In the field of metal manufacturing, sheet metal stamping is one of the core processes, and the selection of fasteners directly determines the stability and durability of the product. As a high-quality supplier with 28 years of experience in custom metal parts production, Kailai Machinery is well versed in the adaptation logic of screws in different scenarios - from shape design to material properties, from surface treatment to special functions, each choice must be deeply matched with the process requirements and use environment of sheet metal stamping parts. The following is a multi-dimensional analysis of screw classification and applicable scenarios to provide accurate reference for sheet metal stamping projects.

1. Classification by head shape: Adapting to the structural and appearance requirements of sheet metal parts

The structural diversity of sheet metal stamping parts requires that the shape of the screw head must be highly consistent with the installation space and surface flatness requirements.

Round head screw: The head is semicircular, and the exposed part is round and smooth after installation. It is widely used in scenes with requirements for appearance, such as electronic equipment sheet metal shells and instrument panels. Its larger force-bearing surface can disperse the pressure and prevent the thin sheet metal from being deformed due to excessive tightening force. It is especially suitable for cold-rolled steel stampings with a thickness of 0.5-2mm.

Flat head screw (countersunk screw): The head can be completely sunk into the preset countersunk hole of the sheet metal to keep the surface flat. It is the first choice for precision sheet metal components (such as automobile dashboard stampings and medical equipment housings). In metal manufacturing, the countersunk hole process with laser drilling can achieve a "zero protrusion" connection between the screw and the sheet metal, meeting the requirements of dust and scratch resistance.

Hexagonal head screw: The hexagonal head can apply a large torque through a wrench, and it undertakes high-strength fastening tasks in heavy sheet metal structures (such as industrial machine tool frames and container stampings). It has a large contact area with the sheet metal, is not easy to loosen in a vibrating environment, and is suitable for hot-rolled steel stampings with a thickness of more than 3mm.

Hexagon socket screws: The head is a concave hexagon, which requires a special wrench to operate. It takes up little space after installation and is suitable for dense sheet metal components (such as stamping brackets inside distribution cabinets). In the precision assembly of metal sheet metal stamping, it can reduce interference with adjacent components.

2. Classification by material: Match the environmental tolerance of sheet metal parts

The selection of screw material needs to be coordinated with the substrate and use environment (such as humidity, corrosiveness, temperature) of the sheet metal parts to avoid electrochemical corrosion and ensure strength.

Carbon steel screws: Low cost and wide strength range, it is the mainstream choice for ordinary sheet metal stamping parts. Low carbon steel (such as 1008 steel) is suitable for non-load-bearing scenarios (such as fixing sheet metal protective covers); medium carbon steel (such as 45 steel) can be used for medium load connections (such as storage shelf stamping beams) after heat treatment; high-strength carbon steel (8.8 grade, 12.9 grade) is suitable for thick sheet metal parts such as automobile chassis and engineering machinery that need to withstand impact loads.

Stainless steel screws: Containing alloy elements such as chromium and nickel, they have excellent corrosion resistance and are indispensable in humid, outdoor or mildly corrosive environments. 304 stainless steel screws are suitable for kitchen equipment and bathroom sheet metal parts; 316 stainless steel screws can withstand the salt spray environment in coastal areas due to the addition of molybdenum elements, and are often used to connect sheet metal stamping parts in marine engineering; 410 stainless steel screws have high strength but slightly weaker corrosion resistance, and are suitable for high-strength sheet metal fixation in dry environments (such as elevator car stamping frames).

Aluminum alloy screws: Lightweight and compatible with aluminum alloy sheet metal parts, they can avoid electrochemical corrosion caused by contact between dissimilar metals. They are widely used in new energy vehicle bodies and aerospace sheet metal components, helping to upgrade the lightweight metal manufacturing.

Copper alloy screws: Mainly brass, they have outstanding electrical and thermal conductivity. In electrical sheet metal parts (such as distribution box stamping housings and motor end covers), they can both fasten components and conduct current, meeting the dual needs of functionality and connectivity.

3. Classification by surface treatment: Improving the compatible life of screws and sheet metal parts

For different working conditions, surface treatment of screws can enhance their corrosion resistance and wear resistance, while optimizing compatibility with sheet metal parts.

Galvanized screws: A zinc layer is formed on the surface through cold galvanizing or hot galvanizing. The cost is lower than stainless steel and is suitable for humid but non-corrosive environments (such as outdoor advertising light box stampings and building curtain wall support sheet metal). The hot-dip galvanizing layer is thicker and more corrosion-resistant, and is suitable for sheet metal structures exposed outdoors for a long time.

Chrome-plated screws: The surface has high hardness and good finish, and has both anti-rust and decorative functions. It is often used for exposed connections of home appliance sheet metal panels (such as washing machine control panels) to enhance product texture.

Phosphate screws: A phosphate film is formed on the surface, which can enhance the adhesion with paint. In sheet metal stampings that need to be painted (such as automobile body covers), it can prevent the paint layer from falling off and improve the anti-rust ability.

4. Classification by special purpose: Solving the complex connection problems of sheet metal stamping

In the special scenario of metal sheet metal stamping, conventional screws are difficult to meet the needs, and special screws become the key solution.

Self-tapping screws: No need to pre-tap, can be directly tapped into the prefabricated small holes of sheet metal parts, suitable for thin plate connection (such as computer case stamping parts), simplifying the assembly process and improving production efficiency.

Expansion screws: Through the expansion tube and the base body, large sheet metal parts (such as air conditioner outdoor unit brackets, industrial equipment bases) are fixed on non-sheet metal substrates such as concrete and walls to ensure stable installation.

Anti-theft screws: The head design is special (such as inner plum blossom with column), and special tools are required for disassembly to prevent human damage in public facility sheet metal parts (such as street light poles, traffic sign stamping parts).

Flange screws: The head has a flange surface, which can increase the force area without additional gaskets, improve the anti-loosening performance in a vibration environment (such as the sheet metal shell of mechanical equipment), and reduce the risk of loosening caused by vibration.

In the practice of metal manufacturing, the adaptation of metal sheet stamping and fasteners is a combination of technology and experience. As a custom metal parts manufacturer with 28 years of experience, Kailai Machinery can not only assist in providing customized services for all categories of screws, but also accurately match the best fastener solutions for you according to the material, structure, and working conditions of sheet metal parts, from shape, material, surface treatment to special functions, to ensure that every connection is both reliable and economical.

Whether it is precision electronic sheet metal or heavy industrial stamping parts, our professional team can help your products stand out in the market competition with deep technical accumulation. Choose us, so that the selection of fasteners in metal sheet stamping will no longer be a problem, and jointly promote the quality upgrade of the metal manufacturing industry.