Q:What are the differences in process principles?
A:Electrogalvanizing: also known as cold galvanizing, is the use of electrolysis principle to form a uniform, dense, well-bonded zinc deposition layer on the surface of Q195 steel. The Q195 steel that has been pre-treated by chemical degreasing, water washing, electrolytic degreasing, etc. is used as the cathode, and zinc is used as the anode. It is immersed in a solution containing zinc salt components. After the power is turned on, under the action of the current, the zinc ions move to the cathode and deposit on the surface of the steel. Hot-dip galvanizing: also called hot-dip galvanizing, is to immerse the rust-free Q195 steel parts in a zinc liquid melted at about 500℃, so that a zinc layer is attached to the surface of the steel components. The steel must first undergo pre-treatment processes such as pickling, water washing, adding a plating solution, and drying, and then immersed in zinc liquid. Iron and molten zinc react to form an alloyed zinc layer.
Q:What is the difference in appearance?
A:Electrogalvanizing: The surface is relatively smooth, and the color is mainly yellow-green, but also colorful, bluish-white, etc. The entire workpiece will basically not have zinc nodules, lumps, etc. Hot-dip galvanizing: The overall appearance is slightly rough, with process water marks, nodules, etc., especially on one end of the workpiece, and the color is usually silver-white.
Q:What is the difference between zinc layer thickness and corrosion resistance?
A:Electrogalvanizing: The zinc layer is thinner, generally 5 microns to 15 microns, and has relatively poor corrosion resistance. However, the zinc layer has good uniformity and can be controlled within ±1μm. It can meet certain anti-corrosion requirements in general atmospheric environments, but has a short anti-corrosion life in harsh environments such as high humidity and high salt fog.
Hot-dip galvanizing: The zinc layer thickness is usually above 35 microns, and the standard requirement is generally around 80 microns, and can even reach 200 microns, with strong corrosion resistance. The zinc layer forms an alloy layer with the steel matrix, which is firmly bonded. Even if the zinc layer is partially damaged, the matrix is not easy to rust, which is suitable for occasions with high corrosion resistance requirements.
Q:What are the differences in application scenarios?
A:Electrogalvanizing: Due to its high surface precision and good appearance, it is often used in places with high requirements for surface quality and not extremely strict requirements for corrosion resistance, such as home appliance housings (such as refrigerator back panels), electronic shielding covers, etc.
Hot-dip galvanizing: Due to its strong corrosion resistance, it is widely used in construction, bridges, energy, machinery, chemical and other industries, such as angle steel, channel steel in building structures, conveying pipelines, and outdoor steel structures, etc., which can provide good anti-corrosion protection when exposed to the natural environment for a long time.
Q:What are the differences in production costs?
A:Electrogalvanizing: The production process requires electricity, and the process is relatively complex, and the equipment investment is large, so the production cost is high.
Hot-dip galvanizing: Although the zinc consumption is large, the production process is relatively simple, the degree of automation is high, and the overall production cost is usually lower than electrogalvanizing.