Expansion screws are a necessary tool for us to decorate houses, which can fix objects and be aesthetically pleasing. However, due to differences in specifications and models, there are some issues to be aware of when making a purchase. Below are the specifications and models of expansion screws introduced by the editor, as well as how to find the appropriate expansion bolt specifications.
1, Expansion screw specifications and models
Expansion screws on the market are mainly used for walls, fixed equipment, and columns, with specifications generally ranging from 3.6, 4.8, 6.8, 8.8, 9.8, and 12.9. The decimal points after these numbers represent the nominal tensile strength and yield strength ratio of the bolt raw materials. For example, bolts of grade 8.8 indicate that the tensile strength of their raw materials can reach 800 MPa, and the yield strength ratio can reach 0.8.
2, How to view the specifications of expansion bolts
When purchasing expansion bolts, we need to pay attention to their thread markings and size numbers. The thread marking generally uses the letter M, and the size number indicates the major diameter of the thread. For example, M14 indicates that the major diameter of a metric bolt is 14 millimeters. The complete thread marking includes thread feature number, dimension number, tolerance zone number, and other joint items, ultimately forming a standard number.
The bolt size number is generally composed of nominal diameter and torque. For coarse thread, the marking can be omitted, while for multi thread, the size number is the nominal diameter multiplied by Ph lead P torque. The tolerance zone number generally consists of numbers and uppercase or lowercase letters. For internal threads, uppercase letters are generally used, while for external threads, lowercase letters are generally used, such as 7H, 8g, etc.
The thread engagement length is also an important marker, generally represented by S, N, or L, where S represents shorter, L represents longer, and N represents medium. If the thread engagement length is not specified, the tolerance zone is generally determined based on the medium engagement length (N). If necessary, the rotation length can also be indicated in the remarks.
Through the above introduction, I believe everyone has understood how to choose suitable expansion screws and bolts. When decorating, it is important to choose the correct specifications and models to ensure the safety and aesthetics of fixed items.
