tiancong fastener logo

中文 / EN

SERVICE HOTLINE +8615533066727

background picture
background picture
  

the strength of hex bolt

2020-06-27

The performance grades of bolts for steel structure connection are divided into more than 10 grades such as 3.6, 4.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9, 12.9, among which the bolts of grade 8.8 and above are made of low-carbon alloy steel or medium-carbon steel and are heat-treated (Quenching, tempering), commonly known as high-strength bolts, and the rest are commonly known as ordinary bolts. The bolt performance grade label consists of two parts, which respectively indicate the nominal tensile strength value and the yield ratio of the bolt material.

For example, a bolt with a performance level of 4.6 means:
1. The nominal tensile strength of the bolt material reaches 400MPa;
2. The yield ratio of the bolt material is 0.6;
3. The nominal yield strength of the bolt material reaches 400×0.6=240MPa level

Performance grade 10.9 high-strength bolts, after heat treatment, the material can reach:
1. The nominal tensile strength of the bolt material reaches 1000MPa;
2. The yield ratio of the bolt material is 0.9;
3. The nominal yield strength of the bolt material is 1000 The meaning of the performance level of ×0.9=900MPa bolts is an international standard. The performance of the bolts of the same performance level is the same regardless of the difference in material and origin. Only the performance level can be selected in the design.

The so-called strength grades of 8.8 and 10.9 refer to the bolt's shear stress resistance grades of 8.8 GPa and 10.9 Gpa

General bolts use "XY" to indicate the strength,
X*100=the tensile strength of this bolt
X*100*(Y/10)=the yield strength of this bolt
(because according to the label: yield strength/tensile strength =Y/10)
Such as 4.8,
the tensile strength of this bolt is: 400MPa
and the yield strength is: 400*8/10=320MPa

Alibaba Store Link
Click Open Alibaba Store
Icaigou Store Link
Click Open Icaigou Store