With the development of society, there are more and more mechanical products. In order to better meet different demands, many enterprises will use various fasteners on their products, such as bolts, nuts, screws, washers, etc. There are a wide variety of fasteners on the market with varying quality. If you don’t pay attention to procurement, the selected fasteners will be unqualified, leading to problems such as looseness, rust, or breakage during connection and assembly, and even causing safety hazards. Therefore, it is necessary to strictly control the selection of fasteners to avoid this situation. So how to select qualified fasteners?
1.Material and strength
In the process of fastening and connecting, breakage is a common occurrence. The reason for this situation may be due to the incorrect selection of the material and model of the fastener, and secondly, the incorrect selection of the strength of the fastener. Fasteners are made of carbon steel , stainless steel, copper, aluminum alloy, titanium alloy, and other materials. Among them, the hardness of medium carbon steel, stainless steel, and titanium alloy is higher than that of copper and aluminum. Therefore, if it is used to connect components with high thickness, hardness, and structural strength, it is necessary to try to choose fasteners made of medium carbon steel, stainless steel, etc.so as not to break the fasteners due to the weight of the connected parts. At the same time, when selecting fasteners, it is also necessary to pay attention to selecting their strength levels. For example, carbon steel screws have multiple levels such as 4.8, 5.8, 6.8, 8.8, 10.9, 12.9,etc. The higher the strength level, the higher the hardness of the fastener, and the relatively less likely it is to break.
2. Finishing
Carbon steel screws are made of iron and are prone to rusting without surface treatment. Manufacturers often apply various surface treatments such as blackening, galvanizing, copper plating, chromium plating, dacromet, etc. on the surface of fasteners. In order to avoid the use of environmental factors, when selecting fasteners, it is necessary to focus on the level of coating technology for fasteners, and the coating thickness should be uniform, with stronger and more durable oxidation resistance.
3. Thread
Fastener threads are generally divided into fine and coarse threads.Coarse threads are widely used due to their high strength and good interchangeability, making them the optimal choice. Fine threads have a small space size and good self-locking performance, and are mostly used in places where there is not much force and can be accurately adjusted. Due to the small pitch of fine threads and the small height of the tooth shape, it is easy to have disordered teeth during installation, resulting in the inability to enter and exit. Overall, coarse thread screws have high strength and fine thread screws are well sealed.
Post time: Jul-25-2023