What Is a Flange Nut?

Flange nuts, also known as washers, toothed nuts, hexagon flange nuts, flange nuts, etc. Mostly used for pipe connection or workpieces that need to increase the nut contact surface.

Flange nut

Flange

Chinese name : flange

Due to the small size of the flange nut, the shape of the flange nut is irregular, and some also require thread fitting, so there are some obvious defects in hot-dip galvanizing.

1. Screwing is difficult after plating. After hot-dip galvanizing, the remaining zinc sticks in the thread is not easy to remove cleanly, and the thickness of the zinc layer is uneven, which affects the fit of the threaded parts. It is stipulated in GB / T13912-1992 "Technical requirements for hot-dip galvanizing of metal covering steel products" and GB / T2314-1997 "General technical requirements for electric power fittings"; the external threads of fasteners should be in accordance with GB196 before hot-dip Standards specify machining or rolling, while internal threads can be machined before or after hot dip plating. However, in actual applications, customers often require galvanized layers on both internal and external threads, so people adopt a variety of measures to solve the hot dip galvanization of threaded fittings. Such as screwback after plating; reserve a large fit clearance; centrifugal shake and other methods. Back tapping can easily damage the plating of the threaded part, and even expose the steel substrate, causing corrosion of the fastener. Intentionally exceeding the range to increase the nut hole diameter or leaving a clearance for the fit, it is easy to reduce the strength of the fit, which is not allowed for high-strength fits.

2. The high operating temperature of hot-dip galvanizing will reduce the mechanical strength of high-strength flange nuts. The strength of some threads of class 8.8 bolts after hot-dip galvanizing is lower than the standard requirements; the strength of bolts above class 9.8 after hot-dip galvanizing cannot basically meet the requirements.

3. Poor working environment and serious pollution. The hot dip galvanizing process of fasteners is performed at high temperature, and it will precipitate when the solvent is dried and the workpiece to be plated is dipped into the bath.

Flange nut standard parameters

Strongly stimulating hydrogen chloride gas; the zinc pool is exposed to high temperature for a long time, the surface of the zinc pool generates zinc vapor, and the atmosphere of the entire working environment is harsh.

Although there are many defects in hot-dip galvanizing of fasteners, the hot-dip galvanizing has a thick coating, good bonding strength, and long-term corrosion resistance. It has been respected in the power, communications and transportation sectors.

With the great development of China's electric power and transportation, the development of hot-dip galvanizing of flange nuts will be promoted; therefore, the development of automatic centrifugal spinning equipment, the improvement of hot-dip galvanizing of fasteners, and the quality of hot-dip galvanizing of fasteners Very important.