SAE-AMS-2451-10A-2007.pdf

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 therefrom, 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 © 2007 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 otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: 724-776-4970 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org AMS 2451/10A AEROSPACE MATERIAL SPECIFICATION Issued JAN 2002 Revised MAY 2007 Superseding AMS 2451/10 Plating, Brush, Tin-Zinc Low Hydrogen Embrittlement RATIONALE This specification was issued as part of the SAE Five Year Review process. 1. SCOPE 1.1 Purpose This specification covers the requirements for brush plating of tin-zinc by electrodeposition. 1.2 Application This process has been used typically to improve corrosion resistance of steel parts, to repair tin-zinc deposits and to repair damaged or worn parts, but usage is not limited to such applications. 1.3 Classification Plating covered by this specification is classified as follows: Type 1 - As-plated Type 2 - With supplementary surface treatment 1.4 Safety - Hazardous Materials See AMS 2451. 2. APPLICABLE DOCUMENTS See AMS 2451. 3. TECHNICAL REQUIREMENTS See AMS 2451. 3.1 Procedure 3.1.1 Tin-zinc alloy plate shall be electrodeposited from low-hydrogen-embrittlement brush plating solution in accordance with processing instructions from the solution manufacturer. When Type 2 plating is specified, the supplementary coating shall be applied using brush, spray or dip. Copyright SAE International Provided by IHS under license with SAELicensee=Defense Supply Ctr/5913977001 Not for Resale, 12/04/2007 20:00:22 MSTNo reproduction or networking permitted without license from IHS -,-,- SAE AMS 2451/10A - 2 - 3.1.2 When specified by the cognizant engineering organization, the hydrogen embrittlement relief baking requirement of AMS 2451 may be waived. See 8.5. When not waived, the hydrogen embrittlement relief baking temperature and time at temperature shall be 340 °F ± 25 (171 °C ± 14) for 12 hours. 3.2 Properties 3.2.1 Composition The tin-zinc alloy deposit shall contain 70 to 90% tin and 10 to 30% zinc, as determined by a method acceptable to purchaser. In case of dispute, one or more of the parts may be stripped of coating, and the resultant solution analyzed by conventional wet chemical methods for relative proportions of tin and zinc. 3.2.2 Corrosion Resistance Parts or specimens with Type 1 plating having a plate thickness of 0.0003 to 0.0005 inch (8 to 13 µm) shall show no evidence of basis metal corrosion after 96 hours of continuous salt spray corrosion testing conducted in accordance with ASTM B 117. Parts or specimens with Type 2 plating having a plate thickness of 0.0003 to 0.0005 inch (8 to 13 µm) shall neither show white corrosion products nor basis metal corrosion after 96 hours of continuous salt spray testing conducted in accordance with ASTM B 117. The presence of white corrosion product within 0.25 inch (6.4 mm) from the edge of the specimen shall not constitute failure. 3.2.3 The heat resistance, corrosion resistance, and stress tests of AMS 2451 section 3.4.2 are not applicable to this deposit. 3.2.4 Hydrogen Embrittlement The plating process shall not cause hydrogen embrittlement in steel parts, determined in accordance with 4.2. 4. QUALITY ASSURANCE PROVISIONS See AMS 2451. 4.1 When specified by the cognizant engineering organization, the hydrogen embrittlement relief testing of 4.2 may be waived. See 8.5. 4.2 Hydrogen Embrittlement Test Test shall be in accordance with the requirements of ASTM F 519 using three Type 1a.1 notched specimens stressed in tension under constant load, unless a different specimen is specified by the purchaser. For test purposes, the plating thickness shall be 0.0003 to 0.0006 inch (8 to 15 µm) measured on the smooth section of the specimen, but with visual plating at the root of the notch. 4.3 Periodic Tests Hydrogen embrittlement (4.2) is a periodic test and shall be performed at least once each month that parts are processed. Tests of cleaning and plating solutions 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. 5. PREPARATION FOR DELIVERY See AMS 2451. 6. ACKNOWLEDGMENT See AMS 2451. 7. REJECTIONS See AMS 2451. Copyright SAE International Provided by IHS under license with SAELicensee=Defense Supply Ctr/5913977001 Not for Resale, 12/04/2007 20:00:22 MSTNo reproduction or networking permitted without license from IHS -,-,- SAE AMS 2451/10A - 3 - 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 changes, have been made to the previous issue of this specification. An (R) symbol to the left of the document title indicates a complete revision of the specification, including technical revisions. Change bars and (R) are not used in original publications, nor in specifications that contain editorial changes only. 8.2 The Notes of AMS 2451 shall apply as herein modified, deleted, or added to. 8.3 Plating meeting the requirements of this specification will meet the requirements of AMS 2434. 8.4 For galvanic compatibility with aluminum alloys, the zinc content of the plate should be 25% or higher. 8.5 An acceptable rationale for exempting the processor from performance of hydrogen embrittlement relief baking and testing is for the processor to demonstrate that unbaked test specimens pass the hydrogen embrittlement relief test requirements of 4.2. The cognizant engineering organization should specify the procedure by which the processor may qualify for such an exemption and any circumstances that may be cause for requalification. PREPARED BY AMS COMMITTEE “B” Copyright SAE International Provided by IHS under license with SAELicensee=Defense Supply Ctr/5913977001 Not for Resale, 12/04/2007 20:00:22 MSTNo reproduction or networking permitted without license from IHS -,-,-