1、MILITARY SPECIFICATION PEENING OF METALS This amendment forms a part of Military Specification MIL-P-81985(AS), dated 18 October 1974, and is approved for use by the Naval Air Systems Command, Department of the Navy and is available for use by all Departments and Agencies of the Department of Defens
2、e. PAGE 5 3.2.3, Delete third sentence which begins with “When so specified,“ Add : “3.2.5 Hardness of shot. Hardness of the shot shall be in accordance with MIL-S-851. Parts to be shot peened having a hardness above Rc 50 should be shot peened with shot having a hardness of Rc 52 to Rc 62.“ PAGE 8
3、3.4.4, Add as new sentence: “For aluminum only, use as large a shot size as possible, taking into consideration surface finish and smallest fillet radii because the larger the shot size on aluminum for any given intensity, the deeper will be the depth of compression.“ PAGE 9 3.4.5, Delete last sente
4、nce and substitute: “Nozzle angles 45 degrees or lower do not produce effective compressive residual stresses and should be avoided.“ 3.5.1, Delete second sentence and substitute the following: “Manufacturing operations, such as straightening, machining and heat treating, grinding, or etching, which
5、 relieve stresses developed by peening or which develop detrimental residual stresses shall not be permitted after peening.“ Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-P-81 985(AS) AMENDMENT 1 PAGE 10 3.5.3, Delete first sentence and substit
6、ute: “It shall be permissible to improve the surface finish after peening by polishing, lapping, honing or vapor blasting provided such operations do not generate temperatures in excess of the applicable limitations (see 3.5.1) and do not remove material layers in excess of 10 percent of the induced
7、 compressive layer.“ 3.6.4, Delete subparagraph (a) and substitute the following: placement and direction, wheel angle and direction of hot spot.“ “(a) Air pressure or wheel speed, nozzle size and type, nozzle PAGE 13 4.2.2, Delete table VI and substitvte: Spec i men I 1 Dimensional-length, inch wid
8、th, inch thickness, inch Arc height as measured on gauge (i nch) Rockwell hardness I I i 3.000 + 0.015 0.094 2 0.001 0.051 - + 0.001 0.745 %o 0.750 0.745 to 0.750 3.000 + 0.015 0.000 + 0.0015 0.000 + 0.0015 C44 to-C50 C44 to-C50 I I 3.000 + .O15 0.745 %o 0.750 0.031 5 0.001 0.000 + 0.0015 A72.5 %o A
9、76 PAGE 14 4.2.5, subparagraph (e), line 3, after “direction,“ add the following: “wheel angle and angle of hot spot ,II. PAGE 16 4.3.2, line 4, Delete “square inch“ and substitute “inch square“ 4.4.3, line 2, Delete “at a magnification of 5X to 10X“ and substi tute “(see 4.4.3.1 1 line 5, Delete fi
10、rst “of“ 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-P-81985(AS) AMENDMENT 1 Add : “4.4.3.1 Visual coverage. Complete visual coverage is defined as uniform denting or obliterating of the original surface of the part or work piece as determi
11、ned by either of the following methods: 4.4.3.1.1 Visual examination using a ten power magnifying glass. 4.4.3.1.2 Peenscan process described as follows: Prepare a control specimen of the same material as the actual work piece. Coat this control specimen with tracer liquid (Dyescan #220 and/or #226
12、or equal 1 by dipping, spraying or painting and al low the tracer 1 iquid to dry. Check coating under a black light to insure complete coverage of the coated area to be shot peened has been accomplished. Shot peen the control specimen under proper shot peening conditions for the required intensity a
13、nd coverage as prescribed. Re-examine under the black 1 ight in order to determi ne if the tracer liquid has been completely removed. Full coverage is indicated by complete removal of the tracer liquid. Areas which do not produce full coverage will show a white color under the black 1 ight whereas f
14、ull coverage wi 11 give off a dark color. Coverage of actual production pieces can be established by using the same procedure used for control specimens. This can be done by uti 1 izing the tracer liquid for each part or on a statistical sampling basis.“ 4.4.4, line 4, Delete “exposure time etc, per
15、 unit area“. After first sentence, add new sentence: “Since shape of a part or article to be shot peened will differ from Almen test strip, exposure time wi 11 depend on time required to achieve full coverage on part. See paragraph 3.4.2 and 4.4.3.“ PAGE 20 Add : “6.16 Dyescan. Dyescan liquid can be obtained fro! Metal Improvement Company, Inc., 472 Bare1 1 Avenue, Carl Stadt, NJ 07072. Preparing activity: Navy - AS (Project No. MFFP-N285) 4U.S. GOVERNMENT PRINTING OFFICE 1984 - 505-038/A5147 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
