1、,(“KIL-P-25732C25 February 1980SUPERSEDINGMIL-P-25732B11 January 1967MILITARY SPECIFICATIONPACKING, PREFORMED, PETROLEUM HYDRAULICFLUID RESISTANT, LIMITED SERVICE AT 275F (135”C)This specification is approved for use by allDepartments and Agencies of the Department of Defense.1. SCOPE1.1 Scope. This
2、 specification covers O-ring packings for use withpetroleum based hydraulic fluids conforming to MIL-H-5606 andKIL-H-83282 Over the temperature range of -65 to 275F (-54 to 135”C).1.2 Sizes. The O-rings conform to sizes shown in t4S28775.2. APPLICABLE DOCUMENTS2.1 Issues of dncuments. The followim=.
3、 effect on date of i.tzti.ccfor bds oipart of this specification to the extent. -. .-documnts of the lsue inrequest fur nroposai form aspecified herein.SPECIFICATIONSFEDEIULQQ-A-25Qf4 -Aluminum Alloy 2024. Plate and SheetQQ-A-25f/ll -Aluminum Alloy 6061, Pliiteand SheetQQ-A-250/12 -Aluminum Alloy 70
4、75, Plate and ShertBeneficial comments (recommendations, additions, deletions) and anypertinent data which may be of use in Improving this document shouldbe addressed to: Air Force Wright Aernna!lticallahoratorics, Atln:MLSE Wright-Patterson APB, Ohio 45433 by using the sel-uddr(,sst,(jStandardizati
5、on Document Improvement Proposal (DD Form 1426) :pp;lr-ing at tileend of this document or hy letter. .1s(:)j-loProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-P-25732cMILITARYMIL-P-4861MIL-H-5440MIL-G-5514MIL-H-5606MIL-H-6083MIL-s-18729MIL-H-8328
6、2MIL-P-83461-Packing, Preformed, Rubber, Pacbging of-Hydraulic Systems, Aircraft, Types I andII, Design, Installation, and DataRequirements for “-Gland Design, Packings, Hydraulic,General Requirements for-Hydraulic Fluid, Petroleum Base, Aircraft,Missile, and Ordinance-Hydraulic Fluid, Petroleum Bas
7、e, forPresewation and Operation-Steel Plate, Sheet, and Strip, Alloy 4130Aircraft Quality-Hydraulic Fluid, Fire, Resistant, SyntheticHydrocarbon Base, Aircraft-Packings, Preformed, Petroleum HydraulirFlu d Resitant, Improved Perfoce at 20c. Elongation, percent 20 (ultimate elongation shallnot be les
8、s than 160%In addition, all physical properties tested shall meet the requirementsspecified in Table I.Table 1. Physical properties.Original properties RequirementsSpecific gr.lvityHardness, Tvoe A, pointsTensile strenth, psiElongation, percentensile str(ss,(modulus) psi at100 per(fntelongationrempe
9、raturc Retraction, TR-;G50 prcen elongation and 10erccnf-r.turn,F.hrrosion ;IlldadlcsionAfter aging 70 hours at 275t 5F in Ml.-H-C,fI6Hardness (11.,Ise,“rvpA, pointsTensil,stl,ligtl(lcorcase,percentElongafion tl,crnremperarr(.L(:r.1.tion T-()50 p(l-( loll!,alionand If)percent r(,llirn,FAs determined
10、68, minimum1350, minimum160. minimum (may not be lowerthan 160Z in produc-tion)500, minimum .-49, maximumSlight corrosion allowed on4130 steel, none on other metals+=),-1550, maximum35, maximum10 to 2055. maximum-49, maximum-. .-Provided by IHSNot for ResaleNo reproduction or networking permitted wi
11、thout license from IHS-,-,-,MIL-P-25732CTable I. Physical Properties cont.Original properties RequirementsAfter aging 70 hours at 275+ 5oF in MIL-H-83282Hardness change, Type A, points +10Tensile strength decrease, percent ZO, maximumElongation decrease, percent 45, maximumVolume change, percent 0.5
12、 to 15Compression set, 25 percent 55, maximumdeflecttan, percent oforiginal deflectionTemperature retraction, TR-10 -47, maximum50 percent elongation and 10 ,percent return, F3.5 Dynamic cycling. When tested in accordance with 4.7, the O-rinsshall withstand a minimum of 75,000 cycles without failure
13、. Failureis determined as that number of cycles at which a test ring leaks atotal of 70 ml of hydraulic fluid. Each test consists of 2-test celscontaining 2 test rings each. A minimum of 3 test runs shall be con-ducted making a total of 6 test cells to be tested. The number ofcycles until “failuresh
14、all be recorded. The highest number of cvt.ll”sand the lowest number of cycles shall be discarded. The renmining4 values shall be averaged and that value must be 75,000 minimum (orthe O-rings to pass the test.3.6 Identification. All O-rings shall be individually packaged. Eachenvelope shall have the
15、 following information printed on the outside:National stock numberMilitary part numberMaterial specificationManufacturers nameManufacturers compound numberManufacturers batch numberContract numberCure date.1. -. .-.-5Provided by IHSNot for ResaleNo reproduction or networking permitted without licen
16、se from IHS-,-,-HIL-P-25732C4. QUALITY .4SSUMNCE PROVISIONS,(J4.1 Responsibility for inspection. Unless otherwise specified inthe contract or purchase order, the supplier is responsible for theperformance C: all inspection requirements as specified herein.Except as othetwise specified in the contrac
17、t or order, the suppliermay use his own or any other facility suitable for the performance ofthe inspection requirements specified herein, unless disapproved bythe Government. The Government reserves the right to perform any ofthe inspectims set forth in the specification where such inspectionsare d
18、eemed necessary to assure supplies and services confom toprescribed requirements.4.2 Classification of tests. The inspectionand testing of the. rubber shall be classified as follows:a. Qualification tests (see 4.3).b. Qualitv conformance inspection (see 4.4).4.3 Qualification tests.4.3.1. )mixim(lmo
19、f 200 pounds. Quality conformancet,sfssh;Ill II(. I.I)IIdUC(LJ(l on each 200 pollndsif the hatch size if moref11:111 “(-m 11(1.1,1s.1.4J !)II:lit,.(tf(rm,ln.c.t(.stSshippinf!container fullv pal”ked,s,.l.t.(jl?ISL !)l”iortf)I!leclosin% operation. Shipping cont;linersfully nrepnr(1fordelivcrv sllalhe
20、examined for closure defects.Examint.- . l)efec-.-7Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-P-25732CExaminePacking (cont.)CountWeightDefectContainer not 8s specified,closures not accomplished byspecified or requfred methodsmaterials.Any no
21、nconforming component,component missing, damaged ororothetise defective, affectingserviceability.Inadequate application of compo-nents, such as incomplete closureof case liners, containing flapslmse or inadequate strapping,bulged or distorted container;Less than specified or indicatedquantity.Gross
22、weight exceeds specified .requirements.Markings Interior or exterior markings, asapplicable, omitted, illegible,incorrect, incomplete or not inaccordance with contract require-ments. Date of cure, storageinstruction missing.The sample size shall be in accordance with inspection level II ofMIL-STD-10
23、5 and the AQL related percent defective shall be 2.5.4.4.5 Clitv conformance tests. The followingconduct.don each batch of material (see .andphysical property determinations shall be conducted in in :ltmosphercof 50 + 15 percent relative humidity and at a temperature of 75 + 501;.4.6 Test methods. .
24、 -4.6.1 Physical properties. Unless otherwise specified herein, phy-sical properties shall be determined in accordance with ASTM D1414.4.6.2 Fluid aging. The containers used for fluid aging sh;llbofthe conventional fruit - jar type. The cover for the container shallbe either the two piece (lid and r
25、ing) fruit - jar tvpe, exrept thatthe lid shall be inverted in order chat the lids flat surface comesin contact with the sealing surface - te container, or :Elasscover held firmly in place b?a wire - lever apparatus. Ilnclean,uneven sealing surfaces of the cover and container and (Ii1 ln:l-twitlthe
26、sealing surfaces shall be avoided. During oil aging (itvO-ringsshall be suspended in the oil by a gl1ss or nichrome wire rack insuch a manner tha the Oncpof corrosion or adhesion. If any exist, the surfacesfthr platls shall be washed in aliphatic naphtha. Deposits deter-mined :srlhhet-compounds or e
27、lements therefrom, which can be removedbv this process and which do not occur on other surfaces of thepl:lt,s,stlallbe construed as adhesion.10Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-,.( r“-.a71 .*M1l.-l-?f7”l2(:1%nolxn tI-1 I- A - -I i-d“il.
28、-lL- -”- - - -i- f-0s;do !, ii-.-f-U)uPw.Juv. -. .-.-.!1Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. -Id iwK mJhrf.-l-25732c-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-P-25732Cb. Any pit
29、s or eroded marks remaining after this process shallbe construed to be corrosion. Discoloration or staining (marks whichdo not physically affect the surfaces of the plates and which easilywash or buff off) shall not be considered detrimental. If any doubtshould arise about the presence of pitting, e
30、rosion or corrosion onthe metal plates from the O-rings , a microscope of approximately 10-to 15-power magnification shall be used to determine the actual condi-tion.4.7 Wnamic cycling. The dymanic cycling shall be performed on a rodseal test apparatus. The apparatus, as shown in Figure 1, is capabl
31、eof evaluating O-rings under a high pressure, high temperature, cyclingenvironment until failure. The apparatus is capable of testing fourO-rings simultaneously. Two test cells are run concurrently with twoO-rings in each cell. A test cell is shown in Figure 2. The testingenvironments are as ,follow
32、s:a.b.c.d.,.both thee.is to bef.IZ.Test temperature - 275F (13SoC).Pressure - 1500 psig (10,300 kPas).Stroke length - 4 inches (10.2 cm).Cycling rate - 30 cycles/reinwhere one cycle is defined asforward and return strokes.Pressures to be applied for one complete cycle and pressurereduced to zero dur
33、ing the next cycle.Hydraulic fluid - MIL-H-5606.Tests are to be conducted without back-up rings. A steelspacer is to be used to maintan theh. I)iametralclearance between0.004 inch (0.0102 cm).i. Surface finish on test rodsproper gap dimension.rod and cell to be maintained atto be between 10-20 micro
34、-inches. . . -_.-13Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. -4- - - -,+ . -vII,-P-25732cUIDEMS28775-214 h.)9-.047in.)18MS28775-2. -FIGURE 3. CYLINDERASSDQ3LYW1HOUT BACK-UP RINGSProvided by IHSNot for ResaleNo reproduction or networking permi
35、tted without license from IHS-,-,-( MIL-P-25732C4.7.1 Procedure. The procedure to be used in conducting dynamic O-ring evaluations is as follows:a. Select 4 size 214 unaged or unconditioned O-rings.b. Lubricate the rings with fresh MIL-H-5606 hydraulic fluid andassemble the rings and spacers into th
36、e test cylinders as shown inFigure 3.c. Rod”and gland dimensions are to conform to ML-C-5514.d. Fill with MIL-H-5606 hydraulic fluid taking care to excludeentrapped air.e. Bleed system at test cell locations to remove entrapped air ,in lines.f. Check of final test cells installation in test fixtures
37、 andinsure that the test c-ellsdo not translate along the rod by more than0.005 inch (0.0127 cm).g. Set dynamic conditions as follows:(1) Stroke - 4 inches (101.6 mm).(2) Rate - 30 cycles/minute.(3) Pressure - 1500 psig (lQ300kPasc).(4) Temperature - 275F (135C).(5) Start tests by turning on heating
38、 elements.(6) Start test cell temperature recorder to record thetemperatureof each cell throughout the test.(7) After temperature reaches the predetermined set point,start cvcling and adjust temperature as required. -.-(8) Start leakage rate recorder at the same time that cv-lin is initiated.Provide
39、d by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-P-25732Ch. Cycle O-rings at given set of conditions until failure of therings.i. Failure is specified as the number of cycles at which eithertest ring in either test cell leaks a total of 70 ml of hydrauli
40、c fluid.At this point, the test celI having the failed ring will be shut downand the remaining cell operated until one or both of the two remainingtest rings fail by leaking more than 70 ml of hydraulic fluid.4.7.2 Interpretation and data recording. Each test ring will beanalyzed to determine, if po
41、ssfble, the mode of failure. The method ofinspection will be as follows:a. Carefully disassemble each test cell.b. Note the position and condition of each test ring prior toremoval.c. Inspect test cell for wear caused by the test rod touching thecell during cycling.d. Carefully inspect each ring for
42、 cause of failure. Note as towhether the ring was nibbled or whether it had been extruded-,pinched.or cracked. Also note any set the ring may have taken. -e. Note if total 1Ci!qe cc,drredSIowIy rivera long period oftime or if it occurred suddenly over a short number of cycles.f. Note any twisting, t
43、urning. or preferential wear patterns ontest ring.g. Photograph each ring for permanent record of wear pattern.II. Record number of cycles to total leakage of 70 ml.4.7.3 Repeat testing. A minimum of 3 test runs using 2 test cellseach time shall be conducted for qualification testing. The highestnum
44、ber of cycles and the lowest number of cycles shall be discarded.The remaining 4 values shall be averaged.5. PACKAGING16Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.MTL-P-25732C5.1 Preservation, packaging, packing, and marking. Unless otherwisest
45、ipulated by the procuring activity, preservation. packaging, packingand marking shall be in accordance with the applicable requirements ofMIL-P-4861 as specified (see 6.2).6. NOTES6.1 Intended use. This specification covers O-rings intended for useat a temperature range of -65 to 275F in hydraulic s
46、ystem in accord-ance with MIL-P-5514 and MIL-H-5440. These rings are suitable for usewith hydraulic fluids conforming to MTL-H-5606 and MTL-H-83282. Use at275F will be limited with this material. A material providing better275F aging is covered by MTL-P-83461.6.2 Ordering data. Procurement documents
47、 shall specify:a. Title, number, and date of this specification.b. Sizes per MS-28775.c. Quantity.d. Applicable federal stock number.c. Applicable levels of preservation, packaging and packincrequired(see 5.1).6.3 ualification. With respect to products requiring qualification,awards will be made onl
48、y for such products as have, prior to the tineset for opening of bids, been tested and approved for incl?sion in theapplicable Qualified Products List whether or not such products haveactually been so listed by that date. The attention of the suppliersis called to this requirement, and manufacturers are urged to arrangeto have L,tproducts that they propose to offer to the Governmenttested f,rqualification in order that they mav he eligible to be
