What About The Specifications And Models Of Expansion Screws And Expansion Bolts?

Expansion screws are a necessary tool for us when decorating houses, which can fix items and are aesthetically pleasing. However, due to differences in specifications and models, there are some issues to pay attention to when choosing. Below are the specifications and models of expansion screws introduced by the editor, as well as how to find a suitable expansion bolt specification.

1、 Specification and model of expansion screw

The expansion screws on the market are mainly used on 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 point after these numbers represents the nominal tensile strength and yield ratio of the bolt material, respectively. For example, 8.8 grade bolts indicate that the tensile strength of their raw materials can reach 800MPa, and the yield strength ratio can reach 0.8.

2、 What are the specifications of expansion bolts

When purchasing expansion bolts, we need to pay attention to their thread markings and size numbers. Thread markings generally use the letter M, and the size number represents the major diameter of the thread. For example, M14 represents a major diameter of 14 millimeters for metric bolts. The complete thread marking includes thread feature number, dimension number, tolerance zone number, and other combination items, ultimately forming a standard number.

The size number of bolts is generally composed of nominal diameter and screw 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 screw 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, usually represented by S, N, or L, where S represents shorter, L represents longer, and N represents medium. If the thread engagement length is not indicated, the tolerance zone is generally determined based on the moderate engagement length (N). If necessary, the screwing 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.