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Classification standards for self-tapping screws

The implementation standards of self-tapping screws for drilling tails are GB / T 15856.1-2002, German standard DIN7504N-1995, and Japanese standard JIS B 1124-2003.

This kind of screw has a drill tail tip, and the tip is named like a twist drill. During assembly, the screw can drill the center hole by itself, and then self-tapping and squeezing the matching hole in the hole on the carrier by means of the adjacent thread part Thread, so called self-drilling self-tapping screw.

Drilling screws can be divided into national standard GB / T, German standard DIN, Japanese standard JIS, and international standard ISO according to the implementation standard.

According to the purpose and shape, it can be divided into the following categories:

1. Cross recessed pan head self-drilling self-tapping screws. Cross recessed pan head drilling screws with tapping screw thread Executive standard: GB / T 15856. 1-2002 has the following specifications: (also known as round head drilling tail).

2. Cross recessed countersunk head self-drilling self-tapping screws. Cross recessed countersunk head drilling screws with tapping screw thread Executive standard: GB / T 15856.2-2002 has the following specifications: (also known as flat head drilling, salad head drilling).

3. Cross recessed countersunk head drilling screws with tapping screw thread: Cross recessed countersunk head drilling screws with tapping screw thread Executive standard: GB / T 15856.3-2002 has the following specifications: This specification is a semi countersunk head and is relatively rare in the market.

4. Hexagon flange head drilling screws with tapping screw thread Implementation standard: GB / T 15856.4-2002 has the following specifications: (also known as hexagonal Dahuas drill tail, which is among the drilling screws The most commonly used and the largest quantity.)

5. Hexagon washer head drilling screws with tapping screw thread. Executive standard: GB / T 15856.5-2002 has the following specifications: (also known as hexagonal small Huasi drill tail.)

According to the material, it can be divided into:

Steel 1022A, stainless iron 410, stainless steel 304.

1. Carbon steel self-drilling screw, 1022A, standard heat-treated steel can be used as material for the production of self-drilling screw, the surface hardness after heat treatment is HV560-750, and the core hardness is HV240-450. Common surface treatment is easy to rust, high hardness and low cost.

2. Stainless steel self-drilling screws, 410, can be heat-treated, the anti-rust ability is better than carbon steel, and worse than stainless steel.

3. Stainless steel self-drilling screws, 304, can not be heat-treated, strong rust resistance, low hardness, high cost, can only drill aluminum, wood, rubber.

4. Compound drilling screws, the drill bit is made of carbon steel, and the thread and head are made of 304 stainless steel.

Uses: generally used for the fastening and connection of aluminum profiles, wood products, thin-walled steel pipes, steel plates and non-ferrous metal plates. Self-tapping and self-drilling screws are often used for the fastening and connection of steel plates or steel pipes with wall thickness greater than 2.0 When connecting, use screws to tap the threads directly.

Advantages: high corrosion resistance, no hydrogen embrittlement, excellent heat resistance and excellent weather resistance