In mechanical manufacturing and construction engineering, bolts are a common connection element. The grade of bolts represents its material strength and performance, and bolts of grade 4.8 and grade 8.8 are common grades. This article will explain in detail the meaning of bolt grade 4.8 and compare it with grade 8.8 bolts to help readers better understand their differences and applicable scenarios.
The meaning of bolt grade 4.8
The grade of bolts consists of two numbers, which represent the material strength and tensile strength of the bolts. In bolt grade 4.8, the first number 4 represents the material strength of the bolt, that is, the tensile strength of the material used in the bolt is 400MPa. The second number 8 represents the tensile strength of the bolt, that is, the maximum bearing capacity of the bolt in tension is 8 times the material strength, that is, 320N.
Bolts of grade 4.8 are usually made of ordinary carbon steel and are suitable for some general low-strength connection scenarios, such as furniture manufacturing, light steel structures, and fixing of mechanical equipment. Due to its low material strength, bolts of grade 4.8 are relatively weak in bearing capacity and seismic resistance, so they are not applicable in some occasions with high connection strength requirements.
The meaning of bolt grade 8.8
Compared with bolt grade 4.8, bolt grade 8.8 has higher material strength and tensile strength. Among them, the first number 8 represents the material strength of the bolt, that is, the tensile strength of the material used in the bolt is 800MPa. The second number 8 represents the tensile strength of the bolt, that is, the maximum bearing capacity of the bolt in the tensile state is 8 times the material strength, that is, 640N.
Bolts grade 8.8 are usually made of alloy steel and are suitable for some occasions with high connection strength requirements, such as heavy machinery and equipment, bridges, high-rise buildings, etc. Due to its high material strength, bolts grade 8.8 are relatively strong in bearing capacity and seismic resistance, and can better meet the needs of engineering projects.
The difference between bolts grade 4.8 and 8.8
- Material strength: The material strength of bolts grade 4.8 is 400MPa, while the material strength of bolts grade 8.8 is 800MPa. The material strength of bolts grade 8.8 is twice that of bolts grade 4.8, so there is a significant difference in bearing capacity.
- Tensile strength: The tensile strength of bolts of grade 4.8 is 320N, while the tensile strength of bolts of grade 8.8 is 640N. The tensile strength of bolts of grade 8.8 is twice that of bolts of grade 4.8, so there is a significant difference in tensile capacity.
- Applicable scenarios: Bolts of grade 4.8 are suitable for some general low-strength connection scenarios, while bolts of grade 8.8 are suitable for occasions with higher connection strength requirements. It is very important to choose the appropriate bolt grade according to the specific project requirements.
Choose the appropriate bolt grade to ensure the safety and reliability of the connection
In mechanical manufacturing and construction engineering, choosing the appropriate bolt grade is crucial to the safety and reliability of the connection. Bolts of grade 4.8 are suitable for some general low-strength connection scenarios, while bolts of grade 8.8 are suitable for occasions with higher connection strength requirements. In practical applications, the appropriate bolt grade should be selected according to the specific project requirements, and the correct installation and use of the bolts should be ensured to ensure the firmness and stability of the connection.
