The meaning of hex flange nut grade

Type I hex flange nut is the most widely used, I-type nut is divided into A, B, C three levels, of which A-class and B-class nuts are suitable for machines, equipment and structures with small surface roughness and high accuracy requirements, while C-class nuts are used for machines, equipment or structures with rough surfaces and low accuracy requirements; the thickness of type II hex flange nut is relatively thick, and they are mostly used in occasions where assembly and disassembly are often needed.

Below is a directory

l Classification of hex flange nuts

l How nut grades should match

Classification of hex flange nuts

Hex flange nuts are divided into three types according to nominal thickness: type I, type II and type thin. Nuts above level 8 are divided into two types: type I and type II.

Nut A; B; C-class is comparable to the US-made G2; G5; The performance level of G8, J995 stipulates that the performance level between the two is basically the same.

Type I nut thread specification is M1.6~ M64 performance class 6; 8; 10; A2-50; A2-70; A4-50; A4-70; CU2; CU3 and AL4 grades, product grades A and B, A class is used for specifications with specifications less than or equal to M16, and class B is used for specifications larger than M16.

Type II nut thread specifications are M5 ~ M36, performance grades are 9 and 12 grades, product grades are A and B grades, A grade is used for specifications less than or equal to M16, and B grades are used for specifications larger than M16.

Due to the high requirements of the performance level of the type 2, the thickness of the nut is thickEr the bolt performance grade is divided into 3.6, 4.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9, 12.9 and other more than 10 grades, of which the bolt material of 8.8 and above is low carbon alloy steel or medium carbon steel and heat treatment (quenching, tempering), commonly known as high-strength bolts, and the rest are commonly referred to as ordinary bolts.

How nut grades should match

Metric bolts are graded: 4.6; 4.8; 5.8; 6.8; 8.8; 9.8; 10.9; 12.9.

The grades of metric nuts are: 4; 5; 6; 8; 10; 4 of 12 of them; 5 is the strength grade of the thin nut.

In some cases, the hex flange nut is a little weaker than the bolt, mainly because: bolt failure is usually less noticeable, sometimes sudden, and nut failure is more easily detected. The security aspect is also considered. This ensures that the life of the screw is longer than that of the hex flange nut when used in combination, and the cost will be lower and easier when the fastener is removed and replaced.

Ningbo Yipianhong Fastener Co., Ltd. was established in 2001, specializing in the production of various high-strength bolts, nuts and screws, with an annual production capacity of 30,000 tons and an annual turnover of 300 million yuan. Products include ANSI/ASTM, DIN, BS, ISO, GB, JS and other standards, mainly used in the field of high-strength seals and oil pipeline valves.