1、Designation: F 835 04e1Standard Specification forAlloy Steel Socket Button and Flat Countersunk Head CapScrews1This standard is issued under the fixed designation F 835; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of l
2、ast revision. A number in parentheses 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 3.1.9 were editorially rev
3、ised in October 2006.1. Scope*1.1 This specification covers the requirements for quenchedand tempered alloy steel hexagon socket button (SBHCS)0.060 through 0.625 thread sizes and flat countersunk (SFHCS)0.060 through 1.5 thread sizes head cap screws having materialproperties for high-strength requi
4、rements.1.2 Fasteners meeting this specification are intended forshear-type applications and have tensile requirements rangingfrom 122 to 150 ksi.1.3 The hazard statement applies only to the test methodsection, Section 11, of this specification. This standard doesnot purport to address all of the sa
5、fety concerns, if any,associated with its use. It is the responsibility of the user of thisstandard to establish appropriate safety and health practicesand determine the applicability of regulatory limitations priorto use.2. Referenced Documents2.1 ASTM Standards:2A 751 Test Methods, Practices, and
6、Terminology forChemical Analysis of Steel ProductsD 3951 Practice for Commercial PackagingE3 Guide for Preparation of Metallographic SpecimensE18 Test Methods for Rockwell Hardness and RockwellSuperficial Hardness of Metallic MaterialsE112 Test Methods for Determining Average Grain SizeE 384 Test Me
7、thod for Microindentation Hardness of Ma-terialsF 606M Test Methods for Determining the MechanicalProperties of Externally and Internally Threaded Fasteners,Washers, and Rivets MetricF 788/F 788M Specification for Surface Discontinuities ofBolts, Screws, and Studs, Inch and Metric Series2.2 ASME Sta
8、ndards:3B18.3 Socket Cap, Shoulder and Set ScrewsInch SeriesB18.24 Part Identifying Number (PIN) Code System Stan-dard for B18 Fastener Products3. Ordering Information3.1 Orders for material under this specification shall includethe following:3.1.1 Quantity (number of screws).3.1.2 Dimensions, inclu
9、ding nominal thread designation,thread pitch, and nominal screw length (inches). A standardpart number may be used for this definition.3.1.3 Name of the screw: SBHCS or SFHCS.3.1.4 Coating, if required. If a protective finish other thanblack oxide is required, it must be specified on the order orpro
10、duct standard.3.1.5 Lot testing, if required (see 10.3).3.1.6 Certification, if required (see 14.1).3.1.7 ASTM designation and year of issue.3.1.8 Any special requirements.3.1.9 For establishment of a part identifying system, seeASME B18.24.3.2 Example1000 pieces 0.250 20 3 0.375 SBHCS lottensile te
11、st. ASTM F 835XX.4. Materials and Manufacture4.1 The screws shall be fabricated from alloy steel made tofine grain practice. In the event of controversy over grain size,referee tests on finished screws conducted in accordance withTest Methods E112shall prevail.4.2 Screws shall be hot or cold upset o
12、r extruded, or both.4.3 Unless otherwise specified, threads shall be rolled fordiameters through 0.625 in. and for screw lengths through 4 in.For diameters and lengths other than this, threads may berolled, cut or ground.1This specification is under the jurisdiction of ASTM Committee F16 onFasteners
13、 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 1986. Last previous edition approved in 2003 as F 835 03.2For referenced ASTM standards, visit the ASTM website, www.a
14、stm.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 Engineers (ASME), ASMEInternational Headquarters, Three Park Ave., New York
15、, NY 10016-5990.1*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.4.4 Screws shall be heat treated by quenching in oil fromabove the transformation temperature and then
16、tempering byreheating to at least 650F to be within the hardness rangespecified in Table 1.4.4.1 The minimum tempering temperature may be verifiedby submitting screws to 635F for 30 min at temperature. Theaverage cross-section hardness of three readings on the screwbefore and after retempering shall
17、 not differ by more than 20DPH.4.5 When protective or decorative coatings are applied tothe screws, precautions as required by the coatings shall betaken to prevent embrittlement.5. Chemical Composition5.1 The chemical composition of the screw material shallconform to the heat analysis specified in
18、Table 2.5.2 One or more of the following alloying elements, chro-mium, nickel, molybdenum, or vanadium, shall be present inthe steel in sufficient quantity to ensure the specific strengthproperties are met after oil quenching and tempering. The steelshall meet the AISI definition of alloy steel, tha
19、t is, maximumand minimum element content requirement or minimum ele-ment limits specified.5.3 Steel to which bismuth, selenium, tellurium, or lead hasbeen added intentionally shall not be permitted.5.4 Material analysis may be made by the purchaser fromfinished products and the chemical composition
20、thus deter-mined shall conform to the requirements specified for theproduct analysis in Table 2.6. Mechanical Properties6.1 The finished screws shall conform to the mechanicalrequirements specified in Table 1.6.2 Screws having a nominal length equal to or greater than3 diameters shall be tested full
21、 size and shall conform to thefull-size tensile requirements specified in Table 3. Tensilefailures through the head are acceptable provided the loadrequirements are satisfied.6.3 Screws having a nominal thread diameter-length com-bination as specified in 6.2 and a breaking load exceeding200 000 lb p
22、referably shall be tested full size and shall meet thefull-size tensile properties in Table 3. When equipment ofsufficient capacity for such tests is not available or if excessivelength of the screws makes full-size testing impractical, stan-dard round machined specimens may be used that shall meett
23、he machined test specimen tensile properties in Table 1.Ifdiscrepancy between full-size and machined specimen results,full-size tests shall be used as the referee method to determineacceptance.6.4 Screws that are too short (lengths less than three timesnominal size) or that have insufficient threads
24、 for tensiontesting shall not be subject to tension tests but shall conform tothe hardness (minimum and maximum) requirements of Table1.6.5 All screws, regardless of size, shall conform to thehardness specified in Table 1. Hardness shall be met anywhereon the cross section through the threaded porti
25、on one diameterfrom the screw point.7. Other Requirements7.1 Decarburization:7.1.1 There shall be no evidence of carburization or grossdecarburization on the surfaces of the heat-treated screws whenmeasured in accordance with 11.5.TABLE 1 Mechanical RequirementsNominal Thread Size, in.0.500 andsmall
26、erOver 0.500Full-size Screws:Tensile, min, ksi 145 135Machined Test Specimen:Yield strength at 0.2 % offset, min, ksiA153Tensile strength, min, ksiA170Elongation in 4D,min,%A8Reduction of area, min, %A35Product Hardness:Rockwell C 3944 3744Vickers DPH 382434 363434ANot applicable.TABLE 2 Chemical Re
27、quirementsElementComposition, %HeatAnalysisProductAnalysisCarbon 0.30 to 0.48 0.28 to 0.50Phosphorus, max 0.035 0.040Sulfur, max 0.040 0.045Alloying elements see 5.2 see 5.2TABLE 3 Minimum Ultimate Tensile LoadsThread Size Stress Area, in.2 Button andCountersunkHeads, Tensile Load,min lbACoarse Fine
28、 Coarse Fine. . . 0.060-80 . . . 0.00180 2600.073-64 0.073-72 0.00263 0.00278 3800.086-56 0.086-64 0.00370 0.00394 5400.099-48 0.099-56 0.00487 0.00523 7100.112-40 0.112-48 0.00604 0.00661 8800.125-40 0.125-44 0.00796 0.00830 11500.138-32 0.138-40 0.00909 0.01015 13200.164-32 0.164-36 0.0140 0.10474
29、 20300.190-24 0.190-32 0.0175 0.0200 25400.250-20 0.250-28 0.0318 0.0384 46100.3125-18 0.3125-24 0.0524 0.0580 76000.375-16 0.375-24 0.0775 0.0878 11 2000.4375-14 0.4375-20 0.1063 0.1187 15 4000.500-13 0.500-20 0.1419 0.1599 20 6000.625-11 0.625-18 0.226 0.258 30 5000.750-10 0.750-16 0.334 0.373 45
30、1000.875-9 0.875-14 0.462 0.509 62 4001.000-8 1.000-12 0.606 0.663 81 8001.125-7 1.125-12 0.763 0.858 103 0001.250-7 1.250-12 0.969 1.073 131 0001.375-6 1.375-12 1.155 1.315 156 0001.500-6 1.500-12 1.405 1.581 190 000ABecause of the head critical configuration of these parts, the full size tensilelo
31、ads are based on 80 % of the minimum heat treated material strength (180 ksi forsizes 0.500 in. and smaller and 170 ksi for sizes larger than 0.500 in.) and thestress areas for coarse thread screws.F83504e127.1.2 The depth of partial decarburization shall be limited tothe values in Table 4 when meas
32、ured as shown in Fig. 1, andin accordance with 11.5.7.2 EmbrittlementCoated screws shall withstand the em-brittlement test in accordance with 11.4 without showingindications of discontinuities. The loading shall be calculatedwith minimum screw tensile requirements.8. Dimensions8.1 Unless otherwise s
33、pecified, the dimensions shall con-form to the requirements of ASME B 18.3.9. Workmanship, Finish, and Appearance9.1 Surface FinishThe screws shall have a black (thermalor chemical) oxide finish, unless otherwise specified.9.2 Surface Discontinuities:9.2.1 The surface discontinuities for these produ
34、cts shallconform to Specification F 788/F 788M and the additionallimitations specified herein.9.2.2 Forging defects that connect the socket to the periph-ery of the head are not permissible. Defects originating on theperiphery and with a traverse indicating a potential to intersectare not permissibl
35、e. Other forging defects are permissible,provided those located in the bearing area, fillet and topsurfaces shall not have a depth exceeding 0.03 D or 0.005 in.,whichever is greater. For peripheral discontinuities, the maxi-mum depth may be 0.06 D not to exceed 0.040 in. (seeFig. 2).9.2.3 Forging de
36、fects 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 0.25 T or amaximum depth of 0.03 D not to exceed 0.005 in. (seeFig. 3).9.2.4 Seams in the
37、shank shall not exceed a depth of 0.03 Dor 0.008 in., whichever is greater.9.2.5 No transverse discontinuities shall be permitted in thehead-to-shank fillet area.9.2.6 Threads shall have no laps at the root or on the flanks,as shown in Fig. 4. Laps are permitted at the crest (Fig. 4c) thatdo not exc
38、eed 25 % of the basic thread depth and on the flanksoutside the pitch cylinder. Longitudinal seams rolled beneaththe root of the thread and across the crests of cut threads areacceptable within the limits of 9.2.4.9.2.7 Quench cracks of any depth, any length, or in anylocation are not permitted.10.
39、Number of Tests10.1 The requirements of this specification shall 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 c
40、ontem-plated.Arecord of individual heats of steel in each test lot shallbe maintained. The container shall be coded to permit identi-fication of the lot.10.2 When specified in the order, the manufacturer shallfurnish a test report certified to be the last complete set ofmechanical tests for each sto
41、ck size in each shipment.10.3 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
42、:Number of Pieces in LotNumber ofSamples800 and less 1Over 800 to 8000, incl 2Over 8000 to 22 000, incl 3Over 22 000 510.4 Should any sample fail to meet the requirements of aspecified test, double the number of samples from the same lotshall be retested for the requirement(s) in which it failed.All
43、 ofthe additional samples shall conform to the specification or thelot shall be rejected.11. Test Methods11.1 Chemical analysis shall be conducted in accordancewith Test Methods, Practices, and Terminology A 751.11.2 Tensile properties shall be determined in accordancewith Test Methods F 606.11.3 Ha
44、rdness shall be determined in accordance with TestMethods E18.11.4 Embrittlement tests shall be conducted in accordancewith Test Methods F 606. The countersunk washer for the flatcountersunk head cap screw shall be placed with the axis of theconical recess at the required wedge angle with the fasten
45、eraxial load.11.5 Decarburization and carburization tests shall be con-ducted as follows:11.5.1 Section the thread area of the bolt longitudinallythrough the axis, mount, and polish it in accordance withPractice E3. Take measurements (1) at the minor diameter inthe center of the thread ridge, and (2
46、) 0.75 h toward the threadcrest on the perpendicular bisector of the thread ridge. Take ameasurement (3) on the thread flank approximately at the pitchline at a depth of 0.003 in. Use one of the two methods forTABLE 4 Decarburization LimitsThreads/in.ThreadHeight, hs0.75 hsfromRoot toCrest, min0.1 h
47、satRoot, max48 0.013 0.010 0.00144 0.014 0.011 0.00140 0.015 0.011 0.00236 0.017 0.013 0.00232 0.019 0.014 0.00228 0.022 0.017 0.00224 0.026 0.020 0.00320 0.031 0.023 0.00318 0.034 0.026 0.00316 0.038 0.029 0.00414 0.044 0.033 0.00413 0.047 0.035 0.00512 0.051 0.038 0.00511 0.056 0.042 0.00610 0.061
48、 0.046 0.0069 0.068 0.051 0.0078 0.077 0.058 0.0087 0.088 0.066 0.0096 0.102 0.077 0.010F83504e13carburization/decarburization evaluation either optical or mi-crohardness measurements. The microhardness measurementshall constitute a referee method in case of dispute.11.5.2 For optical measurement, e
49、tch the section in 2 to 4 %nital. Examine the surface of the etched samples under amicroscope at 1003 using a measuring eyepiece graduated in0.001-in. increments. The width of any light etching bandnormally defines the decarburization depth. A dark etchingband indicates the possibility of carburization.11.5.3 Measure microhardness in accordance with TestMethod E 384 on unetched specimens using a DPH 136indenter or a Knoop indenter using the following load appli-cation:Number of Threadsper InchLoadLess than 40 500 gf40, 44, and 48 200 gfOver 48 Use optical evaluationi
