Process flow and precautions for galvanizing bolts
Author: Marisa
1、 Cleaning and passivation treatment
The first step in galvanizing bolts is cleaning and passivation treatment. Before carrying out galvanizing operations, it is necessary to ensure that the surface is clean, free of oil stains and oxides. Usually, surface dirt is removed by acid and alkali washing, and then treated with passivating agents to increase the adhesion and corrosion resistance of the coating.
2、 Galvanizing operation
After cleaning and passivating the bolt surface, galvanizing can be carried out. Usually, two methods are used: hot-dip galvanizing and electroplating galvanizing.
Hot dip galvanizing is the process of immersing steel parts into a galvanizing tank for galvanizing. The advantages of this method are uniform coating and strong corrosion resistance, but the disadvantages are high cost, fixed thickness of the galvanizing layer, and inability to galvanize bolts with special shapes. Electrogalvanizing uses electrochemical methods for galvanizing, with a uniform coating and easy thickness control, but its corrosion resistance is not as good as hot-dip galvanizing.
3、 Drying and cooling
After the galvanizing operation is completed, the bolts still need to be dried and cooled. The bolts after hot-dip galvanizing need to be dried to remove surface moisture and avoid local corrosion. The bolts after electroplating with zinc require cooling treatment to accelerate the solidification of the coating.
4、 Galvanizing effect and precautions
After being galvanized, a layer of zinc will form on the surface of the bolt, which has the functions of corrosion resistance, oxidation resistance, and aesthetics. However, there are also some precautions to be taken when galvanizing bolts, such as:
1) The thickness of galvanizing should comply with national standards, as being too thick or too thin can affect the galvanizing effect;
2) The pre-treatment process before plating should be strictly followed, otherwise it will affect the quality of the subsequent coating;
3) When galvanizing, it is necessary to ensure that the surface of the steel parts is dry, otherwise problems such as bubbles and pitting may occur;
4）Galvanized steel parts must undergo quality inspection to ensure their corrosion resistance and service life.
The above is the process flow and precautions for bolt galvanizing, hoping to be helpful to you.