The language of fasteners.

The American Association of State Highway and Transportation Officials oversees the advancement of transportation policies and standards for the industry. AASHTO develops technical standards and specifications for highway construction materials, including fasteners used in transportation infrastructure.

Reference identifiers: AASHTO M 164, AASHTO M 253, AASHTO M 270. Verify the applicable current revision for your project.

A steel rod or bar with one end intended to be embedded in concrete and the other end threaded and projected for anchoring material to concrete. The end cast in concrete may be straight, bent hook, a forged head, or welded attachment to resist forces imposed on the anchor bolt. Anchor bolts are critical for structural connections between steel and concrete.

Reference identifiers: ASTM F1554, ASTM A193, ASTM A307. Verify the applicable current revision for your project.

Describes the process of heating and cooling steel to soften hardness caused by manufacturing or previous heat treating. This process improves ductility and reduces internal stresses, making the material easier to machine or form.

Reference identifiers: ASTM A194, ASTM A563. Verify the applicable current revision for your project.

Allowable Stress Design (according to the AISC 9th Ed.). A design methodology where structural members are designed so that stresses under working loads do not exceed specified allowable values. This traditional approach uses safety factors to account for uncertainties.

Reference identifiers: AISC 9th Edition. Verify the applicable current revision for your project.

American Society for Testing and Materials, is a leading standards development organization. This committee has jurisdiction on over 60 fastener standards. ASTM standards ensure quality, consistency, and reliability of fasteners.

Reference identifiers: ASTM A325, ASTM A490, ASTM F1554, ASTM A194, ASTM A563. Verify the applicable current revision for your project.

This is determined as either the value obtained by analytical methods or the mean value of a specified number of local thickness measurements that are evenly distributed over the significant surface. Critical for galvanized and coated fasteners to ensure proper corrosion protection.

Reference identifiers: ASTM A153, ASTM B695. Verify the applicable current revision for your project.

This describes carbon and alloy steel bar that is produced from hot rolled or cast billets with the cross sectional dimensions that have a relatively constant dimension. Used as raw material for manufacturing bolts, rods, and other fasteners.

Reference identifiers: ASTM A36, ASTM A572, ASTM A588. Verify the applicable current revision for your project.

A bolted connection that assumes that shear forces are transmitted by the bolt bearing against the sides of the holes in the connected material. Often denoted on drawings with an 'X' (i.e. A325-X) which excludes threads from the shear plane or 'N' (i.e. A325-N) which includes threads in the shear plane.

Reference identifiers: ASTM A325, ASTM A490. Verify the applicable current revision for your project.

This test is meant to determine the toughness or ductility of a fastener. It is usually performed by bending the fastener through its axis or on a round mandrel. Ensures the fastener can withstand deformation without fracturing.

Reference identifiers: ASTM A325, ASTM A490. Verify the applicable current revision for your project.

A headed and externally threaded fastener designed to be assembled with a nut. Bolts are one of the most common fasteners used in construction and manufacturing, providing strong, removable connections.

Reference identifiers: ANSI B18.2.1, ASTM A325, ASTM A490. Verify the applicable current revision for your project.

This is a common method of determining the hardness of metal products. A test is conducted by forcing a carbide ball indenter into the surface of the test specimen. The resulting indentation is measured and the brinell hardness number is calculated by using a formula that divides the test force by the indentation. Standards for this test are defined under ASTM E10.

Reference identifiers: ASTM E10. Verify the applicable current revision for your project.

A fastener manufactured by cold forming, with tighter dimensional tolerances than a hot forged bolt. Cap screws are typically used in precision applications where exact dimensions are critical.

Reference identifiers: ANSI B18.3. Verify the applicable current revision for your project.

A metal alloy that principle elements are carbon and iron. Contains other trace elements in undetectable amounts. The most common material for fasteners, offering good strength and cost-effectiveness.

Reference identifiers: ASTM A307, ASTM A325. Verify the applicable current revision for your project.

A procedure and action to verify in writing a process or material meets a set of applicable standards. This helps ensure consistent products for both manufacturer and end users. Certifications provide traceability and quality assurance.

Reference identifiers: ISO 9001, ASTM Standards. Verify the applicable current revision for your project.

Also called initial load or preload, is created when tension is applied on a bolt and results in equal force and measures of the compression of two parts. It is commonly calculated as 75% of minimum proof load. Critical for maintaining joint integrity.

Reference identifiers: ASTM A325, ASTM A490. Verify the applicable current revision for your project.

Processing material by forcing metal through various dies, below the recrystallization temperature. Most mass produced fasteners use this technique and require large production runs with long lead times. Produces stronger fasteners with better grain structure.

Reference identifiers: ANSI B18.2.1. Verify the applicable current revision for your project.

The load which tends to compress or shorten the member. The value for compressive strength may depend upon the degree of distortion. Important consideration in structural design.

Reference identifiers: AISC Specifications. Verify the applicable current revision for your project.

This describes the ability of a fastener to resist corrosion under specified conditions. Hot dip galvanizing is a cost effective way to provide a high level of corrosion protection for a variety of applications and environmental conditions.

Reference identifiers: ASTM A153, ASTM B695. Verify the applicable current revision for your project.

A threading method produced by removing material from the surface with a form cutting tool. Traditional method that produces precise threads but may reduce material strength compared to rolled threads.

Reference identifiers: ANSI B1.1. Verify the applicable current revision for your project.

A test to determine the mechanical properties of a material or the behavior of an item which results in the destruction of the sample or item. Used to verify material properties and ensure compliance with specifications.

Reference identifiers: ASTM A325, ASTM A490. Verify the applicable current revision for your project.

A person or organization who purchases fasteners for the purpose of reselling them. They will typically specialize in a certain industry and carry standard fasteners. A distributor may or may not alter the fasteners prior to resale.

Reference identifiers: . Verify the applicable current revision for your project.

(externally threaded fasteners) The measure of a fastener's ability to deform prior to the point of fracturing. Machined test pieces are made to evaluate the metal's elongation and reduction of area. The lower the ratio of its specified minimum yield strength to its specified minimum tensile strength, the greater the fastener's ductility.

Reference identifiers: ASTM A325, ASTM A490. Verify the applicable current revision for your project.

Measures the change in length based on a percentage of the original size. A key indicator of material ductility and ability to deform before failure.

Reference identifiers: ASTM A325, ASTM A490. Verify the applicable current revision for your project.

This device measures the linear deformation of a fastener to sense the elongation under tensile stress in a controlled test environment. Essential for accurate tensile testing and material property determination.

Reference identifiers: ASTM E83. Verify the applicable current revision for your project.

A bolt having one end which is a closed or open ring with a threaded shank. Used for lifting, rigging, and anchoring applications where a connection point is needed.

Reference identifiers: ASME B18.15. Verify the applicable current revision for your project.

A mechanical device that holds or joins two or more components in definite positions with respect to each other and is often described as a bolt, nut, rivet, screw, washer, or special formed part.

Reference identifiers: . Verify the applicable current revision for your project.

A stamp, paint, or other permanent identifier that may include manufacturer information and applicable grade markings for certification purposes. Critical for traceability and quality control.

Reference identifiers: ASTM A325, ASTM A490. Verify the applicable current revision for your project.

An organization that fabricates raw steel into a fastener meeting specified standards. Manufacturers must comply with applicable ASTM, AASHTO, and other industry standards.

Reference identifiers: . Verify the applicable current revision for your project.

A fastener's adherence to its specification for dimensional tolerances, mechanical properties, and other requirements stated under applicable standards. Quality is verified through testing and certification.

Reference identifiers: ASTM Standards, ISO 9001. Verify the applicable current revision for your project.

A precise statement of set requirements to be satisfied by a fastener, its material, or its processing. It also indicates the procedure used to determine whether the requirements given are satisfied. This would include specifications like ASTM A194, A449, F1554 and SAE Grade 2.

Reference identifiers: ASTM A194, ASTM A449, ASTM F1554, SAE J429. Verify the applicable current revision for your project.

A document which details the attributes of a finished fastener and includes such characteristics as geometry, material or chemistry, heat treatment, finish, testing lot size, and packaging. Examples would include organization like: Industrial Fastener Institute (IFI) and American National Standards Institute (ANSI).

Reference identifiers: ANSI Standards, IFI Standards, ASTM Standards. Verify the applicable current revision for your project.

A determination or verification that the fastener meets its specification requirements. Includes mechanical testing, dimensional inspection, and material analysis.

Reference identifiers: ASTM A325, ASTM A490. Verify the applicable current revision for your project.

The process of forming raw steel into specified shapes. Some examples of forged products would be hex bolts, clevises, and barrier pins. Forging improves material strength through grain refinement.

Reference identifiers: ANSI B18.2.1. Verify the applicable current revision for your project.

This may occur during fastener manufacturing at the cutting or forging operations and are located on the top of the head or on the raised periphery of indented head bolts. These defects can compromise fastener integrity and must be detected through quality control.

Reference identifiers: . Verify the applicable current revision for your project.

This can happen when a stainless steel fastener is tightened, the thin oxide layer on the surface of the steel may scrape off resulting in the nut and washer welding together. When disassembled, the welded material may be torn and pitted. Can be prevented with proper lubrication or material selection.

Reference identifiers: . Verify the applicable current revision for your project.

A term that describes a cone point that is threaded completely along the 45 to 50 degree point and is commonly found on lag screws. Facilitates easier starting and self-tapping in wood applications.

Reference identifiers: ANSI B18.2.1. Verify the applicable current revision for your project.

Permanent markings denoting the specification used to manufacture a fastener. This would indicate the appropriate material, mechanical properties and other criteria used to produce the bolt. Essential for proper fastener selection and verification.

Reference identifiers: ASTM A325, ASTM A490. Verify the applicable current revision for your project.

A chemical analysis of a given heat by the producer, which determines the percentages of its elements. Ensures material composition meets specification requirements.

Reference identifiers: ASTM A325, ASTM A490. Verify the applicable current revision for your project.

This describes the extent to which a bolt retains specified properties as measured by exposure of the material to a certain temperature and environment for a specified time. Critical for high-temperature applications.

Reference identifiers: ASTM A193. Verify the applicable current revision for your project.

This refers to a bolt made to ANSI B18.2.1 and has different tolerances than hex cap screw. The most common bolt type, featuring a hexagonal head for wrench or socket application.

Reference identifiers: ANSI B18.2.1. Verify the applicable current revision for your project.

A term which is used commercially to denote ASTM A325 or A490 bolts which are primarily used in construction applications. These bolts provide superior strength for structural connections.

Reference identifiers: ASTM A325, ASTM A490. Verify the applicable current revision for your project.

Bolts specifically manufactured from high temperature alloys to maintain tensile loads at temperatures between 500°F and 1800°F. Refer to ASTM A193 for more information. Used in power generation, petrochemical, and other high-temperature applications.

Reference identifiers: ASTM A193. Verify the applicable current revision for your project.

The process of the immersion of fasteners in a bath of molten zinc for a controlled time period to obtain specified coating weight or thickness. This is a cost effective method for creating highly corrosive resistant steel products. Provides excellent protection in harsh environments.

Reference identifiers: ASTM A153. Verify the applicable current revision for your project.

The process by which high strength steel becomes brittle and fractures following absorption of hydrogen. There is a danger of this occurring when attempting to zinc coat high strength bolts (e.g. ASTM A490, ASTM A354 BD). This can occur during the acid washing process prior to galvanizing. Requires proper processing controls.

Reference identifiers: ASTM A490, ASTM A354. Verify the applicable current revision for your project.

The Industrial Fasteners Institute is the trade association of the North American fastener manufacturing industry. It is a strong supporter of fastener standards and partners ASTM, ASME, SAE and other organizations to develops specifications. The Inch Fastener Standards (2003) is leading reference guide for mechanical fasteners technical data.

Reference identifiers: IFI Standards. Verify the applicable current revision for your project.

Load and Resistance Factor Design (according to AISC 3rd Ed.). A probability-based design methodology that uses load and resistance factors to account for uncertainties. More modern approach than ASD, providing more consistent reliability levels.

Reference identifiers: AISC 3rd Edition. Verify the applicable current revision for your project.

This is a test specimen machined from a full-size fastener to specific dimensions to standardize test results; often specified when a full-size fastener cannot be reasonably or practically tested. This test is used to determine elongation and reduction of area.

Reference identifiers: ASTM A325, ASTM A490. Verify the applicable current revision for your project.

A document verifying the raw material meets specified requirements and includes results of mechanical tests and chemical analyses. Provides traceability and quality assurance documentation.

Reference identifiers: . Verify the applicable current revision for your project.

Describes a coating technique of applying cold zinc powder to bolts by either cold welding or barrel finishing. Alternative to hot-dip galvanizing, suitable for smaller fasteners and specific applications.

Reference identifiers: ASTM B695. Verify the applicable current revision for your project.

The fastener characteristics which relate to its reaction to applied loads; these properties may be those of the basic raw material or result from the manufacturing process. Includes tensile strength, yield strength, elongation, and hardness.

Reference identifiers: ASTM A325, ASTM A490. Verify the applicable current revision for your project.

An internally threaded product intended for use on external or male screw threads such as a bolt or a stud for the purpose of tightening or assembling two or more components. Available in various styles including hex, heavy hex, and specialty types.

Reference identifiers: ANSI B18.2.2, ASTM A194, ASTM A563. Verify the applicable current revision for your project.

The process of forming an oxide film on the surface of stainless steel by chemical treatment to improve corrosion resistance of stainless steel fasteners. This process is usually done after the steel has been subjected to thermal treatment (i.e. hot forging).

Reference identifiers: ASTM A967. Verify the applicable current revision for your project.

The process of removing surface oxides by chemical means. Typically part of the galvanizing or coating preparation process.

Reference identifiers: . Verify the applicable current revision for your project.

Describes a fastener that is free of additional coatings or finishes like zinc, hot-dip galvanizing, or paint. Also referred to as 'black.' Suitable for indoor applications or where corrosion is not a concern.

Reference identifiers: . Verify the applicable current revision for your project.

(externally threaded fastener) The tension applied load that a fastener must withstand without any indication of permanent deformation or failure. Proof load is typically calculated at 90-93% of the minimum yield strength. Critical for ensuring fastener reliability.

Reference identifiers: ASTM A325, ASTM A490. Verify the applicable current revision for your project.

(internally threaded fastener) The axially-applied load using a bolt or threaded mandrel that must be supported by a nut without indication of thread stripping or failure. Ensures nut strength matches bolt requirements.

Reference identifiers: ASTM A194, ASTM A563. Verify the applicable current revision for your project.

The proof stress is the amount of stress (on a stress -strain curve) where a material will exceed the elastic/plastic limit. In other words, it begins to get a permanent set on further stressing. The 0.2% is the offset from the normal stress/strain curve ( a line drawn parallel to the normal curve – offset 0.2% of strain).

Reference identifiers: ASTM A325, ASTM A490. Verify the applicable current revision for your project.

The process during heat treatment of submerging steel in a liquid medium to rapidly cool it, typically in water or oil. Rapid cooling creates desired material properties including increased hardness and strength.

Reference identifiers: . Verify the applicable current revision for your project.

Surface discontinuities in an irregular or erratic pattern on the surface of the fastener which may occur because of excessive thermal or transformation stresses during fastener heat treatment. Can compromise fastener integrity.

Reference identifiers: . Verify the applicable current revision for your project.

A fastener having a body diameter not less than the minimum pitch diameter of its thread nor more than its minimum full body diameter. Used in applications where weight reduction or specific stress distribution is desired.

Reference identifiers: ANSI B18.2.1. Verify the applicable current revision for your project.

The difference between the original cross sectional area of a tensile test specimen and its minimum cross section after the test sample has fractured. A measure of material ductility and ability to deform before failure.

Reference identifiers: ASTM A325, ASTM A490. Verify the applicable current revision for your project.

The threading method that uses dies to displace rather than remove material in order to create threads. Often used in conjunction with reduced diameter body. Produces stronger threads than cut threads due to grain flow.

Reference identifiers: ANSI B1.1. Verify the applicable current revision for your project.

A test in which a bolt is assembled in a steel joint or tension measuring device with a lubricated nut, and tightened to not less than 10% of the bolt proof load. After initial tightening, the nut is rotated through specified degrees of rotation, and torque values are obtained to assure proper performance.

Reference identifiers: ASTM A325, ASTM A490. Verify the applicable current revision for your project.

Society of Automotive Engineers specification's cover fasteners typically used in automotive, equipment, and machinery applications. SAE grades indicate material strength and properties.

Reference identifiers: SAE J429, SAE J995. Verify the applicable current revision for your project.

A mechanical fastener designed to thread by turning the head into a tapped hole or to form its own threads during installation. Unlike bolts, screws typically don't require nuts.

Reference identifiers: ANSI B18.6.1. Verify the applicable current revision for your project.

A maximum load applied to a fastener's axis that can be withstood prior to failure. Critical property for fasteners in shear applications, such as structural connections.

Reference identifiers: ASTM A325, ASTM A490. Verify the applicable current revision for your project.

An area perpendicular to the fastener axis which is based on the root diameter (minor diameter) of an externally threaded bolt or screw. Used in engineering calculations for shear load capacity.

Reference identifiers: . Verify the applicable current revision for your project.

The high-strength bolt clamps the connected parts in such a way that the shearing force is resisted by the friction between the parts, not by the shear on the body of the bolts. This is often denoted on drawings as 'SC' (i.e. A325-SC). Requires proper surface preparation and bolt tension.

Reference identifiers: ASTM A325, ASTM A490. Verify the applicable current revision for your project.

A steel which has as its primary alloying element, chromium ranging from 10% to 30%. Other alloying elements such as nickel and molybdenum may also be added. Provides excellent corrosion resistance but may be susceptible to galling.

Reference identifiers: ASTM A193, ASTM A194. Verify the applicable current revision for your project.

An increase in strength and hardness resulting from the cold working of steel. This is also referred to as work hardening. Occurs during cold forming operations.

Reference identifiers: . Verify the applicable current revision for your project.

A heating process applied to forged/headed fasteners to relieve any mechanical stresses generated during the forming process. Improves dimensional stability and reduces risk of stress-related failures.

Reference identifiers: . Verify the applicable current revision for your project.

A heavy hex head bolt intended for use in structural applications. Most commonly graded as ASTM A325 or A490. Designed for critical structural connections in buildings, bridges, and other infrastructure.

Reference identifiers: ASTM A325, ASTM A490. Verify the applicable current revision for your project.

Irregularities of a fastener. These may include cracks, head bursts, shear bursts, seams, folds, thread laps, voids, tool marks, and nicks or gouges. Must be within acceptable limits per specification.

Reference identifiers: ASTM A325, ASTM A490. Verify the applicable current revision for your project.

A bolt that is threaded to the under the head. ANSI compliant tap bolts are made to the same tolerances as hex cap screws. Used where full thread engagement is required.

Reference identifiers: ANSI B18.2.1. Verify the applicable current revision for your project.

The maximum tensile-applied load a fastener can hold prior to fracture. The ultimate strength of the material, typically measured in pounds per square inch (psi) or megapascals (MPa).

Reference identifiers: ASTM A325, ASTM A490. Verify the applicable current revision for your project.

A written or electronic document provided by the authorized party to certify that a tested fastener's chemical and mechanical properties conform to the specification required. Provides quality assurance and traceability.

Reference identifiers: . Verify the applicable current revision for your project.

The displacement of material between mating threads during tightening, which causes contact points to shear, producing friction, increased resistance to tightening, and even seizing of the threads. Thread galling is most common with fasteners made of materials that self-generate an oxide surface film such as stainless steel.

Reference identifiers: . Verify the applicable current revision for your project.

A piece of steel typically threaded on each end used in an assembly with clevises and turnbuckles, often used to support canopies, awnings and other building structures. Provides adjustable tension support.

Reference identifiers: ASTM A36, ASTM A572. Verify the applicable current revision for your project.

The capability to authenticate manufacturing history by documentation of raw material, heat number, locations, or application of the product. Essential for quality control, recalls, and certification requirements.

Reference identifiers: ISO 9001. Verify the applicable current revision for your project.

The maximum tensile-applied load a fastener can support prior to fracture, and normally expressed in terms of pounds per square inch (psi) or pounds-force (lbf). The absolute maximum load capacity before failure.

Reference identifiers: ASTM A325, ASTM A490. Verify the applicable current revision for your project.