43、rejected.If some are cracked, entire test procedure may be repeated at the testers option.FIG. 4 Metallographic Inspection ChartF945063zone at 500 diameters following metallographic preparationappropriate to the specimen alloy composition.8.5 For the Metallographic Inspection Chart, see Fig. 4.9. De
44、termination of Test Results9.1 Detection of cracks on either the tension or compressionsurfaces of any of the untreated (control) specimens shall because to repeat the entire stress corrosion test using acceptabletitanium alloy sheet material.9.2 Failure to detect cracks on either the tension or com
45、-pression surfaces of all of the NaCl-solution-treated specimensshall be cause to repeat the entire stress corrosion test usingtitanium alloy sheet having a demonstrated susceptibility tostress corrosion cracking.9.3 Examine tension and compression surfaces ofcandidate-solution-treated specimens for
46、 cracks and make oneof the following dispositions:9.3.1 Failure to detect cracks on any specimen shall consti-tute an acceptance test for the candidate cleaning material.9.3.2 Detection of cracks on all specimens shall be cause forrejection of the candidate cleaning material.9.3.3 If some of the spe
47、cimens do not exhibit cracks, theentire stress corrosion test may be repeated at the option of thetesting facility.10. Report10.1 Report the name, type, source, and concentration of thecandidate material.10.2 Report heat treatment method applied, see 8.2.1 or8.2.2.10.3 Report the acceptance or rejec
48、tion of the candidatematerial.10.4 Report a description of any observed corrosion phe-nomena not considered in 9.3.10.5 Report whether retesting was conducted in accordancewith 8.3.1, 9.1, 9.2,or9.3.3.11. Precision and Bias11.1 No statement is made about either precision or bias ofthis test method s
49、ince the result merely states whether there isconformance to the criteria for success specified in the accom-panying material or process specification of the material beingtested, or both.12. Keywords12.1 controlled temperature conditions; engine cleaners;maximum operating concentration; metallographic inspection;prestressed titanium alloys; stress-corrosion cracking (SCC)ANNEX(Mandatory Information)A1. PRECAUTIONARY STATEMENTSA1.1 Solvent (Typical for Toluene)WARNINGFlammable. Vapor harmful.Keep away from heat, sparks and open flame.Kee
