ISO 6157-3 Fasteners - Surface Discontinuities - Bolts for Special Requirements - Screws and Studs

Metal Test Laboratory

ISO 6157-3 Fasteners - Surface Discontinuities - Bolts for Special Requirements - Screws and Studs

EUROLAB, with its state-of-the-art accredited laboratories and expert team, offers precise and rapid testing services within the scope of ISO 6157-3 testing. This part of ISO 6157 establishes limits for various surface discontinuities on bolts, screws and studs for special requirements.

ISO 6157-3 Fasteners - Surface Discontinuities - Bolts for Special Requirements - Screws and Studs

Bolts, screws and studs apply to:

  • Nominal thread diameters 5 mm and larger;
  • Product classes A and B;
  • Nominal lengths I < 10d (or longer if specified);
  • Property class 12.9;
  • Property classes 8.8, 9.8 and 10.9 when specified in the product standards or agreed between the supplier and the buyer.

Where the permissible limits for specified surface discontinuities occur, the minimum values ​​for mechanical and functional properties specified in ISO 898-1 must still be met.

When fatigue strength requirements are determined, the fatigue strength should not be lower than that obtained for defect-free bolts from the same batch.

A crack is a clean (crystalline) fracture that passes through or across grain boundaries and may possibly follow the incorporation of foreign elements. Cracks normally result from excessive stressing of the metal during forging or other forming operations or heat treatment. Where parts have been subjected to significant reheating, the cracks often become discolored due to limescale.

EUROLAB assists manufacturers with ISO 6157-3 test compliance. Our test experts, with their professional working mission and principles, provide you, our manufacturers and suppliers, the best service and controlled testing process in our laboratories. Thanks to these services, businesses receive more effective, high-performance and quality testing services and provide safe, fast and uninterrupted service to their customers.

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