ASTM F568M

This specification covers the chemical and mechanical requirements for nine property classes (Property Class 4.6, 4.8, 5.8, 8.8, 8.8.3, 9.8, 10.9, 10.9.3, and 12.9) of carbon and alloy steel externally threaded fasteners in nominal thread diameters M1.6 through M100 suited for use in general engineering applications. It does not cover the dimensional requirements for fasteners of any property class. The steel used to manufacture bolts, screws, and studs that are covered here shall be made by the open-hearth, basic-oxygen, or electric-furnace process. The fasteners shall adhere to specified values of elemental chemical compositions, which shall be examined by heat and product analyses. Each property class shall also conform to individually specified values of the following mechanical properties: proof load, wedge and axial tensile strengths, yield strength, elongation, reduction of area, surface hardness, Rockwell hardness, Vickers hardness, and stress area.

This abstract is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.

1. Scope

1.1 This specification covers chemical and mechanical requirements for nine property classes of carbon and alloy steel externally threaded metric fasteners in nominal thread diameters M1.6 through M100 suited for use in general engineering applications.

1.2 This specification does not cover dimensional requirements for fasteners of any property class. When referencing this specification for procurement purposes, it is mandatory that size, type, style, and any special dimensions of the product be additionally specified.

1.2.1 In case of any conflict in requirements, the requirements of the individual product specification shall take precedence over those of this general specification.

1.2.2 The purchaser may specify additional requirements which do not negate any of the provisions of this general specification or of the individual product specification. Such additional requirements, the acceptance of which are subject to negotiation with the supplier, must be included in the order information (see Section 3).

1.3 Requirements for seven of the nine property classes, 4.6, 4.8, 5.8, 8.8, 9.8, 10.9, and 12.9, are essentially identical with requirements given for these classes in ISO 898-1. The other two, 8.8.3 and 10.9.3, are not recognized in ISO standards.

1.4 Classes 8.8.3 and 10.9.3 bolts, screws, and studs have atmospheric corrosion resistance and weathering characteristics comparable to those of the steels covered in Specification A 588/A 588M. The atmospheric corrosion resistance of these steels is substantially better than that of carbon steel with or without copper addition. See 5.2. When properly exposed to the atmosphere, these steels can be used bare (uncoated) for many applications.

1.5 When agreed on by the purchaser, Class 5.8 fasteners may be supplied when either Classes 4.6 or 4.8 are ordered; Class 4.8 may be supplied when Class 4.6 is ordered; Class 8.8.3 may be supplied when Class 8.8 is ordered; and Class 10.9.3 may be supplied when Class 10.9 is ordered.

1.6 The product size range for which each property class is applicable is given in Table 1 and Table 2 on chemical composition requirements, and the mechanical requirements table (see Table 3).

1.7 Appendix X1 gives conversion guidance to assist designers and purchasers in the selection of a suitable property class.

1.8 Appendix X2 explains the significance of the property class designation numerals.

2. Referenced Documents

A153/A153M Specification for Zinc Coating (Hot-Dip) on Iron and Steel Hardware
A307 Specification for Carbon Steel Bolts and Studs, 60 000 PSI Tensile Strength
A325 Specification for Structural Bolts, Steel, Heat Treated, 120/105 ksi Minimum Tensile Strength
A325M Specification for Structural Bolts, Steel, Heat Treated 830 MPa Minimum Tensile Strength [Metric]
A354 Specification for Quenched and Tempered Alloy Steel Bolts, Studs, and Other Externally Threaded Fasteners
A449 Specification for Hex Cap Screws, Bolts and Studs, Steel, Heat Treated, 120/105/90 ksi Minimum Tensile Strength, General Use
A490 Specification for Structural Bolts, Alloy Steel, Heat Treated, 150 ksi Minimum Tensile Strength
A490M Specification for High-Strength Steel Bolts, Classes 10.9 and 10.9.3, for Structural Steel Joints (Metric)
A574 Specification for Alloy Steel Socket-Head Cap Screws
A588/A588M Specification for High-Strength Low-Alloy Structural Steel, up to 50 ksi [345 MPa] Minimum Yield Point, with Atmospheric Corrosion Resistance
A751 Test Methods, Practices, and Terminology for Chemical Analysis of Steel Products
B695 Specification for Coatings of Zinc Mechanically Deposited on Iron and Steel
D3951 Practice for Commercial Packaging
F1470 Guide for Fastener Sampling for Specified Mechanical Properties and Performance Inspection
F606 Test Methods for Determining the Mechanical Properties of Externally and Internally Threaded Fasteners, Washers, Direct Tension Indicators, and Rivets
F606M Test Methods for Determining the Mechanical Properties of Externally and Internally Threaded Fasteners, Washers, and Rivets (Metric)
F788/F788M Specification for Surface Discontinuities of Bolts, Screws, and Studs, Inch and Metric Series
G101 Guide for Estimating the Atmospheric Corrosion Resistance of Low-Alloy Steels
B18.2.3.1M Metric Hex Cap Screws
B18.2.3.2M Metric Formed Hex Screws
B18.2.3.3M Metric Heavy Hex Screws
B18.2.3.4M Metric Hex Flange Screws
B18.2.3.5M Metric Hex Bolts
B18.2.3.6M Metric Heavy Hex Bolts
B18.5.2.1M Metric Round Head Short Square Neck Bolts
B18.5.2.2M Metric Round Head Square Neck Bolts
ISO898-1, Mechanical Properties of Fasteners, Part I, Bolts, Screws, and Studs

Index Terms

alloy steel; bolts; carbon steel; metric; screws; steel; structural; weathering steel; Alloy steel bolting materials specifications; Carbon steel bolting materials specifications; Externally threaded articles/fasteners/rods; Fasteners (metal) specifications; Metric threaded bolting components; Steel fasteners specifications ; ICS Number Code 21.060.10

Citing ASTM Standards

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