What grade is the screw?
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What is the commonly used screw grade 8.8, and what does it mean?
The high-strength bolts used in steel structures have a specific meaning, which refers to the use of a special wrench during the installation process to ensure that the screw has a specified pre-tension force, so that the contact surface of the connected panels has a specified pre-pressure. 8. The tensile strength f^bu of grade 8 high-strength bolts is not less than 800N/mm^2, and the yield-strength ratio is 0.8. 8. The commonly used materials for grade 8 high-strength bolts are 40B, No. 45 steel or No. 35 steel. After heat treatment, f^bu is not less than 830N/mm^2. Nuts and washers are made of No. 45 steel and are heat treated.