1、Designation: F812 12 (Reapproved 2017)Standard Specification forSurface Discontinuities of Nuts, Inch and Metric Series1This standard is issued under the fixed designation F812; 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 U.S. Department of Defense.1. Scope*1.1 This specification estab
3、lishes allowable limits for thevarious types of surface discontinuities that may occur duringthe manufacture and processing of metric-series nuts withnominal diameters 5 mm and larger and inch-series nuts withnominal diameters14 in. and larger.1.2 The values stated in either SI (metric) or inch-poun
4、dunits are to be regarded separately as standard. The valuesstated in each system are not exact equivalents; therefore, eachsystem must be used independently of the other. Combiningvalues from the two systems may result in nonconformancewith the specification.1.3 When the engineering requirements of
5、 the applicationnecessitate control of surface discontinuities on nuts, thepurchaser shall specify conformance to this ASTM specifica-tion in the original inquiry and purchase order.1.3.1 When the engineering requirements of the applicationnecessitate that surface discontinuities on nuts be controll
6、edwithin limits closer than those specified in this specification,the purchaser shall specify the applicable limits in the originalinquiry and purchase order.1.4 The allowable limits established in this specification formetric nuts, with nominal diameters 5 to 24 mm inclusive, areessentially identic
7、al with requirements given in ISO/DIS 6157 II. There are no ISO standards for surface disconti-nuities on metric-series nuts with nominal diameters largerthan 24 mm or on any inch-series nuts.1.5 The following precautionary caveat pertains only to thetest method portion, Section 7, of this specifica
8、tion: 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, health, andenvironmental practices and determine the applicability ofregulatory limitations prior to use.1.
9、6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to T
10、rade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2F606/F606M Test Methods for Determining the MechanicalProperties of Externally and Internally ThreadedFasteners, Washers, Direct Tension Indicators, and RivetsF1470 Practice for Fastener Sampling for Specified Me-chanical Properties and
11、 Performance InspectionF1789 Terminology for F16 Mechanical Fasteners2.2 ISO Standard:ISO/DIS 6157 II Fasteners, Surface Discontinuities onNuts33. Ordering Information3.1 Orders for nuts requiring surface discontinuity controlshall include:3.1.1 ASTM designation and date of issue of this specifica-t
12、ion.3.1.2 Special requirements, for example, closer discontinu-ity limits (1.3.1) and inspection sampling plan (6.2).4. Types of Surface Discontinuities (See Standard F1789for definitions not provided)4.1 Crack:4.1.1 Quench CracksTypical quench cracks are shown inFig. 1; limits are specified in 5.2.
13、4.1.2 Forging CracksTypical forging cracks are shown inFig. 2; limits are specified in 5.3.4.1.3 Inclusion CracksNormally caused by nonmetallicinclusions or stringers inherent in the raw material. Typicalinclusion cracks are shown in Fig. 2; limits are specified in 5.3.1This specification is under t
14、he jurisdiction of ASTM Committee F16 onFasteners and is the direct responsibility of Subcommittee F16.93 on QualityAssurance Provisions for Fasteners.Current edition approved Sept. 1, 2017. Published September 2017 Originallyapproved in 1983. Last previous edition approved in 2012 as F812 12. DOI:1
15、0.1520/F0812-12R17.2For 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.3Available from American National Standard
16、s Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.*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 StatesThis international standard was devel
17、oped in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.14.1.4 Locking-Eleme
18、nt CracksOccur due to application ofpressure when forming the locking element of prevailingtorque-type nuts. Such cracks are usually located in the vicinityof the locking element and may be either on the internal orexternal surface. Typical locking element cracks are shown inFig. 3; limits are speci
19、fied in 5.4.4.1.5 Washer-Retainer CracksOpenings in the lip or hubof metal used to retain a washer on a nut. Washer-retainercracks may occur when pressure is applied to the lip or hubduring assembly of the washer. Typical washer-retainer cracksare shown in Fig. 4; limits are specified in 5.5.4.2 Bur
20、stA typical burst is shown in Fig. 5; limits arespecified in 5.6.4.2.1 Shear BurstA typical shear burst is shown in Fig. 5;limits are specified in 5.6.4.3 SeamTypical seams are shown in Fig. 6; limits arespecified in 5.7.4.4 FoldTypical folds are shown in Fig. 7; limits arespecified in 5.8.4.5 VoidV
21、oids are produced by marks or impressions ofchips (shear burrs) or by rust formation on the raw material.FIG. 1 Typical Quench Cracks in NutsFIG. 2 Typical Forging and Inclusion Cracks in NutsFIG. 3 Typical Locking Element Cracks in Prevailing-Torque NutsFIG. 4 Typical Washer Retainer Cracks in Nuts
22、FIG. 5 Typical Bursts and Shear Bursts in NutsFIG. 6 Typical Seams in NutsF812 12 (2017)2They are not planished during forging. Typical voids are shownin Fig. 8; limits are specified in 5.9.4.6 Tool MarksTypical tool marks are shown in Fig. 9;limits are specified in 5.10.4.7 Gouge and Nickan indenta
23、tion on the surface of afastener produced by impact with another fastener, or fromprocessing equipment during manufacture, handling, or trans-port.5. Allowable Limits5.1 Letter DefinitionsThroughout the followingrequirements, D designates the nominal nut size (basic majordiameter of thread); Dc desi
24、gnates flange diameter (specifiedmaximum) on flanged nuts; S designates nominal (specifiedmaximum) width across flats. For metric-series nuts, D, Dc,and S are in millimetres; for inch series nuts, D, Dc, and S arein inches.5.2 Quench CracksQuench cracks of any depth, anylength, or in any location ar
25、e not permitted.5.3 Forging Cracks and Inclusion CracksForging andinclusion cracks located in the top and bottom faces of nuts ofall sizes are permitted provided that (a) there are not more thantwo cracks that extend from the tapped hole across the fullwidth of the face; (b) no crack extends into th
26、e tapped holebeyond the first full thread; (c) no crack in the threads exceedsa depth of 0.5 times the thread height; and (d) the width of anycrack does not exceed 0.02 D or 0.30 mm or 0.012 in.,whichever is greater.5.3.1 Additionally, hex nuts with nominal diameters 5 to 36mm inclusive and14 to 112
27、 in. inclusive, showing discontinuityindications, shall meet the requirements of the cone proof loadtest when sampled in accordance with 6.1, using samplesselected in accordance with 6.5.2.5.4 Locking Element Cracks:5.4.1 Locking-element cracks (or seams) located on theexternal surface of the lockin
28、g element of prevailing torquenuts are permitted provided that the net meets all applicabletorque requirements.5.4.1.1 Additionally, hex nuts with nominal diameters 5 to36 mm inclusive and14 to 112 in. inclusive, showing discon-tinuity indications, shall meet the requirements of the coneproof load t
29、est when sampled in accordance with 6.1, usingsamples selected in accordance with 6.5.2.5.4.2 Locking-element cracks located on the internal sur-face (threaded or unthreaded) of prevailing torque nuts arepermitted provided that (a) no crack exceeds a length of twothread pitches; (b) no crack shall e
30、xtend into the thread root;and (c) no crack shall have a width exceeding the following:5.4.2.1 Metric-Series Nuts0.18 mm for nuts with nominaldiameters 5 to 10 mm inclusive, 0.25 mm for nuts with nominalFIG. 7 Typical Folds on Surfaces of NutsFIG. 8 Typical Voids in NutsFIG. 9 Typical Tool Marks on
31、Nut SurfaceF812 12 (2017)3diameters over 10 to 24 mm inclusive, and 0.40 mm for nutswith nominal diameters larger than 24 mm.5.4.2.2 Inch Series Nuts0.007 in. for nuts with nominaldiameters14 to716 in. inclusive, 0.010 in. for nuts withnominal diameters over716 to 1 in. inclusive, and 0.016 in. forn
32、uts with nominal diameters larger than 1 in.5.5 Washer-Retainer CracksWasher-retainer cracks arepermitted if their location is limited to the contour of the lip orhub used for retaining purposes.5.6 Bursts and Shear Bursts:5.6.1 For hex nuts, bursts and shear bursts are permittedprovided that (a) no
33、 burst or shear burst in the flats extends intothe crown (chamfer) circle on the top of the nut or into thebearing circle on the bottom face; (b) no burst or shear burstlocated at the intersection of the top or bottom face with awrenching flat has a width greater than 0.25 mm or 0.010 in.plus 0.02 S
34、; and (c) no burst occurring at the intersection of twowrenching flats reduces the width across corners below itsspecified minimum.5.6.2 For flanged nuts, bursts and shear bursts at theperiphery of the flange are permitted provided that (a) not morethan one of the bursts or shear bursts has a width
35、greater than0.04 Dc, and (b) the width of the one burst or shear burst thatexceeds a width of 0.04 Dc does not have a width greater than0.08 Dc.5.7 SeamsSeams are permitted provided that no seam hasan open width at the surface greater than 0.013 D for nuts withnominal diameters 5 to 6 mm inclusive;
36、0.02 D for metric nutswith nominal diameters larger than 6 mm; and 0.02 D for allsizes of inch-series nuts.5.7.1 Additionally, hex nuts with nominal diameters 5 to 36mm inclusive and14 to 112 in. inclusive, showing discontinuityindications, shall meet the requirements of the cone proof loadtest when
37、 sampled in accordance with 6.1 using samplesselected in accordance with 6.5.2.5.8 FoldsFolds located at the intersection of the flangeperiphery and bearing surface of flanged nuts shall not projectbelow the bearing surface. All other folds on nuts are permit-ted.5.9 Voids:5.9.1 Voids on the surface
38、s of nuts are permitted providedthat (a) depth of voids does not exceed 0.25 mm or 0.010 in. or0.02 D, whichever is greater, and (b) the combined area of allvoids on the bearing surface does not exceed 10% of thespecified minimum-bearing surface area.5.9.2 The method for determining the area of void
39、s on thebearing surface shall be as agreed upon by purchaser andproducer.5.10 Tool Marks:5.10.1 Tool marks on the bearing surface are permittedprovided the surface roughness measurement does not exceed3.2 m or 125 in., determined as the arithmetic averagedeviation from the mean surface.5.10.2 Tool m
40、arks on other surfaces of the nut are permitted.5.11 Nicks and GougesNicks, gouges, dents, and scrapesare permitted provided that the functionality of the nut is notimpaired.6. Inspection and Evaluation6.1 Nuts shall be inspected for surface discontinuities inaccordance with the procedures in 6.2, 6
41、.3, and 6.4.6.2 The purchaser shall specify in the original inquiry andpurchase order the inspection sampling requirements which theproducer must satisfy to demonstrate the acceptability of nutswith respect to surface discontinuities.6.3 In the absence of purchaser instructions (6.2), inspectionand
42、evaluation shall be in accordance with 6.5.6.4 For referee purposes, unless other procedures have beenspecified by the purchaser (6.2), inspection and evaluation shallbe in accordance with 6.5.6.5 Inspection Procedure:6.5.1 Visual Inspection:6.5.1.1 A random sample shall be taken from the lot inacco
43、rdance with Guide F1470, and examined visually for thepresence of quench cracks, forging cracks, inclusion cracks,locking-element cracks, washer retainer cracks, bursts, shearbursts, seams, folds, voids, tool marks, and nicks and gouges.6.5.1.2 If during this inspection any nuts with quench cracksar
44、e found, the lot may be rejected by the purchaser.6.5.1.3 If during this inspection any nuts are found with anyother surface discontinuity, each discontinuity shall be mea-sured and if any is found that exceeds the allowable dimen-sional limits for that discontinuity as specified in Section 5, thelo
45、t may be rejected by the purchaser.6.5.1.4 Measurement of Surface Discontinuities in Nuts: (1)For discontinuities originating from a flat: at the extremity ofthe discontinuity measure distance D perpendicular to the flatwhere the discontinuity originated (see Fig. 10).(2) For discontinuities origina
46、ting from a corner: at theextremity of the discontinuity measure distance D in a straightline to the corner where the discontinuity originated (see Fig.10).6.5.2 Mechanical TestingDuring the visual inspection, allhex nuts with nominal diameters 5 to 36 mm inclusive and14to 112 in. inclusive, that ha
47、ve indications of forging cracks,inclusion cracks, locking-element cracks on external surfaces,or seams, shall be set aside. From this lot, a sample of size inFIG. 10 Measurement of Surface DiscontinuitiesF812 12 (2017)4accordance with Guide F1470, and consisting of those nutsindicating the most ser
48、ious defects, shall be cone proof loadtested as specified in 7.1. If any nut fails to meet therequirements of this test, the lot may be rejected by thepurchaser.7. Test Method7.1 Cone Proof Load TestIf required in 6.5.2, the coneproof load test shall be conducted in accordance with the ConeProof Loa
49、d Test Methods F606/F606M.8. Keywords8.1 crack; discontinuities (surface); fold; nut; seam; voidSUMMARY OF CHANGESCommittee F16 has identified the location of selected changes to this standard since the last issueF812/F812M-07 that may impact the use of this standard.(1) /812M was removed from the designation.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any s
