1、MIL-S-Lb7A 96 W 77997Ob OLL7020 = 17.- %e-STf MI LIS - 16 788A l_l_ . _. .-.- -.-. . . .- . - . . . . -. . . . . .-. -. - - . -. -, -_ . . ,. _. . 29 Narch 1971 SUPERSEDING 13 November 1951 MIL-S- 16 788 MILITARY SPECIFICATION STEEL, CARBON, HOT-ROLLED OR FORGED (BLOMS, BILLETS, AND SLABS FOR REFORG
2、ING) This specification is mandatory for use by all Depart- ments and Agencies of the Departmenb of Defense. 1. SCOPE 1.1 Scope, This specification covers hot-rolled or forged carbon. steel semifinished products (blooms, billets, and slabs) for reforging. (See 6.1.) 1.2 Classification. The carbon st
3、eel covered by this specification shall be furnished in the following classes, designated according to chemical compositions (see table I), as specified (see 6.2): . Class c1 Class c2 Class c3 Class c4 Clzs c5 Class C6 Class C8 Class c10 . . _-. . _ . . . _i . . . - . . .- . _.-_-_.- - - . .- . A .
4、. . . . . r- _ _-_ . -. - . _. 4 I._* . -. - . . . 1 -. -.- -.- _ . I . ” . . -_I -_ _._ - . _ . _ .-. . I . . _-.-. ,-_. ._. . -.-. -._*_ . . .- - 4 . -. . ,_ . ,_-_ . .-.- . ,. . . -. . -I . . !._ - _. ,_.-_ .-. L . -._.I . . . -.-.-. . -.- _-. -* . . ,_ - _._._-y _ .-_. -._ -_.-.-. . _- ._I.-.-.-
5、 . - - I._ . . ._. . .- .- -.- .- . -._. - 4 . ,Z. APPLICABLE DOCUMENTS 2.1 -I- I_._.-_I.- -. _ ._. -_- ._.I- The following documents o the issue in effect on the date of I-_ . -_ -.- .invitation for bids or request for proposal form a part of this specifi- cation to the extent specified herein: . .
6、 ._ -_.-._ _._I._ _. I - ._._._._.I _- -.- - . -., -.z- . _. . . . .-.-. .-.-.-. . - - .- . . _- ” . ._I- . - . - . .-. . _f_ I -,. ._._ . ._.-. . .- . . .-. - _- _-_ -._ ,_._. . _.- ,._- .f._ I .I._. . - . JFSC-1 THIS DOCUMENT CONTAINS 8 PAGES. 1 . _ . _- _ i-*-.- . . . . - . .s . - 8 Licensed by I
7、nformation Handling ServicesMIL-S-1bA 76 m 777770b OLL7021 b m MIL- S - 16 7 8 8A STANDARDS Mi lit ary MIL-STD- 129 MIL-STD- 163 MI L-STD-430 Federal FED-STD-66 FED-STD- 15 1 Marking for Shipment and Storage Steel Mill Products, Preparation for Shipment and Storage Macrograph Standards for Steel Bar
8、s, Billets, and Blooms Steel : Metals ; Test Methods Chemical Composition and Hardenability (Copies of documents 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,
9、 The following document forms a part of .this specification to the extent specified herein. the issue in effect on date of invitation for bids or request for pro- . posa1 shall apply. Unless otherwise indicated, American Society for Testing and Materials for - ASTM- 3 17 Macroetch Testing and Inspec
10、tion of Steel Forgings (Copies of ASTM publications may be obtained from the American Society Testing and Materials, 1916 Race Street, Philadelphia, Pa. 19103.) 5. REQUIREMENTS 3.1 Process, The steel shall be made by either the electric furnace, open hearth, or basic oxygen process, molds, Steel sha
11、ll be cast in metal ingot The use of hot tops of any suitable material is permitted. 2 . . . . . _ . r 1 . -.-.-. _ . -. . . . , , . p . . ti: Licensed by Information Handling ServicesMIL- S - 16 78 8A 3.2 Discard, Sufficient discard shall be made from each ingot to insure freedom from injurious pip
12、ing and undue segregation. 3.3 Reduction from ingot, Unless otherwise specified, the material shall be made from ingots having at least two times the cross-section-al area of the material. 3.4 Chemical composition. 3.4.1 Ladle analysis, The ladle analysis of the steel shall conform to the chemical c
13、omposition requirements shown in table I. tractor shall furnish a report of the chemical analysis of each heat of steel, The con- Table I CHEMICAL COMPOSITION (PERCE“) Ph os ph orus (maxi mum) Class I Carbon Manganese c1 c2 c3 c4 c5 C6 C8 c10 0.08 - 0.13 0.18 - 0.23 0.28 - 0.34 0.37 - 0.44 0.48 - 0.
14、55 0.55 - 0.65 0.75 - 0.88 0.90 - 1.03 0.30 - 0.60 0.30 - 0.60 0.60 - 0.90 0.60 - 0.90 0.60 - 0.90 0.60 - 0.90 0.60 - 0.90 0.30 - 0.50 0.040 0.040 O ,040 O .O40 0.040 O ,040 O .O40 O ,040 1For commercial chemical designations, see 6.3. Sulphur (maximum) O .O50 O .O50 O .O50 O ,050 O ,050 O ,050 O .O
15、50 O .O50 3.4.2 Check analysis. The chemical composition of blooms, billets, or slabs shall conform to the requirements specified in table I,.subject to check analysis tolerances of FED-STD-66. 3.5 Defects. All material shall be free from cracks or.other imperfections that may affect its usability.
16、3.5.1 Macroetch? When specified by the procuring activity, the material shall be subject to a macroetch test in accordance with 4.3.3. The quality of the steel, as indicated by the results of the macroetch -. . . . -.-.-.- _. _._. . . . . -. . . - - . ._._._ . . _._- I. . ,_ . _.-. . .- . . 1 . . .
17、. I. _ . - . _ . - . . -. i . . - !. . . (:.1.:.: . . . . . . . . . . - i Licensed by Information Handling ServicesflIL-S-16788A 96 = qqqqqo6 0117023 T MIL-S-16788A test for sections up to and including 36 square inches, shall be equal to, or better than, macrograph conditions S4, R4, and C4, over 3
18、6 square inches, macrograph conditions S5, R5, and C5 are con- sidered acceptable limits as classified in MIL-STD-430. For sections 3.6 Conditioning. Unless otherwise specified, the maximum per- missable depth of conditioning for removal of injurious surface defects, provided the width of the condit
19、ioning is at least four times the greatest conditioning depth, shall be as follows. 3.6.1 The depth of conditioning shall not exceed one-sixteenth inch for each inch of material thickness when the material width is less than twice the material thickness. 3.6.2 When the material width is equal to or
20、greater than tliice the . material thickness, the depth of conditioning shall not exceed three thirty-seconds of an inch for each inch of material thickness. 3.6.3 In either case (3.6.1 or 3.6,2), the maximum permissible depth of conditioning shall not exceed three-fourths inch. I . ,.* -._ _-_. . :
21、. . j t:II: . . . *- , e- .-_ 1 - I I . -.- ._ . . -_ _-_. kz .I.-.- -.-.-I-.-.- ,. _.-.- . - 3.6.4 When conditioning is required on both opposite locations of parallel sides, the maximum permissible combined depth of conditioning shall not exceed 1-1/8 inches. 3.7 Dimensions . The nominal dimension
22、s of the material shall be as specified by the procuring activity, -3.8 Weight. Unless otherwise specified by the procuring activity, the permissible variations from the specified or theoretical weight of less than carload lots shall be within +5 percent. the variation shall be within +2-1/2 percent
23、 of the total lot weight, For carload lots, 3.9 Heat treatment. Unless otherwise .specified by the procuring activity, classes C6, C8, and C10 shall be supplied in the annealed condi tion. . 4 Licensed by Information Handling ServicesMIL-S-16788A 76 m 7777706 OL2702Y L m . MIL - S - 16 7 8 8A 3.10 L
24、atent imperfections. Material containing injurious imperfec- tions which are not manifest upon the original inspection, but develop during forging or machining operations, may upon verification be. returned to the contractor for replacement or as othexwise mutually agreed upon, 4. QUALITY ASSURANCE
25、PROVISIONS 4.1 Responsibility for inspection, Unless otherwise the contract or purchase order, the supplier is respons specified in ble for the performance of all inspection requirements as specified herein, as otherwise specified in the contract or order, the supplier may use his own or any other f
26、acilities suitable for the performance of the inspection requirements specified herein, unless disapproved by the Government. inspections set forth in this specification where such inspections are deemed necessary to assure supplies and services conform to prescribed requirements. Except The Governm
27、ent reserves the right to perform any of the 4.2 Quality conformance inspection. - 4.2.1 Lots. 4.2.1.1 Blelting furnace heat identified, If material is positively identified as to melting furnace heat, a lot shall consist of all material - made therefrom. 4.2.1.2 Melting furnace heat not identified.
28、 If material is not identified as to melting heat, a lot shall consist of all material of the same cross section size, 4.2.2 Samples. 4.2.2.1 Chemical analysis. Sampling for chemical analysis shall be in accordance with table II, with tolerances in accordance with FED-STD-66. 4.2.2.2 Macroetch. When
29、 macroetch testing is required, the sampling procedure shall be as specified in 4.2.2.2.1 or 4.2.2.2.2. 5 . . . . . . -. . _.- . . -. . . -_ ._ . _.- . . . ._ . .-_. . - ._ .-. &.* .- . _._- . - . - . - . . -.-.- . I.- -.-._._.-. . .- -. ,-.- _ _ -.- .-.- -._.- ,_-._.- . * I_ . .- -_ _._- -._ . .-.
30、. _- ._. - . -.- ,_ -._. _ ._ . _- _._.- - *_. : . . . Licensed by Information Handling ServicesMIL-S-Lb788A 76 m 777770b OLL7025 3 m MIL-S-16788A Table II SAMPLING FOR CHEMICAL ANALYSIS Number of pieces in lot 1 2 3 - 30 More than 30 Number of sm Lot as defined in 4.2.1.1 1 2 3. 3 les required Lot
31、as defined in 4.2.1.2 1 2 3 10 percent of number of pieces in lot 4.2.2.2.1 Identified material, If material can be identified as to ingot and heat, samples, representing the entire cross-sectional area and approximately one-half inch in thickness, shall be cut from the top of the top billet and the
32、 bottom of the bottom billet of the first, middle, and last usable ingot of heat. 4.2.2.2.2 Unidentified material, If material cannot be identified as to ingot or heat, samples, representing the entire cross-sectional area and approximately one-half inch in thickness, shall be cut from each end of e
33、ach piece of material. On sections larger than 10 inches in diameter or 14 inches diagonal, a segment representing a cross-sectional surface from center to the outside may be used, be made of pieces which are to be cut into shorter lengths prior to . delivery, slices from the ends prior to cutting a
34、re sufficient. Where inspection is to 4.3 Tests. 4.3.1 General procedures. General testing procedures shall be accomplished in accordance with FED-STD-151. 4.3.2 Chemical analysis. Samples shall be subject to a chemical analysis (see 3.4.2) at a laboratory designated by the bureau or agency concerne
35、d. 6 - . . . I . I._. - - c . ,.-._ 1 - . . . - I- - - . -. . . - - ,_. . -.-.- . .- . . . .- 1 -.-. .-.- . ,.- I . -. A . 1 Licensed by Information Handling Services- MIL-S-3678A 76 7977706 0337026 5 =. , MIL-S-16788A 4.3.3 Macroetch. When macroetching is specified by the procuring activity, testin
36、g shall be accomplished in accordance with AS“ 317. 4.3.4 Defective material. Where requirements as to length permit, a defective end may be cut off and a new test or tests made until sound metal is reached. Sufficient metal shall be removed to assure removal of the defects disclosed by the tests. 4
37、.3.5 .Criteria of acceptability. Any sample subjected to the examinations and fsts of section 4 which fails to meet the reqiiire- ments of section“ 3 shall result in rejection of the lot represented. 5. PREPARATION FOR DELIVERY 5.1 Packing. Material shall be prepared for shipment in accordance with
38、MI L-STD - 16 3. 5.2 Marking. accordance with Shipping containers or packages shall be marked in MIL-STD-129. 6. NOTES 6.1. Intended use. The semifinished material covered by this specification is intended for reforging uses. This specification does not include requirements for hot-rolled bar stock.
39、 6.2 Ordering data. Procurement documents should specify the follow- ing : (a) Title, number, and date of this specification (b) Class required (see 1.2) (c) Dimensions (see 3.7) (d) Macroetch tests, when required (see 3.5.1) (e) Permissable variation in weight, if other than 3.8. 6.3 Commercial che
40、mical designations. Table III lists, for infor- mation only, commercial chemical designations equivalent to the com- positions given in 1.2. . . ,. b . - -. . . .- . . . -.- I_. . .- -. - _- -_- . 1 . . I . 1 . . Licensed by Information Handling ServicesMIL-S-16788A Class (this specification) c1 c2
41、c3 c4 c5 C6 C8 c10 Custodians : Navy - OS Air Force - 84 Army - MR Review interest : Navy - SH User activities : Army - MU - ai51 c1010 c1020 C1030 C1040 C1050 C1060 C1080 c1095 Table III COMMERCIAL CHEMICAL COMPOSITION . . b . . . . . . -. . . . Preparing activity : .NAVY - OS - *U. S. OOvWm RiINTING OFFICa: April 1971-433-697/6141 8 . r-7 Licensed by Information Handling Services
