1、Designation: F 879 02a (Reapproved 2008)Standard Specification forStainless Steel Socket Button and Flat Countersunk HeadCap Screws1This standard is issued under the fixed designation F 879; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re
2、vision, the year of last revision. A number in parentheses 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 Department of Defense.1. Scope1.1 This specificatio
3、n covers the chemical 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 The following three conditions are
4、 covered:1.2.1 Austenitic alloy group 1 AF in an annealed conditionat 85 ksi maximum,1.2.2 Austenitic alloy group 1 CW in a cold-worked condi-tion at 80 ksi minimum, and1.2.3 Austenitic alloy group 1 condition CW1 in a coldworked condition at 102 ksi minimum.1.3 UnitsThe values stated in inch-pound
5、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 specification: Thisstandard does not purport to address all of the safety concerns,if any, associated wi
6、th 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 Documents2.1 ASTM Standards:2A 262 Practices for Detecting Susceptibility to Intergranu-lar Attac
7、k in Austenitic Stainless SteelsA 342/A 342M Test Methods for Permeability of FeeblyMagnetic MaterialsA 380 Practice for Cleaning, Descaling, and Passivation ofStainless Steel Parts, Equipment, and SystemsA 555/A 555M Specification for General Requirements forStainless Steel Wire and Wire RodsA 751
8、Test Methods, Practices, and Terminology forChemical Analysis of Steel ProductsA 967 Specification for Chemical Passivation Treatmentsfor Stainless Steel PartsD 3951 Practice for Commercial PackagingE18 Test Methods for Rockwell Hardness of MetallicMaterialsE92 Test Method for Vickers Hardness of Me
9、tallic Mate-rialsE 384 Test Method for Microindentation Hardness of Ma-terialsF 593 Specification for Stainless Steel Bolts, Hex CapScrews, and StudsF 606 Test Methods for Determining the Mechanical Prop-erties of Externally and Internally Threaded Fasteners,Washers, Direct Tension Indicators, and R
10、ivetsF 788/F 788M Specification for Surface Discontinuities ofBolts, Screws, and Studs, Inch and Metric SeriesF 1470 Guide for Fastener Sampling for Specified Mechani-cal Properties and Performance Inspection2.2 ASME Standard:B 18.3 Socket Cap, Shoulder and Set Screws (Inch Series)33. Classification
11、3.1 The designation of the alloy group and condition of thisspecification shall be consistent with the stainless steel desig-nations in Specification F 593.3.2 The austenitic stainless steel socket screw shall bedesignated F 879 Group 1 Condition AF, F 879 Group 1Condition CW, or F879 Group 1 Condit
12、ion CW1.4. Ordering Information4.1 Orders for material under this specification shall includethe following information:4.1.1 Quantity (number of pieces of each item).1This specification is under the jurisdiction of ASTM Committee F16 onFasteners and is the direct responsibility of Subcommittee F16.0
13、4 on NonferrousFasteners.Current edition approved May 1, 2008. Published August 2008. Originallyapproved in 1986. Last previous edition approved in 2002 as F 879 02a.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual B
14、ook of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Global Engineering Documents, 15 Inverness Way, EastEnglewood, CO 80112-5704, http:/.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428
15、-2959, United States.4.1.2 Name of the screw, SBHCS or SFHCS.4.1.3 Dimensions, including nominal thread designation,thread pitch, and nominal screw length (inches). A standardpart number may be used for this definition.4.1.4 Alloy group and condition (Group 1 AF, Group 1 CW,Group 1 CW1).4.1.5 Certif
16、ication, 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. Materials and Manufacture5.1 Screws shall be formed by upsetting or extruding, orboth.5.2 Screws shall be roll threaded.5.3
17、 Heat TreatmentAustenitic alloys Condition AFscrews, following manufacture, shall be annealed by heating to1900 6 50F to obtain maximum corrosion resistance andminimum permeability. The screws shall be held for a sufficienttime at temperature, then cooled at a rate sufficient to preventprecipitation
18、 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 by theraw material manufacturer, then cold worked to developspecific properties.6. Chemical Composition6.1 It is the intent
19、of this specification that screws shall beordered by alloy condition. The chemical composition of thescrews shall conform to the requirements of Table 2.6.2 Unless otherwise specified in the inquiry and purchaseorder (see Supplementary Requirement S2), the choice ofstainless steel used shall be that
20、 of the fastener manufacturer asdetermined by his fabrication methods and material availabil-ity. The specific stainless steel used by the manufacturer shallbe clearly identified on all certification required in the purchaseorder and shall have a chemical composition conforming to thelimits specifie
21、d in Table 2.6.3 When chemical 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 A 555.6.3.1 In the ev
22、ent of a discrepancy, a referee 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 than
23、three diameters shall be tensile tested full size and shall meetthe full size breaking strength requirements specified in Table3. Tensile failures through the head are acceptable providingthe load requirements are satisfied.7.3 Screws that are too short (lengths less than specified in7.2 or that hav
24、e insufficient threads for tension testing) shallnot be subject to tension tests, but shall conform to thehardness requirements of Table 1.8. Corrosion Resistance Requirements Corrosion ResistanceRequirements8.1 Carbide Precipitation:8.1.1 Rod, bar, and wire in the austenitic alloy group 1 usedto ma
25、ke fasteners in accordance with this specification shall becapable of passing the test for susceptibility to intergranularcorrosion as specified in Practice E of Practices A 262.8.1.2 As stated in Practices A 262, samples may be sub-jected to the faster and more severe screening test in accor-dance
26、with Practice A. Failing Practice A, specimens shall betested to Practice E and be considered satisfactory if passingPractice E.9. Dimensions9.1 Unless otherwise specified, the dimensions shall con-form to the requirements of ASME B 18.3.10. Workmanship and Finish10.1 Surface TreatmentUnless otherwi
27、se specified,screws shall be cleaned, descaled, and passivated in accordancewith Practice A 380 or Specification A 967 at the option of themanufacturer.10.2 Surface Discontinuities:10.2.1 The surface discontinuities for these products shallconform to Specification F 788/F 788M and the additionallimi
28、tations specified 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 permissible. Other forging defects are permis-sible provided those located in
29、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).TABLE 1 Mechanical Property RequirementsAlloyConditionFull Size Product TestsAMachined Specimen Tests Core
30、 HardnessBTensileStrength ksiExtensionCminTensileStrength ksiYieldStrength ksiElongation%minVickers RockwellAF 85 max 0.6D 85 max 55 max 40 210 max 95 HRB maxCW 80 min 0.4D 80 min 40 min 25 150 min 50 HRA minCW1 102 min 0.4D 87 min 65 min 20 220 min 59 HRA minAActual full-size testing of condition C
31、W and CW1 may result in decreased tensile strength because of the head 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 produc
32、t testing cannot be accomplished.CD denotes nominal thread size.F 879 02a (2008)210.2.1.2 Forging defects located 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
33、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 shall 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 la
34、ps at the root or on theflanks, as shown in Fig. 3. Laps are permitted at the crests (Fig.3(C) that do not exceed 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 wi
35、thin the limits of 10.2.1.3.11. Number of Tests11.1 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 o
36、f fasteners are not ordinarily necessary.A record of the individual heat of steel in each lot shall bemaintained. The containers shall be coded to permit identifi-cation of the lot.TABLE 2 Alloy Group 1 Chemical RequirementsUNSDesignationAlloyComposition, % maximum except as shownCarbon Manganese Ph
37、osphorus Sulfur Silicon Chromium Nickel Copper MolybdeneunmAustenitic AlloysS30400 304 0.08 2.00 0.045 0.030 1.00 18.0 to 20.0 8.0 to 10.5 1.00 . . .S30403 304L 0.030 2.00 0.045 0.030 1.00 18.0 to 20.0 8.0 to 12.0 1.00 . . .S30500 305 0.12 2.00 0.045 0.030 1.00 17.0 to 19.0 10.5 to 13.0 1.00 . . .S3
38、8400 384 0.08 2.00 0.045 0.030 1.00 15.0 to 17.0 17.0 to 19.0 . . . . . .S30430 189LW 0.10 2.00 0.045 0.030 1.00 17.0 to 19.0 8.0 to 10.0 3.0 to 4.0 . . .S30433 302HQ 0.03 2.00 0.045 0.030 1.00 17.0 to 19.0 8.0 to 10.0 3.0 to 4.0 . . .S31600 316 0.08 2.00 0.045 0.030 1.00 16.0 to 18.0 10.0 to 14.0 .
39、 . . 2.00 to 3.0S31603 316L 0.03 2.00 0.045 0.030 1.00 16.0 to 18.0 10.0 to 14.0 . . . 2.00 to 3.0TABLE 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 t
40、he CW and CW1 conditions are 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 per
41、mits, may be determined by removing 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 49
42、55 0.12540 0.00796 676 509 6526 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 He
43、ad Discontinuities (See 10.2.1)FIG. 2 Socket Discontinuities (See 10.2.1)F 879 02a (2008)311.2 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 in
44、dividual shipments are required,Supplementary Requirement S1 must be specified 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 offe
45、red for inspection and testing at onetime that are of the same type, style, nominal 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 Piec
46、es in Lot Number of Samples800 and less 1Over 800 to 8000, incl 2Over 8000 to 22 000, 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 a
47、dditional samples shall conform to the specification,or the lot shall be rejected.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 Te
48、sts:11.4.1 Unless otherwise specified, inspection for corrosionresistance shall 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 controlledpra
49、ctices to maintain resistance to corrosion. When corrosiontests are required, Supplementary 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 A 262, Practices A or E as applicable.12. Test Methods12.1 Chemical AnalysisThe chemical composition shallbe dete
