SAE AMS 2642E-2016 Structural Examination of Titanium Alloys Etch-Anodize Inspection Procedure.pdf

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4、0 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/AMS2642E AEROSPACE MATERIAL SPECIFICATION AMS2642 REV. E Issued 1972-11 Revised 2

5、016-02 Superseding AMS2642D Structural Examination of Titanium Alloys Etch-Anodize Inspection Procedure RATIONALE AMS2642E results from a Five Year Review and update of this specification and to bring it into alignment with AMS2643E. 1. SCOPE 1.1 Purpose This specification covers a procedure for rev

6、ealing the macrostructure and microstructure of selected titanium alloys. 1.2 Application This procedure has been used typically for detecting segregation, inclusions, and other defects in alpha-beta and certain alpha titanium alloys. 1.3 Safety-Hazardous Materials While the materials, methods, appl

7、ications, and processes described or referenced in this specification may involve the use of hazardous materials, this specification does not address the hazards which may be involved in such use. It is the sole responsibility of the user to ensure familiarity with the safe and proper use of any haz

8、ardous materials and to take necessary precautionary measures to ensure the health and safety of all personnel involved. 2. APPLICABLE DOCUMENTS The issue of the following documents in effect on the date of the purchase order forms a part of this specification to the extent specified herein. The sup

9、plier may work to a subsequent revision of a document unless a specific document issue is specified. When the referenced document has been cancelled and no superseding document has been specified, the last published issue of that document shall apply. 2.1 SAE Publications Available from SAE Internat

10、ional, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or +1 724-776-4970 (outside USA), www.sae.org. AMS4901 Titanium Sheet, Strip, and Plate, Commercially Pure, Annealed, 70.0 ksi (485 MPa) SAE INTERNATIONAL AMS2642E Page 2 of 6 2.2 ASTM Publications Av

11、ailable from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.org. ASTM E1447 Determination of Hydrogen in Titanium and Titanium Alloys by the Inert Gas Fusion Thermal Conductivity/Infrared Detection Method 2.3 ASME Publications

12、Available from ASME, P.O. Box 2900, 22 Law Drive, Fairfield, NJ 07007-2900, Tel: 800-843-2763 (U.S./Canada), 001-800-843-2763 (Mexico), 973-882-1170 (outside North America), www.asme.org. ASME B46.1 Surface Texture (Surface Roughness, Waviness, and Lay) 3. TECHNICAL REQUIREMENTS 3.1 Materials and So

13、lutions 3.1.1 Etch Solution An aqueous acid salt solution shall be prepared, the concentration of which shall be adjusted to maintain a metal removal rate of 0.00003 to 0.00005 inch (0.76 to 1.27 m) in 80 to 100 seconds after the onset of gas evolution. Operation shall be at room temperature. 3.1.2

14、Anodize Solution An aqueous solution of 13 to 17 ounces (weight)/gallon (97 to 127 grams/L) of hydrated trisodium phosphate (Na3PO412H2O) shall be prepared and maintained at 8.5 pH 0.5 pH at room temperature (see 8.3). 3.1.3 Back Strip Solution An agitated aqueous solution of 42.5 to 51.5 ounces (we

15、ight)/gallon (320 to 385 grams/L) of nitric acid (technical grade, approximate sp gr 1.42) and 1.3 to 4.7 ounces (weight)/gallon (10 to 35 grams per liter) hydrofluoric acid (technical grade, approximate sp gr 1.15) shall be maintained at room temperature. 3.1.4 Specimens for Macrostructure 3.1.4.1

16、Bars, Extrusions, Plates, and Stock for Forging or Extruding Specimens shall be transverse cross-sections not less than 0.50 inch (12.7 mm) thick, cut from the product to be tested. Specimens shall be machined to have surface texture of 70 microinches (1.8 m) AA or finer, determined in accordance wi

17、th ASME B46.1. 3.1.4.2 Forgings When dimensions permit, forgings shall be machined all over to remove approximately 0.040 inch (1.0 mm) of metal to ensure freedom from alpha case. If forgings are to be inspected by ultrasonic inspection procedures, the configuration used for such inspection is accep

18、table. Surface roughness shall be 70 microinches (1.8 m) AA or finer, determined in accordance with ASME B46.1. 3.1.4.3 Finished Parts Specimens shall be complete parts. No special preparation is required. SAE INTERNATIONAL AMS2642E Page 3 of 6 3.2 Equipment 3.2.1 A DC voltage source shall be capabl

19、e of providing direct current with a maximum of 6% ripple at 30 VDC (under no load) and shall be capable of ramping up the voltage to 30 VDC in 1 to 3 seconds. Automatic control is preferred. The equipment shall include a volt and amp meter. 3.2.2 Fixtures shall be free of distortion, loose fittings

20、, worn areas and corrosion. 3.3 Preparation 3.3.1 Specimens shall be free from water breaks. If water breaks are observed, parts shall be recleaned and reinspected for water break until no water breaks are observed (see 8.5). 3.3.2 Location of electrical contact points on finished parts shall be acc

21、eptable to the cognizant engineering organization. 3.3.3 Areas on finished parts that are not to be etch-anodize-inspected shall be protected by a suitable masking material. Such areas shall include inspection areas or surfaces, balance and identification markings applied by electrolytic etching, ha

22、rdfaced areas, and nontitanium surfaces. 3.3.4 Etch-Anodize Macrostructure Procedure 3.3.4.1 Specimens shall be immersed for 80 to 100 seconds after the onset of gassing in an agitated acid salt solution in accordance with 3.1.1. Immersed parts shall be agitated to remove entrapped air. Immediately

23、after removal, specimens shall be immersed in clean tap water. Specimens shall be pressure sprayed as required to remove smut. 3.3.4.2 Specimens shall be immersed in agitated anodize solution in accordance with 3.1.2 and then an anodic voltage of 30 VDC 1 VDC shall be applied for 30 seconds 1 second

24、 using equipment in accordance with 3.2.1. Specimens shall not be agitated when the voltage is applied. Specimens shall be removed from the anodizing solution and immediately rinsed in clean water. DO NOT TOUCH THE SPECIMEN WITH BARE HANDS. If the current does not fall below 1 ampere, the part may b

25、e anodized for up to four more additional 30 second cycles until current falls to less than 1 ampere. 3.3.4.3 Specimens shall be immersed in solution in accordance with 3.1.3 until a light blue-to-gray background color is obtained and maximum contrast between any segregation and the background devel

26、ops. 3.3.4.4 Immediately rinse and dry. 3.3.4.5 The specimens shall be immediately inspected for macrostructure and defects such as segregation, laps, folds, cracks, inclusions, arc outs, and pitted areas using 1 to 10X magnification and light intensity not lower than 200 foot-candles (2153 lx) (see

27、 8.6). 3.3.4.6 The hydrogen pick-up permitted when this inspection procedure is used on parts shall not exceed 20 ppm when tested in accordance with ASTM E1447. 3.4 Microstructure If examination (3.3.4.5) results in an inconclusive disposition, further evaluation of the microstructure of etch-anodiz

28、ed specimens shall be established by the following procedure. 3.4.1 Specimens may be cut for examination of other planes as required. 3.4.2 Polish and etch the specimens to be examined using metallographic techniques or replication techniques that will clearly reveal the microstructure (see 8.7). 3.

29、4.3 Specimens shall be inspected to determine the microstructure and the nature of indications found in the macrostructure. SAE INTERNATIONAL AMS2642E Page 4 of 6 3.5 All parts shall be uniform in color and appearance after inspection. 4. QUALITY ASSURANCE PROVISIONS 4.1 Test specimen for hydrogen p

30、ick-up (3.3.4.6) shall be a 0.040 inch (1.0 mm) maximum thickness titanium test strip in accordance with AMS4901. Test frequency shall be as specified by the cognizant engineering organization. 4.2 Acceptance Tests Macrostructure (3.3.4), hydrogen pickup on parts (3.3.4.6), visual color and appearan

31、ce (3.5), and, when applicable, microstructure (3.4) are acceptance tests and shall be performed to determine product acceptance. 4.3 Periodic Tests Tests to maintain all of the solutions used herein are periodic tests and shall be performed at a frequency established by the processor unless frequen

32、cy of testing is specified by the cognizant engineering organization (see 8.4). 5. PREPARATION FOR DELIVERY Not applicable. 6. ACKNOWLEDGMENT A processor shall mention this specification number and its revision letter in all quotations and when acknowledging purchase orders. 7. REJECTIONS Not applic

33、able. 8. NOTES 8.1 Revision Indicator A change bar (l) located in the left margin is for the convenience of the user in locating areas where technical revisions, not editorial changes, have been made to the previous issue of this document. An (R) symbol to the left of the document title indicates a

34、complete revision of the document, including technical revisions. Change bars and (R) are not used in original publications, nor in documents that contain editorial changes only. 8.2 Equipment 8.2.1 The tanks for the solutions of 3.1.1 and 3.1.3 should be lined with polyvinyl chloride or comparable

35、lining material; all others may be unlined. Compatible plastic tanks could also be used. 8.2.2 Temperature indicators and controllers should be used with the alkaline cleaner, anodizing, and hot water tanks. 8.2.3 For best results mechanical stirrers and/or air agitation are recommended in the alkal

36、ine cleaner tank, acid tanks, and the anodizing tank. 8.2.4 Timers should be used on both acid tanks and the anodizing tanks. 8.2.5 A nonramp-controlled rectifier should be equipped with a time actuated switch that, in less than 3 seconds after turning on the current, cut out a 1.2 ohm resistor inst

37、alled in series with the load (resistor reduces the initial surge of current and thereby reduces the chance of arcing). A ramp-controlled rectifier should provide voltage/current regulation with an adjustable current ramp regulator that has a zero to maximum rise time between 1 and 3 seconds. SAE IN

38、TERNATIONAL AMS2642E Page 5 of 6 8.2.6 Fixtures should be designed so that no nontitanium surfaces are exposed to any of the processing solutions. 8.2.7 Contact surfaces of fixtures should be contoured to match the contour of specimens in the contact areas and shall be kept clean and bright to preve

39、nt arcing and pitting. 8.3 The pH of the trisodium phosphate solution of 3.1.2 can be controlled by additions of phosphoric acid (H3PO4) to lower the pH or of sodium hydroxide (NaOH) to raise it. 8.4 ARP4992 is recommended to satisfy the requirements for the control of processing solutions. 8.5 Spec

40、imens should be cleaned in an alkaline cleaner prior to the etch-anodize macrostructure procedure. Specimens that do not contain recesses, in which solvent could be trapped, may be vapor degreased before cleaning in the alkaline cleaner. 8.6 Appearance Various types of segregation appear as follows:

41、 8.6.1 High Aluminum Defect (HAD) (Aluminum-Stabilized Alpha) Appears as a deeper blue irregular line, with or without branches, on a lighter blue-to-gray background. 8.6.2 Alpha Case (Interstitial Element-Stabilized Alpha (Oxygen and Nitrogen Contamination) Also appears blue. Differentiation betwee

42、n this and aluminum-stabilized alpha can generally be achieved by examination of microstructure using surface replication techniques. 8.6.3 Beta Fleck (Vanadium-Stabilized Beta) Appears as a gray or white line, with or without branches. This type of segregation is frequently associated with aluminum

43、-stabilized alpha, appearing as an adjacent parallel line. 8.6.4 Unalloyed Titanium Also appears light gray or white. Differentiation between this and vanadium-stabilized beta can be achieved by examination of microstructure using surface replication techniques. 8.7 The preferred procedure for prepa

44、ring specimens for direct examination of microstructure is as follows: 8.7.1 Polish electrolytically in a solution having approximately the following composition at 40 VDC 1 VDC for approximately 5 seconds: 178 mL perchloric acid 120 mL reagent water 700 mL ethanol 100 mL 2-butoxy ethanol 8.7.2 Etch

45、 with Krolls reagent (approximately 5% hydrofluoric acid (HF) (sp gr 1.15), 12% nitric acid (HNO3) (sp gr 1.42), 83% water) for sufficient time to develop the microstructure, wash in warm running water, and dry. If desired, specimens may be rinsed in a solution of sodium bicarbonate following the wa

46、rm water rinse, but prior to drying. If specimens are rinsed in the bicarbonate solution, a subsequent rinse in warm running water is required, before drying. SAE INTERNATIONAL AMS2642E Page 6 of 6 8.7.3 If surface replication techniques are to be used to evaluate the microstructure, the following p

47、rocedure is preferred. 8.7.3.1 Polish abrasively using usual metallographic techniques and then etch as in 8.7.2. 8.7.3.2 Cut the replicating paper into strips approximately 1 x 1/2 inch (25 x 12.7 mm). Apply 2 to 3 drops of acetone to the area to be replicated. Immediately position the replicating

48、paper over the area, being careful to avoid entrapment of air bubbles. Allow to dry for approximately 15 minutes. 8.7.3.3 Peel the replica off the part and place on a microscope slide with the replicated surface facing upward. Tape the replica down, making sure it lies flat. Examine the replica at 1

49、00X magnification using a metallurgical microscope. If the structure is not clearly revealed, re-etch the specimen and repeat the replication procedure. 8.7.3.4 For better contrast, the replica may be shadowed with a thin film of vapor deposited metallic chromium. 8.8 Typical immersion times for typical alloys are as shown in Table 1 for a hydrofluoric acid concentration of 20 grams/L; times and concentrations for other allo