Fastener knowledge: requirements for hot-dip galvanizing of nuts

The so-called hot-dip galvanizing is an effective metal anti-corrosion method. It is to immerse the derusted screw in a molten zinc solution at about 500°C to attach a zinc layer to the surface of the nut to play a role in corrosion protection. Since the hot-dip galvanized layer is thicker (generally more than 40um), considering its impact on the accuracy of the thread, the hole diameter of the hot-dip galvanized nut must be slightly enlarged than that of the ordinary nut when it is formed. The specific requirements are as follows: Enlarged aperture size mm ≤7/16 >7/16 M10-M14 M16-M20 M24 M27 M30 0.41 0.53 0.35 0.40 0.45 0.50 0.55 2. The upper limit of the final control size of the opposite side and thickness is larger than the upper limit of the specification by 0.5mm. (Guide: Inventory! Moisture-proof and dust-proof measures for mechanical fasteners)

1. The metric system (DIN, ISO, GB) is divided into 6H and 6G grades. Normally, it is 6H level. The metric Japanese standard (JIS) is divided into three types: Class I, Class II, and Class III. The usual condition is level II.

2. The English system is 1B, 2B, and 3B. Normally, it is 2B grade.

3. At present, there are two kinds of angles of thread taps: 600 and 550, 600 has metric thread, British UNC UNF, etc., 550 has Wyeth thread, BSW, BSF, etc.

4. The main geometric parameters of the thread are: thread major diameter, pitch, thread middle diameter, and thread rising angle.

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Inventory! Moisture-proof and dust-proof measures for mechanical fasteners

Inventory! Moisture-proof and dust-proof measures for mechanical fasteners

Inventory! Moisture-proof and dust-proof measures for mechanical fasteners