1、IINCH-POUNDI MIL-S-I9434B(SH) 31 December 1990 SUPERSEDING 1 October 1959 (See 6.6) MIL-S-l9434A(SHIPS) MILITARY SPECIFICATION STEEL GEAR AND PINION FORGINGS, CARBON AND ALLOY, HEAT TREATED, NAVAL SHIPBOARD PROPULSION UNIT AND AUXILIARY TURBINE This specification is approved for use by the Naval Sea
2、 Systems Command, Department of the Navy, and is available for use by all Departments and Agencies of the Department of Defense. 1. SCOPE 1.1 Scope. This specification covers forging rims and blanks for gears and pinions to be used in gear assemblies for Naval shipboard propulsion units and auxiliar
3、y turbines. 1.2 Classification, Forgings shall be of the following classes as specified (see 6.2). Class 1 Class 2 Class 3 Class 4 Class 5 Class 6 Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to:
4、 Commander, Naval Sea Systems Command, SEA 5523, Department of the Navy, Washington, DC 20362-5101 by using the self-addressed Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter. AMSC N/A FSC 2030 DISTRIBUTION STATEMENT A. Approved forpubl
5、ic release; distribution is unlimited. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- MIL-S-L9434B 20 9999906 0470573 IJ I . . MIL-S-l9434B(SH) l l 2. APPLICABLE DOCUMENTS I 2.1 Government documents. 2.1.1 Specifications, standards. and handbooks.
6、The ,allowing speciLAca- tions, standards, and handbooks form a part of this document to the extent .specified herein. those listed in the issue of the Department of Defense Index of Specifications and Standards (DODISS) and supplement thereto, cited in the solicitation (see 6.2). Unless otherwise s
7、pecified, the issues of these documents are S PEC I FI CATIONS FEDERAL PPP-F-320 - Fiberboard; Corrugated and Solid, Sheet Stock (Container Grade), and Cut Shapes. MILITARY MIL-H-6875 - Heat Treatment of Steel, Process for. MIL-L-19140 - Lumber and Plywood, Fire-Retardant Treated. STANDARDS . FEDERA
8、L FED-STD-183 - Continuous Identification Marking of Iron and Steel Products i MI LI TARY MIL-STD-163 - Steel Mill Products Preparation for Shipment and MIL-STD-248 - Welding and Brazing Procedure and Performance MIL-STD-271 - Requirements for Nondestructive Testing Methods. MIL-STD-278 - Welding an
9、d Casting Standard. MIL-STD-792 - Identification Marking Requirements for Special Storage. Qualification. Purpose Components. (Unless otherwise indicated, copies of federal and military specifications, standards, and handbooks are available from the Standardization Documents Order Desk, BLDG. 4D, 70
10、0 Robbins Avenue, Philadelphia, PA 19111-5094.) 2.2 Non-Government publications. The following document(s) form a part of this document to the extent specified herein. issues of the documents which are DOD adopted are those listed in the issue of the DODISS cited in the solicitation, documents not l
11、isted in the DODISS are the issues of the documents cited in the solicitation (see 6.2). Unless otherwise specified, the Unless otherwise specified, the issues of AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM) (DoD adopted) A 370 - Standard Test Methods and Definitions for Mechanical A 751 - Stan
12、dard Methods, Practices, and Definitions for Chemical Testing of Steel Products. Analysis of Steel Products. . D 3951 - Standard Practice for Commercial Packaging. (DoD adopted) 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ASTM (Continued) E 10
13、- Standard Test Method for Brinell Hardness of Metallic E 23 - Standard Methods for Notched Bar Impact Testing of E 45 E 112 - Standard Methods for Determining the Average Grain Size. E 381 - Standard Method of Macroetch Testing, Inspection and Materials. (DoD adopted) Metallic Materials. (DoD adopt
14、ed) Steel. (DoD adopted) (DoD adopted) Rating Steel Products, Comprising Bars, Billets, Blooms, and Forgings. (DoD adopted) - Standard Practice for Determining the Inclusion Content of (Application for copies should be addressed to the American Society for Testing and Materials, 1916 Race Street, Ph
15、iladelphia, PA 19103.) (Non-Government standards and other publications are normally available from These documents also the organizations that prepare or distribute the documents. may be available in or through libraries or other informational services.) 2.3 Order of mecedence. In the event of a co
16、nflict between the text of this document and the references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 3. REQUIREMENTS 3.1 Meltine;. Unless otherwise specified
17、in the contract or order (see 6.2), the material from which the forgings are made shall be continuous cast or cast in metal molds, and shall be manufactured as follows: (a) Classes 1, 2, and 3. (b) Classes 4, 5, and 6. Electric furnace or VIM. Open hearth, basic oxygen, electric furnace, or vacuum i
18、nduction melted (VIM). The primary melting may incorporate separate degassing or refining and may be followed by secondary melting using electroslag remelting (ESR) or vacuum arc remelting (VAR) (see 6.2). 3.1.1 Degassing. Classes 1, 2, and 3 may be vacuum degassed prior to or during pouring of the
19、material, 5, and 6 shall be vacuum degassed prior to or during pouring of the material to remove objectionable gases, particularly hydrogen. Unless otherwise specified (see 6.2), classes 4, 3.1.2 Stabilitv. Material shall be furnished in a condition to withstand, for an indefinite time, exposure to
20、all climatic conditions without developing any external or internal cracks. cast material shall be optional with the manufacturer, but he shall be responsible (in the same manner as for defects disclosed after delivery) for cracks that may develop before material is subjected to reheating, The metho
21、d of cooling or of heat treatment of the 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- MIL-S-L9434B 20 = 9999906 0470575 5 = 3.1.3 Recovered materials, Unless otherwise specified herein, all material incorporated in the products covered by this
22、specification shall be new and may be fabricated using materials produced from recovered materials to the maximum extent practicable without jeopardizing the intended use. The term “recovered materials“ means materials which have been collected or recovered from solid waste and repro- cessed to beco
23、me a source of raw materials, as opposed to virgin raw materials (see 6.2). products is allowed under this specification unless otherwise specifically specified, None of the above shall be interpreted to mean that the use of used 3.1.4 Discard. Sufficient discard shall be made to ensure freedom from
24、 piping and undue segregation. 3.2 Forging process. The original cross-sectional area of the casting shall be at least three times the area of the finished forging. the cross-sectional area shall also be sufficient so that material conforms to the requirements of this specification, need not be redu
25、ced to the ratio of 3 to 1, but shall be reduced in a ratio of not .less than 1.7 to 1. If bored castings are used, the wall of the castings shall be reduced to at least one-half of its original thickness, or the reduction of area shall be at least 2 to 1. Except for forgings expanded on a mandrel o
26、r forgings made from castings of less than 16 inches in minimum cross-sectional dimension, the reduction of cross-sectional area from the original casting to the finished forging shall in no case exceed a ratio of 5 to 1. Where an upsetting operation is employed, or the forging expanded on a mandrel
27、, the material shall be worked to an extent not less than that indicated above, but no fixed ratio between the cross-sectional areas of the casting and of the forging is required. The total reduction of Flanges and other enlargements on forgings 3.2.1 Centerline. Where forgings require a bored cente
28、r hole, the center- line of the bored hole shall be at the centerline of the casting and forging. 3.2.2 Forpinm. Forgings shall conform to the dimensions, tolerances, and . finish specified on the applicable drawing. shall be as shown on the drawings and shall be marked on the forgings. Layout point
29、s, when required (see 6.2), 3.3 Heat treatment. Heat treatment of forgings shall be as specified in 3.3.1 through 3.3.1.7. 3.3.1 Normalizing and auenchinp;. The forgings shall be given a uniform heat treatment at temperatures necessary to produce material that will conform to the requirements of thi
30、s specification. follows : The forgings shall be heat-treated as 3.3.1.1 Cooling - prior to heat treatment. After forging and before reheating for heat treatment, the forgings shall be allowed to cool in a manner to prevent damage to the forging and to accomplish transformation of the austenite, 4 P
31、rovided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-3.3.1.2 NormalizinR. The forgings shall be reheated to and held at the proper temperature for a sufficient time to austenitize and then be withdrawn from the furnace and allowed to cool in air. 3.3.1.3 Q
32、uenching. The forgings shall be reheated to and held at the proper temperature for a sufficient time to austenitize and then quenched in a suitable Medium to meet specification requirements. 3.3.1.4 Tempering procedure for gear rims, gears. and pinions. Gear rims, gears, and pinions shall be reheate
33、d to and held at the proper temperature for final tempering treatment, which shall be below the lower critical austenitizing temperature but not below 1050 degrees Fahrenheit (OF). 3.3.1.5 Stress relieving - procedure for pear rims. pears. and pinions. The gear rims, gears, and pinions shall be stre
34、ss relieved in the same manner as they are tempered except that the temperature shall be not less than 1000F and at least 50F below the tempering temperature applied to the forging. 3.3.1.6 Cooling rate, Following stress relief, forgings shall be furnace cooled to 600F under uniform conditions at a
35、rate not to exceed 500F per hour divided by the maximum thickness of the part in inches, but in no case greater than 500F per hour. 3.3.1.7 Heat treatment euuipment and controls. Continuous or automatic heat treating equipment may be employed, provided it produces heat-treated material meeting the r
36、equirements of this specification. MIL-H-6875 (see 6.3). The temperature of the furnace charge shall be recorded during the heating, holding, and, when applicable, the cooling cycles of the heat treatment (see 6.3 and appendix), Equipment shall comply with 3.4 Surface Conditioning before final forgi
37、nq. Material before final forging may be conditioned to remove injurious surface defects providedthe depth of conditioning does not exceed 1/16 inch (1.6 millimeters (mm) for each 1 inch (25.4 mm) of local forging thickness up to a maximum depth of 3/4 inch (19.1 mm), and provided that the width of
38、the conditioning is at least four times its greatest depth; except that in the case of slabs where the width is at least twice the thickness, the depth of conditioning on the wide surfaces may exceed this allowance by 50 percent up to a maximum depth of 3/4 inch. conditioning on two parallel sides a
39、t opposite locations shall not exceed one and one-half times the maximum allowed for one side. Conditioned areas shall be flared to result in a uniform blending. The maximum depth of 3.5 Macrostructure. Unless otherwise specified (see 6.2), the macrostruc- ture of the starting stock for forging (in
40、the form of blooms, billets, or continuously cast strands after initial reduction) shall be determined for all classes of material, inches shall not exceed S-3, R-2, and C-3 of ASTM E 381. Sizes over 36 square inches and including 100 square inches shall not exceed S-3, R-3 and C-3 of ASTM E 381. Fo
41、r sizes in excess of 100 square inches, macrostructure requirements shall he as specified (see 6.2). Macrostructure for sizes up to and including 36 square 5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-S-19434B 20 = 9999906 0470577 9 m 3.6 Mi
42、croscopic requirements. Specimens from all forgings, when examhed at a magnification of 100 diameters, shall show a homogeneous structure, that is, one in which the normal constituents are evenly distributed, free from decided segregation of any constituents. The grain size for classes 2, 3, 4, 5, a
43、nd 6, when examined at a magnification of 100 diameters, shall have a grain size number of 5 or finer as specified in-the grain size chart in ASTM E 112. The area under examination shall show at least 95 percent of the structure with a grain size of number 5 or finer. 3.7 Nonmetallic inclusion conte
44、nt. The inclusion rating for each heat shall be the average:of the worst field for each inclusion type in each specimen. inclusion rating shall not exceed the following (reference ASTM E 45, plates I and III; plate I is to be used for ratings exceeding 2-1/2): The A: 3.0t/2.0h B: 3.0t/2.5h* C: 2.5t/
45、1.5h D: 2.t/1.5hx * Maximum allowable diameter of heavy oxide inclusions shall be 0.005 inch. 3.8 Repair of defects, Defects shall be repaired as specified in 3.8.1 and 3.8.1.1. 3.8.1 Repair weldinq. Repair welding is not permitted unless specifically approved by the Command or agency concerned or i
46、ts authorized representative (see 6.2). a 3.8.1.1 Weld repair. When approved, weld repair shall be performed in accordance with MIL-STD-278. Welding procedure qualification, prior to production welding, shall be in accordance with MIL-STD-248. 3.9 Chemical comrrostion. The chemical composition of th
47、e forging material, gear rims, gears, and pinions shall be in accordance with the specified class as . shown in table I. 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NIL-S-19434B 20 M 9799906 O470578 O M - MIL-C-l9434B(SH) U c a) o k a) a (Il rl
48、 V 2 00000 rlrlrlrlrl 00000 .e. rl N lrlrl lnlnlnlnln mmmmm 00000 . IlIII lnlnlnlnln rlrlrlrlrl 00000 . ooolnln d.;t.;trlrl 00000 . OOOlnLA c;sc;gg . O oolnoo cncnomm orl . I. IIIII lnlnooo lnlnbou) O . 4 O I lnlnlnoln 44-mlnln O0 . ln a 3 riNrn4W 7 Provided by IHSNot for ResaleNo reproduction or ne
49、tworking permitted without license from IHS-,-,-MIL-S-19434B 20 m 9999906 0470579 2 m MIL - S -.194 34B ( SH) 3.9.1 Heat and DrOdUCt analysis. The heat and product analysis shall- conform to the specified chemical analysis. 3,lO Mechanical DroDerties. The mechanical properties of the final forged material shall be in accordance with the specified class as shown in table II and as specified in 3.10.1. 8 Provided by IHSNot for Re
