Closed End Cap Nut

六角焊接螺帽

a) This metallic nut features a flanged base with serrated grooves encircling its body.

b) This part is used for secure fastening in mechanical assemblies, with features designed to resist loosening under vibration.

c) The external structure, the serrated grooves or knurls, enhances grip for improved stability. 

With 6 projections

Steel two pieces hex collar cap nut

Hexagon flange white nylon insert lock nut serrations 

Carbon steel hex collar weld nut heat treated