1、_ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising there
2、from, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 2010 SAE International All rights reserved. No part of this publication m
3、ay be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-4970 (outside U
4、SA) 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/AMS2642DAEROSPACEMATERIALSPECIFICATIONAMS2642 REV. D Issued 1972-11 Revised 2010-10Supersedin
5、g AMS2642C Structural Examination of Titanium Alloys Etch-Anodize Inspection Procedure RATIONALE AMS2642D results from a Five Year Review and update of this specification. 1. SCOPE 1.1 Purpose This specification covers a procedure for revealing the macrostructure and microstructure of selected titan
6、ium 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, applications, and processes described or referenced in this specif
7、ication 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 hazardous materials and to take necessary precautionary measures
8、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 supplier may work to a subsequent revision of a document unless a
9、 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 International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel:
10、 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org.AMS4901 Titanium Sheet, Strip, and Plate, Commercially Pure, Annealed, 70.0 ksi (485 MPa) Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without l
11、icense from IHS-,-,-SAE AMS2642D Page 2 of 62.2 ASTM Publications Available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.org.ASTM E 1447 Determination of Hydrogen in Titanium and Titanium Alloys by the Inert Gas Fusion T
12、hermal Conductivity Method 2.3 ASME Publications Available from American Society of Mechanical Engineers, 22 Law Drive, P.O. Box 2900, Fairfield, NJ 07007-2900, Tel: 973-882-1170, www.asme.org.ASME B46.1 Surface Texture, Roughness, Waviness and Lay 3. TECHNICAL REQUIREMENTS 3.1 Materials and Solutio
13、ns 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 Anodi
14、ze Solution An aqueous solution of 13 to 17 ounces/gallon (97 to 127 grams/L) of hydrated trisodium phosphate (Na3PO412H2O)shall be prepared and maintained at 8.5 pH 0.5 at room temperature. See 8.3. 3.1.3 Back Strip Solution An agitated aqueous solution of 42.5 to 51.5 ounces/gallon (320 to 385 gra
15、ms/liter) of nitric acid (technical grade, approximate sp gr 1.42) and 1.3 to 4.7 ounces/gallon (10 to 35 grams per liter) hydroflluoric acid (technical grade, approximate sp gr 1.15) shall be maintained at room temperature. 3.1.4 Specimens for Macrostructure 3.1.4.1 Bars, Extrusions, Plates, and St
16、ock 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 from stock for alpha beta forging or alpha beta extrusion shall be heated to a temperature 50 F 25 (28 C 14) degrees below the beta transus
17、as determined for the heat, held at heat for 60 minutes 5, and cooled at a rate equivalent to air cool or faster. Specimens from stock for beta forging or beta extrusion shall be heated to a temperature 50 F 25 (28 C 14) degrees above the beta transus as determined for the heat. Specimens shall be m
18、achined to have surface texture of 70 microinches (1.8 m) AA or finer, determined in accordance with 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
19、inspected by ultrasonic inspection procedures, the configuration used for such inspection is acceptable. Surface roughness shall be 70 microinches (1.8 m) AA or finer, determined in accordance with ASME B46.1. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reprodu
20、ction or networking permitted without license from IHS-,-,-SAE AMS2642D Page 3 of 63.1.4.3 Finished Parts Specimens shall be complete parts. No special preparation is required. 3.2 Equipment 3.2.1 A DC voltage source shall be capable of providing direct current with a maximum of 6% ripple at 30 VDC
21、(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, worn areas and corrosion. 3.3 Preparation 3.3.1 Specimens shall be
22、 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 acceptable to the cognizant engineering organization. 3.3.3 Areas on fin
23、ished 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, hardfaced areas, and nontitanium surfaces. 3.3.4 Etch-Anodize Macrostru
24、cture 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 after removal, specimens shall be immersed in clean tap water. Specim
25、ens 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 shall be applied for 30 seconds 1 using equipment in accordance with 3.2.1. Specimens shall not be agitated when
26、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 be anodized for up to four more additional 30-second cycles until current falls t
27、o 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 develops. Immersion time shall be measured from time of complete immersion of the spe
28、cimen. See 8.8. 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 (21
29、53 lx). See 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 E 1447. 3.4 Microstructure If examination (3.3.4.5) results in an inconclusive disposition, further evaluation of the microstructure of
30、etch-anodized specimens shall be established by the following procedure. 3.4.1 Specimens may be cut for examination of other planes as required. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE AM
31、S2642D Page 4 of 63.4.2 Polish and etch the specimens to be examined using metallographic techniques or replication techniques that will clearly reveal the microstructure. See 8.7. 3.4.3 Specimens shall be inspected to determine the microstructure and the nature of indications found in the macrostru
32、cture. 3.5 All parts shall be uniform in color and appearance after inspection. 4. QUALITY ASSURANCE PROVISIONS 4.1 Test specimen for hydrogen pick-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 th
33、e cognizant engineering organization. 4.2 Acceptance Tests Macrostructure (3.3.4), hydrogen pickup on parts (3.3.4.6), visual color and appearance (3.5), and, when applicable, microstructure (3.4) are acceptance tests and shall be performed to determine product acceptance. 4.3 Periodic Tests Tests t
34、o maintain all of the solutions used herein are periodic tests and shall be performed at a frequency established by the processor unless frequency of testing is specified by the cognizant engineering organization. See 8.4. 5. PREPARATION FOR DELIVERY Not applicable. 6. ACKNOWLEDGMENT A processor sha
35、ll mention this specification number and its revision letter in all quotations and when acknowledging purchase orders. 7. REJECTIONS Not applicable. 8. NOTES: 8.1 A change bar (l) located in the left margin is for the convenience of the user in locating areas where technical revisions, not editorial
36、 changes, have been made to the previous issue of this document. An (R) symbol to the left of the document title indicates a 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 on
37、ly. 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 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,
38、 anodizing, and hot water tanks. 8.2.3 For best results mechanical stirrers and/or air agitation are recommended in the alkaline cleaner tank, acid tanks, and the anodizing tank. 8.2.4 Timers should be used on both acid tanks and the anodizing tanks. Copyright SAE International Provided by IHS under
39、 license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE AMS2642D Page 5 of 68.2.5 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 instal
40、led 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. 8.2.6 Fi
41、xtures 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 prevent arcing and pitting. 8.3 The pH of the
42、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, Periodic Test Plan for Process Solutions, is recommended to satisfy the requirements for the control of processing solutions. 8.5 Sp
43、ecimens 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 follow
44、s: 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 betw
45、een 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 alumin
46、um-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 pre
47、paring 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 for approximately 5 seconds: 178 mL perchloric acid 120 mL reagent water 700 mL ethanol 100 mL 2-butoxy ethanol Copyright SA
48、E International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE AMS2642D Page 6 of 68.7.2 Etch 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 warm water rinse, but prior to drying. If specimens are rinsed in the bicarbonate solution, a subsequent r
