1、Designation: F879M 16Standard Specification forStainless Steel Socket Button and Flat Countersunk HeadCap Screws (Metric)1This standard is issued under the fixed designation F879M; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, th
2、e 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.1. Scope*1.1 This specification covers the chemical and mechanicalrequirements for stainless steel metric hexagon socket
3、 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 are covered:1.2.1 Austenitic Class A1-50 in an annealed condition at585 MPa maximum,1.2.2
4、Austenitic Class A155 in a cold worked condition at550 MPa minimum, and1.2.3 Austenitic Class A1-70 in a cold-worked condition at700 MPa minimum.1.3 UnitsThe values stated in SI units are to be regardedas standard. No other units of measurement are included in thisstandard.1.4 The following hazard c
5、aveat pertains only to Section 12,Test 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 regulat
6、ory limitations prior to use.2. Referenced Documents2.1 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 o
7、f Stainless Steel Parts, Equipment, and SystemsA555/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 Stee
8、l PartsD3951 Practice for Commercial PackagingE18 Test Methods for Rockwell Hardness of Metallic Ma-terialsE92 Test Methods for Vickers Hardness and Knoop Hard-ness of Metallic MaterialsE384 Test Method for Microindentation Hardness of Mate-rialsF606M Test Methods for Determining the Mechanical Prop
9、-erties of Externally and Internally Threaded Fasteners,Washers, and Rivets (Metric)F738M Specification for Stainless Steel Metric Bolts,Screws, and Studs (Withdrawn 2014)3F788 Specification for Surface Discontinuities of Bolts,Screws, and Studs, Inch and Metric SeriesF1470 Practice for Fastener Sam
10、pling for Specified Me-chanical Properties and Performance Inspection2.2 ISO Standards:4ISO 73801 Button head screws-Part 1: Hexagon socketbutton head screwsISO 10642 Hexagon socket countersunk head screws3. Classification3.1 The designation of the property class and conditions ofthis specification
11、shall be consistent with the stainless steeldesignations in Specification F738M.3.2 The austenitic stainless steel socket screw shall bedesignated F879M A1-50, F879M A155, or F879M A1-70.4. Ordering Information4.1 Orders for material under this specification shall includethe following information:1T
12、his specification is under the jurisdiction of ASTM Committee F16 onFasteners and is the direct responsibility of Subcommittee F16.04 on NonferrousFasteners.Current edition approved May 1, 2016. Published July 2016. Originally approvedin 1984. Last previous edition approved in 2015 as F879M 02a(2015
13、). DOI:10.1520/F0879M-16.2For referenced ASTM standards, visit the ASTM website, www.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 h
14、istorical standard is referenced onwww.astm.org.4Available from International Organization for Standardization (ISO), ISOCentral Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier,Geneva, Switzerland, http:/www.iso.org.*A Summary of Changes section appears at the end of this standard
15、Copyright 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 nominal screw length (mill
16、imetres). A stan-dard part number may be used for this definition.4.1.4 Property Class A1-50, A155, or A1-70.4.1.5 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. Ma
17、terials and Manufacture5.1 Screws shall be formed by upsetting or extruding, orboth.5.2 Screws shall be roll threaded.5.3 Heat TreatmentAustenitic alloys Class A1-50 screws,following manufacture, shall be annealed by heating to 1040 630C to obtain maximum corrosion resistance and minimumpermeability
18、. The screws shall be held for a sufficient 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, ge
19、nerallyby the raw material manufacturer, then 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 other
20、wise specified in the inquiry and purchaseorder (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 i
21、dentified on all certification required 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
22、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 referee analysis of thesamples for each lot as specified in 12.1, shall be made inaccordance with 11.3.7. Mechanical Properties7.1 The finis
23、hed 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 tensile tested full size and shall meetthe full size breaking strength requirements specified in Table3. Tensile failures through the head a
24、re 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 Resistance Re
25、quirements8.1 Carbide Precipitation:8.1.1 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 A262.8.1.2 As stated in Practices A262, sa
26、mples 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.8.1.3 If the fasteners pass the requirements of 8.1.1, theyshall be considered acceptable.
27、If they fail, they shall be testedin accordance with Practice C of Practices A262 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 ISO 73801 or ISO 10642, asspecified.10. Workmanship, Finish,
28、and Appearance10.1 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:TABLE 1 Mechanical Property RequirementsProperty ClassNomina
29、l ThreadDiameterAFull 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
30、 HRA minA170 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
31、be agreed upon between the user and manufacturer.BCore hardness is only required when full-size product tensile testing cannot be accomplished.CD denotes nominal thread size.F879M 16210.2.1 The surface discontinuities for these products shallconform to Specification F788 and the additional limitatio
32、nsspecified 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 the be
33、aring area, fillet, and topsurfaces 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
34、 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 0.13 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 transvers
35、e 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 exceed 25 % of the basic thread depth, and onthe flanks outside the pitch cylinder. Longitu
36、dinal 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 incontinuous mass production for stock and the manufacturershall make sample inspection to ens
37、ure that the productconforms to the specified requirements. Additional tests ofindividual shipments of fasteners are not ordinarily necessary.TABLE 2 Chemical RequirementsUNSDesignationAlloyComposition, % maximum except as shownCarbon Manganese Phosphorus Sulfur Silicon Chromium Nickel Copper Molybd
38、enumS30400 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 . . .S38400 384 0.08 2.00 0.045 0.030 1.00 15.0 to 17.0 17.0 to 19.0 . . .S3043
39、0 189LW 0.10 2.00 0.045 0.030 1.00 17.0 to 19.0 8.0 to 10.0 3.00 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
40、2.00 to 3.0TABLE 3 Breaking Strength Values for Full Size FastenersNOTE 1Breaking loads are based on tensile stress area and strengthsof 585 MPa max forA1-50, 550 MPa forA155, and 700 MPa minA1-70.The minimum loads for property classesA155 andA1-70 are reduced by20 % to allow for the head critical n
41、ature of these configurations. See NoteAinTable 1. Actual 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 0.5 5.03 2.94
42、2.21 2.82M4 0.7 8.78 5.14 3.86 4.92M5 0.8 14.2 8.30 6.24 7.94M6 1.0 20.1 11.8 8.9 11.3M8 1.25 36.6 21.4 16.1 20.5M10 1.5 58.0 33.9 25.5 32.5M12 1.75 84.3 49.3 37.1 47.2M14 2.0 115.0 67.5 50.8 64.6M16 2.0 157.0 91.7 68.9 87.7M20 2.5 245.0 143 108 137FIG. 1 Head Discontinuities (See 10.2.1)FIG. 2 Sock
43、et Discontinuities (See 10.2.1)F879M 163A 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, the manufacturershall furnish a test report of the last complete set of chemi
44、calanalysis 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 ap
45、ply: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 be s
46、elected 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 samp
47、les 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,the
48、 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 the s
49、crews 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 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
