1、MIL-C-18759B (AS) 19 Jime 1968 Superseding 6 June 1967 MIL-C-18759A (AS) MILITARY SPECIFICATION MARK 5 AND MODS CARTRIDGE CASE, STEEL, 20-MILLIMETER (FOR 20MM A/C GUNS) 1. SCOPE 1.1 This specifica ion covers the manufacture and preparation for de ivery of the Cartridge Case, Steel, 20-Millimeter Mar
2、k 5 and Mods -ad the methods of exami- nation and tests upon which product acceptance shall be based. 2. APPLICABLE DOCUMENTS 2.1 Governmenr Documents. The following documents of the issue in effect on date of invitation for bids or request for proposal, form a part of the specifi- cation to the ext
3、ent specified herein. SPEC IF1 CATI ON -deral QQ-2-325 PPP-B- 6 3 6 Military MIL-S-3289 MIL-Q-9 85 8 MIL- I - 45 6 O 7 MIL-C- 45662 STANDARDS Federal FED-STD-151 Zinc Plating ( E lec trode s p os i t e d ) Boxes Fiberboard Steel, Plate and Disk Carbon, Forging Quality Quality Program Requirements In
4、spection Equipment, Supply and Maintenance of Calibration System Requirements Metals, Test Methods Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- - MIL-C-187 59B Military MI L-STD- 10 5 MIL- STD- 12 9 DRAWINGS Naval Ordnance Systems Command -NAVAIR
5、SYSCOM 51753.4 . . LD 289036 MIL-C-lt8759B 13 9999906 0299814 7 m - Sampiing Procedures and Tables or Inspection by Attributes Marking for Shipment and Storage 20MM Cartridge Case, MK 5 MOD O Steel 20MM Cartridge Case, Steel, MK 5 MOD O (And LDs, drawings y specifications, standards and publicitions
6、 listed thereon. ) Copies of specifications , standards , drawings and publications required by suppliers in connection with specific procurement functions should be obtained from the procuring activity. or as directed by the contracting officer. 2.2 fication to the extent specified herein. in effec
7、t on date of invitation for bids or request for prop.osal shall apply: Other Publications. The following documents form a part of this speci- Unless otherwise indicated y the issue AMERICAN SOCIETY FOR TESTING AND MATERIALS ASTM E3-62 Preparation of Metallographic Specimens Address request for copie
8、s to American Society for Testing and Materials y. 1916 Race Street , Philadelphia y Pa. 19143 AMERICAN SOCIETY OF MECHANICAL ENGINEERS ASA B46.1-1962 SURFACE TEXTURE (Surface Roughness , Waviness E Lay) Address request for copies to American Society of Mechanical Engineers, United Engineering Cente
9、r, 345 East 47th Street , New York , N.Y. Technical Society and Technical Association specifications and standards are generally available for reference from libraries They are also distributed among technical giriups and using Federal agencies. 3. REQUIREMENTS 3.1 Inspection and Manufacture. The ca
10、rtridge cases shall be manufactured, examined , tested and packed in accordance with contract documents , NAVAIRSYSCOM Drawing 517534, this specification, and all LDs , drawings , specifications , standards and publications listed herein. 3.1.1 Preproduction sample. An acceptable preproduction sampl
11、e of cartridge 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C- 1875 9B cases shall be furnished by the supplier (see 4.1.1). materials shall be of single type, grade, class, size and composition and shall comply with all applicable provision
12、s of this document. shall not be applied as part of the quantity specified for delivery by the con- tract ar order. sample and authorization by procuring agency shall be at the suppliers risk. The cartridges and all The preproduction sample Production of the item prior to acceptance of the preproduc
13、tion 3.1.2 General 3.1.2.1 Material, Materials used in the manufacture of the cartridge case shall be in accordance with Specification MIL-S-3289, except the supplier may use steel OE chemical composition differing from the ranges specified in Specification MIL- S-3289, initially or during productio
14、n, provided that such a change has been proven by the successful performance of a preproduction sample and the change is approved by the procuring activity. representing each preproduction sample and each production lot shall be submitted by the supplier to the procuring activity. A chemical analysi
15、s report of the material 3.1.2.2 Machining. burrs, gouges, or other imperfections which will affect their serviceability. Machining of cartridge cases shall not result in objectionable 3.1.2.3 Surfaces. such as blisters, cracks, slivers, seams, cold shuts, folds and other imperfections and shall be
16、smooth in appearance after protective coating. defined as exceeding 10% of the wall thickness, and shall apply to any and all imperfections. 3.1.2.4 Protective coating. The coating process shall conform to Specification QQ-2-325, Type II, Class 3 , except that the coating shall have a minimum thickn
17、ess of 0.0002-inch on the interior surfaces, 0.0003-inch on the exterior body surface, and a maximum thickness of 0.0008-inch on either surface. All cartridge case surfaces shall be free from injurious defects IInjurious“ shall be 3.2 Examinations. Examinations shall be conducted to ensure cartridge
18、 cases meet all requirements OF Drawing Number 517534. 3.3 Performance and product characteristics 3.3.1 Performance 3.3.1.1 Ballistic. The cartridge case shall meet the following requirements: a. Gun Function in both the MK-11 and MK-12 machine guns: Load and Eject b. No longitudinal or circumferen
19、tial splits, cracks, or fractures other than flange cracks as specified below, before and after ballistic tests. c. The flange area in Regions ItA“ and tlAB1l shall not shear during gun chamber loading, extraction, and ejection. (Flange cracks other than complete penetration of case wall are to be r
20、eported for information only and are not cause for rejection.) Drawing 517534. Regions “A“ and “ABt1 are defined in 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-flIL-C-L7598 13 W 9999906 0299836 O MIL-C-18759B 3.3.2 Product. 3.3.2.1 Microstructu
21、re, uniform fine grain microstructure compatible with the type of conditioning used without evidence of surface carburization or complete decarburization which would, in any way, adversely affect gun functioning or reduce the rate of fire. Decarb shll not exceed ,010 inches complete and/or .O20 inch
22、es total affected area except in instances where adverse effect on gun function is suspected under which circumstances partial decarb shall be restricted to ,003 inches (depth) maximum. 3.3.2.2 Hardness. Hardness values for test regions of the cartridge case shall be in accordance with Drawing 51753
23、4. Region A of the cartridge case head shall be annealed by an appropriate method to reduce the hardness in the head area to a maximum value of 79 Rockwell (30-T). annealing treatment must not extend beyond the limits specified for Region A. All regions of the cartridge case shall display a . *. , .
24、 I - I - _ The area affected by this 3.3.2.3 Tension Test. The yield strengTh of the cartridge case of Region B, as shown on Drawing 517534, should be 135,000 pounds per square inch (min.). The elongation of Region B shall be 6.0 percent in 1-inch (min.). 3.3.2.4 Corrosion. specification. (See 4.3.2
25、.4) The cartridge case shall meet the requirements of this 3.4 Workmanship. The product, in all stages of production, shall be pro- cessed under such inspection control as to assure uniformity in quality. components shall be free of chips, dirt, grit, or other foreign material. The cleaning methods
26、used shall not be inju.rious to any of the parts nor shall the parts be contaminated by the cleaning agents employed. which extend through the protective coating shall render a case liable to rejection. 4. QUALITY ASSURANCE PROVISIONS All The presence of scratches 4.1 Responsibility for inspection.
27、Unless otherwise specified in the contract or purchase order, the supplier is responsible for the performance of all inspection and requirements as specified herein. Except as otherwise specified, the supplier may utilize his own facilities or any commercial laboratory acceptable to the Government.
28、set forth in the specification where such inspections are deemed necessary to assure supplies and services conform to prescribed requirements. 4.1.1 cartridge cases to the destination specified (Section 6.2C) for examination, test- ing, evaluation and acceptance per Table I and 4.2 before general pr
29、oduction on the contract is approved. These cartridge cases shall be made by the same pro- cesses the supplier will use in the fullfillment of the contract. duction Pot shall be submitted for approval before any major changes in the manufacturing process will be accepted by the procuring agency. The
30、 Government reserves the right to perform any of the inspections Preproduction lot. The supplier shall deliver a preproduction lot of 1000 A new prepro- 4.1.2. Production Lot. A production lot shall consist of all cartridge cases from one line or operation offered for delivery at one time and shall
31、not exceed 50,000 units. various lines or operations shall not be combined into production lots unless statistical control charts maintained during the production period for each of The test sample shall be drawn from each production lot. Production from 4 Provided by IHSNot for ResaleNo reproductio
32、n or networking permitted without license from IHS-,-,-MIL-C-18759B the various lines or operations are submitted with corrbined prodiictior, Tots and homogeneity is demonstrated on the charts. required in 4.2 and tested and accepted in conformance with Table I. teristics verified by the tests and e
33、xamination herein are classified as Critical, Major or Minor, in accordance with Drawing 517534. verify ritical characteristics are identified by the symbol (C), and Major characteristics by the symbol (14). uith a classification code are classified Minor. Production lcts shall be ex.mined as The ch
34、arac- Tests and examinations that Test and examinations which are not annotated TABLE I INSPECTION PLANS REFEFSNCE PARAGRAPH PREPRODUCTION SANPLE PRODUCTION Sample Size OT Sample Size Acceptance Criteria Acceptance Criteria (Blank) 4.3.1.1 3.3.1.1 Ballistic Tests 1000 a. Ac O Re 1 a. Ac O Re 1 MI L-
35、STD-105 Cartridge Cases b. Ac O Re 1 c. Ac O Re 1 b. Ac O Re 1 c. Ac O Re 1 Inspection Level II 4.3.2.1 3.3.2.1 4.3.2.2 3.3.2.2 Microstru ture Test and Hardness Test 13 Cartridge Cases Ac O Re 1 MI L-STD- 105 AQL 1.0 Inspection Level S-2 4.3.2.3 3.3.2.3 Ac O Re 1 13 Cartridge Cases MIL-STD-10 5 AQL
36、1.0 Tension Test Corrosior Test Inspection Level S-2 4.3.2.4 3.3.2.4 13 Cartridge Cases NIL-STD- 10 5 Ac O Re 1 I AQL 1.0 Inspection Level S-3 5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C-18759B TABLE II Type of Sampling Preproduction Prod
37、uction Number of Rounds 300 30 O 300 25 75 .- lo 1/3 of Remainder of S amp le 1/3 of Remainder of Sample 1/3 of Remainder of Sample Charge Pressure (Propellant) Service Service Service Proof Misc. Tests - -I_*1_ Proof Service Service Service Temperature of Rounds (Fo) -65 t 70 t165 t70 As required t
38、70 -65 t 70 t165 Each round for testing at service pressure shall be fired under automatic rapid fire, and each round for testing at proof pressure shall be fired in single shot, unless otherwise directed by the procuring activity. All rounds shall be fired with charges and at temperatures as shown
39、in Table II. be performed with a weapon of service quality. feeder mechanism shall be of current service design and in an operating condition satisfactory for unrestricted use. have been prepared for action in accordance with pertinent ordnance publications. A weapon of service quality shall be used
40、 for all ballistic testing of cartridge cases at service pressure. barrel and associated equipment shall be used. All cartridge cases tested under automatic rapid fire action shall be extracted and ejected, and in no way cause the weapon to cease firing. cases with proof charges shall be capable of
41、being extracted by normal methods. Defectives are cartridge cases failing to meet the requirements of 3.3.1.1. The tests shall The gun mechanism, barrel, and All components of the gun mechanism shall For testing at proof pressure an accuracy or Mann When fired in single shot action, the cartridge 6
42、Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C-18759B 4.1.3 Test equipment and gages. All test equipment and gages shall be supplied . and maintained by the supplier as specified in Specification NIL-1-45607. supplier shall maintain a calibrat
43、ion system as specified in Specification MIL-C- 45662, unless otherwise specified in the contract. However, a supplier currently under the requirements of MIL-Q-9858 shall be governed by the requirements of MIL-Q-9858 for items procured in accordance with this specification. Ti-ie It. 2 Examinations
44、. Sampling and inspection characteristics, unless otherwise noted, shall be in accordance with MIL-STD-105 (Table IIa); sampling for characteristics as specified on Drawing 517534 shall be as follows: (a) For critical defects a single sampling is prescribed (double or multiple sampling and reduced i
45、nspection are prohibited) , Sample size shall be as follows: (i) For inspection of lot size of 125 or less, use 100 percent of the lot. (2) For inspection of lot sizes of 126 to 3,200, use 125 units. (3) For inspection of lot sizes greater than 3,200, use the sample size from Table II of MIL-STD-105
46、. (b) Reject the lot for one or more CRITICAL defects. (c) The AQL for MAJOR-defects shall be 1.0 percent by class and for MINOR defects 2.5 percent by class unless otherwise specified. 4.2.1 Cartridge case examination. Examination shall be made to ascertain that the cartridge cases meet the require
47、ments of Drawing Number 517534. cartridge cases containing no defectives shall be used for further testing or returned to the lot. Only 4.2.2 marking of the pack shall conform to Section 5 of this specification. 4.3 specified in Table I as applicable. Packing and marking examination. The packing of
48、the cartridge case and Tests. Random samples of cartridge cases shall be selected and tested as 4.3.1 Perf ormance test. 4.3.1.1 for service use. 4.3.1.1.1 Miscelaneous tests. The testing activity may conduct additional tests as required to assist component manufacturers and assembly activities to m
49、aintain quality control. Test results shall not be used as acceptance or rejection criteria, but shall be in- cluded in Ballistic test reports or information purposes. Ballistic testing. The cartridge cases shall be loaded and crimped as For preconditioning and firing of samples refer to Table II. Such tests shall be authorized by the procuring agency. 4.3.2 Product tests. 4.3.2.1 structure examination in accordance with ASTM E3-62 ; paragraph
