Have you ever understood the strength level of the combination screw, the different combination screws, and the strength level are also different. Combination screws have many national standards and will have a division of strength levels. Combination screws are no exception. The combination of the strength grade of the combined screws is divided according to the material of the screw wire and the hardness index of the screw wire. The general combination screw material is divided into stainless steel and iron, and the stainless steel is divided into stainless steel 201, stainless steel 304 and stainless steel 316. Iron is divided into three types: low carbon steel, medium carbon steel and high carbon steel.
The carbon steel combination screw refers to the combination screw of the iron. The general iron combination screw grade is divided into 4.8, 8.8, 10.9, and 12.9. However, in the market, 10.9, 12.9 combination screws are rarely used, we will not talk about it here. And the combination of screws on the market, the more commonly used combination of 4.8 and 8.8 screws.
The 4.8-level combination screw is generally made of a 1010A pier with a screw wire. After the screw wire pier is screwed, the assembly with the flat pad is combined. After being manufactured, this 4.8-stage combination screw does not need to be hardened. Its hardness can reach 4.8.
The 8.8-class combination screw is generally made of the screw wire 10B21 pier. After the screw wire pier is screwed into the screw, it is equipped with a spring pad and a flat pad, and can automatically wear a flat pad machine to combine the three pieces of the tooth. Fasten the combination of the flat washers on the screws and the flat washers will not fall off. After the combination screw is produced, it needs to be hardened to make the hardness reach 8.8. After the hardness reaches 8.8, we need to take the plating treatment. In order to prevent the elastic pad in the 8.8-stage combination screw with hardness added, it is easy to break. In this way, we have to remove the hydrogen from the hardened combination screws, and then electroplating can be done after the hydrogen is removed.
In short, there are many types of standard screw strength classification, but generally only two types are used in the market, one is the 4.8-level combination screw strength, and the other is the 8.8-level combination screw strength. In the market, the 4.8-level combination screw is the most used and has a wide range of applications. For the standard strength of the 8.8-class combination screw, we generally refer to the 8.8-class hexagonal combination screw, the 8.8-level pan head combination screw, and the 8.8-stage hex combination screw. These three are more commonly used.