1、PLATING CHROMIUM, ELECTRO-DEPOSITED (h TiE INTERIOR SURFACES OF 20 MM MARK 11 GUN BAEELS) This specificatson has been approved by the Breau of Naval Weapons, Department of the Navy. 1. SCOPE 1.1 This specification presents detailed requirements for high contraction electrodeposited chromium plating
2、on the bores, grooves, and chambers of 2Omm Mark 11 Gun Barrels. 1.2 The requirements apply to 2Omm Mark 11 Gun Barrels whose Interior, surfaces have not been nitrided prior to plating 2. APPLICABLE DOCUMENTS 2.1 The following specifications, standards, and publica- tions of the issue in effect on t
3、he date of Invitation for bids, form a part of this specification. SPECIFICATIONS MILITARY MIL-L-3150 - Lubricating oil, preservative medium. MIL-C-16173 - Corro3lon Preventive, Solvent Cutback, Cold Application STANDARDS FEDERAL TED-SPD-151 - Metals; Test Nethods /- t_ THIS DOCUMENT CONTAINS 22 PAG
4、ES. 1 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-P-LSqLSA LO 777770b 0300348 O -STD-lOCj - Sampling Procedures and Tables for Inspec- MIL-STD-129 - Marking for Shipment and Storage. tion by. Attributes . PUBLICATIONS OP 400 - General Instruc
5、tions for the Design, Manufac- OP li05 - Preservation and Preservation Maintenance of ture, and Inspection of Naval Ordnance Equip- ment . Ordnance Equipment in Shore Storage. (Copies of specifications, standards, drawings, and publlca- tions required by contractors in connection with specific pro-
6、curement functions should be obtained from the procuring agency or as directed by the contracting officer.) 3. REQUIREMENTS 3.1 E ui ment. - Equipment for performing the chromium plating -9-E-6- opera ions shall be furnished by the contractor 8ub3aot to Che approval of the procuring activity. 3.2 Ma
7、terial. - 3.2.1 Basic material. - The basic material QT the_ POmmMark 11 Oun Barrel shall be of a quality, composition, and having the physical properties in accordance with the detail specifi- cations for the part. to affect only the surface properties of the interior of the barrel (i. e., hardness
8、, resistance to wear, erosion, corro- sion, and coefficient of friction). Plating with chromium shall be considered 3.2.1.1 Surface finish. - All interior surfaces of the pits, gouges, flakes, slivers, corrosion, or any other surface defects that would affect the application or the performance of th
9、e chromium plate. The surface roughness of the interior surfaces prior to plating shall conform to the applicable drawing requirements for surface roughness after plating. .barrel shall be substantially free fmm tool marks, cracks, P -. 2 Provided by IHSNot for ResaleNo reproduction or networking pe
10、rmitted without license from IHS-,-,-i . MIL-P-194L9A LO m 9999906 0300349 2 MIL-P-19419A (Wep), 3.2.1.2 Protection after machining. - After the final ma- chining operation, both the interior and exterior surfaces of the barrel shall be cleaned to insure removal of all cut- ting oil and other foreig
11、n matter. Immediately following inssection, these surfaces shall be coated with Lubricating Oil, Preservative, Medium, Specification MIL-L-3150, for the protection of all surfaces until the barrels are chromium plated. 3.3 Interior dimensions of the gun barrel before plating and before electropolish
12、ing. - 3.3.1 Removal of metal. - The required interior dimensions of the gun barrel before plating shall be obtained by electro- polishing, by mechanical removal of metal, or by a combination of mechanical removal of metal and electropolishing as speci- fied in the applicable drawings. 3.3.2 Before
13、plating. - The interior dimensions-of the gun barrels before chromium plating shall be such that the barrel dimensions will conform to the drawing dimensions within the prescribed tolerances after plating with the required thick- ness of chromium plate. 3.3.3 Before electropolishing. - The interior
14、dimensions of the gun barrel before electropolishing and chromium plating shall be such that the barrel dimensions will conform to the drawing dimensions within the prescribed tolerances, after removal of the specified amount of metal by electropolishing and plating with the required thickness of ch
15、romiiun plate. . 3.4 Chromium deposit. - 3.4.1 Thickness of deposit. - The thickness of the chromium deFosit on the top of the lands, and in the chamber shall be as specified in the applicable drawings. 3.4.2 Appearance of the depcsit after plating. - The chromium deposit as plated shall be smooth a
16、nd homogeneous. The eposit shall be bright on the tops of the lands but a somewhat dull or- slightly milky deposit in the grooves shall not be cause for rejection. “Burnt and “frosty“ deposits are unacceptable. The deposit shall be free from visible defects, such as unplated areas, blisters, flaking
17、, trees, cracks, pits, and gouges, in accordance with the acceptance standard gf this specification (see appendix). Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-3.5 Interior dimensions of the gun barrel after platinq. The interior dimensions of th
18、e bore, grooves, and chamber after Dlating shall conform to drawing dimensions within the prescribed tolerances , 3.5.1 hlechanical sizing . - Mechanical honing or similar operations shall not be performed on the tops of the lands to bring the dimensions of an undersize bore Nithin drawing dimen- si
19、6nsi sines sch opersticfis praduce sharp cages at the corners of the lands which are easily broken by the honing operation itself or by subsequent firing. operations are permitted in the chamber (where no edges are present) to attain proper size dimensions. Mechanical honing or similar 3.6 Records.
20、- The following data for each gun barrel cov- dimensional ered by this specification shall be recorded and retained until after completion of proof or firing tests: measurements, results of visual examination, and operating conditions for electropolishing and plating. 3.7 Firing test requirements. -
21、 3.7.1 Proof and functional firing. -, The condition of the chromium deposit after proof firing and after functional firing shall meet the requirements of the applicable 2Omm Aircraft Gun Mk 12 Specification when judged in accordance with accept- ance standard of this specification (see appendix). 3
22、.7.1.1 Life firing tests, - The performance of the chromim plated barrel during life firing tests shall conform to the requirements of the applicable 2mm Aircraft Gun Mk 12 Specifi- cations , 4. QUALITY ASSURANCE PROVISIONS 4.J General. - General inspection and test procedures shall be in aucor.danc
23、e with Federal Standard FED-STD-151, Metals; Test Methods, and Publication .OP 400. 4.1.1 Sampling. - Unless otherwise specified, and when ap- plicable, the sampling plans and procedures used by the govern- ment inspector in the determination of the acceptability of products submitted by a supplier
24、for Government inspection shall be in accordance with the provisions of MU-STD-105, 4.1.2 Government Inspection, - The government inspector will make such inspections as are necessary to determine that all components and assemblies are in accordance with the require- ments of the contract, pertinent
25、 drawings and specifications. -a 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- -. MIL-P-19qL9A LO 797990b 0300351 O W MIL-P-19419A (Wep) Unless otherwise specified, these inspections will be con- ducted in accordance with instructions contained
26、In Pub- lication OP 400. 4.1.3 Contractors inspection. - Contractorts inspection shall be conducted in accordance with provisions of “Inspec- tion by Contractor“ as contained in Publication OP 400. 4.1.4 Inspection lot. - The inspec6ion lot size shall be 4.2 Inspection before electropolishing and pl
27、ating. - 4.2.1 Visual inspection, - The interior surfaces of all barrels to be plated shall be illuminated and carefully inspected with suitable instruments to determine conformance with the requirements of 3.2.1.1. Barrels with surface defects that cannot be corrected shall be rejected as unsuit- a
28、ble for chromium plating. and plating, the bores and chambers of all barrels shall be stargaged for conformance to the requirements of 3.3. Barrels with dimensional defects that cannot be corrected shall be rejected as unsuitable for chromium plating. limited to a maximum ofs0 gun barrels. 4.2.2 Dim
29、ensional inspection. - Prior to electropolishing 4.3 Inspection after patinp;. - 4.3.1 Visual inspection of the chromium plate. - The interiors of all barrels after chromium plating shall be illuminated and carefully inspected with- suitable instruments for conformance with the requirements of 3.4.2
30、. Barrels with defects In the chromium plate shall be stripped and replated; the chamber may be mechanically sized in accordance with 3.5.1. All corrosion and stains noted after plating shall be removed from the unplated exterior surfaces of the gun barrels. not be determined with certainty by visua
31、l inspection shall be tested by cleaning the areas with a solvent to remove grease and then swabbing with a solution containing 13.4 ounces er gallon of copper ulfate (Cu 04.5H20) and 20 drops indicate that the surfaces are not covered with chromium. Any copper sulfate-solution remaining in the bore
32、 after the test shall be removed immediately bywiplng with a wet cloth or cotton and the bore dried by wiping or by an air blast. Copper deposits shall be removed from the test areas by light buffing . 4.3.2 Unplated areas. - Suspected unplated areas which can- per gal P on of sulfuric acid 795 perc
33、ent 7 . Deposits of copper Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-P-19419A (Wep) 4.4 Thickness of deposit after platinp;. - The thickness of the chromium deposit in the bore, grooves, and chamber shall be measured by stargaging the barre
34、ls before and after plating to determirre conformance with the requirements of 3.4.1. 4.4.1 Procedure. - Until it has been established that the praaedureFand equipment employed by the contractor consist- ently produce satisfactory chromium deposits of the-required thlcimess, the Inspector sk:a13 che
35、ck the dimensions of tho bores, grooves, and chambers of all barrels for confomnce with thickness requirements. Thereafter, the inspector shall at his discretion check a sufficient percentage of the barrels to insure continuing conformance with thickness requirements. 4.5 Dimensional inspection afte
36、r plating. - The interior surfaces of all b arrels shall b e stargaged after plating to determine conformance with the requirements of 3.5; mechanical sizing is permitted in accordance with 3.5.1. Barrels which do not meet dimensional requirements of the applicable drawings after plating shall be st
37、ripped and replated. 4.6 Inspection after proof and functional firing. - After proof firing, and after functional firing in accordance with the requirements of the applicable 20mm Aircraft Gun Mk 12 Specification, the chromium deposit shall be inspected for conformance with the requirements of 3.7.1
38、. Life firing tests. - Life firing tests shall be con- ducted according to the requirements of the applicable 2Omm Aircraft Gun Mk 12 Specification. 4.7 5. PREPARATION FOR DELIVERY 5.1 Preservation. - 5.1.1 To proof and return. - The gun barrels shall be pre- Application shall be by one served by ap
39、plying type P-2 preservative to outside surfaces and type P-9 to inside surfaces. or more methods specified in Specification MIL-P-116, 5.1.2 Protec%ion during storage. - The gun barrels shall be protected during storage in accordance with Publication OP 1105. 5.2 Marking. - Shipments shall be marke
40、d in accordance with Standard MIL-STD-129 and the applicable drawings. li Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- - - I_ _ ._ MIL-P-LS4LSA LO 777770b 0300353 4 W 6. NOTES MU- P- 1941 9A (kep ) 6.1 Intendeduse. - The chromium deposit .is appl
41、ied to the interiorsurfaces of the gun barrels for the purpose Of re- , ducine; tke amourAt of erosion, wear,.corrosion and friction and for the purpose of reducing the amount and adhesion of copper, brass or other deposits from the projectile rotating bands, re- tained in the bore and grooves. 6.2
42、Typical equipment and procedures for chromium plating the interior surfaces of 20mm Piark 11 Gun Barrels. - 6.2.1. Equipment. - In general, the following types of equip- ment will be Recessary: 6.2.1.1 Current sources. - Generators or rectifiers capable of supplying the necessary current at 6 to 12
43、volts. requirements will depend on production rate (Le-, number of barrels plated in a tank at the same time). Current 6.2.1.2 Tanks. - 6.3.1.2.1 Electropolishing. - Steel, lead lined, equipped with thermostatic controls for heating and cooling. 6.2.1.2.2 Chromium plating and anodic etching. - Steel
44、, lead lined, r lined with such noniconductlve coatings as Koroseal and acid brick, equipped with thermostatic controls for heating and cooling. 6.2.1.2.3 .Alkaline cleaning. - Steel, unlined, equipped with heating coils. 6.2.1.2.4 Stripping. - Containing alkaline solutions for removing chromium pla
45、te. Steel, unlined. 6.2.1.2.5 For lead-tin plating of anodes, - Wood, asphalt lined, or steel, rubber lined. 6.2.1.2.6 Water rinse. - Steel, unlined, or steel, rubber lined. 6.2.1.3 Fume exhaust systems. - Fume exhaus6 Systems equip- ped with exhaust fans, ducts,.hoods, and stacks as required for ex
46、hausting the fumes from eleatropolishing, plating, etching, and stripping solutions. 6.2.1.4 Anodes, cathodes, fixtures, and electrical connec- tions. - Assemble anode and fixtures and electropolish for additional period calculated to complete the process after stargaging. . _- 6.2.2.2.3.4 Minimum d
47、epth electropolishing. - When the mini- . mum enlargement of the Interior dimensions by electropolishing -. . Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-P-ISLILSA 10 777770b 0300357 I W (0.002-inch deep or 0.004-inch on diaineter) is specifi
48、ed, it will not generally be,necessary to stargage the interior di; mensions after the electropolishing operation unless the barrel .-.has been selected for the determination of chromium plate thickness. / 6.2.2.2.3.5 Treatment prior. to plating. - If the barrel has been removed from the electropoli
49、shing solutionfor stargaging, it should be given a 30 td 60 aecond treatment inthe electro- polishing solution immediately before anodic etching and chromium plating. 6.2.2.2.3.6 Rinsing after electropolishing; - To avoid drag- in of the electropolishing solution into the etchinn or chro- mim plating solutions, rznse the barrel and fixtures thoroughly after removal from the electropolishing solution as follows: temper
