AIR FORCE MIL-S-38228-1964 SEALING COMPOUND ENVIRONMENTAL FOR AIRCRAFT SURFACES《飞机外部用环保型密封胶》.pdf

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1、Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Milttary MbH-3136 Standard Test Fluids; Hydrocarbon MIL-S-4383 Sealing Compound, Topcoat, Fuel Tank, Buna-I? Type MIL-$5059. %eel, Corrosion-Resistant (18-8), Plate, Sheet and Strip MIL-F-5566 Fluid; An

2、ti-Icing (Isopropyl Alcohol) MILT-7993 Titanium, Sheet, Strip and Plate (Unalloyed) MILP=8184 Plastic Sheet, Acrylic, . Modified STANDARDS Federal Federal Test ilubbert ,Tampling and Testing Method Std. No, 601 Military MIL-STD-129 Varking for Shipment ana Storage (Copies of specifications, standard

3、s, drawings, and publicat ions required by suppliers in connection with specific procurement functions should ba- obtained from the procuring activity or as dLrected by the contracting officer.) 2.2 Other pubiic8tions.d The following document forms a part of this specification to the exbent spedfied

4、 herein. Unless otherwise Tndicated, the issue in effect on date of invitation for bid.s or request for proposal. shall apply: Consolidated Classif cat ion Committee Untfdrm Freight Classification Rules (Application for copies of the above publication should be addressed to the Consolidated Classifi

5、cation Committee, 202 Chicago Union Station, Chicago, Illinois 60606, ) 3 6 REQUIREMENTS 3.1 Preproduction.- This specification makes provisions for. preproductior testing. 3.2 Materials.- The basic ingredient used in the manufacture of the sealing compound safi be a. synthetic rubber. The sealing c

6、ompound shall cure by the addition of a separate curing compound to the base compound and shall not depena on solvent evaporation for curing, Manufacturers will be given a wide latitude in the selection of materials and curing systems Provided by IHSNot for ResaleNo reproduction or networking permit

7、ted without license from IHS-,-,-MIL-S-38228 80 7777706 030b462 3 M MIL-S-38228 (USAI? 3.2.1 Color,- The color of the cured sealing compound shall be gray. 3.2.2 Appearance.- The base compound and curing compound (accelerator) shall be of a contrasting color , shall eagh be of a uniform blend and sh

8、all be free of skins, lunps, and gelled or coarse particles. There shall be no separation of ingredients which cannot be readily dispersed. 3.2.3 Toxicity.- The material shall have no adverse effect on the . health of personnel when used according to provided instructions and for its intended purpos

9、e. Questions pertinent to this effect shall be referred by the procuring activity to the appropriate department medical service who will act as an advisor to the procuring agenoy. 3.3 Physical properties 3.3.1 Specific gravity.- When tested in accordance with 4.7.1, the specific gravity of the cured

10、 sealing compound shall not exceed 1.65 at standard conditions (see 4.5). 3.3.2 Nonvolatile content.- When tested in accordance with 4.7.2 the nonvolatile content of the freshly mixed compounds (types I and 11s shall not be less than 97 percent by weight. 3.3.3 Viscosity of the base compound.- The s

11、ealing compounds shall be suitable for application by extrusion gun or spatula and the viscosity of the base compound shall be within the range of 6000 to 16,000 poises when tested as specified in 4.7.3. 3.3.4 Flow,- Vhen tested inaccordance with 4.7.4, the freshly mixed sealing compound shall exhib

12、it an initial flow within the limits of 0.10 to 0.50 inch when a cylindrical section formed in the flow .test jig is allowed to flow under its own weight on a vertical surface. In addition, the compound shall retain a flow within the limits of 0.10 to 0,50 inch throughout the eatbe application time.

13、 3.3.5 Application time,- 1Jhen.tested in accordance with 4.7.5, the mixed sealing compound shall have an application time as specified in table I and shall remain suitable for application during that period, The end of the application time shall be when the extrusion rate has diminished to.15 grams

14、 per minute, TABLE I Application Time Type I Hours Type II Rows I - 1/2 1-2 1-4 U2 2 4 II - 1/2 II - 2 11 - 4 112 2 4 . 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-3-3.6 Tack-free %me.- When tested. in accordance with 4.7.6, the mixed compound

15、shall cure to a tack-free condition as specified in table II. 1 7 1/2 10 24. XI - 1/2 5 24. 1-2 24 48 II - 2 24 48 1-4 48 72 II - 4 36 72 3.3.7 Curing rate.- When tested in aocordance with 4.7.7, the sealing compound shall-have a Rex hardness of not less than 35 after curing under standard condition

16、s (see 4.5) for not more than the time specified in table II. 3.3.8 Low temperature flexibility.- When tested in accordance with 4.7.8, the sealing compound shall withstand the low temperature flexi- bility test at -670 1: 2O F without cracking, checking, or loss of adhesion. 3.3.9 Peel strength.- W

17、hen tested in accordance with 4.7.9, the unaged cured sealing compound shall have a minimum peel strength of 20 pounds . It shall exhibit 100 percent cohesive failure, except for bubbles, knife cuts, and other causes that are obviously not the fault of the compound. The aged sealing compound shall c

18、onform to values specified in table III. 3.3.10 Corrosion.= laen tested in accordance with 4.7.10, the sealing compound Shan cause no visible corrosion of the aluminum panels and shall show no- sign of deterioration. 3.3.11 Tensile strength and elongation.- hen tested in accordance with 4.7.11, the

19、ultimate tensile strength and elongation of the cured compound shall be as specified in table III. 3.3.12 Accelerated storage stability.- After storing in accordance with 4.7.12, the base compound shall show no skinning, hardening, separation, nor settling of the material. It shall also conform to t

20、he original viscoslty specified in 3.3.3. The aged curing compound shall not be adversely affected and shall be restorable by normal agitation to a condition suitable for use. The aged base compound and the aged curing oompound, when mixed, shall be in accordance with conditions for flow, applicatio

21、n time, tack-free time and peel strength as specified in 3.3.4, 3.3.5, 3.3.6 and 3.3.9. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-S-38228 80 H 7777706 OLObllbLI 7 W TABU3 III - Physical Properties Properties Type I Type II Original Tensile

22、strength, psi Elongation, percent at 75O F 72 Hours immersion in MIL-H-3136, type III Tensile strength, psi Elongation, percent Peel strength (lb/in. ) (minimum) 72 Hours immersion in Di-2-ethylhexyl sebacate with 1/2 percent phenothiazine at 140 F Tensile strength, psi Elongat ion, percent Peel str

23、ength (lb/in . ) (minimum) 7 Days at 250 F Tensile strength, psi Elongation Tensile strength, psi Elongatfon, percent 7 Days at 500 F 450 100 “ “- - “ “- “- “W “- “ 40 75 3.3.13 Accelerated crazing.- The sealing compound shall not contain hgredients that will cause acrylic plactic sheet oonforming t

24、o Specification MIL-P-Et184 to craze or crack, when tested in accordance With 4.7.13. 3.3.14. Shrinkage.- Linear shrinkage, based on an initial measure- ment made after the appropriate cure time listed in 4,7.l4 and a - final measurement made after 60 days, shall not exceed 1,O percent. 3.3.15 Shavi

25、ng and sanding.- The sealing compound shall be suitable for shaving and sanding, after cure in accordance with 4.7.15. 3.3.16 Weathering.- The sealing compound, mixed-with accelerator, shall not exhibit cracking, chalking, peeling or loss of adhesion after 30 days accelerated weathering in accordanc

26、e with 4.7.16, 3.4 Workmanship.- The workmanship shall be in accordance with high . grade manufacturing practice covering this type of material. It shall be suitable for its intended use and free of defects which may affect its functionability. Provided by IHSNot for ResaleNo reproduction or network

27、ing permitted without license from IHS-,-,-MTGs-38228( USAI?) 4. QUALITY ASSURANCE PROVISIONS 4.1 Responsibility for inspection.- Unless otherwfse specified in the contract or purchase order, the supplier is responsible for the performance of all inspection requirements as specified herein, bcept as

28、 otherwise specified, the supplier may utilize his own facilities or any commercial laboratory acceptable to .the Government. The Government reserves the right to perform any of the inspections set forth in the specification where such inspections are deemed necessary to assure supplies and services

29、 conform to prescribed requirements. 4.2 Classification of tests.- The inspection and testing of the sealing compound shall be classified as follows: ar Preproduction tests b, Quality conformance tests, 4.3 Preproduction tests.- Preproduction tests shall consist of all the tests specified in 4.7. 4.

30、3.1 Sampling.- The preproduction samples shall comist of a sufficient quantity of the sealing compound to perform the tests speoified in 4.7. Samples shall be tested in a laboratory designated .by the,procuring.activity, or, when so stated in the contract or order, at the contractors.plant under the

31、 inspection of the procuring activity (see 6.2) . 4.3.2 Previous approval.- At the discretion of the procuring aotivity preproduction testing may be waived for sealing compound which has been accepted under a.previous contract, 4.4 Quality conformance tests.- The quality conformance tests shall . co

32、nsist.of the tests specified in 4.7.1through 4.7.7 and 4.7.U. 4 . 4 . 1 Sampling 4.4.1.1 ISS OTHERWISE SPECIF ED, TOLERANCES : DEC IMALS k0.016 Figure 1. Flow-Test Jig 7- “ . I. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4.7.5 Application time,-

33、 The base compound, accelerator, and application gun shall be stabilized at standard conditions for at least 8 hours before a minimum of 250 grams of base compound are mixed with the proper amount of accelerator. The mixed sealing compound shall be promptly used to fil1 a standard Semco sealing comp

34、ound gun cartridge, or equal, having a Semco 440 nozzle with an orifioe chamber of 0.125 0,005 inch, The gun and compound shall be maintained at standard conditions throughout the test. The gun shall be attached to a constant ab supply of 90 f 5 pounds per square inch gage (psig), for line variation

35、 or gage error. From 2 to 3 inches of sealing compound shall be extruded initially to clear trapped air. At the end of the rated application time, measured-c from the beginning of the mixing period, the compound shall be extruded onto a suitablereceptacle for 1 minute and the amount of extruded comp

36、ound determined. 4.7.6 Tack-free time.- An aluminum test panel conforming to temper T6 of specification QQ-A-287, and measuring 0,040 by 2-3/4 by 6 inches in size shall be cleaned in accordance with 4.6.1 and covered with freshly mixed sealing compound to a depth of 1/8 f 1/16 inch. The compound sha

37、ll be allowed to cure at standard conditions and at the rate specified in 3.3.6. . At the end of the specified tack-free time, two l-inch by four 0,025 to 0,040 by 2 3/4 by 6 inches stainless steel panels conforming to com- position 302, annealed, finish 2I3 of Specification MILS-5059; and four 0.02

38、5 by 0.040 by 2 3/4 by 6 inches titanium panels conforming to class 1 of Specification EIL-T-7993 shall be cpatecl with a 1/8 f 1/64 inch thick- ness of sealing compound. After the compound has immobilized, 1 end of .a 3- by 12-inch strip of wire screen, 20- to 40-mesh aluminum or monel wire fabric,

39、 or cotton duck conforming to type III of Specification CCC-C-4l9 shall be placed on each panel, leaving a loose end 6 inches in length. An additional 1/32 inch thick coating of sealing compound shall be applied over the screen or fabric strips and the panels allowed to cure for l.4 days. k 1-inch w

40、ide section shall be cut through the strip and compound on each test panel to provide the center inch for the peel test. The specimens shall be stripped back at an angle of 180 degrees to the metal panel in a suitable +,ensile testing machine having a jaw separation rate of 2 inches per minute, The

41、results shall be the numerical average. of the peak loads. 4.7.10 Corssion.- One aluminum panel conforming to Specification QQ-A-283 and measuring 0,040 by 2 3/4 by 6 inches in size shall be pre- pared with 2 parallel sealing compound fillets approximately 1 inch apart. The fillets shall be applied

42、3/16 inch thick by 3/4 Inch wide by 5 inches long and shall extend to within 1/2 inch of the edges of the panel, The panel shall have a 14-day uure. At-least 48 hours before the cure time has expired, the panel shall be dipped in a sealing com-pun3 topcoat con- forming to Specification PELS74383 and

43、 the cure allowed to continue. At the end of the -14-day curing period, the fillets shall be cut down to 1/16 inch and immersed vertically for 20 days in a covered glass vessel containing a 3 percent aqueous sodium chloride solution, The temperature during the test shall he. maintained at 1400 k 2O

44、F. Immediately upon removal from the liquid,the panel shall be examined for complianc with 4.7.11 Tensile strength and elongation.- b!ixed sealing compound 0,125 k O.Gl5 inch thfck shall b prepared by pressing between 2 polyethylene sheets, removing the top sheet at the end of the rated tack-free ti

45、me, and allowing the compound to cure at standard conditions. Tensile test specimens shall be cut from-.the.sheet after 12 . . ” -. 3o3.10. “i- . ,. -Y - r- - Y. -_ - Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-S-38228 80 7777706 0306472 b a

46、28-day cure, using die VI as specified in method 4l11 of Federal Test lethod Standard No. 601. Three specimens shall be exposed to each of the environmental conditions specified in table III. Where fluid immersion is specified, the 3 specimens shall be immersed in 400 cc of the fluid. After 72 hours

47、 of fluid iyers ion, specimens shall be cooled in the fluid for 24 hours-at standard conditions and tested within 5 minutes after removal from the fluid. Specimens that are tested immediately after oven aging shall be allowed to cool for 16 to %4 hours at standard conditions. The tensile and elongat

48、ion tests shall-be conducted at standard conditions in accordance with methods a11 and 4l21, respectively, of Federal Test Hethod Standard No. 601. 4.7.12 Accelerated storage.- An original, unopened, 1-quart container of base compound and an original, unopened container of the curing compound shall

49、be stored for 14 days at 120 k 2O F in a suitable ventilated oven. After cooling at standard conditions for at least 24 hours, tests shall be conducted in accordance with 4.7.3, 4.7.4, 4.7.5, 4.7.6 and 4.7.9. Two aluminum alioy peel panels shall also be prepared and tested, without fluid immersion, in. accordance with 4.7.9. 4.7.13 Accelerated crazing A plastic panel conforming to MIL-P-8l84, having dimensions as