1. Hot galvanizing is a chemical treatment, classified as an electrochemical reaction. Cold galvanizing is a physical process, merely applying a zinc coating on the surface without any galvanizing on the inside, making the zinc layer prone to peeling off. Hot galvanizing is commonly used in construction projects.

2. Hot-dip galvanized pipes are produced by causing the molten metal to react with the iron substrate, thereby forming an alloy layer that bonds the substrate and the coating together. The hot-dip galvanizing process involves first pickling the steel pipes to remove surface oxide iron. After pickling, the pipes are cleaned in a bath of ammonium chloride or zinc chloride solution, or a mixture of both. They are then sent to the hot-dip galvanizing tank. Hot-dip galvanizing offers advantages such as even coating, strong adhesion of steel plank, and long service life. For cold galvanizing, or electroplating, there are various techniques. In general, it involves cleaning, electroplating, and passivation processes. The colored passivation is the color we see on cold-dip pipes; steel planks are zincate galvanized, and after passivation, the part surface is red or green with a hint of yellow (Cr+6 for red, Cr+3 for green), and purple should not appear (indicating a loose passivation layer). A simple test is to rub the part surface with your fingers a few times; there should be no discoloration. Among the scaffolding boards, the most fundamental difference is the thickness of the coating, with electroplated zinc coatings typically only 20-30μm thick, spray galvanized coatings around 100μm, and hot-dip galvanized coatings for steel planks usually around 200μm. However, the thickness of the coating can vary in any given process.