1、. . . - . - - - .- - - . - - - _- G- 9s -.Ys MIL-1-138578 MF m 777770b OL120577 L MIL-I-13857B 3 August 1983 SUPERSEDING MIL-I-l3857A(MF) 20 June 1966 MILITARY SPECIFICATION IMPREGNATION OF METAL CASTINGS This specification is approved for use by all Departments and Agencies of the Department of Def
2、ense b 1. SCOPE c 1.1 Scope. This specification covers the requirements for the impregnation of castings which may contain micropores but not visible blow holes or other major def ects. 1.2 Classification. The impregnation processes covered by this specification shall be of the type as specified. Ty
3、pe I - For use on castings for fire control instruments Type II - For use on castings for mortar shell 2. APPLICABLE DOCUMENTS 2.1 Government documents. 2.1.1 Specifications, standards, and handbooks. Unless otherwise specified, the following specifications, standards, and handbooks of the issue lis
4、ted in that issue of the Department of Defense Index of Specifications and Standards (DoDISS) specified in the solicitation form a part of this specification to the extent specified herein. SPECIFICAT IONS FEDERAL O-S-809 - Sulfuric Acid, Technical P-D-680 - Dry Cleaning Solvent QQ-A-601 - Aluminum
5、Alloy Sand Castings pW-343 - Wire, Electrical and Nonelectrical, Copper (Uninsulated) Beneficial comments ( recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to: Director, US Amy Materials and Mechanics Research Center, A
6、TTN: DRXMR-SMS, Watertown, MA 02172 by using the self-addressed Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter. NO DELIVERABLE DATA REQUIRED BY THIS DOCUMENT / AmA MEFP / Provided by IHSNot for ResaleNo reproduction or networking permi
7、tted without license from IHS-,-,-MIL-I-13857B MF W 777770b OLt20578 3 W MIL-1-1385 7B MILITARY MIL-E-463 - Ethyl Alcohol (for Ordnance Use) MIL-G-5572 - Gasoline, Aviation: Grades, 80/87, 100/130, 115/145 MIL-H-6083 - Hydraulic Fluid, Petroleum Base, for Preservation and Testing MIL-G-23827 - Greas
8、e, Aircraft and Instrument, Gear and Actuator Screw STANDARDS FEDERAL Fed. Test Method Std. No. 141 - Paint, Varnish, Lacquer, and Related Materials, Methods of Inspection, Sampling and Testing MILITARY MIL-STD-286 - Propellants, Solid; Sampling, Examina.tion and Testing (Copies of specifications, s
9、tandards, handbooks, drawings, and publications required by manufacturers in connection with specific acquisition functions should be obtained from the contracting activity or as directed by the contracting officer . ) 2.2 Order of precedence. Zn the event of a conflict between the text of this spec
10、ification and the references cited herein, the text of this specification shall take precedence. 3. REQUIREmNTS 3.1 Material. The impregnants used in the process shall produce a thermoset resin when cured and shall cure without the formation of voids (see 6.1.5). 3.2 Shrinkage. The impregnant shall
11、have a maximum shrinkage of ten percent on curing when tested as specified in 4.4.1. 3.3 Inhibitive effect of copper (type I only). The resin for type I impregnant shall cure to a hard firm mass when polymerized in the presence of copper in accordance with 4.4.2. di scolorat ion. The copper shall ex
12、hibit no greenish 3.4 Reactivity (type II only). The reactivity of the type II impregnant with either TNT or Composition B explosive shall not exceed 2.001111 of gas when tested as specified in 4.4.3. 3.5 Difusion rate after imtnecmation. 3.5.1 Before exposure. Test disks when prepared and tested in
13、 accordance with 4.4.4 shall show a diffusion rate not greater than 107 cubic feet per square inch per hour. 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-O . O O 3.5.2 Ute- exposure. The impregnated disks after exposure as specified in 4.4.5 sha
14、ll show a diffusion rate not greater than 107 cubic feet per square inch per hour when tested as outlined in 4.4.4. 3.6 Exudation. There shall be no observable exudation of impregnants from any surface during the curing operation. 3.7 Workmanship. Quality of workmanship shall be such that impregnati
15、on will meet the requirements for quality as specified in 3.2 to 3.6, inclusive. The completed impregnation shall meet the inspection and test requirements for quality when tested as in 4.4. 4. QUALITY ASSURANCE PROVISIONS 4.1 Responsibility for inspection. Unless otherwise specified in the contract
16、 or purchase order, the contractor is responsible for the performance of all inspection requirements as specified herein. Except as otherwise specified in the contract or purchase order, the contractor may use his own or any other facilities suitable for the performance of the inspection requirement
17、s specified herein, unless disapproved by 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 conform to prescribed requirements. 4.2 Sampling. 4.2.1 Sampling an
18、d inspection of the impregnant. Sampling and inspection of the impregnant shall be performed in accordance with method 1031 of Fed. Test Hethod Std. No. 141. Testing shall be performed in accordance with the applicable procedures of 4.4. 4.2.2 Sampling for testing of the impreqnating process. The ac
19、ceptance test sample shall consist of twelve impregnated disks for each lot of castings inpregnated (see figure 3). The disks shall possess initial diffusion rates varying between spaced as specified in 4.4.4.2 and shall be impregnated at the same time under the same conditions as the lot of casting
20、s it represents. defined as not more than 12 hours production. process a 50 gram sample of impregnated chips is required in addition to the twelve disks. sieve and be retained on a No. 14 meshdeve. and cubic feet per square inch per hour and A lot shall be For the type II impregnating These cups sha
21、ll be of a size to pass through a No. 10 mesh 4.2.2.1 At the option of the contracting officer, the diffusion rate test may be performed on impregnated castings from the lot in place of the sample disks. 4.3 Classification of tests. Testing under this specification shall be for acceptance of individ
22、ual lots. Acceptance tests shall normally consist of tests for all requirements specified in section 3. 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-I-13857B 4.4 Test methods. 4.4.1 Shrinkage test. A 10 ml. graduated cylinder, or a premarked
23、 test tube shall be filled to the mark with impregnant and cured uner the conditions recommended for the impregnant by the manufacturer. to room temperature, the cylinder shall be refilled with water containing a suitable wetting agent from a burette or a pipette. shall be calculated from the f onnu
24、la: After cooling The percent of shrinkage Percent shrinkage = 1OV where V = volume of water aded in ml. 4.4.2 Inhibitive effect of copper (type I only). One gram of the impregnant shall be placed in a small watch glass-containing two one-half inch strands of AWG #i8 copper wire conforming to QQ-W-3
25、43. be cured under the conditions recommended by the manufacturer. after curing shall be done by pressing the mass with the fingers and noting of the mass is solid and firm. the copper wire shows a greenish color the impregnant shall be considered as failing the test and the batch shall be rejected.
26、 The impregnant shall Examination If the impregnant is tacky or compressible, or 4.4.3 Reactivity (type II only). 4.4.3.1 Test method. The test for reactivity of the type II impregnant with explosives shall be conducted in accordance with method 403.1.2 of MIL-STD-286. glycerin and water for the con
27、stant temperature bath. following compositions shall be tested: The test shall be conducted at 1OOoC using a solution of Specimens having the (a) 2.5 grams of type II impregnated metal chips (see 4.2.2). (b) 2.5 grams of TNT (see 6.2). (c) (d) (e) 2.5 grams of Composition B explosive (reduced to a p
28、racticable fineness under gentle pressure) (see 6.2). 2.5 grams of type II impregnated metal chips mixed with 2.5 grams of TNT. 2.5 grams of type II impregnated metal chips mixed with 2.5 grams of Composition B explosive. 4.4.3.2 Calculation. The unit capacity of the capillary and the wlume of gas l
29、iberated during the test shall be calculated as specified in method 403.1.2 of MIL-STD-286. .The reactivity of the impregnant with explosives shall be calculated as follows: 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-I-13857B Reactivity, i
30、n ml. of gas = X - (YiZ) X = ml. of gas produced by the mixture of 2.5/2.5 Y = ml. of gas produced by 2.5 grams of impregnant Z = ml. of gas produced by 2.5 grams of explosive grams of type II impregnant and explosive alone alone 4.4.4 Diffusion rate. . 4.4.4.1 Test equipment. The diffusion test equ
31、ipment shall be as shown in figures 1 and 2. All stopcocks shall have leak proof seals. High vacuum rubber tubing shall be used where required and shall be kept to minimum length. Where rubber tubing is used, it shall be butyl rubber. Care shall be taken that it shall be heavy enough to withstand th
32、e pressure. All glass to rubber tubing shall be made airtight by using a sealing compound. shall be as leak proof as possible. The clamping device for the disk shall be provided with two rubber gaskets to insure leak proofness. The system 4.4.4.2 Test disks. The disks shall be aluminum castings, cla
33、ss B, of QQ-A-601, with dimensions as shown in figure 3. They shall have an initial thickness of 5/32 inch but the top and bottom face surfaces shall be machined (approximately 1/32 inch). The impregnation shall be performed on nine disks with initial leakage rates between 5 x 102 and 5 x 10-3 cubic
34、 feet per square inch per hour and three disks having widely spaced initial leakage rates between and cubic feet per square inch per hour. With these last three disks the leakage rate ratio between successive disks shall be not less than 6 nor more than 10. 4.4.4.3 Diffusion rate of system. To measu
35、re the diffusion rate of the O system the following procedure shall be followed: (see figs. 1 and 2). Fasten the plate firmly between the flanges with the gaskets in place. Open stopcocks #2 and #lo. Close stopcocks #1, #3, #4, #5, #6, #7, #8, and #9. Start pump and reduce pressure to about 100 micr
36、ons. Carefully open stopcocks #3, #4, #5, #6, #7, and #8. (Stopcock #5 should be opened from plate to pump.) Evacuate the system to 10 microns or less. Close stopcocks #4, #5, #6, #7 and #8. Continue evacuating the system to 10 microns or less. Record pressure reading (zero time reading) using the 0
37、-50 micron scale WcLeod gauge and return the gauge to the equalizing position. Simultaneously close stopcock #2 and start thing clock and take pressure readings (Close stopcock #lo.) 5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-I-L3857B MF W
38、 9933706 Oq20582 5 W MIL-I-13857B (k) Tilt the 0-50 micron scale McLeod gauge to the reading position at 3, 6, 9, 12 and 15 minutes, read, record and return gauge to equalizing position. (1) From the above recorded data, the rate of change of pressure (RI) m in microns per minute may be computed by
39、dividing the change in- pressure (15 minutes reading minus zero reading) by the time. The diffusion rate of the system shall not be greater than one micron per minute except in the case of the plate being tested having a high difusion rate, and in no case shall the diffusion rate of the system excee
40、d the difusion rate of the plate. 4.4.4.4 Diffusion rate of system and plate. To measure the diffusion rate of the system and plate, the procedure shall be as follows: After completing the measurement of the diffusion rate of the system (see 4.4.4.31, open stopcock #2 connecting the vacuum pump to t
41、he system and readjusting the pressure to 10 microns or less. Open stopcocks #9 and #S to the helium side, admitting helium to the high pressure side of the system. Adjust pressure control valve on the helium tank until the absolute pressure is 30 inches of mercury. Select proper volume (see 4.4.4.2
42、). Allow at least 15 minutes for the diffusion rate of the helium through the plate to reach equilibrium, making frequent readings. When the system has reached equilibrium, record this initial or zero time reading and return gauge to equalizing position. Simultaneously close stopcock #2 and start ti
43、ming clock. Read and record the pressure at the end of 3, 6, 9, 12 and 15 niinutes. sometimes necessary to choose a smaller time interval since the pressure will rise rapidly.) The diffusion rate of the system and plate (R2) may be computed from the above recorded data in the nianner prescribed by s
44、tep (1) , paragraph 4.4.4.3. (In the case o a plate with large diffusion rate, it is 4.4.4.5 Diffusion rate of the plate. The diffusion rate of the plate is computed as the difference between the diffusion rate of the system and plate and the diffusion rate of the system. Diffusion rate in cubic fee
45、t per square inch per hour = where V = voltme of calibrated system in cubic feet as Vi = voltune of calibrated system when all stopcocks except #3 are closed. 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-I-13857B V2 = volume of calibrated sy
46、stem when all stopcocks except #3 and vg = volume of calibrated system when all stopcocks except #3, #7 #7 are closed. and #8 are closed. Ri = rate of change of pressure of system in microns per minute. Rz = rate of change of pressure of system and plate in microns per A = effective area of plate in
47、 square inches. minute. Note. When a number of plates are to be tested, the following procedure shall be used in changing plates at the end of a test: . (a) Close stopcocks #2, #3, #4 and #5. The pump is kept in operation. (b) (c) Change plates. (d) (e) maluate the system for ten minutes. (f) Open s
48、topcocks #2 and #3, close #5 (9) Continue with (h) in pccragraph 4.4.4.3. Close valve on helium tank. Open stopcocks #4 and #5 from plate to pump. 1 When it is desired to shut down the apparatus, close stopcocks #2, #3, #4, #5 and #6. swply of helium. Open stopcock #i to the atmosphere and turn off
49、pump. Shut off 4.4.5 Exposure test. Using eight of the nine impregnated disks referred to in 4.4.4.2 which possess initial diffusion rates of between 5 x 102 and 5 x following exposures, one disk per exposure. cubic feet per square inch per hour, subject these disks to the (a) (li) (c) Sulfuric acid. A disk shall be immersed in an aqueous solution Diester grease. MIL-G-23827, or 48 hours at room temperature. Hydraulic oil. A disk shall be immers
