1、Designation:F81212Standard 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 year of last revision.Anu
2、mber in parentheses indicates the year of last reapproval.Asuperscriptepsilon()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 establishes allowable limits for thev
3、arious 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 diameters14in.and larger.1.2 The values stated in either SI(metric)or inch-poundunits are to be regarded separately
4、 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 the applicationnecessitate control of s
5、urface 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 controlledwithin limits closer than those specifi
6、ed 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 identical with requirements given in ISO/DIS 6157/
7、II.There are no ISO standards for surface discontinuities onmetric-series nuts with nominal diameters larger than 24 mm oron any inch-series nuts.1.5 The following precautionary caveat pertains only to thetest method portion,Section 7,of this specification:Thisstandard does not purport to address al
8、l 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 regulatory limita-tions prior to use.2.Referenced Documents2.1 ASTM Standards:2F606 Test Methods for Det
9、ermining the Mechanical Proper-ties of Externally and Internally Threaded Fasteners,Washers,Direct Tension Indicators,and RivetsF606M Test Methods for Determining the Mechanical Prop-erties of Externally and Internally Threaded Fasteners,Washers,and Rivets(Metric)F1470 Practice for Fastener Sampling
10、 for Specified Me-chanical Properties and Performance InspectionF1789 Terminology for F16 Mechanical Fasteners2.2 ISO Standard:ISO/DIS 6157/IIFasteners,Surface Discontinuities onNuts33.Ordering Information3.1 Orders for nuts requiring surface discontinuity controlshall include:3.1.1 ASTM designation
11、 and date of issue of this specifica-tion.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
12、;limits are specified in 5.2.4.1.2 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 5.3.4.1.4
13、Locking-Element CracksOccur due to application ofpressure when forming the locking element of prevailingtorque-type nuts.Such cracks are usually located in the vicinity1This specification is under the jurisdiction of ASTM Committee F16 onFasteners and is the direct responsibility of Subcommittee F16
14、.93 on QualityAssurance Provisions for Fasteners.Current edition approved Oct.1,2012.Published November 2012.Originallyapproved in 1983.Last previous edition approved in 2007 as F812/F812M 07.DOI:10.1520/F0812-12.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Custo
15、mer 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 Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.*A Summary of Changes section ap
16、pears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 of the locking element and may be either on the internal orexternal surface.Typical locking element cracks are shown inFig.3;limits are specified 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.Typi
