1、Designation: A 574 04e1Standard Specification forAlloy Steel Socket-Head Cap Screws1This standard is issued under the fixed designation A 574; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in p
2、arentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.e1NOTESections 2.2 and 4.2.8 were editorially revised in October 2006.1. Sco
3、pe*1.1 This specification2covers the requirements forquenched and tempered alloy steel hexagon socket-head capscrews, 0.060 through 4 in. in diameter where high strength isrequired.NOTE 1A complete metric companion to Specification A 574 hasbeen developedA 574M; therefore no metric equivalents are p
4、resentedin this specification.1.2 The following hazard caveat pertains only to the testmethod portion, Section 12, of this specification. This standarddoes not purport to address all of the safety concerns, if any,associated with its use. It is the responsibility of the user of thisstandard to estab
5、lish appropriate safety and health practicesand determine the applicability of regulatory limitations priorto use.2. Referenced Documents2.1 ASTM Standards:3A 751 Test Methods, Practices, and Terminology forChemical Analysis of Steel ProductsD 3951 Practice for Commercial PackagingE3 Guide for Prepa
6、ration of Metallographic SpecimensE112 Test Methods for Determining Average Grain SizeE 384 Test Method for Microindentation Hardness of Ma-terialsF 606 Test Methods for Determining the Mechanical Prop-erties of Externally and Internally Threaded Fasteners,Washers, Direct Tension Indicators, and Riv
7、etsF 788/F 788M Specification for Surface Discontinuities ofBolts, Screws, and Studs, Inch and Metric Series2.2 ASME Standards:4B1.1 Unified Screw ThreadsB18.3 Socket Cap, Shoulder, and Set ScrewsB18.24 Part Identifying Number (PIN) Code System Stan-dard for B18 Fastener Products2.3 Federal Standard
8、:H-28 Handbook of Thread Dimensions53. Terminology3.1 Definitions:3.1.1 Definitions of discontinuities covered by 10.2 follow:3.1.2 crackclean crystalline break passing through thegrain or grain boundary without inclusion of foreign elements.3.1.3 inclusionsparticles of nonmetallic impurities, usu-a
9、lly oxides, sulfides, silicates, and such, which are mechani-cally held in the steel during solidification.3.1.4 nicks or pitsdepressions or indentations in thesurface of the metal.3.1.5 seam or lapnoncrystalline break through the metalwhich is inherently in the raw material.4. Ordering Information4
10、.1 Orders for socket head cap screws under this specifica-tion shall include the following:4.1.1 ASTM designation and year of issue.4.1.2 Quantities (number of pieces by size).4.1.3 Size and length.4.2 Orders for socket head cap screws may include thefollowing optional requirements:4.2.1 Inspection
11、at point of manufacture.4.2.2 Coating, if a protective finish other than black oxide(thermal or chemical) is required, it must be specified.4.2.3 Certified test reports (see 11.2).4.2.4 Additional testing (see 11.3).4.2.5 Special packaging (see 16.1.2).4.2.6 Supplementary requirements (see S1).1This
12、 specification is under the jurisdiction of ASTM Committee F16 onFasteners and is the direct responsibility of Subcommittee F16.02 on Steel Bolts,Nuts, Rivets, and Washers.Current edition approved Aug. 1, 2004. Published August 2004. Originallyapproved in 1967. Last previous edition approved in 2000
13、 as A 574 00.2For ASME Boiler and Pressure Vessel Code applications see related Specifi-cation SA-574 in Section II of that code.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informati
14、on, refer to the standards Document Summary page onthe ASTM website.4Available from American Society of Mechanical Engineers (ASME), ASMEInternational Headquarters, Three Park Ave., New York, NY 10016-5990.5Available from General Services Administration, Specification and ConsumerInformation Distrib
15、ution Branch, Bldg. 197, Washington Navy Yard, Washington,DC 20407.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.2.7 Special requirements.4.2.8 For establishment o
16、f a part identifying system, seeASME B18.245. Materials and Manufacture5.1 The screws shall be fabricated from a steel which hasbeen made by the open-hearth, basic-oxygen, or electric-furnace process.5.2 The screws shall be fabricated from alloy steel made toa fine grain practice. In the event of co
17、ntroversy over grainsize, referee tests on finished screws conducted in accordancewith Test Methods E112shall prevail.5.3 Unless otherwise specified, the heads of screws through1.500-in. diameter shall be fabricated by hot or cold forging.Over 1.500-in. diameter, the heads may be fabricated by hot o
18、rcold forging or by machining. Sockets may be forged ormachined.5.4 Unless otherwise specified, threads of screws shall berolled for diameters through 0.625 in. and for screw lengthsthrough 4 in. For diameters and lengths other than this, threadsmay be rolled, cut, or ground.5.5 The screws shall be
19、heat treated by oil quenching fromabove the transformation temperature and then tempering at atemperature not lower than 650F.5.6 Standard FinishesUnless otherwise specified, thescrews shall be furnished with one of the following “standardsurfaces as manufactured” at the option of the manufacturer:(
20、1) bright uncoated, (2) thermal black oxide, or (3) chemicalblack oxide. Hydrogen embrittlement tests shall not be re-quired for screws furnished in these conditions.5.7 Protective Coatings:5.7.1 When a protective finish other than as specified in 5.6is required, it shall be specified on the purchas
21、e order with theapplicable finish specification.5.7.2 When protective or decorative coatings are applied tothe screws, precautions specified by the coating requirementsto minimize embrittlement shall be exercised.6. Chemical Composition6.1 The screws shall be alloy steel conforming to thechemical co
22、mposition specified in Table 1. See SupplementaryRequirement S1 when specific chemistry grades are required.6.2 One or more of the following alloying elements: chro-mium, nickel, molybdenum, or vanadium shall be present insufficient quantity to ensure that the specified strength proper-ties are met
23、after oil quenching and tempering. As a guide forselecting material, an alloy steel should be capable of meetingthe specified mechanical requirements if the “as oil quenched”core hardness one diameter from the point is equal to orexceeds 25 HRC + (55 3 carbon content).6.3 Product analyses may be mad
24、e by the purchaser fromfinished screws representing each lot. The chemical composi-tion, thus determined, shall conform to the requirementsprescribed for product analysis in Table 1.6.4 Application of heats of steel to which bismuth, sele-nium, tellurium, or lead has been intentionally added shall n
25、otbe permitted.6.5 Chemical analyses shall be performed in accordancewith Test Methods, Practices, and Terminology A 751.7. Mechanical Properties7.1 The hardness of finished screws shall be 39 to 45 HRCfor 0.500 in. and smaller and 37 to 45 HRC for 0.625 in. andlarger. This shall be only the mechani
26、cal requirements forscrews that are shorter than three times the diameter or thathave insufficient threads for tension testing.7.2 Screws, other than those exempted in 7.1 and 7.3, shallmeet the proof load and tensile requirements in Table 2 andTable 3. The screws shall be tension tested with a wedg
27、e of theangle specified in Table 4 under the head. To meet therequirements of the wedge test, there must be a tensile failurein the body or thread section. For the purpose of this test,failure means separation into two pieces. Screws threaded tothe head shall pass the requirements for this test if t
28、he fracturethat caused failure originated in the thread area, even though itmay have propagated into the fillet area or the head beforeseparation.7.3 Screws having a diameter larger than 1.500 in. shall bepreferably tested in full size and shall meet the requirements ofTable 2 and Table 3. When equi
29、pment of sufficient capacity isnot readily available, screws shall meet 170 ksi, min, tensilestrength, 153 ksi, min, yield strength at 0.2 % offset, and 10 %elongation on specimens machined in accordance with TestMethods F 606.8. Metallurgical Requirement8.1 Carburization or Decarburization:8.1.1 Th
30、ere shall be no evidence of carburization or totaldecarburization on the surfaces of the heat-treated screws whenmeasured in accordance with 12.3.8.1.2 The depth of partial decarburization shall be limited tothe values in Table 5 when measured as shown in Fig. 1 and inaccordance with 12.3.9. Dimensi
31、ons9.1 Unless otherwise specified, the product shall conform tothe requirements of B18.3.9.2 Unless otherwise specified, threads shall be Unifiedstandard: Class 3A, UNRC and UNRF series for screw sizes0.060 through 1 in. inclusive; Class 2A, UNRC and UNRFseries for sizes over 1 in. to 1.500 in. incl
32、usive; and Class 2AUNRC series for sizes larger than 1.500 in. in accordance withB1.1.TABLE 1 Chemical RequirementsElementComposition, %HeatAnalysisProductAnalysisCarbon, min 0.33 0.31Phosphorus, max 0.035 0.040Sulfur, max 0.040 0.045Alloying elements See 6.2A57404e1210. Workmanship, Finish, and App
33、earance10.1 DiscontinuitiesThe surface discontinuities for theseproducts shall conform to Specification F 788/F 788M and theadditional limitations specified herein.10.2 Socket Discontinuities:10.2.1 Depth of discontinuities in the socket area will bepermissible within the limits of Condition 1 provi
34、ded they donot affect the usability and performance of the screw. Discon-tinuities exceeding these limits are not acceptable.10.2.2 Longitudinal discontinuities must not exceed 0.25Tin length. Permissible and nonpermissible discontinuities areshown in Fig. 2.NOTE 2T = actual key engagement.10.3 Perm
35、issible Head and Body DiscontinuitiesDiscontinuities as defined above are permitted in the locationsillustrated in Fig. 3 to the depths shown in 10.4. Thesediscontinuities are permitted, provided they do not affect theusability and performance of the screw. All discontinuities areto be measured perp
36、endicular to indicated surfaces.10.4 Conditions for Permissible Discontinuity Depths:10.4.1 Condition 1For bearing area, fillet, and othersurfaces, max depth = 0.03D or 0.005 in. (whichever isgreater).NOTE 3D = nominal diameter of screw.10.4.2 Condition 2For peripheral discontinuities, maxdepth = 0.
37、06D, but not to exceed 0.064.10.5 Thread DiscontinuitiesThreads shall have no laps atthe root or on the flanks located below the pitch line. Laps areTABLE 2 Tensile Requirements for Coarse Thread ScrewsScrewDia (D), in.Threads/in.TensileLoad, min,lbfAStressArea, in.2 BProof Load(LengthMeasure-mentMe
38、thod),min, lbfC0.073 64 473 0.00263 3680.086 56 666 0.00370 5180.099 48 877 0.00487 6820.112 40 1 090 0.00604 8460.125 40 1 430 0.00796 1 1100.138 32 1 640 0.00909 1 2700.164 32 2 520 0.0140 1 9600.190 24 3 150 0.0175 2 4500.250 20 5 730 0.0318 4 4500.3125 18 9 440 0.0524 7 3400.375 16 13 900 0.0775
39、 10 8000.4375 14 19 100 0.1063 14 9000.500 13 25 500 0.1419 19 9000.625 11 38 400 0.226 30 5000.750 10 56 800 0.334 45 1000.875 9 78 500 0.462 62 4001.000 8 103 000 0.606 81 8001.125 7 129 000 0.763 103 0001.250 7 165 000 0.969 131 0001.375 6 196 000 1.155 156 0001.500 6 239 000 1.405 190 0001.750 5
40、 323 000 1.90 256 0002.000 412 425 000 2.50 338 0002.250 412 552 000 3.25 439 0002.500 4 680 000 4.00 540 0002.750 4 838 000 4.93 666 0003.000 4 1 010 000 5.97 806 0003.250 4 1 210 000 7.10 958 0003.500 4 1 420 000 8.33 1 120 0003.750 4 1 640 000 9.66 1 300 0004.000 4 1 880 000 11.08 1 500 000AValue
41、s based on 180 ksi for 0.500 and smaller and 170 ksi for sizes larger than0.500 in. and stress area in accordance with Footnote B.BStress areas based on Handbook H-28 (U.S. Department of Commerce) asfollows:As5 0.7854 D 0.9743/n!#2where:As= stress area,D = nominal screw size, andn = threads/in.CValu
42、es based on 140 ksi for 0.500 and smaller and 135 ksi for sizes larger than0.500 in. and stress area in accordance with Footnote B.TABLE 3 Tensile Requirements for Fine Thread ScrewsScrewDia (D),in.Threads/in.TensileLoad,min, lbfAStressArea,in.2 BProofLoad(LengthMeasure-mentMethod)min, lbfC0.060 80
43、324 0.00180 2520.073 72 500 0.00278 3890.086 64 709 0.00394 5520.099 56 941 0.00523 7320.112 48 1 190 0.00661 9250.125 44 1 490 0.00830 1 1600.138 40 1 830 0.01015 1 4200.164 36 2 650 0.01474 2 0600.190 32 3 600 0.0200 2 8000.250 28 6 500 0.0364 5 1000.3125 24 10 400 0.0580 8 1200.375 24 15 800 0.08
44、78 12 3000.4375 20 21 400 0.1187 16 6000.500 20 28 800 0.1599 22 4000.625 18 43 500 0.256 34 6000.750 16 63 400 0.373 50 4000.875 14 86 500 0.509 68 7001.000 12 113 000 0.663 89 5001.125 12 146 000 0.856 116 0001.250 12 182 000 1.073 145 0001.375 12 224 000 1.315 178 0001.500 12 269 000 1.581 213 00
45、0AValues based on 180 ksi for 0.500 and smaller and 170 ksi for sizes larger than0.500 in. and stress area in accordance with Footnote B.BStress areas based on H-28 as follows:As5 0.7854 D 0.9743/n!#2where:As= stress area,D = nominal screw size, andn = threads/in.CValues based on 140 ksi for 0.500 a
46、nd smaller and 135 ksi for sizes larger than0.500 in. and stress area in accordance with Footnote B.TABLE 4 Wedge Test AnglesScrew Size,D,in.Wedge Angle, DegBody Lengths2D or Lessor Threaded tothe HeadBody LengthsGreater than 2D0.112 0.500, incl 6 100.625 0.750, incl 6 80.875 to 1.500, incl 4 6A5740
47、4e13permissible at the thread crest to a depth of 25 % of the basicthread height and on the thread flanks beyond the pitchdiameter. Longitudinal seams in the threads are acceptablewithin the limits of Condition 1 (10.4.1).11. Number of Tests and Retests11.1 The requirements of this specification sha
48、ll be met incontinuous mass production for stock, and the manufacturershall make sample inspections to ensure that the productconforms to the specified requirements. Additional tests ofindividual shipments of material are not ordinarily contem-plated.Arecord of individual heats of steel in each test
49、 lot shallbe maintained. The container shall be coded to permit identi-fication of the lot.11.2 When specified in the order, the manufacturer shallfurnish a test report certified to be the last complete set ofmechanical tests for each stock size in each shipment.11.3 When additional tests are specified on the purchaseorder, a lot, for purposes of selecting test samples, shall consistof all screws offered for inspection at one time of one diameterand length. From each lot, the number of samples for eachrequirement shall be as follows:Number of Pieces in L
