1、.- - MIL-P-2340B MF 9997906 OLf2077L W - Beneficial comments (recommendations, additions, deletions) and any pertinent data whichmay be of use in improving this document should be addressed to: Specifications and Standards Department (Code 93), Naval Air Engineering Center, Lakehurst , N3 08733, by
2、using the self -addressed Standardization Document Improve- ment Proposal (DD Form 1426) appearing at the end of this document or by letter. Engineering 4 MIL-P -2 34 08 B 23 August $983 SUPERSEDING MIL-P -2 34 08A 19 July 1967 MILITARY SPECIFICATION PLATING: TIN-CADMIUM (ELECTRODEPOSITED) This spec
3、ification is approved for use by all Departments and Agencies of the Depart- ment of Defense. 1. SCOPE 1.1 Scope. This specification covers the requirements for three classes of tin-cadmium alloy plating. 1.2 Classification. Tin-cadmium plating shall be -of the following classes, as specified (see 6
4、.2.1): Class 1 2 3 Thickness, inch (minimum) O. 0005 O. 0003 o. 0002 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 listed in that issue of the Departmen
5、t of Defense Index of Specifications and Standards (DoDISS) specified in the solicitation form a part of this specification to the extent specified herein. STANDARDS FEDERAL FED-STD-15 1 - Metals, Test Methods. (Copies of specifications, standards, handbooks, drawings, and publications re- quired by
6、 manufacturers in connectzon with specific acquisition functions should be obtained from Ehe contracting activity or as directed by the contracting officer.) Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- MIL-P-2340B MF M 9777906 0420772 T MIL-P -2
7、 3 4 08 B 2.2 Other publications. The following document forms a part of this specifi- cation to the extent specified herein. The issues of the document which are indi- cated as DoD adopted shall be the issue listed in the current DoDISS and the sup- plement thereto, if applicable. AMERICAN SOCIETY
8、FOR TESTING AND MATERIALS (ASTM) ASTM B 117 - Salt Spray (Fog) Testing. (Application for copies should be addressed to the American Society for Testing and Materials, 1916 Race Street, Philadelphia, PA 19103.) t s (Industry association specifications and standards are generally available for referen
9、ce from libraries. using Federal agencies.) They are also distributed among technical groups and 2.3 Order of precedence. In the event of a conflict between the text of this specification and the references cited herein, the text of this specification shall take precedence. 3. REQUIREMENTS 3.1 Nater
10、ials. The materials used shall be such as to produce tin-cadmium coatings which meet the requirements of this specification. 3.1.1 Composition. The plating shall contain 25 to 50 percent tin by weight and the remainder shall be cadmium. 3.2 Workmanship. 3.2.1 Basis metal. The basis metal shall be fr
11、ee from defects that will be detrimental to the appearance or the protective value of the plating. metal shall be subjected to such cleaning, pickling and plating procedures as necessary to yield deposits as herein specified. The basis 3.2.2 Plating. The basis metal shall be either plated with tin a
12、nd cadmium in two consecutive layers and subjected to a diffusion treatment or plated with tin- cadmium alloy. continuous, free from visible blisters, pits, nodules, indications of burning, excessive edge build-up and other defects. demonstrated as resulting from rinsing, or slight discoloration res
13、ulting from baking, as specified below (see 3.3.3), shall not be cause for rejection. All de- tails of workmanship shall conform to the best practice for high quality plating. The tin-cadmium plating shall be smooth, fine grained, adherent, Superficial staining which has been 3.3 General . requireme
14、nt s. 3.3.1 Application. Unless otherwise specified, the plating shall be applied after al1 machining, brazing, welding, forming and perforating of the article have been completed. 3.3.2 Stress-relief heat treatment. Unless otherwise specifiedA all steel parts a having an ultimate tensile strength o
15、f 150,000 psi and above, whichcare machined, ground, cold formed or cold straightened after heat treatment, shall be baked at a 2 Y- 7 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-P-234 08B O minimum of 191 ir 14OC (375 f 25 F) for three hours
16、 or more prior to cleaning and plating for the relief of damaging residual tensile stresses. 3.3.3 Baking. A10 Steg1 partg havigg a Rockwell hardness of C 40 and higher shall be baked at 168 f 6 C (335 5 10 F) for three or more hours within eight hours after plating to provide embrittlement relief (
17、see 4.4.2.5). or other parts subject to flexure shall not be flexed prior to baking operations (see 6.4). Plated springs Carburized parts shall be baked at 135 $: 14OC (275O f 25F). 3.3.4 Diffusion treatment. All steel parts plated with tin and cadmium as discrete layers shall be given a diffusion t
18、reatment at 168 2 6OC (335 2 10F for 30 to 45 minutes, except when baking is required for embrittlement relief (see 3.3.3). fusion treatment. In that case, the baking treatment is considered equivalent to the dif- 3.3.5 Deposition. Unless otherwise specified, tin-cadmium shall be deposited directly
19、on the basis metal without a preliminary plating of other metal. 3.4 Detail requirements. 3.4.1 Thickness of plating. The thickness of the tin-cadmium shall be as specified in Table I on all visible surfaces which can be touched by a ball 0.75 inch in diameter. Where Class 1 is specified, all other
20、visible surfaces shall be Class 2 minimum thickness. Where Class 2 is specified, all other visible surfaces shall be Class 3 minimum thickness. Where Class 3 is specified, all other visible surfaces shall be 0.00015 inch minimum thickness. 3.4.1.1 Thickness. Tin-cadmium plating shall be Class 1 thic
21、kness, unless otherwise specified or controlled by the following exceptions (see 6.5): a. Bolts, studs, washers and articles with portions externally threaded. These parts shall have a minimum of Class 2 thickness. b. Holes and other openings and internal threads from which the external environment
22、is completely excluded, where a con- trolled deposit can not be normally obtained, shall not be subject to a thickness requirement, 3.4.2 Adhesion. The adhesion of the plating shall be such, that when examined at a magnification of approximately 4 diameters, it does not show separation from the basi
23、s metal at the interface when subjected to the test described in 4.5.3. The interface between the tin-cadmium and the basis metal is the surface of the basis metal before plating. The formation of cracks in the plate caused by rup- ture of the basis metal which do not result in flaking, peeling, or
24、blishtering of the plate shall not be considered as nonconformance to this requirement. 3.4.3 Corrosion resistance. Plated specimens shall show no basis metal cor- rosion products at the end of 168 hours when tested by continuous exposure to salt spray as specified in 4.5.4. 4. QUALITY ASSURANCE PRO
25、VISIONS Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- _ MIL-P-23408B MF 777770b 0420774 3 W MIL-P -234 08B 4.1 Responsibility for inspection. Unless otherwise specified in the contract or purchase order, the contractor is responsible for the perfo
26、rmance of all in- spection requirements as specified herein. contract or purchase order, 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 right to per
27、- form any of the inspections set forth in the specification where such inspections are deemed necessary to assure supplies and services conform to prescribed require- ment s, Except as otherwise specified in the 4.2 Classification of inspections. The inspections specif ied herein are classified.as
28、quality conformance inspections. 4.2.1 Separate specimens. When the plated articles are of such form, as to be not readily adaptable to a test specified herein or are for destructive tests of small lot sizes, the test shall be made by the use of separate specimens plated concurrently with the articl
29、es represented, The separate specimens shall be of a basis metal equivalent to that of the articles represented. metal includes chemical composition, grade, condition and finish of surface prior to plating. sent a hot-rolled steel surface. .Due to the impracticality of forging or casting separate te
30、st specimens, hot-rolled steel specimens may be used to represent forged and cast-steel articles. mately 1 inch wide, 4 inches long and 0.04 inch thick for adhesion test; but shall be at least 4 inches wide, 6 inches long and approximately 0.04 inch thick for all other tests, These Specimens shall b
31、e introduced into a lot at regular intervals prior to the cleaning operations preliminary to plating and shall not be separated therefrom until after completion of plating. Conditions affecting the plating of specimens including the spacing and positioning in respect to anodes and to other objects b
32、eing plated shall correspond as nearly as possible to those affecting the significant surfaces of the articles represented. Separate specimens shall not be used for thickness measurements, however, unless the necessity for thelr use has been demonstrated. Equivalent basis For example, a cold-rolled
33、steel surface should not be used to repre- The separate specimens shall be strips approxi- 4.3 - Lot. A lot shall consist of plated articles of the same class plated under the same conditions, and approximately the same size and shape submitted for inspection at one time. 4.4 Sampling. 4.4.1 For vis
34、ual examination and nondestructive tests. Samples for visual examination and nondestructive tests shall be selected at random form each lot. The number of articles shall be as indicated in Table II. The lot shall be accept- ed or rejected according to the procedures in 4.4.1.1 for visual examination
35、 and 4.4.1.2 for plating thickness. (nondestructive tests). 4.4.1.1 Visual examination. Samples selected in accordance with 4.4.1 shall be examined for compliance with the requirements of 3.2.1 before plating, unless otherwise specified, and 3.2.2 after plating. articles exceeds the acceptance numbe
36、r for that sample, as stated in Table II, the lot represented by the sample shall be rejected. If the number of nonconforming Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-P -2 3 4 08 B 4.4.1.2 Thickness of plating (nondestructive tests). Sampl
37、es selected in accordance with 4.4.1 shall be inspected and the plating thickness measured at locations on each article as defined in 3.4.1 for compliance with the require- ments. The article shall be considered nonconforming if one or more measurements fail to meet the specified minimum thickness.
38、any sample exceeds the acceptance number for the specified sample, as stated in Table II, the lot represented by the sample shall be rejected. (see 4.2.1) shall not be used for thickness measurements unless a need has been demonstrated. If the number of defective items in Separate specimens 4.4.2 Fo
39、r destuctive tests. A random sample of four plated parts or articles shall be taken from each lot or four separately plated specimens shall be prepared in accordance with 4.2.1 to represent each lot-. -If the number of articles in the lot is four or less, the number of articles. in the sample shall
40、be specified by the contracting agency (see 6.2 .I). 4.4.2.1 Composition (destructive tests). Samples .selected in accordance with 4.4.2 shall be tested for composition as specified in 3.1.1 (see 4.5.1). 4.4.2.2 Thickness of plating (destructive tests). Samples selected in accord- ance with 4.4.2 sh
41、all be measured for plating thickness at several locations on - each article, as defined in 3.4.1, for compliance with the specified requirements. Measurements on threaded articles, such as screws, nuts, bolts and other fasteners shall be made on the shank or other smooth surfaces as close to the th
42、reads as possible. If the plating thickness at any place on any article or specimen is less than the specified minimum thickness, the lot shall be rejected. specimens (see 4.2.1) shall not be used for thickness measurements unless a need has been demonstrated. Separate 4.4.2.3 Adhesion (destructive
43、tests). The articles or specimens used for the destructive thickness test (see 4.4.2.2), if of suitable size and form, may be used as the speimens for the adhesion test to determine compliance with the re- quirements of 3.4.2. stitute failure of the lot. Failure of one or more of the test specimens
44、shall con- 4.4.2.4 Corrosion resistance (destructive tests). When .specified, compliance with the requirements for corrosion resistance shall be determined (see 3.4.3). A set af four separate test specimens prepared in accordance with 4.2.1 shall be tested. Failure of one or more of the test specime
45、ns shall reject the lot. 4.4.2.5 Embrittlement relief (destructive tests). Unless otherwise specified, conformance to the requirements of 3.3.3 for enbrittlement relief shall be deter- mined. A random sapl; of four plated articles shall be taken from each lot. samples shall be considered nonconformi
46、ng if cracks are found after test or failure by fracture. (see 4.5.5). The Failure of one or more of the test specimens shall reject the lot 4.5 Test methods. 4.5.1 Composition. Either Method 111 or 112 of FED-STD-151 may be used for determination af composition of the tin-cadmium plating. Provided
47、by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-P-2340B MF M 7797706 0420776 7 MIL-P-234 08B 4.5.2 Thickness. Either Method 520, electronic test; Method 522, magnetic test; or Method 521, microscopic test of FED-STD-151 may be used for measuring the tin-c
48、admium plating thickness. However, for referee tests, the microscopic test method shall be used. 4.5.3 Adhesion. Adhesion may be determined by scraping the surface or shear- ing with a sharp edge, knife or razor through the plating down to. the basis metal and parallel to surface of the basis metal
49、and examining at four diameters magni- fication for evidence of nonadhesion. Alternately the article may be clamped in a vise and the projecting portion bent back and forth until rupture occurs. If the edge of the ruptured plate can be peeled back or if a separation between the plate and the basis metal can be seen at the point of rupture when examined at four diameters magnification, adhesion is not satisfactory. 4.5.4 Corrosion resistance, Corrosion resistance shall
