1、Designation: F 879M 02aMETRICStandard Specification forStainless Steel Socket Button and Flat Countersunk HeadCap Screws Metric1This standard is issued under the fixed designation F 879M; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revis
2、ion, the year of 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
3、covers the chemical and mechanicalrequirements for stainless steel metric hexagon socket button(SBHCS) and flat countersunk (SFHCS) head cap screws withnominal thread M 3 through M 20 intended for use in applica-tions requiring general corrosion resistance.1.2 The following three property classes ar
4、e covered:1.2.1 Austenitic Class A 1-50 in an annealed condition at585 MPa maximum,1.2.2 Austenitic Class A155 in a cold worked condition at550 MPa minimum, and1.2.3 Austenitic Class A 1-70 in a cold-worked condition at700 MPa minimum.1.3 The following hazard caveat pertains only to Section 12,Test
5、Methods: This standard does not purport to address all ofthe safety problems, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referen
6、ced 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 ofStainless Steel Parts, Equipment, and Systems
7、2A 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 Parts2D 3951 Practice for Commercial Packaging4E
8、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 606M Test Methods for Determining the MechanicalProperties of Externally and Internally Threade
9、d Fasteners,Washers, and Rivets Metric6F 738M Specification for Stainless Steel Metric Bolts,Screws, and Studs6F 788/F788M Specification for Surface Discontinuities ofBolts, Screws, and Studs, Inch and Metric Series6F 1470 Guide for Fastener Sampling for Specified Mechani-cal Properties and Performa
10、nce Inspection62.2 ASME Standards:B 18.3.4M Hexagon Socket Button Head Cap Screws (Met-ric Series)7B 18.3.5M Hexagon Socket Flat Countersunk Head CapScrews (Metric Series)73. Classification3.1 The designation of the property class and conditions ofthis specification shall be consistent with the stai
11、nless steeldesignations in Specification F 738M.3.2 The austenitic stainless steel socket screw shall bedesignated F879M A1-50, F879M A155, or F 879M A1-70.4. Ordering Information4.1 Orders for material under this specification shall includethe following information:4.1.1 Quantity (number of pieces
12、of each item).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 F 879 84. Last previous edition F 879 0
13、2.2Annual 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 Inverness Way East,Englewood, CO 80112.
14、1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, 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 (millimetres). A stan-dard part number may be used
15、for this definition.4.1.4 Property Class A 1-50, A155, or A 1-70.4.1.5 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 S3).5. Materials and Manufacture5.1 Screws shall be f
16、ormed by upsetting or extruding, orboth.5.2 Screws shall be roll threaded.5.3 Heat TreatmentAustenitic alloys Class A 1-50 screws,following manufacture, shall be annealed by heating to 1040 630C to obtain maximum corrosion resistance and minimumpermeability. The screws shall be held for a sufficient
17、 time attemperature, then cooled at a rate sufficient to prevent precipi-tation of the carbide and provide the properties specified inTable 1.5.4 When Property Class A1-55 or A1-70 is specified, theaustenitic alloys shall be annealed as specified in 5.3, generallyby the raw material manufacturer, th
18、en cold worked to developspecific properties.6. Chemical Composition6.1 It is the intent of this specification that screws shall beordered by property class. The chemical composition of thescrews shall conform to the requirements of Table 2.6.2 Unless otherwise specified in the inquiry and purchaseo
19、rder (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 required in
20、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. Chemical com
21、position shall conform to the tolerancesspecified in Specification A 555/A 555M.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 11.3.7. 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、 Austenitic alloy rod, bar, and wire used to makefasteners in accordance with this specification shall be capableof passing the test for susceptibility to intergranular corrosionas specified in Practice E of Practice A 262.8.1.2 As stated in Practices A 262, samples may be sub-jected to the faster a
25、nd 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.8.1.3 If the fasteners pass the requirements of 8.1.1, theyshall be considered acceptable. If they fail, they shall be testedin
26、 accordance with Practice C of Practices A 262 and shallshow a corrosion rate not exceeding 0.05 mm/month.9. Dimensions9.1 Unless otherwise specified, the dimensions shall con-form to the requirements of ASME B 18.3.4M or ASMEB 18.3.5M, as specified.10. Workmanship, Finish, and Appearance10.1 Surfac
27、e TreatmentUnless otherwise specified,screws shall be cleaned, descaled and passivated in accordancewith Practice A380 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
28、 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 toTABLE 1 Mechanical Property RequirementsProperty ClassNominal ThreadDiame
29、terAFull SizeProduct TestsMachined Specimen Tests Core HardnessBTensileStrength, MPaMinimumExtensionCTensileStrength, MPaYield Strength,MPaElongation,%, minVickers RockwellA1-50 M3M20 585 max 0.6D 585 max 380 max 40 210 max 95 HRB maxA155 M3M20 550 min 0.4D 550 min 270 min 25 160 min 50 HRA minA170
30、M3M20 700 min 0.4D 600 min 450 min 20 220 min 59 HRA minAActual full-size testing of Class A155 and A170 may result in decreased tensile strength because of the head configuration (see Table 3). For fasteners with nominalthread diameters larger than M20, the mechanical properties shall be agreed upo
31、n between the user and manufacturer.BCore hardness is only required when full-size product tensile testing cannot be accomplished.CD denotes nominal thread size.F 879M 02a2intersect are not permissible. Other forging defects are permis-sible provided those located in the bearing area, fillet, and to
32、psurfaces shall not have a depth exceeding 0.03 D or 0.13 mm,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 wall within0.1 times the actual key engagement, T, from the bottom of thesocket are not perm
33、issible. Discontinuities located elsewhere inthe socket shall not have a length exceeding 0.25 T,oramaximum depth of 0.03 D not to exceed 0.13 mm (see Fig. 2).10.2.1.3 Seams in the shank shall not exceed a depth of 0.03D or 0.2 mm, whichever is greater.10.2.1.4 No transverse discontinuities shall be
34、 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 exceed 25 % of the basic thread depth, and onthe flanks outside the pitch cylinder. Longitudinal seams rolledbeneath
35、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 incontinuous mass production for stock and the manufacturershall make sample inspection to ensure that the productconfor
36、ms 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 bemaintained. The containers shall be coded to permit identifi-cation of the lot.11.2 When specified in the purchase order, t
37、he manufacturershall furnish a test report of the last complete set of chemicalTABLE 2 Chemical RequirementsUNSDesignationAlloyComposition, % maximum except as shownCarbon Manganese Phosphorus Sulfur Silicon Chromium Nickel Copper MolybdenumS30400 304 0.08 2.00 0.045 0.030 1.00 18.0 to 20.0 8.0 to 1
38、0.5 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 . . .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
39、0 to 4.00 . . .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 2.00 to 3.00S31603 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 Faste
40、nersNOTE 1Breaking loads are based on tensile stress area and strengthsof 585 MPa max for A1-50, 550 MPa for A155, and 700 MPa min A1-70.The minimum loads for property classes A155 and A1-70 are reduced by20 % to allow for the head critical nature of these configurations. See NoteA in Table 1. Actua
41、l strength of the threaded section, if size permits, maybe determined by removing the head and testing the threaded section as astud.Nominal Size andThread PitchStress Area,mm2Property ClassA150 A155 A170kN, max kN, min kN, minM3 3 0.5 5.03 2.94 2.21 2.82M4 3 0.7 8.78 5.14 3.86 4.92M5 3 0.8 14.2 8.3
42、0 6.24 7.94M6 3 1.0 20.1 11.8 8.9 11.3M8 3 1.25 36.6 21.4 16.1 20.5M10 3 1.5 58.0 33.9 25.5 32.5M12 3 1.75 84.3 49.3 37.1 47.2M14 3 2.0 115.0 67.5 50.8 64.6M16 3 2.0 157.0 91.7 68.9 87.7M20 3 2.5 245.0 143 108 137FIG. 1 Head Discontinuities (See 10.2.1)FIG. 2 Socket Discontinuities (See 10.2.1)F 879
43、M 02a3analysis and mechanical tests for each stock 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
44、 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, nominal diameter, threadpitch, nominal length, material, property class, and surfacefinish.11.3.1.2 From each lot, samples shall b
45、e selected at randomand tested for each requirement in accordance with thefollowing:Number of Pieces in LotNumber ofSamples800 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 s
46、amples from the samelot shall be retested for the requirement(s) in which it failed.All of the additional samples shall conform to the specificationor 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,
47、the specimen shall be discarded and another test 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 th
48、e screws shall be produced fromsuitable raw material and manufactured by properly controlledpractices to maintain resistance to corrosion. When corrosiontests are required, Supplementary Requirement S4 must bespecified in the inquiry and order, except as noted in 11.4.2.11.4.2 Products that have bee
49、n 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 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 materialpro
