1、Designation: A574 16Standard Specification forAlloy Steel Socket-Head Cap Screws1This standard is issued under the fixed designation A574; 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 paren
2、theses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope*1.1 This specification covers the requirements for quenchedand temp
3、ered alloy steel hexagon socket-head cap screws,0.060 through 4 in. in diameter where high strength is required.1.2 The values stated in inch-pound units are to be regardedas standard. No other units of measurement are included in thisstandard.1.3 The following hazard caveat pertains only to the tes
4、tmethod portions, sections 5.1, 5.6, 8, and 12, of this specifi-cation. This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the a
5、pplica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A751 Test Methods, Practices, and Terminology for Chemi-cal Analysis of Steel ProductsE112 Test Methods for Determining Average Grain SizeF606/F606M Test Methods for Determining the MechanicalProperties o
6、f Externally and Internally ThreadedFasteners, Washers, Direct Tension Indicators, and RivetsF788 Specification for Surface Discontinuities of Bolts,Screws, and Studs, Inch and Metric SeriesF1470 Practice for Fastener Sampling for Specified Me-chanical Properties and Performance InspectionF1789 Term
7、inology for F16 Mechanical FastenersF1940 Test Method for Process Control Verification toPrevent Hydrogen Embrittlement in Plated or CoatedFastenersF2282 Specification for QualityAssurance Requirements forCarbon and Alloy Steel Wire, Rods, and Bars for Me-chanical FastenersF2328 Test Method for Dete
8、rmining Decarburization andCarburization in Hardened and Tempered Threaded SteelBolts, Screws, Studs, and Nuts2.2 ASME Standards:3B18.3 Socket Cap, Shoulder, and Set ScrewsB18.12 Glossary of Terms for Mechanical FastenersB18.24 Part Identifying Number (PIN) Code System Stan-dard for B18 Fastener Pro
9、ducts3. Terminology3.1 Definitions of Terms Specific to This StandardThedefinition of terms used in this specification shall be asspecified in Terminology F1789, ASME B18.12, or the appli-cable referenced standards, unless otherwise defined herein. Inthe event that there are differences for a given
10、term, ASTMdefinitions shall be used.4. Ordering Information4.1 Orders for socket head cap screws under this specifica-tion shall include the following information:4.1.1 ASTM designation and year of issue.4.1.2 Name of the screw (SHCS).4.1.3 Quantity (number of pieces by size).4.1.4 Dimensions, inclu
11、ding nominal thread designation,thread pitch, and nominal screw length.4.2 Orders for socket head cap screws shall include thefollowing optional requirements if specified by the purchaser:4.2.1 Inspection at point of manufacture.4.2.2 Coating, if a protective finish other than those, whichare descri
12、bed in 5.5 is required, it must be specified (see 5.6).4.2.3 Test reports or certificate of conformance, as required(see Section 15).4.2.4 Additional testing (see 12.1).4.2.5 Special packaging (see 18.1.2).4.2.6 Supplementary requirements (see S1).4.2.7 Special requirements.1This specification is un
13、der 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 Oct. 1, 2016. Published November 2016. Originallyapproved in 1967. Last previous edition approved in 2013 as A574 13. DOI:10
14、.1520/A0574-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American Society of Mechanical
15、 Engineers (ASME), ASMEInternational Headquarters, Three Park Ave., New York, NY 10016-5990, http:/www.asme.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2.8 For
16、 establishment of a part identifying system, seeASME B18.24.5. Materials and Manufacture5.1 The screws shall be fabricated from alloy steel made toa fine grain practice. In the event of controversy over grainsize, referee tests on finished screws conducted in accordancewith Test Methods E112 shall p
17、revail.5.2 Screws in sizes through 0.750 in. diameter, and withlengths through ten times the nominal product size or 6.0inches, whichever is shorter, shall be cold headed, except thatwhen specified by the purchaser the screws shall be hot headed.Larger sizes and longer lengths shall be cold or hot h
18、eaded atthe option of the manufacturer, unless otherwise specified bythe purchaser. Screws larger than 1.500 in. nominal diametershall be permitted to be machined. Sockets shall be forged ormachined at the option of the manufacturer.5.3 Screws in sizes through 0.625 in. diameter, and forproduct leng
19、ths through 4 in. shall be roll threaded, unlessotherwise specified by the purchaser. Larger products shall berolled, cut, or ground at the option of the manufacturer.5.4 Screws shall be heat treated by quenching in oil fromabove the transformation temperature and then tempered byreheating to at lea
20、st 700F to achieve the mechanical propertiesspecified in Section 7 and Table 1.5.4.1 When specified by the purchaser, the minimum tem-pering temperature shall be verified by subjecting screws to680F for 30 minutes at temperature. The mean cross sectionhardness of three readings on the screw before a
21、nd afterretempering shall not differ by more than 2 points hardnessRockwell C (HRC).5.5 Standard FinishesUnless otherwise specified, thescrews shall be furnished with one of the following “standardsurfaces as manufactured” at the option of the manufacturer:(1) bright uncoated, (2) thermal black oxid
22、e, or (3) chemicalblack oxide. Hydrogen embrittlement tests shall not be re-quired for screws furnished in these conditions.5.6 Protective Coatings:5.6.1 When a protective finish other than as specified in 5.5is required, it shall be specified on the purchase order with theapplicable finish specific
23、ation.5.6.2 When protective or decorative coatings are applied tothe screws, precautions specified by the coating requirementsto minimize internal hydrogen embrittlement shall be exer-cised. Additional precautions such as the requirements in TestMethod F1940 and Test Methods F606/F606M shall be byag
24、reement with the purchaser.6. Chemical Composition6.1 The screws shall be alloy steel conforming to thechemical composition specified in Table 2 and the require-ments in Specification F2282. See Supplementary RequirementS1 when additional alloy steel grades are required.6.2 One or more of the follow
25、ing alloying elements:chromium, nickel, molybdenum, or vanadium shall be presentin sufficient quantity to ensure that the specified strengthproperties are met after oil quenching and tempering. As aguide for selecting material, an alloy steel should be capable ofmeeting the specified mechanical requ
26、irements if the “as oilquenched” core hardness one diameter from the point is equalto or exceeds 25 HRC + (55 carbon content).6.3 When product analyses are made by the purchaser fromfinished screws representing each lot, the chemicalcomposition, thus determined, shall conform to the require-ments pr
27、escribed for product analysis in Table 2.6.4 Steel to which bismuth, selenium, tellurium, or lead hasbeen intentionally added shall not be permitted.6.5 Chemical analyses shall be performed in accordancewith Test Methods, Practices, and Terminology A751.7. Mechanical Properties7.1 Socket head cap sc
28、rews shall be tested in accordancewith the mechanical testing requirements specified in Table 3,and shall meet the mechanical requirements in Table 1, andeither Table 4 or Table 5.NOTE 1For design purposes only, a minimum yield strength at 2%offset of 153 ksi may be assumed for bolt diameters less t
29、han 1.0 in.7.2 The screws that are tested for wedge tensile strengthshall utilize a wedge of the angle specified in Table 6 under thehead.To meet the requirements of the wedge test, there must bea tensile failure in the body or thread section. For the purposeof this test, failure means separation in
30、to two pieces. Screwsthreaded to the head shall pass the requirements for this test ifthe fracture that caused failure originated in the thread area,TABLE 1 Mechanical RequirementsProperty#0.5 in.Nom. Dia.0.5 in. and 270,000 Over 3DAB.BZC. XCYCYCYCYCAD denotes nominal diameter of product.BDenotes ma
31、ndatory test.CEither all tests denoted by X or all tests denoted by Y shall be performed. In case of arbitration full-size tests, denoted X, shall be decisive. Proof load test denoted Zshall be conducted when purchaser requests the test in inquiry and order.TABLE 4 Tensile Requirements for Coarse Th
32、read ScrewsScrewDia (D),in.Threads/in.TensileLoad,min, lbfAStressArea,in.2 BProof Load(LengthMeasurementMethod),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 9
33、600.190 24 3 150 0.0175 2 4500.216 24 4 350 0.0242 3 3800.250 20 5 730 0.0318 4 4500.3125 18 9 440 0.0524 7 3400.375 16 13 900 0.0775 10 8000.4375 14 19 100 0.1063 14 9000.500 13 25 500 0.1419 19 9000.5625 12 30 900 0.182 24 6000.625 11 38 400 0.226 30 5000.750 10 56 800 0.334 45 1000.875 9 78 500 0
34、.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 5 323 000 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
35、.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 000AValues 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
36、areas based on Handbook H-28 (U.S. Department of Commerce) asfollows:As5 0.7854 fD 2 s0.9743/ndg2where:As= stress area,D = nominal screw size, andn = threads/in.CValues 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.TAB
37、LE 5 Tensile Requirements for Fine Thread ScrewsScrewDia (D),in.Threads/in.TensileLoad,min, lbfAStressArea,in.2 BProof Load(LengthMeasurementMethod)min, lbfC0.060 80 324 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 0.0083
38、0 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 1000.216 28 4 600 0.0258 3 6000.3125 24 10 400 0.0580 8 1200.375 24 15 800 0.0878 12 3000.4375 20 21 400 0.1187 16 6000.500 20 28 800 0.1599 22 4000.5625 18 34 500 0.203 27 4000.625 18 4
39、3 500 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 000AValues based on 180 ksi for 0.500 and smaller and 170 ksi for sizes larger t
40、han0.500 in. and stress area in accordance with Footnote B.BStress areas based on H-28 as follows:As5 0.7854 fD 2 s0.9743/ndg2where:As= stress area,D = nominal screw size, andn = threads/in.CValues based on 140 ksi for 0.500 and smaller and 135 ksi for sizes larger than0.500 in. and stress area in a
41、ccordance with Footnote B.A574 1639. Dimensions9.1 Unless otherwise specified, the product shall conform tothe requirements of ASME B18.3.10. Workmanship, Finish, and Appearance10.1 Surface DiscontinuitiesThe surface discontinuitiesfor these products shall conform to Specification F788 and theadditi
42、onal limitations specified herein.10.2 Forging Cracks:10.2.1 Forging cracks that connect the socket to the periph-ery of the head as shown in Fig. 1 are not permissible.10.2.2 Forging cracks originating on the periphery of thehead and with a traverse indicating a potential to intersect onthe top of
43、the socket head as shown in Fig. 1 are notpermissible.10.2.3 Other forging cracks are permissible provided thosethat are located in the bearing area, fillet, and top surfaces donot have a depth exceeding 0.03D or 0.005 in., whichever isgreater. For peripheral discontinuities, the maximum depthshall
44、be 0.06D or 0.064 in., whichever is greater (see Fig. 1).10.2.4 Forging cracks located in the socket wall within 0.1times the actual key engagement (T) from the bottom of thesocket are not permissible. Discontinuities located elsewhere inthe socket shall not have a length exceeding 0.25T,oramaximum
45、depth of 0.03D or 0.005 in., whichever is greater(see Fig. 2).10.3 Seams in the shank shall not exceed a depth of 0.03Dor 0.005 in., whichever is greater.10.4 Thread DiscontinuitiesThreads shall have no laps atthe root or on the flanks located below the pitch line, as shownin Fig. 3, when inspected
46、in accordance with SpecificationF788, S1.2. Laps are permissible at the thread crest (Fig. 3C)TABLE 6 Wedge Test AnglesScrew Size,D,in.Wedge Angle, DegBody Lengths2D or Lessor Threadedto the HeadBody LengthsGreater than 2D0.112 0.500, incl 6 100.625 0.750, incl 6 80.875 to 1.500, incl 4 6FIG. 1 Head
47、 and Body Discontinuity Location and LimitsA574 164to a depth of 25 % of the basic thread height and on the threadflanks above the pitch diameter. Longitudinal seams rolledbeneath the root of the thread and across the crests of thethreads are acceptable within the limits of 10.3.11. Sampling and Num
48、ber of Tests11.1 Guide F1470 shall be used to determine the necessarysampling plan and the number of tests that must be performedto demonstrate that all of the requirements of this standard aremet for each lot.12. Test Methods12.1 Testing, to demonstrate that the requirements in 5.4.1,Section 7, or
49、any additional mechanical tests that are requiredby the purchaser have been met, shall be in accordance withTest Methods F606/F606M at room temperature.12.2 The inspection and evaluation of surface discontinui-ties shall be in accordance with the requirements in Specifica-tion F788.12.3 Decarburization and carburization tests shall be con-ducted in accordance with Test Method F2328, Class 3.13. Inspection13.1 If the inspection described in 13.2 is required by thepurchaser, it shall be specified in the inquiry and contract ororder.FIG. 2 Socket Discontinuity Locatio
