1、AEROSPACE MATERIAL SPECIFICATION AMS4918 REV. N Issued 1965-09 Revised 2014-10 Superseding AMS4918M Titanium Alloy, Sheet, Strip, and Plate 6Al - 6V - 2Sn Annealed (Composition similar to UNS R56620) RATIONALE AMS4918N results from a Five Year Review and update of this document that includes the rem
2、oval of sample size allowance for hydrogen of Table 1, revises tensile strength of Table 2 to match other specifications, ultrasonic testing of all plate 0.500 inch (12.70 mm) and over (3.6.2), the addition of AS6279 (3.8) and revises the report paragraph (4.4). 1. SCOPE 1.1 Form This specification
3、covers a titanium alloy in the form of sheet, strip, and plate up through 4.000 inches (101.60 mm), inclusive (Also see 8.6). 1.2 Application These products have been used typically for parts not requiring heat treatment but requiring high mechanical properties in the annealed condition, but usage i
4、s not limited to such application. This alloy exhibits high strength-to-weight ratios up to 750 F (399 C). 1.2.1 Certain processing procedures and service conditions may cause these products to become subject to stress-corrosion cracking; ARP982 recommends practices to minimize such conditions. 2. A
5、PPLICABLE 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 specific document issue is specified. When the referenced docu
6、ment 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: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside
7、USA), or www.sae.org. AMS2242 Tolerances, Corrosion and Heat-Resistant Steel, Iron Alloy, Titanium, and Titanium Alloy Sheet, Strip, and Plate _ 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 t
8、his report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, 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, stabi
9、lized, or cancelled. SAE invites your written comments and suggestions. Copyright 2014 SAE International All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or o
10、therwise, 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 USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technic
11、al Report, please visit http:/www.sae.org/technical/standards/AMS4918N SAE INTERNATIONAL AMS4918N Page 2 of 7 AMS2249 Chemical Check Analysis Limits, Titanium and Titanium Alloys AMS2368 Sampling and Testing of Wrought Titanium Raw Material, Except Forgings and Forging Stock AMS2631 Ultrasonic Inspe
12、ction of Titanium Alloys AMS2750 Pyrometry AMS2809 Identification, Titanium and Titanium Alloy Wrought Products ARP982 Minimizing Stress Corrosion Cracking in Wrought Titanium Alloy Products AS6279 Industry Standard Practices for Production, Distribution, and Procurement of Metal Stock 2.2 ASTM Publ
13、ications Available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, or www.astm.org. ASTM E 8 / E 8M Tension Testing of Metallic Materials ASTM E 290 Bend Testing Material for Ductility ASTM E 384 Knoop and Vickers Hardness of Materi
14、als ASTM E 399 Plane-Strain Fracture Toughness of Metallic Materials ASTM E 1409 Determination of Oxygen and Nitrogen in Titanium and Titanium Alloys by the Inert Gas Fusion Technique ASTM E 1447 Determination of Hydrogen in Titanium and Titanium Alloys by the Inert Gas Fusion Thermal Conductivity/I
15、nfrared Detection Method ASTM E 1941 Determination of Carbon in Refractory and Reactive Metals and Their Alloys by Combustion Analysis ASTM E 2371 Analysis of Titanium and Titanium Alloys by Direct Current Plasma and Inductively Coupled Atomic Emission Spectrometry 3. TECHNICAL REQUIREMENTS 3.1 Comp
16、osition Shall 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 elements in accordance with ASTM E 2371. Other analytical methods may
17、 be used if acceptable to the purchaser. SAE INTERNATIONAL AMS4918N Page 3 of 7 TABLE 1 - COMPOSITION Element min max Aluminum 5.00 6.00 Vanadium 5.00 6.00 Tin 1.50 2.50 Iron 0.35 1.00 Copper 0.35 1.00 Oxygen - 0.20 Carbon - 0.05 Nitrogen - 0.04 (400 ppm) Hydrogen - 0.015 (150 ppm) Yttrium (3.1.1) -
18、 0.005 ( 50 ppm) Other Elements, each (3.1.1) - 0.10 Other Elements, total (3.1.1) - 0.40 Titanium remainder 3.1.1 Determination not required for routine acceptance. 3.1.2 Check Analysis Composition variations shall meet the applicable requirements of AMS2249. 3.2 Melting Practice Alloy shall be mul
19、tiple 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 melt or melts shall be made under vacuum using vacuum arc remelting (VAR) practice. Alloy additions are not permitted
20、in the final (VAR) remelt 3.2.1 The atmosphere for nonconsumable electrode melting shall be vacuum or shall be argon and/or helium at an absolute pressure not higher than 1000 mm of mercury. 3.2.2 The electrode tip for nonconsumable electrode melting shall be water-cooled copper. 3.3 Condition The p
21、roduct shall be supplied in the following condition: 3.3.1 Sheet and Strip Hot rolled, with or without subsequent cold reduction, annealed, descaled, and leveled, having a surface appearance comparable to a commercial corrosion-resistant steel No. 2D finish (See 8.2). 3.3.2 Plate Hot rolled, anneale
22、d, descaled, and flattened, having a surface appearance comparable to a commercial corrosion-resistant steel No. 1 finish (See 8.2). Plate product shall be produced using standard industry practices designed strictly for the production of plate stock to the procured thickness. Bar, billet, forgings,
23、 or forging stock shall not be supplied in lieu of plate. 3.4 Annealing The product shall be annealed by heating to a temperature within the range 1300 to 1500 F (704 to 816 C), holding at the selected temperature within 25 F (14 C) for a time commensuate with the section thickness, the heating equi
24、pment, and procedure used, and cooling at a rate that will produce product meeting the requirements of 3.5. Pyrometry shall be in accordance with AMS2750. SAE INTERNATIONAL AMS4918N Page 4 of 7 3.5 Properties The product shall conform to the following requirements and shall meet the requirements of
25、3.5.1 and 3.5.2 in the annealed condition and after heating in air to any temperature up to 1000 F 25 (538 C 14), holding at heat for 20 minutes 2, cooling in air, and descaling: 3.5.1 Tensile Properties Shall be as specified in Table 2, determined in accordance with ASTM E 8 / E 8M with the rate of
26、 strain set at 0.005 inch/inch/minute (0.005 mm/mm/minute) and 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 Nominal Thickness Inches Tensile Strength ksi, min Yield Strength at 0.2%
27、Offset ksi Elongation in 2 inches or 4D, %, min Long. Elongation in 2 inches or 4D, %, min Trans. Up to 0.025, incl 155 145 to 170 8 6 Over 0.025 to 0.1874, incl 155 145 to 170 10 8 Over 0.1874 to 2.000, incl 150 140 to 165 10 8 Over 2.000 to 4.000 incl 145 135 to 160 8 6 TABLE 2B - TENSILE PROPERTI
28、ES, SL UNITS Nominal Thickness Millimeters Tensile Strength MPa, min Yield Strength at 0.2% Offset MPa Elongation in 50.8 mm or 4D, %, min Long. Elongation in 50.8 mm or 4D, %, min Trans. Up to 0.64, incl 1069 1000 to 1172 8 6 Over 0.64 to 4.760, incl 1069 1000 to 1172 10 8 Over 4.760 to 50.80, incl
29、 1034 965 to 1138 10 8 Over 50.80 to 101.60, incl 1000 931 to 1103 8 6 3.5.1.1 Requirements of Table 2 apply in both the longitudinal and transverse direction but tests in the transverse direction need be made only on product that a specimen not less than 2.50 inches (63.5 mm) in length can be taken
30、. 3.5.1.2 Mechanical property requirements for product outside the range covered by Table 2 shall be agreed upon between purchaser and producer. 3.5.2 Bending Product under 0.1875 inch (4.762 mm) in nominal thickness shall have a test sample prepared nominally 0.750 inch (19.05 mm) in width, with it
31、s axis of bending 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 inch (0.25 mm) minimum, and the plunger shall have a rad
32、ius equal to the bend factor shown in Table 3 times the nominal thickness. Examination of the bent sample shall not show evidence of cracking when examined at 15 to 25X magnification. TABLE 3 - BENDING REQUIREMENTS Nominal Thickness Inch Nominal Thickness Millimeters Bend Factor Up to 0.070, incl Up
33、 to 1.78, incl 4 Over 0.070 to 0.1874, incl Over 1.78 to 4.760, incl 4.5 SAE INTERNATIONAL AMS4918N Page 5 of 7 3.5.3 Fracture Toughness Properties When specified, product shall be subjected to fracture toughness testing. 3.5.3.1 For product less than 0.500 inch (12.70 mm) thick, the method of test
34、and acceptance criteria shall be as specified by purchaser. 3.5.3.2 For product 0.500 inch (12.70 mm) thick and over, test per ASTM E399. Acceptance criteria shall be as specified by the purchaser. 3.5.4 Microstructure Shall be that structure resulting from processing within the alpha-beta phase fie
35、ld (See 8.3.2). Microstructure shall conform to 3.5.4.1 or 3.5.4.2. 3.5.4.1 Equiaxed and/or elongated primary alpha in a transformed beta matrix with no continuous network of alpha at prior beta grain boundaries. 3.5.4.2 Essentially complete field of equiaxed and/or elongated alpha with or without i
36、ntergranular beta and with no continuous network of alpha at prior beta grain boundaries. 3.5.5 Surface Contamination The product shall be free of any oxygen-rich layer, such as alpha case, or other surface contamination, determined in accordance with 3.5.5.1, 3.5.5.2, 3.5.5.3, or other method accep
37、table to purchaser. 3.5.5.1 The bend test of 3.5.2. 3.5.5.2 Microscopic examination at 400X magnification. 3.5.5.3 A surface hardness more than 40 points higher than the subsurface hardness, determined in accordance with ASTM E 384 on the Knoop Scale using a 200-gram load, shall be evidence of unacc
38、eptable surface contamination. 3.6 Quality 3.6.1 The product, as received by purchaser, shall be uniform in quality and condition, sound, and free from “oil cans” (See 8.3.1) of depth in excess of the flatness tolerances, ripples, and foreign materials and from imperfections detrimental to usage of
39、the product. 3.6.2 Plate 0.500 inch (12.70 mm) and over in nominal thickness shall be ultrasonically inspected in accordance with AMS2631 and shall meet Class A1 of that document. 3.7 Tolerances Shall conform to all applicable requirements of AMS2242. 3.8 Production, distribution, and procurement of
40、 metal stock shall comply with AS6279. This requirement becomes effective April 1, 2016. 4. QUALITY ASSURANCE PROVISIONS 4.1 Responsibility for Inspection The vendor of the product shall supply all samples for vendors tests and shall be responsible for the performance of all required tests. Purchase
41、r reserves the right to sample and to perform any confirmatory testing deemed necessary to ensure that the product conforms to specified requirements. SAE INTERNATIONAL AMS4918N Page 6 of 7 4.2 Classification of Tests 4.2.1 Acceptance Tests Composition (3.1), tensile properties (3.5.1), bending (3.5
42、.2), fracture toughness (3.5.3) when specified, microstructure (3.5.4), surface contamination (3.5.5), and tolerances (3.7) are acceptance tests and shall be performed on each heat or lot as applicable. 4.2.1.1 Ultrasonic quality (3.6.2) of each plate when required. 4.2.2 Periodic Tests Tensile prop
43、erties (3.5.1) and bending (3.5.2) after reheating to 1000 F 25 (538 C 14) are periodic tests and shall be performed at a frequency selected by the vendor unless frequency of testing is specified by purchaser. 4.3 Sampling and Testing Shall be in accordance with AMS2368 and the following; a lot shal
44、l be all product of the same nominal size from the same heat processed at the same time and annealed in the same batch. 4.3.1 For Acceptance Tests 4.3.1.1 Composition One sample from each heat, except that for hydrogen determination one sample from each lot obtained after thermal and chemical proces
45、sing has been completed. 4.3.1.2 Tensile Properties, Bending, Microstructure and Surface Contamination One or more samples from each lot for each requirement. 4.3.1.2.1 Specimens for tensile tests of widths 9 inches (229 mm) and over shall be taken with the specimen axes in both longitudinal and tra
46、nsverse directions; for widths under 9 inches (229 mm), specimens shall be taken with specimen axis in the longitudinal direction. Specimens from product under 2 inches (50.8 mm) in width shall be as agreed upon by purchaser and vendor. 4.3.1.3 Other Requirements As agreed upon by purchaser and vend
47、or. 4.4 Reports 4.4.1 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 metal processed by multiple melting operations), results of tests for composition of each heat, hydrogen content, tensile proper
48、ties, bending, and surface contamination of each lot, ultrasonic quality when required, and, when performed, to the periodic test requirements, and stating that the product conforms to the other technical requirements. This report shall include the purchase order number, heat and lot numbers, AMS491
49、8N, specific annealing treatment, product form, size, and quantity. 4.4.2 When the product size is outside the range covered by Table 2, the report shall contain a statement to that effect. 4.5 Resampling and Retesting If any specimen used in the above tests fails to meet specified requirements, disposition of the product may be based on the results of testing three additional specimens for each original nonconf
