1、Beneficial comments, recommendations, additions, deletions, clarifications, etc. and any data that may improve this document should be sent to: Commander, Naval Sea Systems Command, ATTN: SEA 05M2, 1333 Isaac Hull Avenue, SE, Stop 5160, Washington Navy Yard DC 20376-5160 or emailed to CommandStandar
2、dsnavy.mil, with the subject line “Document Comment”. Since contact information can change, you may want to verify the currency of this address information using the ASSIST Online database at http:/assist.daps.dla.mil. FSC 9320 INCH-POUND ZZ-R-768B 15 June 2009 SUPERSEDING ZZ-R-768A November 25, 196
3、6 FEDERAL SPECIFICATION RUBBER FOR MOUNTINGS (UNBONDED-SPOOL AND COMPRESSION TYPES) The General Services Administration has authorized the use of this federal specification by all federal agencies. 1. SCOPE AND CLASSIFICATION 1.1 Scope. This specification covers uncured rubber compound or finished (
4、cured) resilient components to be used in unbonded-spool and compression typed mountings, as specified. 2. APPLICABLE DOCUMENTS 2.1 Government publications. The following documents, of the issues in effect on the date of invitation for bids or request for proposal, form a part of this specification
5、to the extent specified herein. FEDERAL STANDARDS FED-STD-123 - Marking for Shipment (Civil Agencies) FED-STD-601 - Rubber: Sampling and Testing MILITARY STANDARDS MIL-STD-129 - Military Marking for Shipment and Storage MIL-STD-407 - Visual Inspection Guide for Rubber Molded Items (Copies of these d
6、ocuments are available online at http:/assist.daps.dla.mil/quicksearch/ or http:/assist.daps.dla.mil or from the Standardization Document Order Desk, 700 Robbins Avenue, Building 4D, Philadelphia, PA 19111-5094.) 2.2 Other publications. The following documents form a part of this specification to th
7、e extent specified herein. Unless a specific issue is identified, the issue in effect on date of invitation for bids or request for proposal shall apply. ASTM INTERNATIONAL ASTM D395 - Standard Test Methods for Rubber Property Compression Set (DoD adopted) ASTM D412 - Standard Test Methods for Vulca
8、nized Rubber and Thermoplastic Elastomers Tension (DoD adopted) ASTM D573 - Standard Test Method for Rubber Deterioration in an Air Oven (DoD adopted) Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ZZ-R-768B ASTM D624 - Standard Test Method for Tear
9、 Strength of Conventional Vulcanized Rubber and Thermoplastic Elastomers (DoD adopted) ASTM D792 - Standard Test Methods for Density and Specific Gravity (Relative Density) of Plastics by Displacement (DoD adopted) ASTM D945 - Standard Test Methods for Rubber Properties in Compression or Shear (Mech
10、anical Oscillograph) (DoD adopted) ASTM D1229 - Standard Test Method for Rubber Property Compression Set at Low Temperature (DoD adopted) ASTM D2240 - Standard Test Methods for Rubber Property Durometer Hardness (DoD adopted) (Copies of these documents are available from ASTM International, 100 Barr
11、 Harbor Dr., P.O. Box C700, West Conshohocken, PA 19428-2959 or online at www.astm.org.) 3. REQUIREMENTS 3.1 First article. When specified (see 3.1.1 and 6.2), a sample shall be subjected to first article inspection in accordance with 4.3. 3.1.1 First article inspection. First article inspection sha
12、ll be performed when one or more of the following apply: a. Upon initial offering of a material to the government by the vendor. b. When any change in material formulation is made from previous first article test samples. c. When any change in manufacturing processes or conditions are made from prev
13、ious first article test samples. d. When the product being offered is manufactured at a plant different than that of previous first article test samples. e. When required by the Naval Sea Systems Command. 3.2 Material. The material shall be a synthetic rubber compound using a copolymer product of bu
14、tadiene and acrylonitrile which meets the requirements of 3.4 when cured. 3.2.1 Uncured compound. Uncured compound shall be furnished in sheet form ranging in size from 2 feet to 3 feet wide, by 3 feet to 6 feet in length, and inch to 1 inch thick. 3.2.2 Recovered materials. The offeror/contractor i
15、s encouraged to use recovered materials to the maximum extent practicable, in accordance with paragraph 23.403 of the Federal Acquisition Regulation (FAR). 3.3 Type, dimensions, and tolerances of resilient components. The type, dimensions, and tolerances of resilient components shall be as specified
16、 in the contract or purchase order (see 6.2). 3.4 Physical requirements. The cured rubber shall conform to the requirements specified in table I. 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ZZ-R-768B TABLE I. Physical requirements and tests. Pr
17、operties First Article Testing Required Conformance Testing Required Requirement Test Method Paragraph Initial properties Tensile strength, psi, minimum X X 1,800 4.5.1 Ultimate elongation, percent, minimum X X 300 4.5.1 Tensile stress (modulus) psi at 100% elongation X X As determined 4.5.1 Hardnes
18、s, Type A durometer X X 555 4.5.2 Specific gravity X X 1.250.10 4.5.3 Tear resistance, pounds per inch, minimum X 130 4.5.4 Properties after oven aging for 96 hour at 1942 F (901.1 C) Tensile strength, percent of initial, minimum X 80 4.5.5 Ultimate elongation, percent of initial, minimum X 75 4.5.5
19、 Tensile stress (modulus) psi at 100% elongation X As determined 4.5.5 Hot compression set, percent, maximum X 45 4.5.6 After immersion in medium No. 3 oil for 96 hour at 1222 F (501.1 C) Volume change, percent X 10 4.5.7 Properties at 73.42 F (231.1 C) Deformation, percent X 192 4.5.8 Resilience, p
20、ercent, maximum X 70 4.5.8 Frequency, Hz X 4.10.3 4.5.8 Absorbed energy, inch-pounds per cubic inch X 293 4.5.8 Properties at 322 F (01.1 C) Deformation, percent of value at 73.42 F (231.1 C), minimum X 75 4.5.8 Resilience, percent, maximum X 70 4.5.8 Frequency, Hz, minimum X 3.6 4.5.8 Absorbed ener
21、gy, percent of value at 73.42 F (231.1 C), minimum X 45 4.5.8 Cold compression set, percent, maximum X 15 4.5.9 3.5 Marking. 3.5.1 Civil agencies. In addition to any special marking specified in the contract or order (see 5.1 and 6.2), shipping containers shall be marked in accordance with FED-STD-1
22、23. The information shall include nomenclature, Federal stock number, or manufacturers part number, contract or order number, cure date, contractors name and destination. 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ZZ-R-768B 3.5.2 Military agen
23、cies. In addition to any special marking required by the contract or order (see 5.1 and 6.2), interior packages and exterior containers shall be marked in accordance with MIL-STD-129 and shall also include nomenclature, Federal stock number or manufacturers part number, contract or order number, cur
24、e date, contractors name and destination. 3.6 Workmanship. The workmanship shall meet all the applicable requirements of this specification. 4. QUALITY ASSURANCE PROVISIONS 4.1 Responsibility for inspection. Unless otherwise specified in the contract, the contractor is responsible for the performanc
25、e of all inspection requirements as specified herein. Except as otherwise specified in the contract, the contractor may use his own or any other facilities suitable for the performance of the inspection requirements specified herein, unless disapproved by the government. The government reserves the
26、right to perform any of the inspections set forth in the specification where such inspections are deemed necessary to assure that supplies and services conform to prescribed requirements. 4.2 Classification of examinations and tests. The inspection requirements specified herein are classified as fol
27、lows: a. First article inspection (see 4.3). b. Quality conformance inspection (see 4.4). 4.3 First article inspection. First article inspection shall be performed when a first article sample is required (see 3.1.1 and 6.2). This inspection shall include the examination of 4.4.2.1 (for resilient com
28、ponents only) and the tests specified in table I. 4.3.1 First article samples and tests. Material submitted for first article examinations and tests shall be certified to have the same composition, construction, and manufacturing process as the material to be supplied on subsequent lots. A represent
29、ative sample of 10 resilient components shall be submitted for first article examination. Samples in accordance with 4.4.1.4 shall be submitted for first article tests. If any of the first article examinations or tests do not conform to the applicable requirements, this shall be cause for denial to
30、proceed with production of the uncured compound and finished resilient components. When specified (see 6.2), the supplier shall prepare a first article test report. Production of the uncured rubber compound or finished resilient (cured) components by the supplier prior to approval of the procuring a
31、ctivity or the completion of first article examinations and tests shall be at the suppliers risk. 4.4 Quality conformance inspection. Conformance inspection shall include the examination of 4.4.2.1 (for resilient components only) and the conformance tests in table I. 4.4.1 Sampling. 4.4.1.1 Lot of u
32、ncured compound. For the purposes of sampling for examination and tests, a lot of uncured compound shall consist of not more than 200 pounds of the material produced in one plant under the same conditions, and offered for delivery at one time. 4.4.1.2 Lot of resilient components. For the purpose of
33、sampling for examination, a lot of resilient components shall consist of those components of the same form, type, and dimensions produced in one plant under the same conditions, and offered for delivery at one time. 4.4.1.3 Sampling for visual and dimensional examination. For the examination specifi
34、ed in 4.4.2.1, representative samples shall be taken at random from each lot of resilient components in accordance with table II. 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ZZ-R-768B TABLE II. Sampling for examination. Major Defects Number of
35、Components in Lot Number of Components in Sample Acceptance Number 40 and under 10 0 41 to 110 15 0 111 to 300 25 1 301 to 500 35 1 501 to 800 50 2 801 to 1300 75 3 1,301 and over 110 4 4.4.1.3.1 Major defect defined. A major defect is a defect that is likely to result in failure or to reduce materi
36、ally the usability of the resilient components for its intended purpose. 4.4.1.4 Sampling for tests. For the tests specified in 4.5, the contractor shall furnish three cured sample pieces 6 inches long by 6 inches wide by 0.0800.010 inch thick and one cured sample piece at least 6 inches long by 6 i
37、nches wide by 0.5000.010 inch thick, to represent each lot of either uncured compound or resilient components. The sample pieces shall be certified by the supplier to be identical in composition and prepared at the same time from material used in the lot offered for delivery. 4.4.2 Quality conforman
38、ce examination and tests. 4.4.2.1 Examination. Each of the samples taken in accordance with 4.4.1.3 shall be subjected to examination for workmanship, dimensions, and tolerances. MIL-STD-407 shall be used to determine and evaluate defects. 4.4.2.1.1 Rejection. Any component in the sample containing
39、one or more defects shall not be offered for delivery. If the number of defective components in any sample exceeds the acceptance number for that sample, this shall be cause for rejection of the lot represented by the sample. 4.4.2.2 Tests. The samples submitted in accordance with 4.4.1.4 shall be s
40、ubjected to the conformance tests specified in table I. 4.4.2.2.1 Action in case of nonconformance. If any of the samples representing a lot is found to be not in conformance with the requirements of this specification, this shall be cause for rejection of the lot it represents. 4.5 Test methods. 4.
41、5.1 Tensile properties. Tensile strength, ultimate elongation, and tensile stress (modulus) at 100 percent elongation shall be determined in accordance with ASTM D412, Test Method A. Die C specimens shall be used for all determinations of tensile properties. 4.5.2 Hardness. Hardness shall be determi
42、ned by ASTM D2240, Type A durometer. The three-second reading shall be taken on a 0.5000.010 inch thick specimen. 4.5.3 Specific gravity. Specific gravity shall be determined in accordance with ASTM D792. 4.5.4 Tear resistance. Tear resistance shall be determined by ASTM D624 using Die C specimens t
43、hat are 0.8000.010 inch thick. 4.5.5 Tensile properties after oven aging. Tensile strength, ultimate elongation, and tensile stress (modulus) at 100 percent elongation after oven aging shall be determined in accordance with ASTM D573. The aging period shall be 96 hour at 1942 F (901.1 C). Determinat
44、ion shall be made not less than 20 hours or more than 48 hours after removal from the oven. 5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ZZ-R-768B 4.5.6 Hot compression set. Hot compression set shall be determined by ASTM D395, Test Method B, wi
45、th specimens clamped to 40 percent deflection and aged for 96 hour at 1942 F (901.1 C). 4.5.7 Volume change after immersion in oil. The volume change shall be determined by Method 6211 of FED-STD-601 after immersion in medium No. 3 oil of Method 6001 of FED-STD-601 for 96 hour at 1222 F (501.1 C). 4
46、.5.8 Deformation, resilience, frequency, and absorbed energy. Deformation, resilience, frequency, and absorbed energy shall be determined using a Yerzley oscillograph following the procedure for measurements in compression detailed in ASTM D945. The mechanical properties shall be determined at both
47、73.42.0 F (23.01.1 C) and 32.02.0 F (0.01.1 C), after conditioning the specimens for 2 days at room temperature plus 4.00.1 hour at each test temperature 4.5.8.1 Deformation. Deformation is the percent deflection of the specimen caused by five standard weights, calculated as one inch equals 20 perce
48、nt. 4.5.8.2 Resilience. The resilience shall be calculated by dividing the vertical distance of the upstroke of the first cycle (rebound) by the vertical distance of the down-stroke of the first cycle from the starting point and multiplying by 100. 4.5.8.3 Frequency. The frequency shall be determine
49、d by counting a convenient number of cycles, then measuring in inches the horizontal distance along the center axis of the set of oscillations covered by this number of cycles, and by dividing the number of cycles by the measured distance. 4.5.8.4 Absorbed energy. The absorbed energy shall be calculated by multiplying the vertical distance in inches of the down-st
