1、Designation: F 879 02aStandard 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 revision, the year o
2、f last 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.1. Scope1.1 This specification covers the chem
3、ical 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 covered:1.2.1 Au
4、stenitic 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 The following precautionary caveat pertains only to th
5、etest method portion, Section 12, of this specification: 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 re
6、gulatory limita-tions prior to use.2. Referenced Documents2.1 ASTM Standards:A 262 Practices for Detecting Susceptibility to Intergranu-lar Attack in Austenitic Stainless Steels2A 342 Test Methods for Permeability of Feebly MagneticMaterials3A 380 Practice for Cleaning, Descaling, and Passivation of
7、Stainless Steel Parts, Equipment, and Systems2A 555/A555M Specification for General Requirements forStainless Steel Wire and Wire Rods2A 751 Test Methods, Practices, and Terminology forChemical Analysis of Steel Products2A 967 Specification for Chemical Passivation Treatmentsfor Stainless Steel Part
8、s2D 3951 Practice for Commercial Packaging4E 18 Test Methods for Rockwell Hardness and RockwellSuperficial Hardness of Metallic Materials5E 92 Test Method for Vickers Hardness of Metallic Mate-rials5E 384 Test Method for Microhardness of Materials5F 593 Specification for Stainless Steel Bolts, Hex C
9、ap,Screws, and Studs6F 606 Test Methods for Determining the Mechanical Prop-erties of Externally and Internally Threaded Fasteners,Washers, and Rivets6F 788/F 788M Specification for Surface Discontinuities ofBolts, Screws, and Studs, Inch and Metric Series6F 1470 Guide for Fastener Sampling for Spec
10、ified Mechani-cal Properties and Performance Inspection62.2 ASME Standard:B 18.3 Socket Cap, Shoulder and Set Screws (Inch Series)73. Classification3.1 The designation of the alloy group and condition of thisspecification shall be consistent with the stainless steel desig-nations in Specification F
11、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 Condition CW1.4. Ordering Information4.1 Orders for material under this specification shall includethe following information:4.1.1 Quantity (number of pieces
12、of each item).4.1.2 Name of the screw, SBHCS or SFHCS.1This specification is under the jurisdiction of ASTM Committee F16 onFasteners and is the direct responsibility of Subcommittee F16.04 on NonferrousFasteners.Current edition approved Oct. 10, 2002. Published November 2002. Originallypublished as
13、 F 879 86. Last previous edition F 879 02.2Annual Book of ASTM Standards, Vol 01.03.3Annual Book of ASTM Standards, Vol 03.04.4Annual Book of ASTM Standards, Vol 15.09.5Annual Book of ASTM Standards, Vol 03.01.6Annual Book of ASTM Standards, Vol 01.08.7Available from Global Engineering Documents, 15
14、 Inverness Way East,Englewood, CO 80112.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.1.3 Dimensions, including nominal thread designation,thread pitch, and nominal screw length (inches). A standardpart number may be used for thi
15、s definition.4.1.4 Alloy group and condition (Group 1 AF, Group 1 CW,Group 1 CW1).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. Materials and Manufacture5.1
16、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 permeability. The screws shall be held
17、 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 by theraw material manufacture
18、r, then cold worked to developspecific properties.6. Chemical Composition6.1 It is the intent 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 pur
19、chaseorder (see Supplementary Requirement S2), the choice ofstainless steel used shall be that 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 requir
20、ed in the purchaseorder and shall have a chemical composition conforming to thelimits specified 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. Chemic
21、al composition shall conform to the tolerancesspecified in Specification A 555.6.3.1 In the event 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 mechanica
22、lrequirements specified in Table 1.7.2 Screws having a nominal length equal to or greater thanthree 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 requireme
23、nts 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 Resistance Requirements8.1 Carbide Precipitation:8.1.1
24、 Rod, bar, and wire in the austenitic alloy group 1 usedto make 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
25、 to the faster and more severe screening test in accor-dance 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 B18.3.10
26、. Workmanship and Finish10.1 Surface TreatmentUnless otherwise 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 shall
27、conform to Specification F 788/F 788M and the additionallimitations 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
28、 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 located in the socket
29、 wall within0.1 times the actual key engagement, T, from the bottom of theTABLE 1 Mechanical Property RequirementsAlloyConditionFull Size Product TestsAMachined Specimen Tests Core HardnessBTensileStrength ksiExtensionCminTensileStrength ksiYieldStrength ksiElongation% minVickers RockwellAF 85 max 0
30、.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 CW and CW1 may result in decreased tensile strength because of the head configuration (see Table 3). For fasteners with
31、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.F 879 02a2socket are not permissible. Discontinuities l
32、ocated 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 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-
33、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 exceed 25 % of the basic thread depth, and onthe flanks outside the pitch cylinder. Longitudinal seams rolledbeneath the root of the thread
34、 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 incontinuous mass production for stock and the manufacturershall make sample inspections to ensure that the productconforms to the specified r
35、equirements. Additional tests ofindividual shipments of 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 RequirementsUNSDesignationAlloyCom
36、position, % maximum except as shownCarbon Manganese Phosphorus 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
37、.045 0.030 1.00 17.0 to 19.0 10.5 to 13.0 1.00 . . .S38400 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
38、0.08 2.00 0.045 0.030 1.00 16.0 to 18.0 10.0 to 14.0 . . . 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 ks
39、i min (CW), and 82 ksi for CW1. The minimumloads for the 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
40、1. Actual strength ofthe threaded section, if size permits, 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
41、.09948 0.00487 414 312 3994 0.11240 0.00604 513 386 4955 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 12 061 908
42、2 11 63658 0.62511 0.226 19 210 14 464 18 532FIG. 1 Head Discontinuities (See 10.2.1)FIG. 2 Socket Discontinuities (See 10.2.1)F 879 02a311.2 When specified in the purchase order, the manufacturershall furnish a test report of the last complete set of chemicalanalysis and mechanical tests for each s
43、tock size in eachshipment.11.3 When tests of individual 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 selec
44、ting samples, shallconsist of all products offered 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
45、 in accordance with thefollowing:Number of Pieces 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
46、 requirement(s) in which it failed.All of the additional 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
47、 specimensubmitted.11.4 Corrosion Resistance Tests: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 mate
48、rial and manufactured by properly controlledpractices 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 teste
49、d 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 determined in accordance with Test Method A 751.12.1.1 The fastener manufacturer may accept the chemicalanalysis of each heat of raw material purchased and reported onthe raw material certification furnished by the raw materialproducer. The fastener manufacturer is not required
