发布时间：2020-01-16 18:44 浏览：
When discussing whether the lengthening hexagonal flange screws should be divided into 8.8 and 10.9 grades, we first need to understand the meaning behind these two performance grades and the differences in practical applications. As an indispensable part of the connection, the performance level of the bolt is directly related to the stability and safety of the connection.
1. Definition and difference of performance levels
The performance grade of the bolt is determined through a series of standard tests, which mainly includes two key indicators: tensile strength and yield strength. Class 8.8 and 10.9 bolts are two important classes of high strength bolts, and the main difference between them is the numerical value of these mechanical properties.
8.8 bolt: After heat treatment (such as quenching, tempering), the nominal tensile strength of the bolt reaches 800MPa, and the nominal yield strength is 0.8 times the tensile strength, that is, 640MPa. This means that under normal conditions of use, the 8.8 bolt can withstand a large tensile force without breaking, while maintaining a certain elastic deformation capacity until the yield strength is reached.
Class 10.9 bolts: Compared to class 8.8, the performance of class 10.9 bolts is superior. Its nominal tensile strength reaches 1000MPa, and the nominal yield strength is 0.9 times of the tensile strength, that is 900MPa. This class of bolts not only has higher tensile strength, but also maintains structural integrity at higher stress levels, and is suitable for applications that require higher joint strength.
2. Differences in application scenarios
Due to the different performance levels, 8.8 and 10.9 bolts also have significant differences in application scenarios.
Class 8.8 bolts: Due to their moderate strength and good cost performance, Class 8.8 bolts are widely used in general industrial equipment, building structures, Bridges, automobiles and other fields. Although these occasions have certain requirements for connection strength, they are not extremely harsh, so 8.8 class bolts can meet most needs.
Class 10.9 bolts: Due to their higher strength and better fatigue resistance, Class 10.9 bolts are usually used in applications that require extremely high connection strength, such as heavy machinery, large steel structures, high-speed railways, aerospace and other fields. In these areas, connectors need to withstand huge dynamic loads and complex working environments, so more superior bolts must be selected to ensure the safety and reliability of the connection.
Third, selection principles and precautions
When selecting Grade 8.8 or 10.9 bolts, comprehensive consideration should be made according to the specific application scenario and requirements. Here are some selection principles and precautions:
1. Clear requirements: First of all, clear the type of load required to be borne by the connector, the size and the working environment and other factors, on this basis, select the appropriate bolt performance level.
2. Consider economy: under the premise of meeting the requirements of use, bolts with high cost performance should be selected as far as possible. Although the performance of class 10.9 bolts is superior, the cost is also relatively high, so unnecessary waste should be avoided.
3. Pay attention to matching: high-strength bolts usually need to be used with corresponding nuts, washers, etc., to ensure the integrity and reliability of the connection. When selecting, ensure that the performance levels of all components match.
4. ** Comply with standard specifications: When selecting and installing bolts, the relevant standard specifications should be strictly followed to ensure that the design, manufacturing, installation and inspection of the connecting parts meet the standard requirements.
5. Pay attention to the installation quality: The installation quality of high-strength bolts is crucial to the reliability of the connection. During the installation process, the size and distribution of the preload should be strictly controlled to ensure that the bolts achieve the expected tightening effect.
In summary, whether the lengthened hexagonal flange screws should be divided into 8.8 and 10.9 levels depends on the specific application scenarios and needs. By rationally selecting the performance grade of the bolt, the safety and reliability of the connector can be ensured, and the economic benefits can be maximized.
#8.8 Extended hex flange screws #10.9 Extended Hex flange screws # Extended hex flange screws # flange long screws # Fasteners
