1、AEROSPACE MATERIAL SPECIFICATIONAMS 3420FIssuedRevisedSuperseding AMS 3420EDehydrating AgentSilica Gel1. SCOPE:1.1 Form: This specification covers silica gel dehydrating agent in the form of a granular powder in either plain or indicator grades.1.2 Application: This product has been used typically f
2、or corrosion prevention of metals during storage in closed spaces, but usage is not limited to such applications.1.3 Classification: Covered by this specification are classified as follows:Grade D - Large particle size with indicatorGrade E - Medium particle size without indicatorGrade F - Medium pa
3、rticle size with indicator type2. 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
4、 specified. When the referenced document has been canceled and no superseding document has been specified, the last published issue of that document shall apply.2.1 SAE Publications: Available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.AS167 Chart, Humidity Indicator, Color Comparis
5、onReaffirmed 1942-032001-012010-05SAE 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 p
6、atent 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 2010 SAE International All rights reserve
7、d. 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)
8、 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 Technical Report, please visit http:/www.sae.org/technical/standards/AMS3420F Copyright SAE International Provided by IHS under li
9、cense with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-AMS 3420F SAE AMS 3420F- 2 -2.2 ASTM Publications: Available from ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959.ASTM B 214 Sieve Analysis of Granular Metal Powder 3. TECHNICAL REQUIREMENT
10、S: 3.1 Material:Material shall be non-deliquescent and shall absorb water by physical means and not by chemical combination except for the cobalt chloride in indicator grades.3.2 Properties:The product shall conform to the following requirements; tests shall be performed on the product supplied and
11、in accordance with specified test methods:3.2.1 Composition:3.2.1.1 Grades D and F shall be silica gel containing not less than 99.6% Si02impregnated with not more than 1.5 pounds (0.68 kg) of anhydrous cobalt chloride (CoC12) per 100 pounds (45 kg) of finished material on a dry weight basis determi
12、ned by test method acceptable to purchaser.3.2.1.2 Grade E shall be silica gel containing not less than 99.4% Si02on a dry weight basis.3.2.2 Color: Indicating grades shall have characteristic colors when in equilibrium with the atmosphere and shall closely match the colors shown on AS167 for relati
13、ve humidities of 0, 20, 40 and 60% at 25 C 2 (77 F 4).3.2.3 Water Content: Shall not exceed 5.75% by weight for Grades D and F, determined in accordance with 4.4.1; no limit is established for Grade E.3.2.4 Water Vapor Adsorption Capacity: Shall be not lower than shown in Table 1 when in equilibrium
14、 with the relative humidities given, determined as in 4.4.2.Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-AMS 3420F SAE AMS 3420F- 3 -3.2.5 Particle Size: Shall be as shown in Table 2 for the respe
15、ctive grades, determined in accordance with 4.4.3.3.2.6 Particle Strength: Shall be as shown in Table 3 for the respective grades, determined in accordance with 4.4.4.TABLE 1 - Water Vapor Adsorption CapacityRelative Humidity%Water Vapor Adsorption% by WeightGrades D and FWater Vapor Adsorption% by
16、WeightGrade E10 4.3 5.720 8.6 10.540 18.2 21.560 27.7 28.080 32.9 31.2TABLE 2 - Particle Size DistributionScreenSize DistributionPercentGrade DSize DistributionPercentGrades E and FRetained on No. 6 (3.35 mm), maximum 2.0Through No. 6 (3.35 mm), Retained onNo. 12 (1.70 mm), minimum 55.0Through No. 1
17、2 (1.70 mm), Retained onNo. 18 (1.00 mm), minimum 19.0Through No. 18 (1.00 mm), maximum 3.5Through No. 20 (850 m), maximum 0.5Retained on 0.530 inch (13.5 mm) opening 0.0Through 0.530 inch (13.5 mm) opening, retainedon No. 80 (180 m), minimum 96.0Through No. 80 (180 m), maximum 4.0Copyright SAE Inte
18、rnational Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-AMS 3420F SAE AMS 3420F- 4 -3.2.7 Corrosion: The product shall not have a corrosive effect on other materials when exposed to conditions normally encountered in service,
19、 determined by a procedure acceptable to purchaser.Discoloration of metal shall not be considered objectionable.3.3 Quality:The drying agent, as received by purchaser, shall be a uniform in quality and condition and free from foreign materials and from imperfections detrimental to usage of the produ
20、ct. 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. Purchaser reserves the right to sample and to perform any confirmatory testing deemed neces
21、sary to ensure that the product conforms to the requirements of this specification.4.2 Classification of Tests: 4.2.1 Acceptance Tests: Composition (3.2.1), color (3.2.2), water content (3.2.3) and quality (3.3) are acceptance tests and shall be performed on each lot.4.2.2 Preproduction Tests: All t
22、echnical requirements are preproduction tests and shall be performed prior to or on the initial shipment of the product to a purchaser, when a change in ingredients and/or processing requires reapproval as in 4.4.2, and when purchaser deems confirmatory testing to be required.4.3 Sampling and Testin
23、g: Shall be as follows:4.3.1 For Acceptance Tests: Sufficient product shall be taken at random from each lot to perform all required tests. The number of determinations for each requirement shall be as specified in the applicable test procedure or, if not specified therein, not less than three.TABLE
24、 3 - Particle StrengthScreenPowderingGrade DPercentPowderingGrades E each bottle shall have not less than 500 mL capacity and shall be equipped with a petticoat bubbler. Pass air from a flowmeter through the saturator bottles at a rate of 14 cubic feet (0.4 m3) per minute; each bottle shall be fille
25、d to 1/3 to 1/2 its volume with sulfuric acid of the proper concentration to give the desired relative humidity in accordance with Table 4. Pass the air from the saturator bottles through a mist trap, which can be an ordinary drying tube or cylinder approximately 1.5 inches (38 mm) in diameter and 8
26、 to 9 inches (203 to 229 mm) high packed with glass wool, and then through the adsorption bulb, which can be a cylindrical bulb with a flat bottom, a short tubular arm, a top with a ground glass joint, and a tubular opening for the air to pass (See Figure 2). Duplicate sets of apparatus shall be pro
27、vided to make simultaneous determinations for relative humidities of 10, 20, 40, 60 and 80% at temperature of 25 to 30 C, (77 to 86 F). Temperature change during a test shall be not greater than 1 C (2 F) degrees.TABLE 4 - Water Vapor AbsorptionRelative HumidityPercent at 25 to 30 CRelative Humidity
28、Percent at 77 to 86 FSulfuric Acid SolutionPercent by Weight10 10 64.720 20 58.240 40 47.860 60 38.480 80 26.4Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-AMS 3420F SAE AMS 3420F- 6 -4.4.2.2 Place
29、 5 to 10 grams of product, weighed to the nearest milligram, in a tared adsorption bulb. Do not expose the product to air any more than necessary. Make a tight rubber connection to the outlet of the mist trap and adjust air flow to 240 cubic inches 30 (4.0 L 0.5) per minute. After three hours, weigh
30、 the adsorption bulb quickly; repeat the weighings until two successive weighings approximately one hour apart show a variation not greater than ten milligrams.Generally, the weight increase will rise to a maximum and then decrease slightly before reaching constant weight. The gain in weight, expres
31、sed as a percentage of the original weight, is the percentage of water vapor the product will hold in equilibrium with air of the relative humidity attained in the saturators. The attained relative humidity in the saturators shall be determined on the exit end solution in each chain after the produc
32、t has attained equilibrium.4.4.3 Particle Size: Bring a sample of the product to approximate equilibrium with the atmosphere.Place a five ounce (142 gram) sample of the product on the coarsest screen in a nest of the applicable sizes and shake for three minutes on a screen shaker. Equipment shall be
33、 in accordance with ASTM B 214. 4.4.4 Particle Strength: Repeat the particle size test of 4.4.3. Mix separately, the portions of the Grade D sample retained on the No. 18 or coarser screens and the portion of Grade E or F retained on the No. 80 or coarser screens, bring to approximate equilibrium wi
34、th the atmosphere, weigh out a 1.5-ounce 0.2 (43-gram 5) sample to an accuracy of 0.01 ounce (0.2 gram) and place on the No. 18 or No. 80 screen, as applicable, together with five copper disks approximately 0.50 inch thick and 0.750 inch in diameter (1.3 x 19 mm). Fit the screen with a tight cover a
35、nd nest with a finer screen and a retaining pan; the finer screen shall be No. 30 for Grade D and No. 200 for Grades E and F. Shake the sample for 15 minutes in the apparatus specified in 4.4.3. Weigh the powder collected in the retaining pan and report as a percentage of the original sample weight.
36、4.5 Reports:The vendor of the product shall furnish with each shipment a report showing the results of tests to determine conformance to the acceptance test requirements and stating that the product conforms to the other technical requirements. This report shall include the purchase order number, lo
37、t number, AMS 3420F, formula number, and quantity.4.6 Resampling and Retesting: If 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. Fai
38、lure of any retest specimen to meet the specified requirements shall be cause for rejection of the product represented. Results of all tests shall be reported.Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from
39、IHS-,-,-AMS 3420F SAE AMS 3420F- 7 -5. PREPARATION FOR DELIVERY: 5.1 Identification:Dehydrating agent shall be assigned a unique name or other alphanumeric code identification traceable to a specific set of ingredients and raw materials, manufacturing processes and sequences, controls and inspection
40、 processes. In the event of any change in ingredients, raw materials, manufacturing processes, inspection procedures, that name or other coded identification shall also be changed.5.1.1 Each package of product shall be permanently and legibly marked with not less than the following information:DEHYD
41、RATING AGENT, SILICA GELAMS 3420FGRADE _SIZE OR PART NUMBER _LOT NUMBER _PURCHASE ORDER NUMBER _QUANTITY _MANUFACTURERS IDENTIFICATION (See 5.1.1) _5.2 Packaging:5.2.1 Packaging shall be accomplished to ensure that the product, during shipment and storage, will be protected against damage from expos
42、ure to weather or any other normal hazard.5.2.2 A lot of dehydrating agent may be packaged in small quantities and delivered under the same basic lot designation provided lot identification is maintained.5.2.3 Packages of product shall be prepared for shipment in accordance with commercial practice
43、and in compliance with applicable rules and regulations pertaining to the handling, packaging, and transportation of the product to ensure carrier acceptance and safe delivery.6. ACKNOWLEDGMENT:A vendor shall mention this specification number and its revision letter in all quotations and when acknow
44、ledging purchase orders.7. REJECTIONS:Product not conforming to this specification, or to modifications authorized by purchaser, will be subject to rejection.Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from I
45、HS-,-,-AMS 3420F SAE AMS 3420F- 8 -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 ti
46、tle 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 Dimensions and properties in inch/pound units and the Celsius temperatures are primary; dime
47、nsions and properties in SI units and the Fahrenheit temperatures are shown as the approximate equivalents of the primary units and are presented only for information.8.3 Purchase documents should specify not less than the following:AMS 3420FGrade desiredQuantity of product desired.8.4 Key Words: Co
48、rrosion prevention, storagePREPARED UNDER JURISDICTION OF AMS COMMITTEE “B“Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-AMS 3420F SAE AMS 3420F- 9 -FIGURE 1 - Apparatus for Water Vapor Adsorption TestsCopyright SAE International Provided by IHS under license w
