PROPERTY CLASS 10 NUTS (ISO 898-2) — TECHNICAL DATASHEET AND ENGINEERING REPORT

Property Class 10 represents a critical high-tensile classification for metric nuts, governed by the international specification ISO 898-2 ED-2022. These high-strength nuts are engineered specifically to pair with Property Class 10.9 bolts and studs, ensuring secure clamping forces in heavy-duty machinery, automotive suspensions, and critical structural steelwork applications.

To maintain joint integrity and prevent catastrophic thread stripping, Class 10 nuts are designed with a minimum proof stress (typically 1040 MPa) that exceeds the minimum ultimate tensile strength of a mating Class 10.9 bolt. This ensures that in an extreme over-tension scenario, the bolt will safely yield and fracture before the nut's internal threads shear, providing a predictable and visible indication of joint overload.

The chemical composition for Class 10 nuts is strictly controlled to guarantee exceptional hardenability during thermal processing and to maintain structural integrity under extreme dynamic loads. Phosphorus and sulfur are tightly capped to minimize the risk of grain boundary embrittlement.

To guarantee absolute performance under maximum preload conditions, Ananka ensures absolute chemical and mechanical precision through rigorous testing protocols.

• EN 10204 Type 3.1: Detailed reporting of actual ladle chemical analysis, specifically verifying strict Phosphorus and Sulfur caps alongside mandatory mechanical proof load testing.
• EN 10204 Type 3.2: Third-party witness certification (e.g., DNV, TUV, ABS) provided for critical heavy machinery and structural steelwork applications.

Property Class 10 nuts are subjected to rigorous thermal processing routes across all metric sizes. Hardening is achieved via oil quenching, followed by air cooling during the tempering phase to stabilize the martensitic microstructure and hit designated high-strength hardness and proof load parameters.

ISO 898-2 dictates that a Class 10 nut must be able to withstand the specified proof load without failure or thread stripping. The following values reflect the minimum proof loads for standard coarse pitch threads.

• Material Specification: Manufactured strictly according to ISO 898-2.CL 10 ED-2022 standards.
• Dimensional Standards: Tolerances, flat widths, and overall profiles are maintained precisely as per approved international drawings (DRG).
• Mating Compatibility: Class 10 nuts are strictly intended for mating with bolts of Property Class 10.9 or lower. Utilizing these nuts with Class 12.9 bolts risks nut stripping prior to bolt yield, leading to unpredictable joint failure.
• Hydrogen Embrittlement Risk: With hardness levels reaching up to 36 HRC, Class 10 nuts are highly susceptible to hydrogen embrittlement. If electroplating (e.g., zinc plating) is required, an immediate post-treatment de-embrittlement bake (typically 200°C for ≥4 hours) is mandatory to preserve structural integrity.
• Corrosion Protection: For marine or corrosive outdoor environments, specify Hot-Dip Galvanizing (HDG) or Zinc Flake coatings to prevent rapid oxidation while avoiding the embrittlement risks associated with standard electroplating.