The spherical nut for the anchor rod is an element of the anchor tie, which is used to improve the tension of the structure and increase the stability in the rock: igneous, sedimentary, metamorphic. The main external feature is a hemisphere at the bottom with a built-in hex nut with a female metric thread.
A spherical nut is produced from steel of different grades: alloyed, low-alloyed, high-alloyed. The product is high-strength, resistant to mechanical loads, static shocks and vibrations. For additional protection against corrosion the surface of the nut is covered with a layer of nickel or zinc by galvanic method. The thickness of the protective layer is 0.02-0.05 mm.