1、Designation: F945 06 F945 12Standard Test Method forStress-Corrosion of Titanium Alloys by Aircraft EngineCleaning Materials1This standard is issued under the fixed designation F945; the number immediately following the designation indicates the year of originaladoption or, in the case of revision,
2、the year of last revision. A number in parentheses indicates the year of last reapproval. A superscriptepsilon () 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 co
3、mpounds 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 determining the propensity of aircraft turbine engine cleaning a
4、ndmaintenance materials for causing stress corrosion cracking of titanium alloy parts.1.2 The evaluation is conducted on representative titanium alloys by determining the effect of contact with cleaning andmaintenance materials on tendency of prestressed titanium alloys to crack when subsequently he
5、ated to elevated temperatures.1.3 Test conditions are based upon manufacturers maximum recommended operating solution concentration.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
6、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 responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of reg
7、ulatorylimitations prior to use. For specific precautionary statements, see 5.3 and 5.6.2. Referenced Documents2.1 ASTM Standards:2D740 Specification for Methyl Ethyl KetoneD841 Specification for Nitration Grade TolueneD1193 Specification for Reagent Water2.2 SAE Aerospace Material Specifications:AM
8、S 4911 Sheet, Strip and Plate-6AL-4V Annealed3AMS 4916 Sheet, Strip, and Plate-8AL 1MO 1V, Duplex Annealed33. Significance and Use3.1 Because of the tendency of prestressed titanium alloy parts to crack if heated while in contact with certain chemical reagents,it is necessary to ensure that cleaning
9、 and maintenance materials will not initiate stress corrosion of titanium alloys undercontrolled conditions. For test specimens, two common titanium alloys are selected, one that is very susceptible (AMS 4916) andone that is not very susceptible (AMS 4911) to stress corrosion cracking.4. Apparatus4.
10、1 Measuring Device capable of linear measurement with a 60.01-in. (60.25-mm) tolerance.4.2 Press Forming Apparatus4with 0.56-in. (14-mm) diameter mandrel capable of producing approximately 65 bends in0.050-in. (1.25-mm) titanium alloy sheet specimens.4.3 Beakers or Small Tanks for containment of cle
11、aning, rinsing, and test solutions, appropriately lined to prevent contaminationof the solutions by container materials.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.4 Vise, capable of precise manipulation at jaw opening of 0.65 i
12、n. (16.5 mm). A standard sheet metal workers vise with a 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,
13、 stainless steel, 0.25-in. (6-mm) diameter with stainless steel washers and nut.4.9 Test Specimens, AMS 4911 and AMS 4916 Titanium Alloyswith specimens prepared from the same sheet stock for eachalloy and cut parallel to the rolling direction to the dimensions of Fig. 1. The specimen edges shall not
14、 be deburred or otherwiserelieved before testing.4.10 Cotton Gloves, white.4.11 Volumetric Flask of Low Sodium Glass with Ground Glass Stopper, 1000 and 100 mL.4.12 Volumetric Pipette, 10 mL.4.13 Volumetric Flask with Ground Glass Stopper, 100 mL.5. Reagents and Materials5.1 Purity of ReagentReagent
15、 grade chemicals shall be used in all cases. Unless otherwise indicated, it is intended that allreagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, wheresuch specifications are available.5 Other grades may be used, provided it is fir
16、st ascertained that the reagent is of sufficiently highpurity to permit its use without lessening the accuracy of analysis.5.2 Purity of WaterUnless otherwise indicated, references to water shall be understood to mean reagent water conforming toSpecification D1193 Type IV.5.3 Cleaning Solution, mix
17、35 volume % nitric acid (42 Be) (Warning See Annex A1.2) and 3 volume % hydrofluoric acid (70 %) (WarningSee Annex A1.3) with reagent water.5.4 2Propanol (Isopropanol), HPLC grade.5.5 Salt Solutions:5.5.1 100ppm sodium chloride solution in 2propanol.1 This test method is under the jurisdiction of AS
18、TM Committee F07 on Aerospace and Aircraft and is the direct responsibility of Subcommittee F07.07 on QualificationTesting of Aircraft Cleaning Materials.Current edition approved April 1, 2006Nov. 1, 2012. Published April 2006November 2012. Originally approved in 1985. Last previous edition approved
19、 in 20012006 asF945 - 01.F945 06. DOI: 10.1520/F0945-06.10.1520/F0945-12.2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on th
20、e ASTM website.3 Available from Society of Automotive Engineers, 400 Commonwealth Dr., Warrendale, PA 15096.4 The sole source of supply of the apparatus (A laboratory bench hydraulic press ENER PAC Model No. P-39 has been found satisfactory) known to the committee atthis time is Black Hawk Industria
21、l Products, Butler, WI 53007. If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters.Your comments will receive careful consideration at a meeting of the responsible technical committee,1 which you may attend.5 Reagent Chemicals, American Chemic
22、al Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Ph
23、armacopeial Convention, Inc. (USPC), Rockville, MD.FIG. 1 U-Bend Specimen DimensionsF945 1225.5.1.1 Preparation of 1000ppm NaCl in 2Propanol Stock Solution (Shelf Life Three Months in Flask, see 4.11)Weigh1.000g NaCl 6 0.001 g into a 1000mL volumetric flask. Add 250- 6 25-mL reagent water and stir t
24、o dissolve. Fill to the markwith 2propanol and mix.5.5.1.2 Preparation of 100ppm NaCl Test Solution (Shelf Life Seven Days in Flask, see 4.11)Pipette 10 mL of the stocksolution into a 100mL volumetric flask. Fill to the mark with 2-propanol and mix.5.5.2 Preparation of 3 Weight % Sodium Chloride in
25、2Propanol (Shelf Life Three Months)Weight 3.00g NaCl into a100mL volumetric flask (see 4.13). Add about 50 mL of reagent water and stir to dissolve. Fill to the mark with 2propanol andmix.5.6 Solvent, toluene conforming to Specification D841 or methyl ethyl ketone conforming to Specification D740. (
26、WarningSee Annex A1.1).NOTE 1The use of 2propanol is important to ensure an even distribution of the salt by evaporating quickly. This decreases the effect of a “drop”at the bottom of the specimens.6. Precleaning Test Specimens6.1 Handling contamination and shop soils shall be removed by washing in
27、a solvent. Dry thoroughly.7. Specimen Fabrication7.1 With the short specimen axis as the bend axis, press form the specimen around an approximately 0.45-in. (14-mm) diametermandrel in one operation so that an unrestrained preform angle of approximately 65 is obtained. See Fig. 2.7.2 Clean the specim
28、en preform by immersing in cleaning solution of 5.3 for 15 6 5 s. Rinse in clean water, then in reagentwater. Air dry with the bend zone up. Use white cotton gloves when handling specimens and do not touch the bend zone aftercleaning.7.3 Final U-bend configuration shall be accomplished by bending th
29、e 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 with sides approximately parallel by fastening the ends with a clean 0.25-in. (6-mm) diameterstainless steel bolt with washers. Unplated st
30、ainless steel nuts may be used. See Fig. 3.7.5 Load the specimen by tightening the bolt until the legs are 0.535 6 0.005 in. (13.6 6 0.10 mm) apart. See Fig. 3.NOTE 2Before acquiring titanium alloy sheet for the fabrication of test panels, notably AMS 4916, it is recommended to establish that suscep
31、tibilityfor SCC is present according to Section 8, using the appropriate salt solutions. If no cracking is exhibited, the test must be repeated using another lotof AMS 4916 titanium alloy.8. Procedure (See Fig. 4.)8.1 Test a minimum of nine specimens of each alloy using the following procedure.8.1.1
32、 To establish acceptability of the titanium alloy sheet materials for use in these tests, test three restrained test specimensof each alloy without contacting any test solution after acid cleaning.8.1.2 To establish sensitivity of the titanium alloy sheet materials to stress corrosion attack, wet th
33、ree restrained test specimensof AMS 4916 alloy by immersing in the 100ppm sodium chloride solution and three restrained test specimens of AMS 4911 alloyby 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 m
34、ust be included in each actual test to ensure proper materials, technique, and examination.8.1.3 To evaluate the effect of the candidate solution, wet three restrained test specimens of each alloy by immersing in thecandidate solution at the maximum recommended concentration. Hang to dry with the be
35、nd zone down and test as in 8.2.8.2 Heat the restrained specimens in an air circulation furnace in accordance with method(s) to be specified by the purchaseras follows:FIG. 2 Brake Formed U-Bend SpecimenF945 1238.2.1 Method AHeat at 900 6 20F (480 6 10C) for 8 6 0.2 h.8.2.2 Method BHeat at 500 6 20F
36、 (260 6 10C) for 168 6 4 h.Removed. Use Method A.8.2.3 After heating, remove the specimens from the furnace, allow to cool, and inspect for cracks.8.3 Preliminary EvaluationInspect all of the restrained specimens visually using 20-diameters magnification.8.3.1 If cracks are found on the untreated (c
37、ontrol) specimens, repeat the entire stress corrosion test using acceptable titaniumalloy sheet material.8.3.2 If cracks are found on all candidate-solution-treated specimens, this shall be cause for rejection of the candidate cleaningmaterial.8.3.3 All restrained specimens not found to be cracked d
38、uring visual inspection at 20-diameters magnification prepare forfurther inspection as follows:8.3.3.1 Remove the bolt restraints.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 5.3 for 15 6 5 s.8.3.3.4 Rinse in tap water and air dry.8.3.
39、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 bend normal to the bend axis (parallel to the test panel long axis). Cut thespecimens using a fine-tooth hacksaw or other apparatus capable of producing a smooth cut with minim
40、al disturbance of specimenedges. Make the cut approximately at the center axis in line with the holes. The metallographic specimen shall encompass materialfrom the bend to a point approximately 0.5 in. (13 mm) from the bend. Examine the cut surface over the 0.5-in. (13-mm) distanceon both sides of t
41、he bend zone at 500 diameters following metallographic preparation appropriate to the specimen alloycomposition.8.5 For the Metallographic Inspection Chart, see Fig. 4.9. Determination of Test Results9.1 Detection of cracks on either the tension or compression surfaces of any of the untreated (contr
42、ol) specimens shall be causeto repeat the entire stress corrosion test using acceptable titanium alloy sheet material.9.2 Failure to detect cracks on either the tension or compression surfaces of all of the NaCl-solution-treated specimens shall because to repeat the entire stress corrosion test usin
43、g titanium alloy sheet having a demonstrated susceptibility to stress corrosioncracking.9.3 Examine tension and compression surfaces of candidate-solution-treated specimens for cracks and make one of thefollowing dispositions:9.3.1 Failure to detect cracks on any specimen shall constitute an accepta
44、nce test for the candidate cleaning material.9.3.2 Detection of cracks on all specimens shall be cause for rejection of the candidate cleaning material.9.3.3 If some of the specimens do not exhibit cracks, the entire stress corrosion test may be repeated at the option of the testingfacility.10. Repo
45、rt10.1 Report the name, type, source, and concentration of the candidate material.10.2 Report heat treatment method applied, see 8.2.1 or 8.2.2.10.3 Report the acceptance or rejection of the candidate material.10.4 Report a description of any observed corrosion phenomena not considered in 9.3.10.5 R
46、eport whether retesting was conducted in accordance with 8.3.1, 9.1, 9.2, or 9.3.3.FIG. 3 Loaded U-Bend SpecimenF945 12411. Precision and Bias11.1 No statement is made about either precision or bias of this test method since the result merely states whether there isconformance to the criteria for su
47、ccess specified in the accompanying material or process specification of the material being tested,or both.12. Keywords12.1 controlled temperature conditions; engine cleaners; maximum operating concentration; metallographic inspection;prestressed titanium alloys; stress-corrosion cracking (SCC)ANNEX
48、(Mandatory Information)A1. PRECAUTIONARY STATEMENTSA1.1 Solvent (Typical for Toluene)A1.1.1 WARNINGFlammable. Vapor harmful.Keep away from heat, sparks and open flame.Keep container closed.Use with adequate ventilation.Avoid breathing of vapor or spray mist.Avoid prolonged or repeated contact with s
49、kin.A1.2 Nitric Acid (Concentrated)A1.2.1 DANGERPoison. Corrosive. Strong oxidizer.Contact with organic material may cause fire.May be fatal if swallowed.Liquid and vapor cause severe burns.Harmful if inhaled.May cause delayed lung injury.Spillage may cause fire or liberate dangerous gas, or both.Do not get in eyes, on skin, or on clothing.Do not breathe vapor, spray, or mist.Dilute by adding acid to water.Keep in tightly closed container in approved acid storage cabinet.Keep cool.Preliminary Examination20XExamine Control Specim
