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 revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2015 SAE International All rights reserved. No part of this p
3、ublication 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: +1 724-776-497
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/AMS6920C AEROSPACE MATERIAL SPECIFICATION AMS6920 REV. C Issued 2004-01 Revised 2
5、015-07 Superseding AMS6920B Titanium Alloy Bars, Forgings and Forging Stock 3Al - 8V - 6Cr - 4Mo - 4Zr Solution Heat Treated (Composition Similar to UNS R58640) RATIONALE AMS6920C results from a Five Year Review and update of this specification that includes the removal of sample size allowance for
6、hydrogen of Table 1 (covered by ASTM E1447), requires agreement on mechanical property values for material outside specification ranges (3.5.1.1.5, 3.5.2.3 and 8.6), the addition of AS6279 (3.8) and revises the report paragraph (4.4). 1. SCOPE 1.1 Form This specification covers a titanium alloy in t
7、he form of bars up through 4.000 inches (101.60 mm) in nominal diameter or least distance between parallel sides, inclusive, forgings of thickness up through 4.000 inches (101.60 mm), inclusive, and stock for forging of any size (See 8.6). 1.2 Application This material has been used typically for pa
8、rts, including springs, fabricated in the solution heat treated condition and subsequently precipitation heat treated, requiring higher tensile strength than is available in alpha-beta alloys, and corrosion resistance, but usage is not limited to such applications. 1.2.1 Certain processing procedure
9、s and service conditions may cause these products to become subject to stress-corrosion cracking; ARP982 recommends practices to minimize such conditions. 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 th
10、e extent specified herein. The supplier 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. SAE INTERNATIO
11、NAL AMS6920C Page 2 of 8 2.1 SAE Publications Available from SAE International, 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. AMS2241 Tolerances, Corrosion and Heat-Resistant Steel, Iron Alloy, Titanium, an
12、d Titanium Alloy Bars and Wire 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 Inspection, Titanium and Titanium Alloy Bar and Billet AMS2643 Structural Examination
13、 of Titanium Alloys, Chemical Etch Inspection AMS2750 Pyrometry AMS2808 Identification Forgings AMS2809 Identification, Titanium and Titanium Alloy Wrought Products ARP982 Minimizing Stress-Corrosion Cracking in Wrought Titanium Alloy Products AS6279 Production, Distribution, and Procurement of Meta
14、l Stock 2.2 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 E8/E8M Tension Testing of Metallic Materials ASTM E1409 Determination of Oxygen and Nitrogen in Titanium and Titanium Alloys
15、by the Inert Gas Fusion Technique ASTM E1447 Determination of Hydrogen in Titanium and Titanium Alloys by the Inert Gas Fusion Thermal Conductivity/Infrared Detection Method ASTM E1941 Determination of Carbon in Refractory and Reactive Metals and Their Alloys by Combustion Analysis ASTM E2371 Analys
16、is of Titanium and Titanium Alloys by Direct Current Plasma and Inductively Coupled Plasma Atomic Emission Spectrometry 3. TECHNICAL REQUIREMENTS 3.1 Composition Shall conform to the percentages by weight shown in Table 1; carbon shall be determined in accordance with ASTM E1941, hydrogen in accorda
17、nce with ASTM E1447, oxygen and nitrogen in accordance with ASTM E1409, and other elements in accordance with ASTM E2371. Other analytical methods may be used if acceptable to the purchaser. SAE INTERNATIONAL AMS6920C Page 3 of 8 Table 1 - Composition Element min max Vanadium 7.50 8.50 Chromium 5.50
18、 6.50 Molybdenum 3.50 4.50 Zirconium 3.50 4.50 Aluminum 3.00 4.00 Iron - 0.30 Oxygen - 0.12 Carbon - 0.05 Nitrogen - 0.03 (300 ppm) Hydrogen - 0.020 (200 ppm) Yttrium (3.1.1) - 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 Determinat
19、ion 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 multiple melted. The first melt shall be made by vacuum consumable electrode, nonconsumable electrode, electron beam cold hearth
20、, or plasma arc cold hearth melting practice. The subsequent melt or melts shall be made under vacuum using vacuum arc remelting (VAR) practice. Alloy additions are not permitted in the final melt cycle. 3.2.1 The atmosphere for nonconsumable electrode melting shall be vacuum or shall be argon or he
21、lium 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 product shall be supplied in the following condition: 3.3.1 Bars Hot finished (with or without subsequent cold reduction), solu
22、tion heat treated, and descaled. A machined or ground surface is permitted unless prohibited by purchaser. The product shall be processed to the final thickness/diameter by metallurgical working operations prior to any straightening, dimensional sizing or surface finishing operations. Bar shall not
23、be cut from plate. 3.3.2 Forgings Solution heat treated and descaled. 3.3.3 Stock for Forging As ordered by the forging manufacturer. SAE INTERNATIONAL AMS6920C Page 4 of 8 3.4 Heat Treatment Bars and forgings shall be solution heat treated by heating to a temperature within the range 1450 to 1700 F
24、 (788 to 927 C), holding at the selected temperature within 25 F (14 C) for a time commensurate with section thickness and the heating equipment and procedure used, and water quenched (except that sections under 0.5 inch (12.7 mm) may be air cooled). Pyrometry shall be in accordance with AMS2750. 3.
25、5 Properties 3.5.1 Bars and Forgings as Solution Heat Treated 3.5.1.1 Tensile Properties Shall be as specified in Table 2, determined in accordance with ASTM E8/E8M with the rate of strain set at 0.005 inch/inch/minute (0.005 mm/mm/minute) and maintained within a tolerance of 0.002 inch/inch/minute
26、(0.002 mm/mm/minute) through the 0.2% offset yield strain. 3.5.1.1.1 Tensile property requirements apply in both the longitudinal and transverse directions. Transverse tensile properties of Table 2 apply only to product that a test specimen not less than 2.50 inches (63.5 mm) in length can be obtain
27、ed. 3.5.1.1.2 Specimens for the longitudinal requirements in Table 2 shall be taken with the axis of the specimen within 15 degrees of parallel to the grain flow. 3.5.1.1.3 Yield strength and reduction of area requirements do not apply to product under 0.125 inch (3.18 mm) in nominal diameter or lea
28、st distance between parallel sides. 3.5.1.1.4 Values in brackets apply to the short transverse direction for short transverse dimensions of 3.00 inches (76.2 mm) or greater. When short transverse properties are determined, long transverse properties do not need to be determined. Table 2 - Minimum te
29、nsile properties (see 8.2) Nominal Diameter or Least Distance Between Parallel Sides Inch (mm) Tensile Strength ksi (MPa) Yield Strength At 0.2% Offset ksi (MPa) Elongation in 2 Inches (50.8 mm) or 4D, % (3.5.1.1.4) Reduction of Area % (3.5.1.1.4) Up to 1.50 ( 38.10), incl. 125 (861) 120 (827) 10 30
30、 Over 1.50 ( 38.10) to 4.00 (101.60), incl. 120 (827) 115 (793) 10 8 25 20 3.5.1.1.5 Mechanical property requirements for product outside the size range covered by Table 2 shall be agreed upon between purchaser and producer. 3.5.1.2 Microstructure Shall be uniform and essentially that structure resu
31、lting from beta processing. Microstructure shall not be cause for rejection unless standards have been agreed upon by purchaser and producer. 3.5.1.3 Surface Contamination Except as specified in 3.5.1.3.1, the product shall be free of any oxygen-rich layer (See 8.3), such as alpha case, or other sur
32、face contamination, determined by microscopic examination at not lower than 400X magnification or by other method agreed upon by purchaser and producer. 3.5.1.3.1 When permitted by purchaser, product to be machined all over may have an oxygen-rich layer, provided such layer is removable within the m
33、achining allowance on the product. SAE INTERNATIONAL AMS6920C Page 5 of 8 3.5.1.4 Macrostructure Product shall be uniform in quality and condition, homogenous, sound, and free from foreign materials and from internal imperfections detrimental to fabrication or performance of parts. 3.5.2 After Preci
34、pitation Heat Treatment Product shall conform to the following requirements after being precipitation heat treated by heating to 875 to 1150 F (468 to 624 C), holding at the selected temperature within 15 F (8 C) for 2 to 30 hours and cooled in air to room temperature. Precipitation heat treatment s
35、hall precede final machining of specimens. Pyrometry shall be in accordance with AMS2750. 3.5.2.1 Tensile Properties Shall be as shown in Table 3, determined in accordance with ASTM E8/E8M with the rate of strain set at 0.005 inch/inch/minute (0.005 mm/mm/minute) and maintained within a tolerance of
36、 0.002 inch/inch/minute (0.002 mm/mm/minute) through the 0.2% offset yield strain. Table 3 - Minimum tensile properties (see 8.2) Nominal Diameter or Least Distance Between Parallel Sides Inch (mm) Tensile Strength ksi (MPa) Yield Strength At 0.2% Offset ksi (MPa) Elongation in 2 Inches (50.8 mm) or
37、 4D, % (3.5.2.2) Reduction of Area % (3.5.2.2) Up to 1.50 ( 38.10), incl. 190 (1310) 180 (1241) 8 15 Over 1.50 ( 38.10) to 3.00 ( 76.20), incl. 180 (1241) 170 (1172) 8 6 15 5 Over 3.00 ( 76.20) to 4.00 (101.60), incl. 170 (1172) 160 (1103) 8 3 15 5 3.5.2.2 Values in brackets apply to the short trans
38、verse direction for short transverse dimensions of 3.00 inches (76.2 mm) or greater. 3.5.2.3 Mechanical property requirements for product outside the size range covered by Table 3 shall be agreed upon between purchaser and producer. 3.5.3 Forging Stock When a sample of stock is forged to a test coup
39、on and heat treated as in 3.4 and/or 3.5.2, specimens taken from the heat treated coupon shall conform to the requirements of 3.5.1.1 and 3.5.2.1 respectively. If specimens taken from the stock after heat treatment as in 3.4 and/or conform to the requirements of 3.4 and/or 3.5.2, the tests shall be
40、accepted as equivalent to tests of a forged coupon. 3.6 Quality The product, as received by purchaser, shall be uniform in quality and condition, sound, and free from foreign materials and from imperfections detrimental to usage of the product. 3.6.1 Ultrasonic Inspection When specified, the product
41、 shall be ultrasonically inspected in accordance with AMS2631 and shall meet the quality standards agreed upon between the purchaser and producer. 3.7 Tolerances Bars shall conform to all applicable requirements of AMS2241. 3.8 Production, distribution, and procurement of metal stock shall comply wi
42、th AS6279. This requirement becomes effective September 1, 2016. SAE INTERNATIONAL AMS6920C Page 6 of 8 4. QUALITY ASSURANCE PROVISIONS 4.1 Responsibility for Inspection The producer of the product shall supply all samples for producers tests and shall be responsible for the performance of all requi
43、red tests. Purchaser reserves the right to sample and to perform any confirmatory testing deemed necessary to ensure that the product conforms to the specified requirements. 4.2 Classification of Tests 4.2.1 Acceptance Tests The following requirements are acceptance tests and shall be performed on e
44、ach heat or lot as applicable. 4.2.1.1 Composition (3.1) of each heat. 4.2.1.2 Hydrogen content (3.1), tensile properties (3.5.1.1), tensile properties after precipitation hardening (3.5.2.1), microstructure (3.5.1.2), surface contamination (3.5.1.3), and macrostructure (3.5.1.4) of each lot of bars
45、 and forgings. 4.2.1.3 When specified (See 8.6), ultrasonic quality of each bar, forging or forging stock as required by 3.6.1. 4.2.1.4 Tolerances (3.7) of bars. 4.2.2 Periodic Tests Ability of forging stock (3.5.2) to develop specified properties is a periodic test and shall be performed at a frequ
46、ency selected by the producer unless frequency of testing is specified by purchaser. 4.3 Sampling and Testing Shall be in accordance with AMS2368 and as follows: A lot shall be all product of the same nominal size from the same heat processed at the same time. 4.3.1 For Acceptance Tests 4.3.1.1 Comp
47、osition At least one sample from each heat, except that for hydrogen determinations one sample from each lot obtained after all thermal and chemical processing is completed. 4.3.1.2 Tensile Properties At least one sample from bars from each lot. The number, location, and orientation of samples from
48、each lot of forgings shall be as agreed upon by purchaser and producer. 4.3.1.3 A specimen at least 0.5 inch (12.7 mm) long by full cross-section from each end of the bars selected for sampling shall be macrostructurally examined for conformance to the quality requirements. Unless otherwise specifie
49、d, macrostructural examination shall be performed in accordance with AMS2643. The number of bars selected for examination shall not be less than the amounts shown in Table 4. Table 4 - Number of bars selected for macrostructural examination Number of Bars in Lot Number of Bars Selected 1 to 15 1 16 to 50 2 51 to 150 3 151 to 500 5 over 500 4 + amount shown above over 500 SAE INTERNATIONAL AMS692
