ASTM F812/F812M-12(2022)e1

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

ABSTRACT
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.
SCOPE
1.1 This specification establishes allowable limits for the various types of surface discontinuities that may occur during the manufacture and processing of metric-series nuts with nominal diameters 5 mm and larger and inch-series nuts with nominal diameters 1/4 in. and larger.  
1.2 The values stated in either SI (metric) or inch-pound units are to be regarded separately as standard. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the specification.  
1.3 When the engineering requirements of the application necessitate control of surface discontinuities on nuts, the purchaser shall specify conformance to this ASTM specification in the original inquiry and purchase order.  
1.3.1 When the engineering requirements of the application necessitate that surface discontinuities on nuts be controlled within limits closer than those specified in this specification, the purchaser shall specify the applicable limits in the original inquiry and purchase order.  
1.4 The allowable limits established in this specification for metric nuts, with nominal diameters 5 to 24 mm inclusive, are essentially identical with requirements given in ISO/DIS 6157/II. There are no ISO standards for surface discontinuities on metric-series nuts with nominal diameters larger than 24 mm or on any inch-series nuts.  
1.5 The following precautionary caveat pertains only to the test method portion, Section 7, of this specification:  This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Jul-2022
• ICS: 21.060.20 - Nuts
• Technical Committee: F16 - Fasteners
• Drafting Committee: F16.93 - Quality Assurance Provisions for Fasteners

Relations

• Refers: ASTM F1470-24 - Standard Practice for Fastener Sampling for Specified Mechanical Properties and Performance Inspection
• Effective Date: 01-Jan-2024
• Refers: ASTM F1789-23 - Standard Terminology for F16 Mechanical Fasteners
• Effective Date: 01-Nov-2023
• Refers: ASTM F1470-18 - Standard Practice for Fastener Sampling for Specified Mechanical Properties and Performance Inspection
• Effective Date: 01-Feb-2018
• Refers: ASTM F1789-17 - Standard Terminology for F16 Mechanical Fasteners
• Effective Date: 01-Jun-2017
• Refers: ASTM F606/F606M-16 - Standard Test Methods for Determining the Mechanical Properties of Externally and Internally Threaded Fasteners, Washers, Direct Tension Indicators, and Rivets
• Effective Date: 01-Sep-2016
• Refers: ASTM F1789-16 - Standard Terminology for F16 Mechanical Fasteners
• Effective Date: 01-Aug-2016
• Refers: ASTM F1789-15a - Standard Terminology for F16 Mechanical Fasteners
• Effective Date: 01-Mar-2015
• Refers: ASTM F1789-15 - Standard Terminology for F16 Mechanical Fasteners
• Effective Date: 01-Feb-2015
• Refers: ASTM F606/F606M-14a - Standard Test Methods for Determining the Mechanical Properties of Externally and Internally Threaded Fasteners, Washers, Direct Tension Indicators, and Rivets
• Effective Date: 01-Nov-2014
• Refers: ASTM F1789-14a - Standard Terminology for F16 Mechanical Fasteners
• Effective Date: 01-Sep-2014
• Refers: ASTM F1789-14 - Standard Terminology for F16 Mechanical Fasteners
• Effective Date: 01-Feb-2014
• Refers: ASTM F1789-12a - Standard Terminology for F16 Mechanical Fasteners
• Effective Date: 01-Dec-2012
• Refers: ASTM F1470-12 - Standard Practice for Fastener Sampling for Specified Mechanical Properties and Performance Inspection
• Effective Date: 15-Nov-2012
• Refers: ASTM F1789-12 - Standard Terminology for F16 Mechanical Fasteners
• Effective Date: 01-Jun-2012
• Refers: ASTM F1789-11b - Standard Terminology for F16 Mechanical Fasteners
• Effective Date: 01-Nov-2011

Overview

ASTM F812/F812M-12(2022)e1, "Standard Specification for Surface Discontinuities of Nuts, Inch and Metric Series," is a recognized standard developed by ASTM International to define and control the allowable limits for surface discontinuities in nuts. The specification covers both inch-series and metric-series nuts with nominal diameters starting from 5 mm (metric) or 1/4 inch (inch series). It addresses types of surface flaws that may develop during manufacturing and processing, such as cracks, bursts, seams, folds, voids, tool marks, and nicks.

This standard aims to ensure the mechanical and functional integrity of nuts used in critical applications. It is referenced in procurement, engineering, and quality assurance documents to support defect control and reliable fastener performance.

Key Topics

• Surface Discontinuity Types
  The standard details several recognized types of discontinuities, including:

  • Quench cracks
  • Forging cracks
  • Inclusion cracks
  • Locking-element cracks
  • Washer-retainer cracks
  • Bursts and shear bursts
  • Seams and folds
  • Voids
  • Tool marks
  • Gouges and nicks

• Allowable Limits
  It establishes specific allowable limits on the location, size, number, and depth of these discontinuities to prevent adverse effects on nut performance. Notably, the limits for metric nuts (5-24 mm) are essentially identical to ISO/DIS 6157/II requirements, creating alignment with international practices.

• Inspection and Acceptance Criteria

  • Visual inspection as per specified sampling plans (ASTM F1470)
  • Measurement techniques for discontinuities
  • Criteria for lot acceptance or rejection based on defect findings

• Mechanical Testing

  • Requirement for cone proof load tests (referencing ASTM F606/F606M) to ensure that nuts exhibiting surface discontinuities maintain required mechanical properties.

• Purchaser Options
  The standard allows purchasers to specify closer limits for discontinuities or unique inspection sampling plans when required by engineering needs.

• Dual Unit System

  • Specifies requirements using both SI (metric) and inch-pound units. These units are not interchangeable and must be used independently.

Applications

• Quality Assurance in Nut Production:
  Manufacturers use ASTM F812/F812M as a guideline to inspect and control surface discontinuities during and after production, helping to ensure that final products meet rigorous safety and reliability standards.

• Purchasing and Procurement:
  Engineering and procurement teams specify this standard in purchase orders when the integrity of nuts is critical to assembly safety or mechanical performance, especially in sectors like automotive, aerospace, construction, and energy.

• Product Conformance Verification:
  End-users and third-party inspectors reference this standard to verify that supplied nuts conform to established quality specifications before use.

• International Trade and Regulations:
  As an internationally aligned standard, ASTM F812/F812M helps companies comply with global trade and regulatory requirements concerning fastener quality and defect control.

Related Standards

• ASTM F606/F606M - Test Methods for Determining the Mechanical Properties of Externally and Internally Threaded Fasteners
• ASTM F1470 - Practice for Fastener Sampling for Specified Mechanical Properties and Performance Inspection
• ASTM F1789 - Terminology for F16 Mechanical Fasteners
• ISO/DIS 6157/II - Fasteners, Surface Discontinuities on Nuts (metric series, 5-24 mm nominal diameter)

By referencing ASTM F812/F812M-12(2022)e1, stakeholders can achieve improved control of nut quality, enhance component safety, and align with international best practices for fastener inspection and specification.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
´1
Designation: F812/F812M − 12 (Reapproved 2022)
Standard Specification for
Surface Discontinuities of Nuts, Inch and Metric Series
This standard is issued under the fixed designation F812/F812M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—Editorially updated designation in September 2023.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* environmental practices and determine the applicability of
regulatory limitations prior to use.
1.1 This specification establishes allowable limits for the
1.6 This international standard was developed in accor-
various types of surface discontinuities that may occur during
dance with internationally recognized principles on standard-
the manufacture and processing of metric-series nuts with
ization established in the Decision on Principles for the
nominal diameters 5 mm and larger and inch-series nuts with
Development of International Standards, Guides and Recom-
nominal diameters ⁄4 in. and larger.
mendations issued by the World Trade Organization Technical
1.2 The values stated in either SI (metric) or inch-pound
Barriers to Trade (TBT) Committee.
units are to be regarded separately as standard. The values
stated in each system are not exact equivalents; therefore, each 2. Referenced Documents
system must be used independently of the other. Combining 2
2.1 ASTM Standards:
values from the two systems may result in nonconformance
F606/F606M Test Methods for Determining the Mechanical
with the specification.
Properties of Externally and Internally Threaded
Fasteners, Washers, Direct Tension Indicators, and Rivets
1.3 When the engineering requirements of the application
F1470 Practice for Fastener Sampling for Specified Me-
necessitate control of surface discontinuities on nuts, the
chanical Properties and Performance Inspection
purchaser shall specify conformance to this ASTM specifica-
F1789 Terminology for F16 Mechanical Fasteners
tion in the original inquiry and purchase order.
2.2 ISO Standard:
1.3.1 When the engineering requirements of the application
necessitate that surface discontinuities on nuts be controlled ISO/DIS 6157 ⁄II Fasteners, Surface Discontinuities on
Nuts
within limits closer than those specified in this specification,
the purchaser shall specify the applicable limits in the original
3. Ordering Information
inquiry and purchase order.
3.1 Orders for nuts requiring surface discontinuity control
1.4 The allowable limits established in this specification for
shall include:
metric nuts, with nominal diameters 5 to 24 mm inclusive, are
3.1.1 ASTM designation and date of issue of this specifica-
essentially identical with requirements given in ISO/
tion.
DIS 6157 ⁄II. There are no ISO standards for surface disconti-
3.1.2 Special requirements, for example, closer discontinu-
nuities on metric-series nuts with nominal diameters larger
ity limits (1.3.1) and inspection sampling plan (6.2).
than 24 mm or on any inch-series nuts.
1.5 The following precautionary caveat pertains only to the
4. Types of Surface Discontinuities (See Standard F1789
test method portion, Section 7, of this specification: This
for definitions not provided)
standard does not purport to address all of the safety concerns,
4.1 Crack:
if any, associated with its use. It is the responsibility of the user
4.1.1 Quench Cracks—Typical quench cracks are shown in
of this standard to establish appropriate safety, health, and
Fig. 1; limits are specified in 5.2.
1 2
This specification is under the jurisdiction of ASTM Committee F16 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Fasteners and is the direct responsibility of Subcommittee F16.93 on Quality contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Assurance Provisions for Fasteners. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Aug. 1, 2022. Published August 2022. Originally the ASTM website.
approved in 1983. Last previous edition approved in 2017 as F812 – 12 (2017). Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
DOI: 10.1520/F0812_F0812M-12R22E01. 4th Floor, New York, NY 10036, http://www.ansi.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
F812/F812M − 12 (2022)
FIG. 1 Typical Quench Cracks in Nuts
4.1.2 Forging Cracks—Typical forging cracks are shown in
Fig. 2; limits are specified in 5.3.
4.1.3 Inclusion Cracks—Normally caused by nonmetallic
inclusions or stringers inherent in the raw material. Typical
inclusion cracks are shown in Fig. 2; limits are specified in 5.3.
4.1.4 Locking-Element Cracks—Occur due to application of
pressure when forming the locking element of prevailing
torque-type nuts. Such cracks are usually located in the vicinity
of the locking element and may be either on the internal or
external surface. Typical locking element cracks are shown in
FIG. 3 Typical Locking Element Cracks in Prevailing-Torque Nuts
Fig. 3; limits are specified in 5.4.
4.1.5 Washer-Retainer Cracks—Openings in the lip or hub
of metal used to retain a washer on a nut. Washer-retainer
cracks may occur when pressure is applied to the lip or hub
during assembly of the washer. Typical washer-retainer cracks
are shown in Fig. 4; limits are specified in 5.5.
4.2 Burst—A typical burst is shown in Fig. 5; limits are
specified in 5.6.
4.2.1 Shear Burst—A typical shear burst is shown in Fig. 5;
limits are specified in 5.6.
4.3 Seam—Typical seams are shown in Fig. 6; limits are
specified in 5.7.
FIG. 4 Typical Washer Retainer Cracks in Nuts
4.4 Fold—Typical folds are shown in Fig. 7; limits are
specified in 5.8.
4.5 Void—Voids are produced by marks or impressions of
chips (shear burrs) or by rust formation on the raw material.
They are not planished during forging. Typical voids are shown
in Fig. 8; limits are specified in 5.9.
FIG. 5 Typical Bursts and Shear Bursts in Nuts
4.6 Tool Marks—Typical tool marks are shown in Fig. 9;
limits are specified in 5.10.
4.7 Gouge and Nick—an indentation on the surface of a
fastener produced by impact with another fastener, or from
processing equipment during manufacture, handling, or trans-
FIG. 2 Typical Forging and Inclusion Cracks in Nuts port.
´1
F812/F812M − 12 (2022)
5.4.2.2 Inch Series Nuts—0.007 in. for nuts with nominal
1 7
diameters ⁄4 to ⁄16 in. inclusive, 0.010 in. for nuts with
nominal diameters over ⁄16 to 1 in. inclusive, and 0.016 in. for
nuts with nominal diameters larger than 1 in.
5.5 Washer-Retainer Cracks—Washer-retainer cracks are
permitted if their location is limited to the contour of the lip or
hub used for retaining purposes.
5.6 Bursts and Shear Bursts:
5.6.1 For hex nuts, bursts and shear bursts are permitted
provided that (a) no burst or shear burst in the flats extends into
the crown (chamfer) circle on the top of the nut or into the
FIG. 6 Typical Seams in Nuts
bearing circle on the bottom face; (b) no burst or shear burst
located at the intersection of the top or bottom face with a
wrenching flat has a width greater than 0.25 mm or 0.010 in.
5. Allowable Limits
plus 0.02 S; and (c) no burst occurring at the intersection of two
5.1 Letter Definitions—Throughout the following
wrenching flats reduces the width across corners below its
requirements, D designates the nominal nut size (basic major
specified minimum.
diameter of thread); Dc designates flange diameter (specified
5.6.2 For flanged nuts, bursts and shear bursts at the
maximum) on flanged nuts; S designates nominal (specified
periphery of the flange are permitted provided that (a) not more
maximum) width across flats. For metric-series nuts, D, Dc,
than one of th
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