Hexagon槽螺母 are categorized into Type I, Type II, and Thin Type according to nominal thickness. Nuts with a grade of 8 and above are available in two types: Type I and Type II.

The Type I hexagon slot nuts are widely used. The 1-type nuts are further divided into A, B, and C grades. Grade A and B nuts are suitable for machines, equipment, and structures with low surface roughness and high precision requirements, while grade C nuts are used for machines, equipment, or structures with relatively rough surfaces and lower precision requirements; the Type 2 hexagon slot nuts have a thicker thickness and are commonly used in situations that frequently require assembly and disassembly.

Type 1 nut refers to a general hex socket cap screw with a nominal height m ≥ 0.8D, whose dimensional specifications should comply with the requirements of GB/T6170.

The height of type 2 nuts is higher than that of type 1 nuts, and their dimensions should comply with GB/T6175. The purpose of increasing the type 2 nut involves two aspects: first, by increasing the nut's height, a heat-treatment-free and more cost-effective nut is achieved.