1、MIL-S-7393C 28 August 1960 Superseding 20 December 1967 MIL-S-7393B MILITARY SPECIFICATION * STBEL ALLOY CARBURIZIN6, BARS AND BILLBTS, STGBL NICKEL-CHROMIUM (3310, 3316 and 9310), AIRCRAFT QUALITY lo scorn * 1.1 Scope.- This specification covers air melted nickel- chromium - molybdenum steels inten
2、ded for use in carburized aircraft parts o 1,2 Classification Q 1.2.1 Compositiono- The steel shall be furnished in three compositions, as specified (see 6,2): Composition I (3310) Composition II (3316) Composition III (9310) 1.2.2 Physical condition.- Products shall be furnished in one of the follo
3、wing physical conditions, as specified (see 6.2): * * (A) As forged (B) As rolled (C) Annealed (D) Normalized (E) Normalized and tempered 1.2,3 Surface conditions.- Products shall be furnished in one of the following surface conditions, as specified (see 6.2): (1) Black, as forged or rolled (2) Pick
4、led or blast cleaned (3) Rough turned (4) Cold or rolled or cold drawn (5) Turned, ground, and polkhed 2. APPLICABLE DOCUMENTS 2,l The following documents, of the issue in effect on date of invitation for bids or request for proposal, form a part of this specification to the extent specified herein.
5、 FSC 9510 Licensed by Information Handling ServicesProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-S-7393C SPEC IF ICATIONS Military * MIL-1-6868 STANDARDS Federal FED. STD, NO. 183 FBDo TEST METHOD STD. NO, 151 Military MIL-STD-163 MIL-STD-430 I
6、nspection Process, Magnetic Par ticle Continuous Identification Marking Metals; Test Methods of Iron and Steel Products Steel Mill Products, Preparation for Shipment and Storage Macrograph Standards for Steel Bars, Billets, and Blooms (Copies of specifications, standards, drawings, and publications
7、required by suppliers in connection with specific procurement functions should be obtained from the procuring activity or as directed by the contracting officer.) 2.2 Other publications.- The following documents form a part of this specification to the extent specified herein. Unless otherwise indic
8、ated, the issue in effect on date of invitation for bids or request for proposal shall apply. * Society of Automotive Engineers (Aerospace Material SpecificationsL AMs2301 Aircraft Quality Steel Cleanliness, Magnetic Particle AMs2251 Tolerances, Alloy Steel Bars AMs2640 Magnetic Particle Inspection
9、Inspection Procedure (Copies of SU publications may be obtained from the Society of Automotive Engineers, Inc., 485 Lexington Avenue, New York, New York 10017.) American Society for Testing and Materials ASTM E112 Bstimating.the Average Grain Size of Metals (Copies of ASTM publications may be obtain
10、ed from the American Society for Testing and Materials, 1916 Race Street, Philadelphia, Pennsylvania 19103. ) 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-S-7373C 75 W 777770b OLLL1765 3 W MIL-S-7393C 3. REQUIRBMBNTS * 3.1 Materials.- The st
11、eel shall be of aircraft quality and satisfactory for the fabrication of parts which may be subject to magnetic particle inspection. requirements of AMS2301. The material shall meet the cleanliness 3.1.1 Sufficient discard shall be taken from each ingot to insure freedom from piping and undue segreg
12、ation. 3.2 Chemical composition.- Chemical composition shall be as specified in table I. TAELS I. Chemical composition Check tolerance L/ Composition I Compos;ttion II Composition III analysis E1 emen t (percent ) (per cent ) (percent) Carbon Manganese * Sulfur * Phosphorous Si li con Nickel Chromiu
13、m Molybdenum * Copper * Iron 0.08 - 0.13 O045 - 0.60 0.025 (rnax.) 0.025 (max.) 0.20 - 0.35 3.25 - 3.75 1.25 - 1.75 - 0.35 (mu.) Remainder 0.14 - 0.19 0.45 - 0.60 0.025 (max.) 0.025 (rnax.) 0.20 - 0.35 3.25 - 4.00 1.25 - 1.75 .- - 0.35 (mu.) Remainder 0.07 - 0.13 0.40 0.70 0.025 (rnax.) 0.025 (mu.)
14、0.20 - 0.35 3.00.- 3.50 1-00 - 1.40 0.08 - 0.15 0.35 (mu.) Remainder *o. o1 f .O3 + .O05 + .O05 g .o2 f .o1 + .O7 L + .O5 + .O3 - i/ Individual determination may vary from the specified range to the extent shown in the check analysis column, except that elements in any heat shall not vary both above
15、 and below the specified range. For sizes over 100 square inches in cross sectional area, the check analysis shall be negotiated. 3.3 Grain size.- The austenitic grain size shall be predominantly No. 5, or finer, with grains as large as No. 3 permissible, in accordance with ASTM B112. * 3.4 Hardness
16、 limits for conditions (Cl, and (E).- * 3.4.1 nie hardness for material in physical conditions (C), and E shall be not more than Brinell 229 (Rockwell C-21) when furnished in surface condition (i), (2), or (3). 3.4.2 The hardness for material in physical conditions (C) and (E) shall be not more than
17、 Brinell 248 (Rockwell C-24) when furnished in surface condition (4). 3.5 Hardenability .- 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-S-7393C 3.5.1 shall be Rockwell C-43 maximum at 1/16 inch and Rockwell C-31 minimum at 6/16 inch. 3.5.2 s
18、hall be Rockwell C-47 maximum at 1/16 inch and Rockwell C-35 minimum at 8/16 inch. End-quench hardenability values for composition I steel End-quench hardenability values for composition II steel 3.5.3 End-quench hardenability values for composition III steel shall be Rockwe1.i C-41 maximum at 1/16
19、inch and Rockwell C-32 minimum at 6/16 inch. 3.6 Macrostructure.- Visual examination of deep acid etched specimens shall comply with MIL-STD-430 at levels S-2, R-1, and C-2. 3.7 Identification marking.- Each bar shall be identified in In lieu accordance with Fed. Std. No. 183. The markings shall inc
20、lude the heat number of the metal and the designation of the specification. of continuous marking, bars under 0.5 inch in diameter may be bundled and each bundle identified by metal tags impression stamped with the legend specified in Fed. Std. No. 183 and securely attached near each end of the bund
21、le. 3.8 Tolerances.- 3.8.1 Diameter or thickness.- The permissible variations in the dimensions of bar or billets shall be as shown in AMS2251, except that when bars are intended for reforging, the requirements of AMs2251 are waived. 3.9 Angles and corners.- The angles and corners of square, rectang
22、ular, and hexagonal bars shall be in accordance with best mill practice. 3.10 Workmanship.- Material shall be sound, of uniform quality and condition, free from pipe, and shall not contain laps, cracks, twists, seams, or other defects detrimental to the fabrication or performance of parts. 4. QUALIT
23、Y ASSURANCE PROVISIONS * 4.1 Responsibility for inspection. The supplier is responsible for the performance of all inspection requirements as specified herein. Except as otherwise specified in the contract or order, the supplier may use his own or any other facilities suitable for the performance of
24、 &;he inspection requirements as specified herein, unless disapproved by the purchaser. The purchaser reserves the right to perform any of the inspections set forth in the specification where such inspections are 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license
25、from IHS-,-,-MIL-S-7373C 75 m 7797060LL4767 7 = MIL-S-7393C deemed necessary to assure supplies and services conform to prescribed requirements. * 4.1.1 E.- A lot shall consist of all bars and billets subjected to inspection at one time of the same heat, condition, and size. 4.2 Examination of produ
26、ct.- Examination shall be made to assure compliance with the surface condition, identification, dimensional, and workmanship requirements (see table II). TABL5 II. Sampling for examination of product Lot size Sample size Acceptance number 1 to 15 16 to 180 181 to 300 301 to 500 ver 500 All 15 35 50
27、75 8 4.2.1 Classification of test.- All the tests required for the testing of the product are classified as acceptance tests, for which necessary sampling techniques and methods of testing are specified in this section. * 4.3 Magnetic inspection quality. - The specimens shall be selected and rated i
28、n accordance with the procedures of AMs 2301. Inspection shall be in accordance with MIL-1-6868 or AMs 2640. 4.4. Chemical analysis.- 4.4.1 Sampling.- Samples for check chemical analysis shall be selected as described in Federal Test Method Standard No. 151 to represent each heat from which material
29、 is submitted for inspection. 4.4.2 Location.- Samples shall be taken parallel to the axis of the bar from a zone midway between the center and the surface, except that material less than 1-1/4 inches thick shall be sampled through the entire cross section. 4.4.3 Waiver.- Samples for check chemical
30、analysis may be waived, with the approval of the procuring activity, provided that all of the material under inspection can be identified as being made from a heat previously analyzed and found to be in conformance with the chemical composition specified in table I. 5 Provided by IHSNot for ResaleNo
31、 reproduction or networking permitted without license from IHS-,-,-MIL-S-7393C 4.4.4 Method.- Samples shall be prepared in accordance with Fed. Test Method Std. No. 151 and analyzed by wet chemical, or spectrographic methods. In the event of dispute, analysis shall be by wet chemical methods. 4.5. G
32、xain size.- 4.5.1 Sampling.- One sample shall be selected to represent each lot of material. * 4.5.2 Method.- Specimens shall be sectioned and polished to appropriate fineness by metallographic methods and suitably etched to reveal the grain structure. in accordance with ASTM Method E112. The austen
33、itic grain size shall be determined 4.6 Hardness of bars in physical conditions (C), (D), and (EL.- 4.6.1 Sampling.- At least five bars of each cond5tion and size chali be tested to ascertain conformance with the permissible hardness values. When less than-five bars are ordered, each bar shall be te
34、sted. * 4.6.2 Method.- Hardness testing shall conform to ASTM EU0 or ASTM B18. 4 . 7 4.7.1 Sampling.- ne or more samples for the end-quench i-iardenabili ty - hardenability test shall be selected from each heat of steel from which material is presented for acceptance. Specimens for the end-quench ha
35、rdenability test shall conform to ASTM A255. 4.7.2 Method.- End-quench hardenability tests shall be conducted in accordance with ASTM A255. at 1550 +lOF. Specimens shall be austenitized * 4.8 Deep acid etch.- * 4.8.1 Samp1inq.- Samples shall be taken from bars, billets, or blooms representing the to
36、p and bottom of each ingot in the heat. 4.8.2 Preparation of specimens.- Specimens for deep acid etching shall be cut from samples taken in 4.8.1 so as to represent the entire cross section and shall be 1/4 inch thick minimum. One of the faces of the specimens shall be finished flat and smooth by a
37、fine machining cut or by grinding to afinfsh; of 63 micro-inch maximum. finished face of each specimen shall be etched in accordance with The ASTM A317 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-S-7393C * 4.8.3 Test reports.- The material
38、supplier shall furnish with.each shipment a report of the results of the tests for chemical composition, grain size, magnetic particle inspection rating, deep acid etch, and hardenability of each heat in the shipment. This report shall also include: (a) Purchase order number (b) Heat number (c) Mate
39、rial specification number (d) Size (e) Quantity from heat 4.9 Rejection and retest.- Where failure of a sample or specimen is definitely ascribed to faculty material, the entire lot of material represented shall be rejected. At the discretion of the supplier, retest will be permitted. A retest sampl
40、e of five specimens shall be tested to replace each failed specimen of the initial sample. If one of the retest specimens fails, the lot represented shall be rejected with no further retesting. 4.9.1 Resubmittal.- Where failure of any lot of material to meet the requirements of this specimen is due
41、to inadequate heat treat- ment, the material amy be reheat treated and resubmitted for test. Only two such reheat treatments will be allowed. 5. PREPARATION FOR DELIVERY 5.1 Preservation, packaging, and packing.- Materials shall be prepared for shipment in accordance with the methods prescribed by M
42、IL- - STD-163. with preservative as prescribed for condition (4). Materials in surface conditions (2) through- (5) shall be coated 5.2 Marking of shipments.- Shipping containers shall be marked in accordance with MIL-STD-163. 6. NOTES * 6.1 Intended use.- These steels are intended for use in the man
43、ufacture of carburized parts. 6.2 Orderinq data.- Procurement documents should specify: (a) Title, number, and date of this specification. (b) Composition, physical, and surface conditions (see 2.1). (c) Size and shape (exact lengths and length tolerances required if mill lengths are not acceptable)
44、. 6.2.1 When bars are intended for reforging purposes, it should be so stated. 7 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-S-7393C 6.3 Marginal indicia.- Asterisks are used in this revision to identify changes (additions, deletions) with re
45、spect to the previous issue. Custodians : Army - AV Navy - AS Air Force - 11 Reviewer activities : Army - MR, MI Air Force - 82, 84 User activity: Army - WC 8 Preparing activity: Air Force - 11 Fro ject 9510-0116 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
