Lock nut
Prevailing torque lock nuts are made from Grade 5 or 8 carbon steel with hot-dip galvanized or dichromate coating. Their common inner diameter ranges from M3 to M24 per ISO 7040 standard. The total nut height is typically 0.8 to 1.5 times the nominal diameter. The locking element features an integrated washer or a nylon-6,6 ring with 30% glass fiber. The operational temperature range for this polymer ring is -40 to +120°C. The minimum breakaway torque after locking is 0.5 to 1.5 times the nominal tightening torque. The steel body hardness reaches 70 to 100 Rockwell B after heat treatment. Coating thickness on the body is between 8 and 12 microns. This coating ensures corrosion resistance for up to 500 hours in salt spray tests.
The nut structure consists of a hexagonal base and an integral locking section. The internal nylon ring typically covers 180 to 360 degrees of the thread circumference. The effective diameter of the polymer ring is about 1.1 times the base thread diameter. This design creates a radial pressure of 50 to 100 MPa on the screw. The recommended tightening torque with a torque wrench is between 5 and 400 Nm. Grade 8 nuts maintain their locking capability under vibrations of 10 to 2000 Hz. The tensile strength of these nuts ranges from 520 to 830 MPa. The int
