ASTM F945-22

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it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: F945 − 12 (Reapproved 2019) F945 − 22
Standard Test Method for
Stress-Corrosion of Titanium Alloys by Aircraft Engine
Cleaning Materials
This standard is issued under the fixed designation F945; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
INTRODUCTION
Chemical solutions and compounds used for preinspection cleaning or for preservation of titanium
alloy aircraft turbine engine parts shall be subject to qualification requirements of this test method.
1. Scope
1.1 This test method establishes a test procedure for determining the propensity of aircraft turbine engine cleaning and
maintenance 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 and
maintenance materials on tendency of prestressed titanium alloys to crack when subsequently heated to elevated temperatures.
1.3 Test conditions are based upon manufacturer’s maximum recommended operating solution concentration.
1.4 Units—The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions 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 any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use. For specific precautionary statements, see 5.3 and 5.6.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D740 Specification for Methyl Ethyl Ketone
D841 Specification for Nitration Grade Toluene
D1193 Specification for Reagent Water
This test method is under the jurisdiction of ASTM Committee F07 on Aerospace and Aircraft and is the direct responsibility of Subcommittee F07.07 on Qualification
Testing of Aircraft Cleaning Materials.
Current edition approved May 1, 2019Sept. 1, 2022. Published June 2019September 2022. Originally approved in 1985. Last previous edition approved in 20122019 as
F945 – 12.F945 – 12(2019). DOI: 10.1520/F0945-12R19.10.1520/F0945-22.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F945 − 22
2.2 SAE Aerospace Material Specifications:
AMS 4911 Sheet, Strip and Plate-6AL-4V Annealed 0.050” Thick
AMS 4916 Sheet, Strip, and Plate-8AL 1MO 1V, Duplex Annealed 0.050” Thick
AMS 4919 Sheet, Strip, and Plate-6AL 2 Sn, 4 Zr, 2 Mo, Duplex Annealed 0.050” Thick
3. Significance and Use
3.1 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 and maintenance materials will not initiate stress corrosion of titanium alloys under
controlled conditions. For test specimens, two common titanium alloys are selected, one that is very susceptible (AMS 4916) 4916
or AMS 4919) and one that is not very susceptible (AMS 4911) to stress corrosion cracking.
4. Apparatus
4.1 Measuring Device capable of linear measurement with a 60.01-in. (60.25-mm)60.01 in. (60.25 mm) tolerance.
4.2 Press Forming Apparatus with 0.56-in. (14-mm)0.56 in. (14 mm) diameter mandrel capable of producing approximately 65°
bends in 0.050-in. (1.25-mm)0.050 in. (1.25 mm) titanium alloy sheet specimens.
4.3 Beakers or Small Tanks for containment of cleaning, rinsing, and test solutions, appropriately lined to prevent contamination
of the solutions by container materials.
4.4 Vise, capable of precise manipulation at jaw opening of 0.65 in. (16.5 mm). A standard sheet metal worker’s vise with a
3-in.3 in. jaw has been found satisfactory.
4.5 Air Circulation Furnace capable of operating at 900 °F (480 °C) with control to 620 °F (10 °C).
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)0.25 in. (6 mm) diameter with stainless steel washers and nut.
4.9 Test Specimens, AMS 4911 and AMS 4916 Titanium Alloys—or AMS 4919 Titanium Alloys with specimens prepared from the
same sheet stock for each alloy and cut parallel to the rolling direction to the dimensions of Fig. 1. The specimen edges shall not
be deburred or otherwise relieved before testing. Specimens shall not be machined or mechanically treated in any way such as
benching, sanding, etc.
FIG. 1 U-Bend Specimen Dimensions
Available from Society of Automotive Engineers, 400 Commonwealth Dr., Warrendale, PA 15096.
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 at
this time is Black Hawk Industrial 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, which you may attend.
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4.10 Cotton Gloves, white.
4.11 Volumetric Flask of Low Sodium Glass with Ground Glass Stopper, 1000 and 100 mL.100 mL.
4.12 Volumetric Pipette, 10 mL.10 mL.
4.13 Volumetric Flask with Ground Glass Stopper, 100 mL.100 mL.
5. Reagents and Materials
5.1 Purity of Reagent—Reagent grade chemicals shall be used in all cases. Unless otherwise indicated, it is intended that all
reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where
such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high
purity to permit its use without lessening the accuracy of analysis.
5.2 Purity of Water—Unless otherwise indicated, references to water shall be understood to mean reagent water conforming to
Specification D1193 Type IV.
5.3 Cleaning Solution, mix 35 volume % nitric acid (42° Be') (Warning —See Annex A1.2) and 3 volume % hydro–hydro-
fluoric acid (70 %) or 4.5 volume % hydrofluoric acid (49 %) (Warning—See Annex A1.3) with reagent water.
5.4 2–Propanol (Isopropanol), HPLC grade.
5.5 Salt Solutions:
5.5.1 100–ppm sodium chloride solution in 2–propanol.
5.5.1.1 Preparation of 1000–ppm NaCl in 2–Propanol Stock Solution (Shelf Life Three Months in Flask, see 4.11)—Weigh
1.000–g1.000 g NaCl 6 0.001 g into a 1000–mL1000 mL volumetric flask. Add 250- 6 25-mL reagent water and stir to dissolve.
Fill to the mark with 2–propanol and mix.
5.5.1.2 Preparation of 100–ppm NaCl Test Solution (Shelf Life Seven Days in Flask, see 4.11)—Pipette 10 mL of the stock solution
into a 100–mL100 mL volumetric flask. Fill to the mark with 2-propanol and mix.
5.5.2 Preparation of 3 Weight % Sodium Chloride in 2–Propanol (Shelf Life Three Months)—Weight 3.00–g3.00 g NaCl into a
100–mL100 mL volumetric flask (see 4.13). Add about 50 mL of reagent water and stir to dissolve. Fill to the mark with
2–propanol and mix.
5.6 Solvent, toluene conforming to Specification D841 or methyl ethyl ketone conforming to Specification D740. (Warning—See
Annex A1.1).
NOTE 1—The use of 2–propanol 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 Specimens
6.1 Handling contamination and shop soils shall be removed by washing in a solvent. Dry thoroughly.
Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by
the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National
Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.
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7. Specimen Fabrication
7.1 With the short specimen axis as the bend axis, press form the specimen around an approximately 0.45-in. (14-mm)0.45 in.
(14 mm) diameter mandrel in one operation so that an unrestrained preform angle of approximately 65° is obtained. See Fig. 2.
7.2 Clean the specimen preform by immersing in cleaning solution of 5.3 for 15 6 5 s. Rinse in clean water, then in reagent water.
Air dry with the bend zone up. Use white cotton gloves when handling specimens and do not touch the bend zone after cleaning.
7.3 Final U-bend configuration shall be accomplished by bending the free ends of the preform together in a vise until the distance
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)0.25 in. (6 mm)
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