A hex head bolt is a fastener consisting of a head and a shank. Bolts are classified by material into iron bolts and stainless steel bolts, namely hex head bolts (partially threaded) - Grade C and hex head bolts (fully threaded) - Grade C.
A hex head
bolt is a fastener consisting of a head and a shank. Bolts are classified by material into iron bolts and stainless steel bolts, namely hex head bolts (partially threaded) - Grade C and hex head bolts (fully threaded) - Grade C.
Performance Grades: Bolts used for steel structure connections are classified into more than 10 performance grades, including 3.6, 4.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9, and 12.9. Bolts of grade 8.8 and above are made of low-carbon alloy steel or medium-carbon steel and undergo heat treatment (quenching and tempering), commonly referred to as high-strength bolts. The rest are commonly referred to as ordinary bolts. The bolt performance grade designation consists of two parts, representing the nominal tensile strength and yield strength ratio of the bolt material. For example: A bolt with a performance grade of 4.6 means:
1. The nominal tensile strength of the bolt material reaches 400 MPa;
2. The yield strength ratio of the bolt material is 0.6;
3. The nominal yield strength of the bolt material reaches 400 × 0.6 = 240 MPa.
A high-strength bolt with a performance grade of 10.9, after heat treatment, can achieve:
1. The nominal tensile strength of the bolt material reaches 1000 MPa;
2. The yield strength ratio of the bolt material is 0.9;
3. The nominal yield strength of the bolt material reaches 1000 × 0.9 = 900 MPa. The meaning of bolt performance grades is an internationally accepted standard. Bolts with the same performance grade have the same performance regardless of their material or origin; only the performance grade needs to be selected in the design.
The strength grades 8.8 and 10.9 refer to the bolt's shear stress resistance grades of 8.8 GPa and 10.9 GPa, respectively.
