1、Designation: F879 10 F879 12Standard 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 y
2、ear of last revision. A number in parentheses indicates the year of last reapproval. A superscriptepsilon () 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. Scope*1.1 This specification covers the
3、 chemical and mechanical requirements for stainless steel inch hexagon socket button (SBHCS)and flat countersunk (SFHCS) head cap screws with nominal thread 0.060 through 0.625 in. intended for use in applicationsrequiring general corrosion resistance.1.2 Two groups of austenitic stainless steel all
4、oys and three conditions are covered. See Table 1 and Table 2.1.3 UnitsThe values stated in inch-pound units are to be regarded as standard. No other units of measurement are includedin this standard.1.4 The following precautionary caveat pertains only to the test method portion, Section 12, of this
5、 specification:This standarddoes not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of thisstandard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.2. Ref
6、erenced Documents2.1 ASTM Standards:2A262 Practices for Detecting Susceptibility to Intergranular Attack in Austenitic Stainless SteelsA342/A342M Test Methods for Permeability of Feebly Magnetic MaterialsA380 Practice for Cleaning, Descaling, and Passivation of Stainless Steel Parts, Equipment, and
7、SystemsA555/A555M Specification for General Requirements for Stainless Steel Wire and Wire RodsA751 Test Methods, Practices, and Terminology for Chemical Analysis of Steel ProductsA967 Specification for Chemical Passivation Treatments for Stainless Steel PartsD3951 Practice for Commercial PackagingE
8、18 Test Methods for Rockwell Hardness of Metallic MaterialsE92 Test Method for Vickers Hardness of Metallic Materials (Withdrawn 2010)3E384 Test Method for Knoop and Vickers Hardness of MaterialsF593 Specification for Stainless Steel Bolts, Hex Cap Screws, and StudsF606 Test Methods for Determining
9、the Mechanical Properties of Externally and Internally Threaded Fasteners, Washers, DirectTension Indicators, and RivetsF788/F788M Specification for Surface Discontinuities of Bolts, Screws, and Studs, Inch and Metric SeriesF1470 Practice for Fastener Sampling for Specified Mechanical Properties and
10、 Performance Inspection2.2 ASME Standard:B 18.3 Socket Cap, Shoulder and Set Screws (Inch Series)43. Classification3.1 The designation of the alloy group and condition of this specification shall be consistent with the stainless steel designationsin Specification F593.1 This specification is under t
11、he jurisdiction of ASTM Committee F16 on Fasteners and is the direct responsibility of Subcommittee F16.04 on Nonferrous Fasteners.Current edition approved May 1, 2010June 1, 2012. Published June 2010December 2012. Originally approved in 1986. Last previous edition approved in 20082010 asF879 02aF87
12、9(2008).-10. DOI: 10.1520/F0879-10.10.1520/F0879-12.2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The
13、last approved version of this historical standard is referenced on www.astm.org.4 Available from Global Engineering Documents, 15 Inverness Way, East Englewood, CO 80112-5704, http:/.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of w
14、hat changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered t
15、he official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2 Screws shall be designated by group and condition (for example, F879 Group 1 Condition AF).4. Or
16、dering Information4.1 Orders for material under this specification shall include the following information:4.1.1 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 (inches). A
17、 standard partnumber 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 (see Supplementary Requirements S1 through S6).5. Materials and Manufacture
18、5.1 Screws shall be formed by upsetting or extruding, or both.5.2 Screws shall be roll threaded.5.3 Heat TreatmentAustenitic alloys Condition AF screws, following manufacture, shall be annealed by heating to 1900 650F to obtain maximum corrosion resistance and minimum permeability. The screws shall
19、be held for a sufficient time attemperature, then cooled at a rate sufficient to prevent precipitation of the carbide and provide the properties specified in Table 1.5.4 When Condition CW or CW1 is specified, the austenitic alloys shall be annealed as specified in 5.3, generally by the rawmaterial m
20、anufacturer, then cold worked to develop specific properties.6. Chemical Composition6.1 The chemical composition of the screws shall conform to the requirements of Table 2.6.2 Unless otherwise specified in the inquiry and purchase order (see Supplementary Requirement S2), the choice of an alloyfrom
21、within a group shall be that of the fastener manufacturer as determined by his fabrication methods and material availability.The specific alloy from within a group used by the manufacturer shall be clearly identified on all certification required in thepurchase order.TABLE 1 Mechanical Property Requ
22、irementsAlloy Group AlloyConditionFull Size Product TestsA Machined Specimen Tests Core HardnessBTensileStrength ksiExtensionCminTensileStrength ksiYieldStrength ksiElongation% min Vickers 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 HR
23、A minAll CW1 102 min 0.4D 87 min 65 min 20 220 min 59 HRA minA Actual 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 nominalthread diameters larger than 0.625 in., the mechanical properties shall
24、be agreed upon between the user and manufacturer.B Core hardness is only required when full-size product testing cannot be accomplished.C D denotes nominal thread size.TABLE 2 Chemical RequirementsAlloyGroupUNSDesignation AlloyComposition, % maximum except as shownCarbon Manganese Phosphorus Sulfur
25、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 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
26、.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 to10.03.0 to 4.0 . . .1 S30433 302HQ 0.03 2.00 0.045 0.030 1.00 17.0 to19.08.0 to10.03.0 to 4.0 . . .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
27、0.03 2.00 0.045 0.030 1.00 16.0 to18.010.0 to14.0. . . 2.00 to 3.0F879 1226.3 When chemical analysis is performed by the purchaser using finished fasteners, the chemical composition obtained shallconform to the limits specified in Table 2 for the specific alloy. Chemical composition shall conform to
28、 the tolerances specifiedin Specification A555/A555M.6.3.1 In the event of a discrepancy, a referee analysis of the samples for each lot as specified in 12.1 shall be made in accordancewith 11.3.1.7. Mechanical Properties7.1 The finished screws shall conform to the mechanical requirements specified
29、in Table 1.7.2 Screws having a nominal length equal to or greater than three diameters shall be tensile tested full size and shall meet thefull size breaking strength requirements specified in Table 3. Tensile failures through the head are acceptable providing the loadrequirements are satisfied.7.3
30、Screws that are too short (lengths less than specified in 7.2 or that have insufficient threads for tension testing) shall not besubject to tension tests, but shall conform to the hardness requirements of Table 1.8. Corrosion Resistance Requirements8.1 Carbide Precipitation:8.1.1 Rod, bar, and wire
31、used to make fasteners in accordance with this specification shall be capable of passing the test forsusceptibility to intergranular corrosion as specified in Practice E of Practices A262.8.1.2 As stated in Practices A262, samples may be subjected to the faster and more severe screening test in acco
32、rdance withPractice A. Failing Practice A, specimens shall be tested to Practice E and be considered satisfactory if passing Practice E.9. Dimensions9.1 Unless otherwise specified, the dimensions shall conform to the requirements of ASME B18.3.10. Workmanship and Finish10.1 Surface TreatmentUnless o
33、therwise specified, screws shall be cleaned, descaled, and passivated in accordance withPractice A380 or Specification A967 at the option of the manufacturer.10.2 Surface Discontinuities:10.2.1 The surface discontinuities for these products shall conform to Specification F788/F788M and the additiona
34、l limitationsspecified herein.10.2.1.1 Forging defects that connect the socket to the periphery of the head are not permissible. Defects originating on theperiphery and with a traverse indicating a potential to intersect are not permissible. Other forging defects are permissible providedthose locate
35、d in the bearing area, fillet, and top surfaces shall not have a depth exceeding 0.03 D or 0.005 in. whichever is greater.For peripheral discontinuities, the maximum depth may be 0.06 D (see Fig. 1).TABLE 3 Breaking Strength Values for Full Size FastenersNOTE 1Breaking loads are based on tensile str
36、ess 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 based on the tensile propertiesof 80 ksi minimum material strength and 102 ksi minimum materialstrength, respectively, reduced by 20 % to allow for the head criticalnatur
37、e of these configurations. See Note A in Table 1. Actual strength ofthe threaded section, if size permits, may be determined by removing thehead and testing the threaded section as a stud.Nominal Size Tensile StressArea, in.2 Alloy Condition, lb. minAF CW CW10 0.06080 0.00180 153 115 1471 0.07364 0.
38、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 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
39、0.0775 6587 4959 635412 0.50013 0.1419 12 061 9082 11 63658 0.62511 0.226 19 210 14 464 18 532F879 12310.2.1.2 Forging defects located in the socket wall within 0.1 times the actual key engagement, T, from the bottom of the socketare not permissible. Discontinuities located elsewhere in the socket s
40、hall not have a length exceeding 0.25 T, or a maximum depthof 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 0.03 D or 0.008 in. whichever is greater.10.2.1.4 No transverse discontinuities shall be permitted in the head-to-shank fillet area.10.2.1
41、.5 Threads shall have no laps at the root or on the flanks, 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 on the flanks outside the pitch cylinder. Longitudinal seams rolled beneaththe root of the thread and across the crests of
42、 the threads are acceptable within the limits of 10.2.1.3.11. Number of Tests11.1 The requirements of this specification shall be met in continuous mass production for stock and the manufacturer shallmake sample inspections to ensure that the product conforms to the specified requirements. Additiona
43、l tests of individual shipmentsof fasteners are not ordinarily necessary. A record of the individual heat of steel in each lot shall be maintained. The containersshall be coded to permit identification of the lot.11.2 When specified in the purchase order, the manufacturer shall furnish a test report
44、 of the last complete set of chemicalanalysis and mechanical tests for each stock size in each shipment.11.3 When tests of individual shipments are required, Supplementary Requirement S1 must be specified in the inquiry and order.11.3.1 When the purchaser does not specify the sampling plan and basis
45、 of acceptance, the following shall apply:11.3.1.1 The lot, for purposes of selecting samples, shall consist of all products offered for inspection and testing at one timethat are of the same type, style, nominal diameter, thread pitch, nominal length, material, condition, and surface finish.11.3.1.
46、2 From each lot, samples shall be selected at random and tested for each requirement in accordance with the following:FIG. 1 Head Discontinuities (See 10.2.1)FIG. 2 Socket Discontinuities (See 10.2.1)F879 124Number of Pieces in Lot Number of Samples800 and less 1Over 800 to 8000, incl 2Over 8000 to
47、22 000, incl 3Over 22 000 511.3.1.3 Should any sample fail to meet the requirements of a specified test, double the number of samples from the same lotshall be retested for the requirement(s) in which it failed. All of the additional samples shall conform to the specification, or thelot shall be rej
48、ected.11.3.1.4 If the failure of a test specimen is due to improper preparation of the specimen or an incorrect testing technique, thespecimen shall be discarded and another test specimen submitted.11.4 Corrosion Resistance Tests:11.4.1 Unless otherwise specified, inspection for corrosion resistance
49、 shall be in accordance with the manufacturers standardquality control practices. No specific method of inspection is required but the screws shall be produced from suitable raw materialand manufactured by properly controlled practices to maintain resistance to corrosion. When corrosion tests are required,Supplementary Requirement S5 must be specified in the inquiry and order, except as noted in 11.4.2.11.4.2 Products that have been hot worked shall be solution annealed and tested to determine freedom from precipitatedcarbides. Not
