Advantages and disadvantages of hot-dip galvanized wire pipe and cold-dip galvanized JDG pipe

Nowadays, people's lives are inseparable from the use of various wiring, especially electrical wiring. Without wiring, we wouldn't be able to use electricity. Electrical wiring is particularly vulnerable to damage and is a hassle to replace. Power outages in some factories, in particular, can cause significant losses during repairs. Therefore, using galvanized electrical conduit to protect vulnerable wires, such as electrical wiring, is essential. Let's examine the advantages and disadvantages of hot-dip galvanized and cold-dip galvanized JDG conduits produced by JDG Steel Pipe.

Advantages and Disadvantages of Hot-Dip Galvanized and Cold-Dip Galvanized JDG Conduits:

1. Hot-dip galvanized conduits have blue ink-marked rings on both ends, and their specifications and models meet national standards. Hot-dip galvanized conduits have a zinc needle or small nub on one end, but are completely galvanized internally and externally, with a smooth appearance and no cold-dip galvanizing. When the cold-dip galvanized layer is angled against the sun, the light becomes vibrant and colorful. Cold-dip galvanized conduits have only a small amount of zinc coating on the ends of the holes, with no zinc coating inwards. Cold-dip galvanized household conduits also have smooth ends and absolutely no zinc nubs. Their appearance does not meet standards.

2. Hot-dip galvanizing, also known as hot-dip galvanizing, refers to the process of leaching a metallic coating from a molten zinc solution onto steel components.

Principle: Hot-dip galvanizing provides excellent coverage, a dense coating, and is free of organic matter. Its atmospheric corrosion resistance is known to be mechanical and electrochemical. Under atmospheric corrosion conditions, an alkaline protective film composed of ZnO, Zn(OH)2, and zinc carbonate forms on the zinc surface, which mitigates zinc corrosion to a certain extent. When this protective film is damaged, white rust forms, and a new protective film forms. When the zinc layer is severely damaged and endangers the iron substrate, zinc provides electrochemical protection. The standard potential of zinc is -0.76V, and that of iron is -0.44V. When zinc and iron form a miniature battery, zinc dissolves in the anode, while iron acts as the cathode. Hot-dip galvanizing significantly improves the atmospheric corrosion resistance of the base iron compared to electroplating.

3. The hot-dip galvanizing layer is formed by forming an iron-zinc alloy between the iron substrate and the outer pure zinc layer. During the hot-dip galvanizing process, an iron-zinc alloy layer forms on the workpiece surface, creating a tighter bond between the iron and the pure zinc layer.

1. The process can be described as follows: When an iron workpiece is immersed in molten zinc, zinc first forms at the interface—the solid molten α-iron (core) layer. The base metal iron dissolves in the zinc atoms in its solid state, forming crystals. The two metal atoms fuse together, with minimal interatomic attraction.

2. Consequently, when the zinc in the solid melt reaches saturation, the zinc and iron atoms diffuse into each other. The zinc atoms migrate within the matrix lattice and diffuse outward, forming an alloy in the molten zinc solution. The iron diffused into the molten zinc solution forms an intermetallic compound, FeZn13, with the zinc, which sinks to the bottom of the hot-dip galvanizing pot, known as zinc slag. When the workpiece is removed from the galvanizing bath, a layer of pure zinc, consisting of hexagonal crystals, forms on its surface.

3. A cold-dip galvanizing process with an iron content of no more than 0.003% is used to protect the metal from corrosion. A zinc filler coating is applied. The zinc filler is applied to the protective surface by any coating method. After drying, a zinc-filled coating is formed and the dried coating contains up to 95% zinc.