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Nut Surface Discontinuities

Standards for surface discontinuities on fasteners establish limits and acceptance criteria for surface discontinuities on bolts, screws, studs, and nuts. Particular attention is paid to screw threading on high-strength fasteners intended for use under high pressures. Standards are available for both inch and metric series fasteners. This list for nut surface discontinutities includes standards from SAE, ASTM, and ISO.

ASTM F812-12(2017)

Standard Specification for Surface Discontinuities of Nuts, Inch and Metric Series

This specification establishes allowable limits for the various types of surface discontinuities such as cracks that may occur during the manufacture and processing of metric-series nuts and inch-series nuts. The different types of surface discontinuities and allowable limits are presented in details. The nuts shall be inspected for surface discontinuities to meet the requirements prescribed. Cone proof load test shall be performed to meet the requirements prescribed.

SAE AS 5447-2000 (SAE AS5447-2000)

Acceptance Criteria for Nuts - Magnetic Particle, Fluorescent Penetrant, and Visible Penetrant Examination ( Reaffirmed: Jul 2004 )

This standard establishes the acceptance criteria for surface discontinuities as revealed by magnetic particle or liquid penetrant examination of nuts.

ISO 6157-2:1995

Fasteners - Surface discontinuities - Part 2: Nuts

Establishes limits for various types of surface discontinuities on nuts with nominal thread diameters from 5 mm up to and including 39 mm. Applies also for all mechanical property classes according to ISO 898-2 and ISO 898-6.


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