1、Designation: F879 15Standard Specification forStainless Steel Socket Button and Flat Countersunk HeadCap Screws1This standard is issued under the fixed designation F879; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of l
2、ast revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon () 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 chemic
3、al and mechanicalrequirements for stainless steel inch hexagon socket button(SBHCS) and flat countersunk (SFHCS) head cap screws withnominal thread 0.060 through 0.625 in. intended for use inapplications requiring general corrosion resistance.1.2 Two groups of austenitic stainless steel alloys and t
4、hreeconditions are covered. See Table 1 and Table 2.1.3 UnitsThe values stated in inch-pound units are to beregarded as standard. No other units of measurement areincluded in this standard.1.4 The following precautionary caveat pertains only to thetest method portion, Section 12, of this specificati
5、on: Thisstandard does not purport to address all of the safety concerns,if any, associated with its use. It is the responsibility of the userof this standard to establish appropriate safety and healthpractices and determine the applicability of regulatory limita-tions prior to use.2. Referenced Docu
6、ments2.1 ASTM Standards:2A262 Practices for Detecting Susceptibility to IntergranularAttack in Austenitic Stainless SteelsA342/A342M Test Methods for Permeability of WeaklyMagnetic MaterialsA380/A380M Practice for Cleaning, Descaling, and Passi-vation of Stainless Steel Parts, Equipment, and Systems
7、A555/A555M Specification for General Requirements forStainless Steel Wire and Wire RodsA751 Test Methods, Practices, and Terminology for Chemi-cal Analysis of Steel ProductsA967/A967M Specification for Chemical Passivation Treat-ments for Stainless Steel PartsD3951 Practice for Commercial PackagingE
8、18 Test Methods for Rockwell Hardness of Metallic Ma-terialsE92 Test Method for Vickers Hardness of Metallic Materials(Withdrawn 2010)3E384 Test Method for Knoop and Vickers Hardness ofMaterialsF593 Specification for Stainless Steel Bolts, Hex CapScrews, and StudsF606/F606M Test Methods for Determin
9、ing the MechanicalProperties of 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 Pe
10、rformance Inspection2.2 ASME Standard:B 18.3 Socket Cap, Shoulder and Set Screws (Inch Series)42.3 JIS Standard:5JIS G 4309 Stainless Steel Wires3. Classification3.1 The designation of the alloy group and condition of thisspecification shall be consistent with the stainless steel desig-nations in Sp
11、ecification F593.3.2 Screws shall be designated by group and condition (forexample, F879 Group 1 Condition AF).4. Ordering Information4.1 Orders for material under this specification shall includethe following information:1This specification is under the jurisdiction of ASTM Committee F16 onFastener
12、s and is the direct responsibility of Subcommittee F16.04 on NonferrousFasteners.Current edition approved May 1, 2015. Published July 2015. Originally approvedin 1986. Last previous edition approved in 2012 as F879-12. DOI: 10.1520/F0879-15.2For referenced ASTM standards, visit the ASTM website, www
13、.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.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from American Society of
14、Mechanical Engineers (ASME), ASMEInternational Headquarters, Two Park Ave., New York, NY 10016-5990, http:/www.asme.org.5Available from Japanese Industrial Standards Committee (JIS) 1-3-1Kasumigaseki, Chiyoda-ku, Tokyo 100-8901, JAPAN. http:/www.jisc.go.jp*A Summary of Changes section appears at the
15、 end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.1.1 Quantity (number of pieces of each item).4.1.2 Name of the screw, SBHCS or SFHCS.4.1.3 Dimensions, including nominal thread designation,thread pitch, and nomin
16、al screw length (inches). A standardpart number may be used for this definition.4.1.4 Alloy group and condition.4.1.5 Certification, if required (see Section 15).4.1.6 ASTM specification and year of issue.4.1.7 Any special or supplemental requirements (seeSupplementary Requirements S1 through S6).5.
17、 Materials and Manufacture5.1 Screws shall be formed by upsetting or extruding, orboth.5.2 Screws shall be roll threaded.5.3 Heat TreatmentAustenitic alloys Condition AFscrews, following manufacture, shall be annealed by heating to1900 6 50F to obtain maximum corrosion resistance andminimum permeabi
18、lity.The screws shall be held for a sufficienttime at temperature, then cooled at a rate sufficient to preventprecipitation of the carbide and provide the properties specifiedin Table 1.5.4 When Condition CW or CW1 is specified, the austeniticalloys shall be annealed as specified in 5.3, generally b
19、y theraw material manufacturer, then cold worked to developspecific properties.6. Chemical Composition6.1 The chemical composition of the screws shall conformto the requirements of Table 2.6.2 Unless otherwise specified in the inquiry and purchaseorder (see Supplementary Requirement S2), the choice
20、of analloy from within a group shall be that of the fastenermanufacturer as determined by his fabrication methods andmaterial availability. The specific alloy from within a groupused by the manufacturer shall be clearly identified on allcertification required in the purchase order.6.3 When chemical
21、analysis is performed by the purchaserusing finished fasteners, the chemical composition obtainedshall conform to the limits specified in Table 2 for the specificalloy. Chemical composition shall conform to the tolerancesspecified in Specification A555/A555M.6.3.1 In the event of a discrepancy, a re
22、feree analysis of thesamples for each lot as specified in 12.1 shall be made inaccordance with 11.3.1.7. Mechanical Properties7.1 The finished screws shall conform to the mechanicalrequirements specified in Table 1.7.2 Screws having a nominal length equal to or greater thanthree diameters shall be t
23、ensile tested full size and shall meetthe full size breaking strength requirements specified in TableTABLE 1 Mechanical Property RequirementsAlloy GroupAlloyConditionFull Size Product TestsAMachined Specimen Tests Core HardnessBTensileStrength ksiExtensionCminTensileStrength ksiYieldStrength ksiElon
24、gation%minVickers RockwellAll AF 85 max 0.6D 85 max 55 max 40 210 max 95 HRB maxAll CW 80 min 0.4D 80 min 40 min 25 150 min 50 HRA minAll CW1 102 min 0.4D 87 min 65 min 20 220 min 59 HRA minAActual full-size testing of condition CW and CW1 may result in decreased tensile strength because of the head
25、 configuration (see Table 3). For fasteners with nominalthread diameters larger than 0.625 in., the mechanical properties shall be agreed upon between the user and manufacturer.BCore hardness is only required when full-size product testing cannot be accomplished.CD denotes nominal thread size.TABLE
26、2 Chemical RequirementsAlloyGroupUNSDesignationAlloyComposition, % maximum except as shownCarbonManganesePhosphorus Sulfur Silicon Chromium Nickel Copper MolybdeneunmAustenitic Alloys1 S30400 304 0.08 2.00 0.045 0.030 1.00 18.0 to20.08.0 to10.51.00 . . .1 S30403 304L 0.030 2.00 0.045 0.030 1.00 18.0
27、 to20.08.0 to12.01.00 . . .1 S30500 305 0.12 2.00 0.045 0.030 1.00 17.0 to19.010.5 to13.01.00 . . .1 S38400 384 0.08 2.00 0.045 0.030 1.00 15.0 to17.017.0 to19.0. .1 S30430 189LW 0.10 2.00 0.045 0.030 1.00 17.0 to19.08.0 to10.03.0to4.0 .1 S30433 302HQ 0.03 2.00 0.045 0.030 1.00 17.0 to19.08.0 to10.0
28、3.0to4.0 .1 . 304J3A0.08 2.00 0.045 0.030 1.00 17.0 to19.08.0 to10.51.00 to3.00.2 S31600 316 0.08 2.00 0.045 0.030 1.00 16.0 to18.010.0 to14.0. . . 2.00 to 3.02 S31603 316L 0.03 2.00 0.045 0.030 1.00 16.0 to18.010.0 to14.0. . . 2.00 to 3.0A304J3 from JIS G 4309.F879 1523. Tensile failures through th
29、e head are acceptable providingthe load requirements are satisfied.7.3 Screws that are too short (lengths less than specified in7.2 or that have insufficient threads for tension testing) shallnot be subject to tension tests, but shall conform to thehardness requirements of Table 1.8. Corrosion Resis
30、tance Requirements8.1 Carbide Precipitation:8.1.1 Rod, bar, and wire used to make fasteners in accor-dance with this specification shall be capable of passing the testfor susceptibility to intergranular corrosion as specified inPractice E of Practices A262.8.1.2 As stated in Practices A262, samples
31、may be subjectedto the faster and more severe screening test in accordance withPractice A. Failing Practice A, specimens shall be tested toPractice E and be considered satisfactory if passing Practice E.9. Dimensions9.1 Unless otherwise specified, the dimensions shall con-form to the requirements of
32、 ASME B18.3.10. Workmanship and Finish10.1 Surface TreatmentUnless otherwise specified, screwsshall be cleaned, descaled, and passivated in accordance withPractice A380/A380M or Specification A967/A967M at theoption of the manufacturer.10.2 Surface Discontinuities:10.2.1 The surface discontinuities
33、for these products shallconform to Specification F788 and the additional limitationsspecified herein.10.2.1.1 Forging defects that connect the socket to theperiphery of the head are not permissible. Defects originatingon the periphery and with a traverse indicating a potential tointersect are not pe
34、rmissible. Other forging defects are permis-sible 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 (see Fig. 1).10.2.1.2 Forging defects locat
35、ed in the socket wall within0.1 times 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,oramaximum depth of 0.03 D not to exceed 0.005 in. (see Fig. 2).10.2.1.3 Seams in the shank sh
36、all not exceed a depth of 0.03D or 0.008 in. whichever is greater.10.2.1.4 No transverse discontinuities shall be permitted inthe head-to-shank fillet area.10.2.1.5 Threads shall have no laps at the root or on theflanks, as shown in Fig. 3. Laps are permitted at the crests (Fig.3(C) that do not exce
37、ed 25 % of the basic thread depth, and onthe flanks outside the pitch cylinder. Longitudinal seams rolledbeneath the root of the thread and across the crests of thethreads are acceptable within the limits of 10.2.1.3.11. Number of Tests11.1 The requirements of this specification shall be met inconti
38、nuous mass production for stock and the manufacturershall make sample inspections to ensure that the productconforms to the specified requirements. Additional tests ofindividual shipments of fasteners are not ordinarily necessary.A record of the individual heat of steel in each lot shall bemaintaine
39、d. The containers shall be coded to permit identifi-cation of the lot.TABLE 3 Breaking Strength Values for Full Size FastenersNOTE 1Breaking loads are based on tensile stress area and strengthsof 85 ksi max (AF), 64 ksi min (CW), and 82 ksi for CW1. The minimumloads for the CW and CW1 conditions are
40、 based on the tensile propertiesof 80 ksi minimum material strength and 102 ksi minimum materialstrength, respectively, reduced by 20 % to allow for the head criticalnature of these configurations. See Note A in Table 1. Actual strength ofthe threaded section, if size permits, may be determined by r
41、emoving thehead and testing the threaded section as a stud.Nominal SizeTensile StressArea, in.2Alloy Condition, lb. minAF CW CW10 0.06080 0.00180 153 115 1471 0.07364 0.00263 223 168 2152 0.08656 0.00370 314 237 3033 0.09948 0.00487 414 312 3994 0.11240 0.00604 513 386 4955 0.12540 0.00796 676 509 6
42、526 0.13832 0.00909 772 581 7458 0.16432 0.0140 1191 897 114910 0.19024 0.0175 1490 1122 143814 0.25020 0.0318 2705 2037 2609516 0.31218 0.0524 4457 3356 429938 0.37516 0.0775 6587 4959 635412 0.50013 0.1419 12 061 9082 11 63658 0.62511 0.226 19 210 14 464 18 532FIG. 1 Head Discontinuities (See 10.2
43、.1)F879 15311.2 When specified in the purchase order, the manufacturershall furnish a test report of the last complete set of chemicalanalysis and mechanical tests for each stock size in eachshipment.11.3 When tests of individual shipments are required,Supplementary Requirement S1 must be specified
44、in theinquiry and order.11.3.1 When the purchaser does not specify the samplingplan and basis of acceptance, the following shall apply:11.3.1.1 The lot, for purposes of selecting samples, shallconsist of all products offered for inspection and testing at onetime that are of the same type, style, nom
45、inal diameter, threadpitch, nominal length, material, condition, and surface finish.11.3.1.2 From each lot, samples shall be selected at randomand tested for each requirement in accordance with thefollowing:Number of Pieces in Lot Number of Samples800 and less 1Over 800 to 8000, incl 2Over 8000 to 2
46、2 000, incl 3Over 22 000 511.3.1.3 Should any sample fail to meet the requirements ofa specified test, double the number of samples from the samelot shall be retested for the requirement(s) in which it failed.All of the additional samples shall conform to the specification,or the lot shall be reject
47、ed.11.3.1.4 If the failure of a test specimen is due to improperpreparation of the specimen or an incorrect testing technique,the specimen shall be discarded and another test specimensubmitted.11.4 Corrosion Resistance Tests:11.4.1 Unless otherwise specified, inspection for corrosionresistance shall
48、 be in accordance with the manufacturersstandard quality control practices. No specific method ofinspection is required but the screws shall be produced fromsuitable raw material and manufactured by properly controlledpractices to maintain resistance to corrosion. When corrosiontests are required, S
49、upplementary Requirement S5 must bespecified in the inquiry and order, except as noted in 11.4.2.11.4.2 Products that have been hot worked shall be solutionannealed and tested to determine freedom from precipitatedcarbides. Not less than one corrosion test shall be made fromeach lot. Corrosion tests shall be performed in accordance withPractices A262, Practices A or E as applicable.12. Test Methods12.1 Chemical AnalysisThe chemical composition shallbe determined in accordance with Test Method A751.12.1.1 The fastener manufacturer may accept the chemical
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