Hexagonal Nut

Hexagonal nut can be divided into three types according to their nominal thickness: type I, type II and thin type. Nuts above grade 8 can be divided into type I and type II.
Type I hexagonal nuts are the most widely used. Type 1 nuts are classified into three levels: A, B and C. Among them, Class A and B nuts are suitable for machines, equipment and structures with small surface roughness and high accuracy requirements, while Class C nuts are used for machines, equipment or structures with rough surface and low precision requirements.
Type II hexagonal nuts are thicker and are often used in occasions where assembly and disassembly are often required.
Type I nuts refer to hexagonal nuts with nominal height m (> 0.8D), whose type and size should meet the requirements of GB/T6170.

The height of type II nut is higher than that of type 1 nut, and its type size should conform to GB/T6175. There are two purposes for adding type II nuts. One is to get a cheaper nut without heat treatment by increasing the height of the nut.
Because type I nuts of Grade 8 with D < M16 need not be heat treated, type II nuts are used only for the specifications of Grade 8 nuts with D > M16 ~ 39.
It is obvious that type I nuts without heat treatment can not meet the mechanical performance requirements of grade 9 nuts. A 12-level nut with better toughness is obtained for another purpose of type II nuts. As the height of the nut increases, the guaranteed stress index can be achieved at lower quenching and tempering hardness, so the toughness of the nut is increased.
Classified by spacing: standard teeth, regular teeth, fine teeth, superfine teeth and reverse teeth.
According to material classification: stainless steel hexagonal nuts and carbon steel hexagonal nuts, copper hexagonal nuts, iron hexagonal nuts.
Classified by thickness: hexagonal thick nut and hexagonal thin nut.
Classified according to usage: hot-melt copper nut, hot-pressed copper nut, embedded copper nut and ultrasonic copper nut.