The Sengimir method for hot-dip galvanized channel steel combines annealing process and hot-dip galvanizing process. The hot-dip galvanized channel steel manufacturer's in line annealing mainly consists of two parts: an oxidation furnace and a reduction furnace. The strip steel is directly heated to a higher temperature by the gas flame in the oxidation furnace to burn off the residual rolling oil on the surface of the strip steel to purify the surface, and then the strip steel is heated to a higher temperature to complete recrystallization to achieve annealing. The temperature before entering the zinc pot is controlled at the standard reading through the cooling section, and then it enters the zinc pot for galvanizing without contacting the air. Therefore, the output of Senjimil method is relatively good and the quality of galvanizing is also good, This method has been widely used. The American Steel Union method for hot-dip galvanized channel steel is a variant of the Sengimir method, which only uses an alkaline electrolytic degreasing tank to replace the degreasing effect of the oxidation furnace. The other processes are basically the same as the Sengimir method
The Silas method of hot-dip galvanized channel steel is known as the direct flame heating method. The strip steel is first degreased by alkaline washing, followed by the use of hydrochloric acid to remove surface oxide skin. After washing and drying, it enters the vertical line directly heated by the gas flame and returns to the furnace. By strictly controlling the burning ratio of gas and air in the furnace, the hot-dip galvanized channel steel undergoes incomplete flame burning in the presence of excess gas and insufficient oxygen, This creates a reducing atmosphere in the furnace, rapidly heating to achieve the effect of recrystallization temperature, cooling the strip steel in a low hydrogen protective atmosphere, and finally immersing it in zinc liquid under closed conditions for hot dip galvanizing treatment. This method has compact equipment, low investment cost, and high output. However, the production process of hot-dip galvanized channel steel is complex, especially when the unit is stopped. In order to comprehensively avoid burning the strip steel, galvanized channel steel manufacturers need to use the method of furnace moving horizontally away from the steel strip for direct sales, which has many operational problems. Therefore, this method is rarely used in the hot-dip galvanized industry.