Hot dip galvalume steel sheet processing

The test material is hot-dip galvalume steel plate, the base plate is aluminum steel, and the plate thickness is 2mm. The galvanizing process is as follows: after annealing, the sample enters an aluminum-zinc pot filled with plating solution, is purged by an air knife to control the thickness of the coating, and then cooled through a cooling tower. The composition of the plating solution is: Al55%, Zn45%, Si5%. 2 Sample preparation: Process the aluminum-zinc coating sample into a block sample The full name of aluminized steel plate is "hot-dip aluminized steel plate". In terms of manufacturing process, it is similar to hot-dip galvanized steel plate. But its heat resistance is better than galvanized steel plate. Aluminized plates have the following five characteristics: High temperature resistance: Due to the specific combination of the steel plate base material and coating structure, an iron-aluminum alloy is formed, which makes the aluminum plated plates have excellent high temperature resistance. At 450℃, extremely high reflectivity can be guaranteed. Above 480°C, the coating will appear gray. At temperatures as high as 650°C, the protective layer that prevents oxidation of the steel plate is still intact and no peeling off is seen. Heat reflectivity: At a high temperature of 480 degrees Celsius, aluminized panels can reflect 80% of incident heat. Therefore, aluminized sheets can be made into efficient thermal barriers or heat reflectors in high-temperature applications, rapidly increasing the temperature in the furnace through effective heat reflection. Mechanical strength: At room temperature, the mechanical strength of the aluminized plate is consistent with that of its base material. At the same high temperature of 480°C, the strength of aluminized steel plates is 10 times that of aluminum plates, so the thickness of the steel plates can be reduced by at least 30%.

Date: 2019052 Hot-dip galvanizing (hot-dip galvanizing) refers to a method of plating by immersing plated fasteners in liquid metal zinc or its alloy. Hot-dip galvanizing is widely used to protect steel and its parts from atmospheric corrosion, and is especially suitable for the mass production of standard parts and fasteners. Hot-dip aluminum-zinc steel plates are based on cold-rolled steel plates of various strengths and thickness specifications, and are hot-dip coated with a layer of ALZN aluminum-zinc alloy coating on both sides. The mass percentage of the resulting pre-coated steel plate is approximately 55% AL aluminum, 45% ZN zinc, 6% Si silicon. It combines the physical protection and high durability of AL with the electrochemical protection of ZN.

The production and processing of galvanized steel coils can be divided into three major steps: first, the entire coil of steel strip is pickled to remove rust and dirt to make the surface of the galvanized steel strip bright and clean; after pickling, it is processed through ammonium chloride or aqueous solution Or clean it in ammonium chloride and mixed aqueous solution, and then send it to the hot-dip plating tank for galvanizing process; after the galvanizing process is completed, it can be packed in the warehouse. Development History of Hot-dip Galvanizing Hot-dip galvanizing was invented in the middle of the 18th century. It was developed from the hot-dip tin plating process and has now entered the fourth century. So far, hot-dip galvanizing is still the most commonly used and effective process measure for steel corrosion protection. In 1742, Dr. Marouin conducted pioneering experiments on hot-dip galvanizing of steel and announced it at the French Royal Academy. In 1837, Solier of France applied for a patent for hot-dip galvanizing and proposed the idea of using the galvanic battery method to protect steel, that is, a process of galvanizing the iron surface to prevent rust. In the same year, Crawford of the United Kingdom applied for a patent for galvanizing using ammonium chloride as a solvent. This method has been followed today after many improvements.

On a hot-dip galvanizing production line, the coating is obtained by immersing pre-treated steel strips in molten zinc. The zinc content in the molten zinc liquid should be no less than 99%. Subsequently, a zinc-iron alloy layer is formed on the entire coating through an alloying process. The iron content in the alloy coating is usually 7 to 15%.