1、Designation:A 574-08INTERNATIONALStandard Specification forAlloy Steel Socket-Head Cap ScrewsThis 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
2、 in parentheses indicates the year of last reapproval.Asuperscript epsilon(2)indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1.Scope*Prevent Hydrogen Embrittlement in Plated or Coated1.1 This specifi
3、cation covers the requirements for quenchedFastenersand tempered alloy steel hexagon socket-head cap screws,F2282 Specification for Quality Assurance Requirements0.060 through 4 in.in diameter where high strength is required.for Carbon and Alloy Steel Wire,Rods,and Bars for1.2 The values stated in i
4、nch-pound units are to be regardedMechanical Fastenersas standard.No other units of measurement are included in thisF 2328 Test Method for Determining Decarburization andstandard.Carburization in Hardened and Tempered Threaded SteelBolts,Screws and StudsNorE 1-A complete metric companion to Specific
5、ation A 574 has2.2 ASME Standards:3been developed-A 574M;therefore no metric equivalents are presentedin this specification.B18.3 Socket Cap,Shoulder,and Set ScrewsB18.12 Glossary of Terms for Mechanical Fasteners1.3 The following hazard caveat pertains only to the testB18.24 Part Identifying Number
6、(PIN)Code System Stan-method portions,sections 5.1,5.6,8,and 12,of this specifi-dard for B18 Fastener Productscation.This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is the3.Terminologyresponsibility of the user of this standard to establish appro
7、-3.1 Definitions of Terms Specific to This Standard-Thepriate safety and health practices and determine the applica-definition of terms used in this specification shall be asbility of regulatory limitations prior to use.specified in Terminology F 1789,ASME B18.12,or the appli-2.Referenced Documentsc
8、able referenced standards,unless otherwise defined herein.Inthe event that there are differences for a given term,ASTM2.1 ASTM Standards:2definitions shall be used.A 751 Test Methods,Practices,and Terminology forChemical Analysis of Steel Products4.Ordering InformationE 112 Test Methods for Determin
9、ing Average Grain Size4.1 Orders for socket head cap screws under this specifica-F 606 Test Methods for Determining the Mechanical Prop-tion shall include the following information:erties of Externally and Internally Threaded Fasteners,4.1.1 ASTM designation and year of issue.Washers,Direct Tension
10、Indicators,and Rivets4.1.2 Name of the screw(SHCS).F 788/F 788M Specification for Surface Discontinuities of4.1.3 Quantity(number of pieces by size).Bolts,Screws,and Studs,Inch and Metric Series4.1.4 Dimensions,including nominal thread designation,F1470 Practice for Fastener Sampling for Specified M
11、e-thread pitch,and nominal screw length.chanical Properties and Performance Inspection4.2 Orders for socket head cap screws shall include theF 1789 Terminology for F16 Mechanical Fastenersfollowing optional requirements if specified by the purchaser:F 1940 Test Method for Process Control Verificatio
12、n to4.2.1 Inspection at point of manufacture.4.2.2 Coating,if a protective finish other than those,whichare described in 5.5 is required,it must be specified(see 5.6).This specification is under the jurisdiction of ASTM Committee F16 on4.2.3 Certified test reports,as required(see Section 15).Fastene
13、rs and is the direct responsibility of Subcommittee F16.02 on Steel Bolts,Nuts,Rivets and Washers.4.2.4 Additional testing(see 12.1).Current edition approved Dec.1,2008.Published January 2009.Originally4.2.5 Special packaging(see 18.1.2).approved in 1967.Last previous edition approved in 2004 as A 5
14、74-04.2 For referenced ASTM standards.visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of A.STM3 Available from American Society of Mechanical Engineers(ASME).ASMEStandards volume information,refer to the standards Document Summary page onInterna
15、tional Headquarters,Three Park Ave.,New York,NY 10016-5990.http:/the ASTM website.www.asme.org.*A Summary of Changes section appears at the end of this standard.CopyrightASTM Intemational,100 Barr Harbor Drive,PO Box C700.West Conshohocken.PA 19428-2959.United States.1A574-084.2.6 Supplementary requ
16、irements(see S1)to minimize internal hydrogen embrittlement shall be exer4.2.7 Special requirements.cised.Additional precautions such as the requirements in Test4.2.8 For establishment of a part identifying system,seeMethod F 1940 and Test Methods F 606 shall be by agreementASME B18.24.with the purc
17、haser.5.Materials and Manufacture6.Chemical Composition5.1 The screws shall be fabricated from alloy steel made to6.1 The screws shall be alloy steel conforming to thea fine grain practice.In the event of controversy over grainchemical composition specified in Table 2 and the require-size,referee te
18、sts on finished screws conducted in accordancements in Specification F 2282.See Supplementary Require-with Test Methods E 112 shall prevail.ment SI when additional alloy steel grades are required.5.2 Screws in sizes through 0.750 in.diameter,and with6.2 One or more of the following alloying elements
19、:chro-lengths through ten times the nominal product size or 6.0mium,nickel,molybdenum,or vanadium shall be present ininches,whichever is shorter,shall be cold headed,except thatsufficient quantity to ensure that the specified strength proper-when specified by the purchaser the screws shall be hot he
20、aded.ties are met after oil quenching and tempering.As a guide forLarger sizes and longer lengths shall be cold or hot headed atselecting material,an alloy steel should be capable of meetingthe option of the manufacturer,unless otherwise specified bythe specified mechanical requirements if theas oil
21、 quenchedthe purchaser.Screws larger than 1.500 in.nominal diametercore hardness one diameter from the point is equal to orshall be permitted to be machined.Sockets shall be forged orexceeds 25 HRC+(55 X carbon content).machined at the option of the manufacturer.6.3 When product analyses are made by
22、 the purchaser from5.3 Screws in sizes through 0.625 in.diameter,and forfinished screws representing each lot,the chemical composi-product lengths through 4 in.shall be roll threaded,unlesstion,thus determined,shall conform to the requirementsotherwise specified by the purchaser.Larger products shal
23、l beprescribed for product analysis in Table 2.rolled,cut,or ground at the option of the manufacturer.6.4 Steel to which bismuth,selenium.tellurium.or lead has5.4 Screws shall be heat treated by quenching in oil frombeen intentionally added shall not be permitted.above the transformation temperature
24、 and then tempered by6.5 Chemical analyses shall be performed in accordancereheating to at least 700F to achieve the mechanical propertiesspecified in Section 7 and Table 1.with Test Methods,Practices,and Terminology A 751.5.4.1 When specified by the purchaser,the minimum tem-7.Mechanical Properties
25、pering temperature shall be verified by subjecting screws to680F for 30 minutes at temperature.The mean cross section7.1 Socket head cap screws shall be tested in accordancehardness of three readings on the screw before and afterwith the mechanical testing requirements specified in Table 3,retemperi
26、ng shall not differ by more than 2 points hardnessand shall meet the mechanical requirements in Table 1,andRockwell C(HRC).either Table 4 or Table 5.5.5 Standard Finishes-Unless otherwise specified,the7.2 The screws that are tested for wedge tensile strengthscrews shall be furnished with one of the
27、followingstandardshall utilize a wedge of the angle specified in Table 6 under thesurfaces as manufacturedat the option of the manufacturer:head.To meet the requirements of the wedge test,there must be(1)bright uncoated,(2)thermal black oxide,or(3)chemicala tensile failure in the body or thread sect
28、ion.For the purposeblack oxide.Hydrogen embrittlement tests shall not be re-of this test,failure means separation into two pieces.Screwsquired for screws furnished in these conditions.threaded to the head shall pass the requirements for this test if5.6 Protective Coatings:the fracture that caused fa
29、ilure originated in the thread area5.6.1 When a protective finish other than as specified in 5.5even though it may have propagated into the fillet area or theis required,it shall be specified on the purchase order with thehead before separationapplicable finish specification.5.6.2 When protective or
30、 decorative coatings are applied to8.Metallurgical Requirementthe screws,precautions specified by the coating requirements8.1 Carburization or Decarburization:8.1.1 There shall be no evidence of carburization or totalTABLE 1 Mechanical Requirementsdecarburization on the surfaces of the heat-treated
31、screws whenmeasured in accordance with Test Method F2328(Class 3Property0.500in0.500inNom.Dia.Nom.Dia.Product).Full-size screws:Tensile or wedge tensile strength,min,ksi180170Proof load(stress).ksi140135TABLE 2Chemical RequirementsProduct hardness:Composition,Rockwell(HRC)39-4537-45ElementHeatProduc
32、tMachined test specimen:AnalysisAnalysisYield strength at 0.2%offset,min.,ksi153153Carbon,min0.330.31Tensile strength,min.,ksi180170Phosphorus,max0.0350.040Elongation in 5D.min.10%10%Sulfur,max0.0400.045Reduction of area,min.35%35%Alloying elementsSee 6.24A574-08PERMISSIBLE-DOCS NOT EXTENDAND EDGE O
33、F HEAD】天PERMIS等BLE=P我M想专线用LrPERMISSIBLE(MAX.DEPTH)BEARING AREA BODY.ANDTH东EAG道【L。NCITUDINALDIRECTION ONLY.FIG.1 Head and Body Discontinuity Location and LimitsPERMISSIBLE IF NOT IN EXCESS OF 9.25TIN LENGTH AND NOT WITHIN 0.I0T FROMBOTTOM OF SOCKET.D.IOTNO CRACKSPERMITTED IN THISAREA._PERMISSIBLE NOT IN AREA OFKEY ENGAGEMENT.NOT PERMISSIBLE-BOTTOM OF(BOTTOM OF SOCKET!SOCKET OR WITHIN 0.10T OFBOTTOM OF SOCKET.FIG.2 Socket Discontinuity Location and Limits18.2.1.2Size,18.2.1.4 Number of pieces,18.2.1.3 Name and brand or trademark of the manufacturer,18.2.1.5 Purchase order number,and
