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 theref
2、rom, is the sole responsibility of the user.”SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions.Copyright 2013 SAE InternationalAll rights reserved. No part of this publi
3、cation may 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 (out
4、side USA)Fax: 724-776-0790Email: CustomerServicesae.orgSAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedbackon this Technical Report, please visithttp:/www.sae.org/technical/standards/AMS4988CAEROSPACE MATERIAL SPECIFICATIONAMS4988 REV. CIssued 2003-04Revised 2014-03Supersedin
5、g AMS4988BTitanium Alloy Sheet, Strip, and Plate6Al -6V -2SnSolution Heat Treated(Composition similar to UNS R56620)RATIONALEAMS4988C results from an update of this specification that requires vacuum in the first consumable electrode melt (3.2),revises transition from sheet to plate in Tables 3 and
6、4, requires agreement on mechanical property values on material outside specification ranges (3.5.2.1.2 and 8.7) and ultrasonic testing of all plate 0.500 inch (12.7 mm) and over (3.6.1), adds AS6279 (3.8), and revises the report paragraph (4.4).1. SCOPE1.1 FormThis specification covers a titanium a
7、lloy in the form of sheet, strip, and plate in thicknesses up through 4.000 inches (101.60 mm), inclusive (See 8.7).1.2 ApplicationThis material has been used typically for parts to be formed or machined in the solution heat treated condition and subsequently precipitation heat treated requiring hig
8、h strength-to-weight ratio and stability up to 550 F (288 C) in the precipitation heat treated condition, but usage is not limited to such applications.1.3 Certain processing procedures and service conditions may cause these products to become subject to stress-corrosion cracking; ARP982 recommends
9、practices to minimize such conditions.2. APPLICABLE DOCUMENTSThe 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 specific document iss
10、ue 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.SAE INTERNATIONAL AMS4988C Page 2 of 82.1 SAE PublicationsAvailable from SAE International, 400 Commonwealth Drive, Warrendale, PA 15
11、096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org.AMS2242 Tolerances, Corrosion and Heat-Resistant Steel, Iron Alloy, Titanium, and Titanium Alloy Sheet, Strip, and PlateAMS2249 Chemical Check Analysis Limits, Titanium and Titanium AlloysAMS2368 Sampling
12、and Testing of Wrought Titanium Raw Material Except Forgings and Forging StockAMS2631 Ultrasonic Inspection of Titanium AlloysAMS2750 PyrometryAMS2809 Identification, Titanium and Titanium Alloy Wrought ProductsARP982 Minimizing Stress-Corrosion Cracking in Wrought Titanium Alloy ProductsAS6279 Indu
13、stry Standard Practices for Production, Distribution, and Procurement of Metal Stock2.2 ASTM PublicationsAvailable 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 8 / E 8M Tension Testing of Metallic MaterialsAST
14、M E 112 Determining Average Grain SizeASTM E 290 Bend Testing of Material for DuctilityASTM E 384 Knoop and Vickers Hardness of MaterialsASTM E 1409 Determination of Oxygen and Nitrogen in Titanium and Titanium Alloys by the Inert Gas Fusion TechniqueASTM E 1447 Determination of Hydrogen in Titanium
15、 and Titanium Alloys by the Inert Gas Fusion Thermal Conductivity/Infrared Detection MethodASTM E 1941 Determination of Carbon in Refractory and Reactive Metals and Their Alloys by Combustion AnalysisASTM E 2371 Analysis of Titanium and Titanium Alloys by Direct Current Plasma and Inductively Couple
16、d Plasma Atomic Emission Spectrometry3. TECHNICAL REQUIREMENTS3.1 CompositionShall conform to the percentages by weight shown in Table 1; carbon shall be determined in accordance with ASTM E 1941, hydrogen in accordance with ASTM E 1447, oxygen and nitrogen in accordance with ASTM E 1409, and other
17、elements in accordance with ASTM E 2371. Other analytical methods may be used if acceptable to the purchaser.SAE INTERNATIONAL AMS4988C Page 3 of 8TABLE 1 - COMPOSITIONElement min maxAluminum 5.00 6.00Vanadium 5.00 6.00Tin 1.50 2.50Iron 0.35 1.00Copper 0.35 1.00Oxygen - 0.20Carbon - 0.05Nitrogen - 0
18、.04 (400 ppm)Hydrogen - 0.015 (150 ppm)Yttrium (3.1.1) - 0.005 ( 50 ppm)Other Elements each (3.1.1) - 0.10Other Elements, total (3.1.1) - 0.40Titanium remainder3.1.1 Determination not required for routine acceptance.3.1.2 Check AnalysisComposition variations shall meet the applicable requirements of
19、 AMS2249.3.1.3 Sample size, when using ASTM E 1447, may be as large as 0.35 gram.3.2 Melting PracticeAlloy shall be multiple melted. The first melt shall be made by vacuum consumable electrode, nonconsumable electrode, electron beam cold hearth, or plasma arc cold hearth melting practice. Subsequent
20、 melt or melts shall be made under vacuum using vacuum arc remelting (VAR) practice. Alloy additions are not permitted in the final (VAR) melt 3.2.1 The atmosphere for non-consumable electrode melting shall be vacuum or shall be argon and/or helium at an absolute pressure not higher than 1000 mm of
21、mercury.3.2.2 The electrode tip for nonconsumable electrode melting shall be water-cooled copper.3.3 ConditionThe product shall be supplied in the following condition:3.3.1 Sheet and StripHot rolled, with or without subsequent cold reduction, solution heat treated, descaled, and leveled, having a su
22、rface appearance comparable to a commercial corrosion-resistant steel No. 2D finish (See 8.3).3.3.2 PlateHot rolled, solution heated, and flattened, having a surface appearance comparable to a commercial corrosion-resistant steel No. 1 finish (See 8.3). Plate product shall be produced using standard
23、 industry practices designed strictly for the production of plate stock to the procured thickness. Bar, billet, forgings, or forging stock shall not be supplied in lieu of plate.3.4 Heat TreatmentThe product shall be solution heat treated as follows; pyrometry shall be in accordance with AMS2750:SAE
24、 INTERNATIONAL AMS4988C Page 4 of 83.4.1 Sheet, strip and plate shall be solution heat treated by heating to a temperature within the range 1550 to 1700 F (843 to 927 C), holding at selected temperature within 25 F (14 C) for 2 to 60 minutes, and quenching in agitated water. Air cooling may be appli
25、ed in thin material.3.5 PropertiesProduct shall conform to the following requirements:3.5.1 As Solution Heat Treated3.5.1.1 Tensile PropertiesShall be as specified in Table 2, determined in accordance with ASTM E 8 / E 8M with the rate of strain set at 0.005 inch/inch/minute (0.005 mm/mm/minute) and
26、 maintained within a tolerance of 0.002 inch/inch/minute (0.002 mm/mm/minute) through the 0.2% offset yield strain.TABLE 2A - TENSILE PROPERTIES, INCH/POUND UNITS (SEE 8.2)Nominal Thickness InchTensileStrengthksiYield Strengthat 0.2% Offsetksi, maxElongation in2 Inches or 4D%, minUp to 0.1875, excl
27、(3.5.1.1.1) 160 10 (3.5.1.1.2)TABLE 2B - TENSILE PROPERTIES, SI UNITS (SEE 8.2)Nominal ThicknessMillimetersTensileStrengthMPaYield Strengthat 0.2% OffsetMPa, maxElongation in50.8 mm or 4D%, minUp to 4.76, excl (3.5.1.1.1) 1103 10 (3.5.1.1.2)3.5.1.1.1 Spread between tensile strength and yield strengt
28、h shall be 15 ksi (103 MPa) minimum.3.5.1.1.2 For thickness under 0.025 inch (0.64 mm), elongation values shall be as agreed upon.3.5.1.2 BendingProduct under 0.1875 inch (4.762 mm) in nominal thickness, shall have a test sample prepared nominally 0.750 inch (19.06 mm) in width, with its axis of ben
29、ding parallel to the direction of rolling. The sample shall be bend tested in conformance with the guided bend test defined in ASTM E 290 through an angle of 105 degrees. The test fixture supports shall have a contact radius 0.010 minimum, and the plunger shall have a radius equal to the bend factor
30、 shown in Table 3 times the nominal thickness. Examination of the bent sample shall show no evidence of cracking when examined at 15 to 25X magnification.TABLE 3 - BEND FACTORNominal ThicknessInchNominal ThicknessMillimetersBendFactorUp to 0.070, excl Up to 1.78, excl 40.070 to 0.1875, excl 1.78 to
31、4.762, excl 4.53.5.1.3 MicrostructureShall be that structure resulting from processing within the alpha-beta phase field. Microstructure shall conform to 3.4.1.3.1 (See 8.5).3.5.1.3.1 Equiaxed and/or elongated primary alpha in a transformed beta matrix with no continuous network of alpha at prior be
32、ta grain boundaries.3.5.1.3.2 A microstructure showing a continuous network of alpha in prior beta grain boundaries is not acceptable.SAE INTERNATIONAL AMS4988C Page 5 of 83.5.1.4 Surface ContaminationThe product shall be free of any oxygen-rich layer, such as alpha case, or other surface contaminat
33、ion, determined as in any one of the following: 3.5.1.4.1, 3.5.1.4.2, 3.5.1.4.3, or other method acceptable to purchaser.3.5.1.4.1 The bend test of 3.5.1.2.3.5.1.4.2 Microscopic examination at 400X minimum.3.5.1.4.3 Hardness difference; a surface hardness more than 40 points higher than the subsurfa
34、ce hardness, determined in accordance with ASTM E 384 on the Knoop scale using a 200 gram load, being evidence of unacceptable surface contamination.3.5.1.5 Average Grain SizeShall be ASTM No. 6 or finer determined by comparison of a polished and etched specimen with the chart in ASTM E 112.3.5.2 Re
35、sponse to Heat TreatmentProduct shall conform to the following requirements after being precipitation heat treated by heating to a temperature within the range of 875 to 1150 F (468 to 621 C), holding at selected temperature within 15 F (8 C) for 2 to 10 hours, and cooling in air. Precipitation heat
36、 treatment shall precede final machining of specimens.3.5.2.1 Tensile PropertiesShall be as shown in Table 4, determined per 3.5.1.1. TABLE 4A - MINIMUM TENSILE PROPERTIES (SEE 8.2)Nominal ThicknessInchesTensile StrengthksiYield Strengthat 0.2% OffsetksiElongationin 2 in. or 4D%Up to 0.1875, excl 17
37、0 160 8 (6) (See 3.5.2.1.1)0.1875 to 1.500, excl 170 160 81.500 to 2.500, excl 160 150 62.500 to 4.000, incl 150 140 6TABLE 4B - MINIMUM TENSILE PROPERTIES, SI UNITS (SEE 8.2)Nominal ThicknessMillimetersTensile StrengthMPaYield Strengthat 0.2% OffsetMPaElongationin 50.8 mm or 4D%Up to 4.76, excl 117
38、2 1103 8 (6) (See 3.5.2.1.1)4.76 to 38.10, excl 1172 1103 838.10 to 63.50, excl 1103 1034 663.50 to 101.60, incl 1034 965 63.5.2.1.1 Elongation value in parentheses is for transverse direction only.3.5.2.1.2 Mechanical property requirements for product outside the size range covered by 1.1 shall be
39、agreed upon between purchaser and producer.3.6 QualityThe product, as received by purchaser, shall be uniform in quality and condition, sound, and free from “oil cans” (See 8.4) of depth in excess of the flatness tolerances, ripples, and foreign materials and from imperfections detrimental to usage
40、of the product.SAE INTERNATIONAL AMS4988C Page 6 of 83.6.1 Ultrasonic InspectionPlate 0.500 inch (12.70 mm) and over in nominal thickness shall meet Class A1 requirements of AMS2631.3.7 TolerancesShall conform to all applicable requirements of AMS2242.3.8 Production, distribution, and procurement of
41、 metal stock shall comply with AS6279. This requirement becomes effective October 1, 2015.4. QUALITY ASSURANCE PROVISIONS4.1 Responsibility for InspectionThe vendor of the product shall supply all samples for vendors tests and shall be responsible for the performance of all required tests. Purchaser
42、 reserves the right to sample and to perform any confirmatory testing deemed necessary to ensure that the product conforms to specified requirements.4.2 Classification of TestsAll technical requirements are acceptance tests and shall be performed on each heat or lot as applicable.4.3 Sampling and Te
43、stingShall be in accordance with AMS2368 and the following; a lot shall be all product of the same nominal size from the same heat processed at the same time and in the same heat treatment batch.4.3.1 CompositionOne sample from each heat, except that for hydrogen determinations one sample from each
44、lot obtained after thermal and chemical processing is completed.4.3.2 Tensile Properties, Bending, Microstructure, Surface Contamination, Average Grain Size, and Tensile Properties after Precipitation HardeningAt least one sample from each lot.4.3.2.1 Specimens for tensile tests of widths 9 inches (
45、229 mm) and over shall be taken in both the longitudinal and transverse directions; for widths under 9 inches (229 mm), specimens shall be taken in the longitudinal direction.4.3.2.2 Bend SpecimensWhenever possible, the specimen shall be long enough to permit two separate bends so that each surface
46、is tested in tension.4.3.3 Ultrasonic ExaminationEach plate 0.500 inch (12.70 mm) and over.SAE INTERNATIONAL AMS4988C Page 7 of 84.4 Reports4.4.1 The producer shall furnish with each shipment a report showing producer identity, country where the metal was melted (i.e., final melt in the case of meta
47、l processed by multiple melting operations) and the results of tests for composition of each heat and for the hydrogen content, tensile and bending properties, average grain size, and surface contamination of each lot and ultrasonic quality of each plate, and stating that the product conforms to the
48、 other technical requirements. This report shall include the purchase order number, heat and lot numbers, AMS4988C, product form, mill produced size, specific aging treatment used to develop precipitation hardened properties, and quantity.4.4.2 When the product size is outside the range covered by T
49、able 4, the report shall contain a statement to that effect.4.5 Resampling and RetestingIf any specimen used in the above tests fails to meet the specified requirements, disposition of the product may be based on the results of testing three additional specimens for each original nonconforming specimen. Failure of any retest specimen to meet the specified requirements shall be cause for rejection of the product
