Product Introduction
Prevailing torque hexagon lock nuts manufactured to DIN 982, now superseded by ISO 7040 (coarse thread) and ISO 10512 (fine thread). The nut incorporates a non-metallic polyamide ring permanently retained in the upper threaded section. During installation, the nylon insert deforms around the bolt threads, creating frictional resistance that holds the nut in place under vibration and dynamic loading. The high-profile (thick) body provides increased thread engagement compared to standard hex nuts. Sizes from M3 to M48 in metric coarse and fine pitches.

Material & Mechanical Properties
Carbon steel versions are supplied in property classes 6, 8, and 10 per ISO 898-2 (class 4.8 also available in limited sizes). Class 8 is standard for general industrial use; class 10 is specified where higher proof load is required. Stainless steel versions conform to A2-70 and A4-80 per ISO 3506, with A4-80 selected for chloride-exposed environments. Mechanical values are certified by lot, traceable to heat number.

Geometry & Thread
High-profile nut heights and widths across flats follow DIN 982 / ISO 7040 tables. For example, M16 height is 17.7 mm and M20 height is 22.0 mm, providing greater thread engagement than standard nuts. Width across flats for M10, M12, and M14 are 16 mm, 18 mm, and 21 mm respectively under the current ISO standard. Metric coarse and fine thread series are available. The nylon insert is located at the top of the nut, leaving the lower threads free for initial bolt engagement.

Locking Mechanism & Temperature Limits
The polyamide (nylon 66) insert is mechanically retained, not bonded. As the bolt threads pass through, the insert is compressed and cut into, generating prevailing torque independent of clamp load. This resistance prevents loosening from vibration and eliminates the need for additional locking washers or adhesives. Maximum continuous service temperature for the insert is approximately 120 °C; above this, the nylon softens and locking performance degrades. The nut is not recommended for high-temperature service. After removal, the insert may not fully recover its original shape; reuse is not recommended for critical joints.

Corrosion Protection
Standard finishes for carbon steel include zinc electroplating with clear, yellow, white, or blue passivation; hot-dip galvanizing for structural exposure; and black oxide for appearance. RoHS-compliant coatings are available. Stainless steel nuts are supplied passivated.

Application Suitability
Automotive assemblies, agricultural machinery, conveyors, engine mounts, and general industrial equipment where vibration resistance and simplified assembly are required. The one-piece prevailing torque design reduces part count and eliminates the need for separate locking elements. Stainless A4 versions are used in marine, food processing, and chemical environments.