In the construction site, through repeated inspection and test of the products, the situation that the products are not tightened due to the existence of grooves, pits and oil contamination on the surface of combination screw, welding nut and washer is eliminated. Through the analysis and comparison with the similar products of surface phosphating treatment, it is found that the problem that the products can not tighten up to the pre-tightening force value lies in the way and technology of surface treatment. Because the oxide layer is too thick, the combination screw is not tight, so that the phenomenon that can not meet the pre-tightening force numerical requirements occurs.

As we all know, in combination screw, if it is three combination screw, it is generally disk head screw, or external hexagonal screw, with a cushion in a flat cushion combination of three components. But what specific requirements are there in the elastic pad? Next, we will briefly introduce the specific requirements for the flat mat in the combined screw.

I believe that we usually encounter various kinds of screws in daily life. Bicycles have screws, carriage screws, computers, telephones, MP4 and other electronic products. They also have screws, so that we can find a screw in the eyeglasses frame, so that we can find the combination screws that are everywhere in our life. The combination screws have basically covered our lives.

Titanium alloy screw has the characteristics of low density and high strength. It is generally used in places where both weight and strength are required, but titanium alloy screw is not a high strength material.