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Phone: +86 13679287344
E-mail: [email protected]
Add: Room1102, Land Center T1, Yanzhan Road, No. 1111, Qujiang New District, Xi'an, China.
Bolt coat surface treatment methods
Time: 2024-10-15 Source: Hexagon Flange Bolt Author: Julie
In order to make the bolt more beautiful, corrosion prevention, increased strength and environmental protection, a layer of covering film is formed on the surface of the workpiece by a certain method, wearing a layer of “coat”, which is the bolt surface treatment. Several common surface treatment methods are described below.
1. Electroplating
Electroplating is the process of using the principle of electrolysis to plate a thin layer of other metals or alloys on some metal surfaces, which is the use of electrolysis to attach a layer of metal film to the surface of metal or other materials to prevent metal oxidation (such as rust), improve abrasion resistance, electrical conductivity, reflective property, corrosion resistance (copper sulfate, etc.) and improve beauty.
Electrogalvanizing is the most commonly used surface treatment method for screw fasteners, which not only has low cost, but also the appearance of screw fasteners after frequent galvanizing treatment is more beautiful, and can be electroplated into black and army green. However, the corrosion resistance of electric galvanizing is general, its corrosion resistance is the lowest in the electroplating (coating) layer, the screws after electric galvanizing can pass the neutral salt spray test within 72 hours, and there is also a special sealant, so that the zinc plating can be achieved after the salt spray test to reach more than 200 hours, but its price is expensive, is generally galvanized 5-8 times.
2.Hot-dip galvanizing
Hot-dip galvanizing is an effective method to prevent bolt corrosion. It produces an alloy layer by reacting the molten metal with the iron substrate, thus combining both the substrate and the coating. After the surface has been cleaned and activated, steel products are immersed in molten zinc, and through the reaction and diffusion between iron and zinc, the surface of the steel products is coated with a zinc alloy coating with good adhesion. Hot-dip galvanizing has the advantages of uniform coating, strong adhesion and long service life. The hot dip galvanizing process is favored for its low plating cost, excellent protective properties and beautiful appearance.
3.Phosphating
Phosphating is a chemical and electrochemical reaction to form a phosphate chemical conversion film process, the formation of phosphate conversion film called phosphate film. The purpose of phosphating is to protect the base metal and prevent the metal from being corroded to a certain extent. It is used for primer before painting to improve the adhesion and anti-corrosion ability of the paint film. It is used for antifriction lubrication in metal cold working process.
4.Black oxidation treatment
Black oxidation treatment is a common means of chemical surface treatment, the principle is to produce a layer of oxide film on the metal surface to isolate the air and achieve the purpose of rust prevention. In order to improve the anti-rust ability of steel parts, the surface of steel parts is oxidized into dense and smooth iron tetroxide with strong oxidant. This thin layer of ferric oxide can effectively protect the inside of the steel from oxidation. At high temperatures (about 550 ° C), the oxidized ferric oxide is sky blue, so it is called blue treatment. The ferric oxide formed at low temperature (about 350 ° C) is dark, so it is called black treatment. In industrial production, blackening is commonly used.
To sum up, there are many kinds of surface treatment methods. The customer can select the most suitable one among them to meet their requirements.
1. Electroplating
Electroplating is the process of using the principle of electrolysis to plate a thin layer of other metals or alloys on some metal surfaces, which is the use of electrolysis to attach a layer of metal film to the surface of metal or other materials to prevent metal oxidation (such as rust), improve abrasion resistance, electrical conductivity, reflective property, corrosion resistance (copper sulfate, etc.) and improve beauty.
Electrogalvanizing is the most commonly used surface treatment method for screw fasteners, which not only has low cost, but also the appearance of screw fasteners after frequent galvanizing treatment is more beautiful, and can be electroplated into black and army green. However, the corrosion resistance of electric galvanizing is general, its corrosion resistance is the lowest in the electroplating (coating) layer, the screws after electric galvanizing can pass the neutral salt spray test within 72 hours, and there is also a special sealant, so that the zinc plating can be achieved after the salt spray test to reach more than 200 hours, but its price is expensive, is generally galvanized 5-8 times.
2.Hot-dip galvanizing
Hot-dip galvanizing is an effective method to prevent bolt corrosion. It produces an alloy layer by reacting the molten metal with the iron substrate, thus combining both the substrate and the coating. After the surface has been cleaned and activated, steel products are immersed in molten zinc, and through the reaction and diffusion between iron and zinc, the surface of the steel products is coated with a zinc alloy coating with good adhesion. Hot-dip galvanizing has the advantages of uniform coating, strong adhesion and long service life. The hot dip galvanizing process is favored for its low plating cost, excellent protective properties and beautiful appearance.
3.Phosphating
Phosphating is a chemical and electrochemical reaction to form a phosphate chemical conversion film process, the formation of phosphate conversion film called phosphate film. The purpose of phosphating is to protect the base metal and prevent the metal from being corroded to a certain extent. It is used for primer before painting to improve the adhesion and anti-corrosion ability of the paint film. It is used for antifriction lubrication in metal cold working process.
4.Black oxidation treatment
Black oxidation treatment is a common means of chemical surface treatment, the principle is to produce a layer of oxide film on the metal surface to isolate the air and achieve the purpose of rust prevention. In order to improve the anti-rust ability of steel parts, the surface of steel parts is oxidized into dense and smooth iron tetroxide with strong oxidant. This thin layer of ferric oxide can effectively protect the inside of the steel from oxidation. At high temperatures (about 550 ° C), the oxidized ferric oxide is sky blue, so it is called blue treatment. The ferric oxide formed at low temperature (about 350 ° C) is dark, so it is called black treatment. In industrial production, blackening is commonly used.
To sum up, there are many kinds of surface treatment methods. The customer can select the most suitable one among them to meet their requirements.
