SAE AMS 2771F-2017 Heat Treatment of Aluminum Alloy Castings.pdf

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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 2017 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:/standards.sae.org/AMS2771F AEROSPACE MATERIAL SPECIFICATION AMS2771 REV. F Issued 1987-10 Revised 2017-04 Superse

5、ding AMS2771E Heat Treatment of Aluminum Alloy Castings RATIONALE AMS2771F results from limited scope ballots with changes to refrigeration equipment (3.1.5), solution treatment batch furnace interruption (3.2.6.1), quenchant temperature rise (3.2.9.4.1), refrigeration processing (3.2.10.2), solutio

6、n treatment (Table 1) for A201 and A206, and adding A206-T71 precipitation treatment (Table 2). 1. SCOPE 1.1 Purpose This specification covers the engineering requirements for heat treatment of aluminum alloy castings and for parts machined from castings. 1.2 Application This specification is applic

7、able to castings of the following aluminum alloys and modifications (see 8.2.8): 201.0 328.0 520.0 203.0 333.0 705.0 206.0 336.0 707.0 222.0 354.0 712.0 242.0 355.0 713.0 243.0 356.0 850.0 295.0 357.0 851.0 296.0 358.0 852.0 319.0 359.0 1.3 When AMS2771 is specified and specific heat treat processin

8、g instructions are included in the material specification, the equipment and control requirements of AMS2771 shall apply. For alloys not specifically covered, the provisions of this specification shall be applicable, but temperatures, times, and quenching procedures shall be as specified by the purc

9、haser. 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 specific document issue is specified. When the refe

10、renced document has been cancelled and no superseding document has been specified, the last published issue of that document shall apply. SAE INTERNATIONAL AMS2771 F Page 2 of 12 2.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-73

11、23 (inside USA and Canada) or +1 724-776-4970 (outside USA), www.sae.org. AMS2750 Pyrometry AMS3025 Polyalkylene Glycol Heat Treat Quenchant ARP1917 Clarification of Terms Used in Aerospace Metals Specifications ARP1962 Training and Approval of Heat-Treating Personnel 2.2 ANSI Accredited Publication

12、s Copies of these documents are available online at http:/webstore.ansi.org/. ANSI H35.1/H35.1M Standard Alloy and Temper Designation System For Aluminum 3. TECHNICAL REQUIREMENTS 3.1 Equipment Equipment used for thermal processing shall conform to the requirements of this specification and AMS2750,

13、 except (1) requirements for working zone controls, instruments and sensors shall apply to all heating zones of continuous and semi-continuous furnaces and (2) recordings from instruments may be stored on magnetic or optical media providing a hard copy is available on request. 3.1.1 Pyrometry Shall

14、meet the requirements of AMS2750. 3.1.2 Furnaces 3.1.2.1 Heating Media Shall be air, protective atmosphere, combusted gases, molten salt bath, oil bath, or fluidized bed. Electrical heating elements and radiant tubes shall be shielded to prevent direct radiation from striking any part. The products

15、of combustion in the furnace, and the composition and maintenance of salt baths and fluidized beds shall be such as to prevent attack or contamination of the castings. Ammonium fluoroborate, or equivalent, may be used in air furnaces as necessary. Nitrate salt baths shall not be used to heat treat 5

16、20.0 alloy due to a potential explosion safety hazard. 3.1.2.1.1 Salt Entrapment Castings that will entrap salt shall not be heated in a molten salt bath. 3.1.2.2 Temperature Uniformity Survey Requirements Temperature uniformity surveys shall be performed as defined in AMS2750. 3.1.2.2.1 Solution He

17、at Treating and Aging Furnaces shall be Class 2 minimum as defined in AMS2750. 3.1.2.2.2 Annealing Furnaces shall be Class 5 minimum as defined in AMS2750. SAE INTERNATIONAL AMS2771 F Page 3 of 12 3.1.3 Quenching Unless otherwise approved by the cognizant engineering organization, the following prov

18、isions apply. Equipment shall be provided for quenching in water, air blast, oil, or in polymer quenchants and for measuring quenchant temperature. Provisions shall be made for mechanical, hydraulic, or air agitation of the quenching medium or agitation of the castings or both and for heating and co

19、oling of the quenchant, as required. Air agitation shall be allowed provided the air doesnt come in contact with the castings being quenched. The volume of quenching medium for immersion quenching shall be sufficient so that its temperature rise due to quenching meets the requirements of 3.2.9.4.1.

20、3.1.3.1 Polymer Quenchants Polyalkalene glycol shall meet the requirements of AMS3025. Other synthetics may be used provided that they are not detrimental to the material and that the parts meet the required specified properties in the final heat treated condition. Polymer concentration shall be est

21、ablished for the particular casting configuration prior to use. 3.1.3.2 Salt Contamination of Polymer Quenchants Shall not exceed 6% by weight. 3.1.4 Cleaning Equipment shall be provided to clean castings, as necessary for heat treatment, and to remove residual quenchant after solution heat treatmen

22、t. Examples include: water rinse to remove polymer quenchant residue, detergent and rinse to remove oil quenchant residue, and fresh water overflow to remove salt quenchant residue. 3.1.5 Refrigeration Refrigeration or liquid baths shall be provided for cold storage of castings when prevention of na

23、tural aging is necessary to produce required properties or is used at the discretion of the producer to facilitate straightening. 3.2 Procedures 3.2.1 General Cast parts that require heat treatment to a T4X, T6X, or T7X temper (refer to ANSI H35.1/H35.1M) shall be solution heat treated (including qu

24、enching), refrigerated after quenching, when necessary, and aged, when required, as specified herein. Castings in the T5X condition shall be refrigerated after casting, when necessary, and aged as specified herein. Heat treatment shall be performed only on entire castings, never on a portion of a pa

25、rt. 3.2.2 Racking and Spacing Product shall be supported or hung and spaced to permit flow of the heating and cooling media over all surfaces to ensure that the castings will meet the specified requirements. Alternate racking methods are acceptable if tests have been performed to demonstrate that al

26、l castings so racked will meet specified requirements. Written instructions, drawings, photographs, etc., shall be used to ensure proper spacing. 3.2.2.1 Small castings as defined in 8.2.4 may be heated and soaked in baskets or continuous furnaces. Care must be used to provide access for heating and

27、 quench media and to prevent damage during loading and quenching. Arrangement in baskets may be either orderly or random provided that the castings meet the required specified properties in the final heat treated condition. 3.2.2.2 Water Entrapment Racks and fixtures used for solution heat treatment

28、 shall be constructed to preclude entrapment of water. 3.2.3 Loading The temperature of the furnace during part loading shall not exceed the solution treating temperature of the castings being heat treated. SAE INTERNATIONAL AMS2771 F Page 4 of 12 3.2.4 Post Quench Reload to Furnace Batch type furna

29、ces that momentarily reload the freshly quenched material back into the furnace work zone as part of the unloading/quench tank transfer sequence is allowed provided objective evidence is available to qualify this process. The evidence shall demonstrate the thinnest material processed is not heated a

30、bove 212 F (100 C) by this post quench process using radiation survey process in AMS2750. The castings shall not be held in the furnace for more than 5 minutes during this post-quench sequence. The process used to provide the objective evidence shall be performed at the minimum furnace open time est

31、ablished by the heat treaters documented process after quenching the castings. The documented process shall include the maximum temperature of the furnace as measured by the control thermocouple or a specified minimum furnace cooling time prior to raising the load into the furnace. 3.2.5 Set Tempera

32、ture Control instrument(s) shall be set at the temperature specified in 3.2.9 for solution treating and 3.2.11 for aging, and should be set at the recommended annealing temperature specified in 3.2.12. Sensor/control offsets, if used, shall comply with AMS2750. 3.2.6 Soaking Soaking time starts when

33、 all temperature control sensing elements and load thermocouples (if used) are within 10 F (6 C) of the set or offset temperature. 3.2.6.1 Batch Furnaces Interruptions during solution treatment are permitted provided the minimum soak time is met and at least a 2 hour soak time occurs after the inter

34、ruption. When acceptable to the cognizant engineering organization, producer may use a shorter soak time after interruption that is documented and based on test results and data applicable to the castings being processed. During aging and annealing treatments, a maximum of four interruptions are per

35、mitted for removal or loading of castings. The time between door opening and furnace or load thermocouple recovery is not to be counted as part of the total aging time. 3.2.6.2 Continuous and Semi-Continuous Furnaces During soaking, a drop-in temperature indicated by furnace instrument(s) is permiss

36、ible provided (1) that temperature does not drop more than 20 F (11 C) below the minimum of the specified range, (2) time below the minimum of the specified range does not exceed 5 minutes, and (3) soaking is continued for not less than 10 minutes after recovery before quenching. 3.2.6.2.1 If furnac

37、e temperature does not drop more than 20 F (11 C) below the minimum of the specified range, but does not recover to the minimum of the specified range within 5 minutes, the total soaking time, if less than 1 hour was required, shall be increased by 1/2 hour. If 1 hour or more was required, the total

38、 soaking time shall be increased by 1 hour. 3.2.6.3 Load thermocouples shall be used, when needed, to determine and control metal temperature and heating time or when required by the cognizant engineering organization (see 8.2.7). 3.2.7 Logs A record (written or electronic storage media), traceable

39、to temperature recording information (chart(s) or electronic storage media) and to shop travelers or other documentation, shall be kept for each furnace and load. The information on the combination of documents shall include: equipment identification, approved personnels identification, date, part n

40、umber or product identification, number of castings, alloy, lot identification, AMS2771 or other applicable specification, actual thermal processing times and temperatures used. When applicable, atmosphere control parameters, quench delay, quenchant type, polymer concentration, and quenchant tempera

41、ture shall also be recorded. The maximum thickness, when process parameters are based on thickness, shall be recorded and shall be taken as the minimum dimension of the heaviest section of the part. The log data shall be recorded in accordance with the heat treaters documented procedures. SAE INTERN

42、ATIONAL AMS2771 F Page 5 of 12 3.2.8 Cleaning Castings shall be clean of contaminants that will react during heat treatment or cause adverse effects. Residue from heating and quenching media shall be removed from castings after solution heat treatment. 3.2.9 Solution Heat Treating 3.2.9.1 Temperatur

43、e Castings that require solution heat treatment shall be soaked at the temperature specified in Table 1, except as permitted in 3.2.9.3. 3.2.9.2 Soaking Time Shall conform to Table 1 (see 8.2.5). 3.2.9.3 Variations Solution treating set temperatures may vary from the requirements of Table 1 to obtai

44、n required properties for a specific casting configuration. Departure from the required set temperature of more than 10 F (6 C) shall require approval of the cognizant engineering organization (see 8.2.6). 3.2.9.4 Quenching Castings, after being soaked at the solution heat treating temperature for t

45、he required time, shall be quenched. 3.2.9.4.1 Quenchant Temperature The quenchant temperature shall not rise more than 25 F (14 C) at the conclusion of the quenchant contact time (see 3.2.9.4.4). To prevent excessive warpage and possible cracking, castings may be quenched in oil or water with tempe

46、rature varying from cold to hot (212 F (100 C) or in a polymer quenchant at room temperature providing it is substantiated that the combination of quench and solution temperature will produce mechanical properties meeting the material specification. Exceptions to the temperature rise are permitted p

47、rovided that it has been demonstrated by testing and documentation that the castings meet the required specified properties in the final heat treated condition. Unless otherwise specified in a drawing or procurement document, castings of Alloy 520.0 shall be quenched by total immersion in oil heated

48、 to 300 F (149 C) and castings of Alloy 242.0 shall be air-quenched. 3.2.9.4.2 Quench Delay Time The quench delay time shall not exceed 15 seconds. The delay shall be measured from the time the furnace door of an air furnace starts to open, or the first portion of the load emerges from a fluidized b

49、ed or salt bath, to complete immersion of the load in the quenchant. This delay time may be exceeded providing that the cooling rate does not result in a loss of any mechanical property typically obtained by the established process for that casting configuration. 3.2.9.4.3 Agitation Castings, quenchant, or both shall be agitated during quenching. Small parts heated and soaked in baskets may be quenched by dumping when