BS EN ISO 898-2:2013 is a technical standard that specifies mechanical properties, dimensional tolerances, and testing requirements for carbon steel and alloy steel fasteners. It is part of the ISO 898 series, which covers various types of externally threaded fasteners.
Mechanical Properties
The standard defines different classes of fasteners based on their mechanical properties, including tensile strength, yield strength, elongation, and hardness. These properties are important for determining the suitability and performance of the fasteners in specific applications.
Tensile strength refers to the maximum amount of tensile load a fastener can withstand before fracturing. It is an essential property for ensuring the reliability and safety of fastening connections. Yield strength, on the other hand, represents the stress at which a fastener deforms plastically. It indicates the point at which a fastener starts to permanently elongate under load.
Elongation measures the amount of plastic deformation a fastener can exhibit before fracture. It is crucial in applications where dynamic loads or vibrations might be present. Hardness, typically measured using the Rockwell scale, provides information about the material's resistance to indentation or deformation.
Dimensional Tolerances
BS EN ISO 898-2:2013 also specifies dimensional tolerances for fasteners, such as thread diameter, pitch, and length. These tolerances ensure compatibility and interchangeability between fasteners from different manufacturers.
Thread diameter refers to the major diameter of the external threads of a fastener, while pitch represents the distance between adjacent threads. Length tolerance ensures that the fastener has the required length, allowing proper engagement with the mating parts. Dimensional conformity is vital for avoiding assembly issues and maintaining the integrity of the fastened joint.
Testing Requirements
The standard outlines testing methods and procedures to evaluate the mechanical properties of fasteners. These tests include tension testing, hardness testing, and impact testing.
Tension testing involves applying an axial load to a fastener until it fractures. This test determines the ultimate tensile strength and elongation characteristics of the fastener. Hardness testing measures the resistance of a fastener's surface to localized deformation or penetration.
Impact testing assesses the toughness and resistance to brittle fracture of the material used in the fastener. The results obtained from these tests provide valuable information about the reliability and performance of the fasteners under different loading conditions.
BS EN ISO 898-2:2013 is an essential standard in the fastener industry, ensuring the quality and reliability of carbon steel and alloy steel fasteners. It sets precise requirements for mechanical properties, dimensional tolerances, and testing procedures, enabling engineers and manufacturers to produce and select suitable fasteners for various applications.
Nina She