The metal or alloy product is used as an anode, and an oxide film is formed on the surface by electrolysis.
Metal oxide films change the surface state and properties, such as surface coloration, improve corrosion resistance, enhance wear resistance and hardness, which protects parts surfaces.
Non-ferrous metals or alloys (such as aluminum, magnesium and alloys, etc) can be anodized.
This method is widely used in custom fasteners, mechanical parts, aircraft and auto parts, precision instruments and radio equipment, daily necessities and architectural decoration.
Passivation refers to the process in which the metal is oxidized by a strong oxidant or electrochemical method to turn the surface into an inactive state.
Passivation is due to the action of metal and oxidizing substances, and a very thin, dense and well-covered passivation film is formed on the metal surface when it acts, and is firmly adsorbed on the metal surface.
This film exists as a separate phase, usually a compound of metal oxides.
It plays the role of completely separating the metal from the corrosive medium, preventing the metal from contacting the corrosive medium, so that the metal basically stops dissolving and forms a passive state to prevent corrosion.
Polishing surface finish is also known as buffing finish, a process of rubbing the surface of fasteners and parts or utilizing a chemical action to produce a smooth and shiny surface, make the surface get significant specular reflection or reduce diffuse reflection in some materials.
Plating is also known as electroplating.
It is a technology that uses electrolysis to attach a metal film to the surface of the metal.
The process of using an electric current to reduce dissolved metal cations so that they form a thin coherent metal coating on an electrode, to change the properties of the metal surface or build up thickness for undersized parts.
Chrome plating, nickel plating, zinc plating, copper plating and more are often applied at HZW.
Painting finishing refers to an altering surface finishing process, spraying paint, pigment, or color to a solid surface as a colored protective layer, and can be done not only on metal but also on non-metal CNC machined components of any shapes.
Painting finishing is usually applied on aluminum, copper, stainless steel and special alloy parts.
The purpose of painting is to improve aesthetic appearance and prevent corrosion or oxidation.
Black oxide is also known as blackening process, gun bluing or hot blackening, a chemical process of forming a black conversion coating on stainless steel, copper and nickel alloys.
Black oxide finishing can help improve corrosion resistance of metal parts and minimize light reflection.
Powder coating is the use of powder spraying equipment to spray powder coating on the surface of the workpiece.
Under the action of static electricity, the powder will be uniformly adsorbed on the surface of the workpiece to form a powder coating.
The powder coating is cured by high temperature baking and leveling, and becomes the final coating with different effects.
The spraying effect of powder spraying is superior to the normal spraying process in terms of mechanical strength, adhesion, corrosion resistance and aging resistance, and the cost is low.
Brushing is a surface process method that forms lines on the surface of the workpiece by grinding products to achieve a decorative effect.
According to the different lines after drawing, it can be divided into: straight drawing, chaotic drawing, corrugation, and swirling.
Brushing finish is widely used on stainless steel materials where a series of tiny parallel lines are scratched onto the surface with a wire brush or polishing tool.
About 90% of fasteners are steel based, and the required strength levels are often developed in steel fasteners using a quenching and tempering process.
Some heat treatments such as annealing soften the metal, while others harden and strengthen it.
Annealing heat treatments are used to relieve residual stress, remove cold work and dissolve alloying elements or segregation and provide a more homogeneous material.
During quenching and temper hardening, steel fasteners are first heated to a temperature where their structure transforms into austenite and then quenched or rapidly cooled in water, oil or air to a temperature at which the crystal structure transforms into martensite.
While the hardening heat treatment increases the strength of the fastener material, hardened alloys have reduced ductility, which means that they will crack at less strain or deformation than annealed fasteners.
The steel is first carburized or carbonitrided to increase the carbon content in the outer layer or shell. Then, the carburized steel pins or fasteners are usually hardened by a quench and temper process.
The resulting fasteners have a soft, tough, low carbon steel inner core and a case hardened, high carbon steel outer surface. Hardened surface resists abrasion, abrasion or cutting.
Phosphating is one commonly used pretreatment finishing technology.
It should belong to chemical conversion film treatment, which is mainly used for phosphating of steel surface, and phosphating can also be applied to non-ferrous metal (such as aluminum, zinc) parts.
Phosphating is a process of chemical and electrochemical reaction to form a phosphate chemical conversion film, and the formed phosphate conversion film is called a phosphating film.
The main purpose of phosphating is to protect the base metal and prevent the metal from being corroded to a certain extent.
It is used as a primer before painting to improve the adhesion and anti-corrosion ability of the paint film to reduce friction and lubricate in the metal cold working process.
Hot Dip Galvanizing
The most widely used metal and steel materials in the industry will corrode to varying degrees when used in environments such as atmosphere, seawater, soil and building materials.
In order to ensure the normal use of steel products and prolong their service life, the anti-corrosion protection technology of steel has always received widespread attention.
Hot dip galvanizing is one of the most effective ways to delay the environmental corrosion of iron and steel materials.
It is to immerse the iron and steel products whose surfaces have been cleaned and activated in molten zinc solution. The surface is coated with a zinc alloy coating with good adhesion.
Compared with other metal protection methods, the hot dip galvanizing process has the protection characteristics of the combination of the physical barrier and electrochemical protection of the coating, the bonding strength of the coating and the substrate, the compactness, durability, maintenance-free and economical of the coating.
It has unparalleled advantages in terms of flexibility and adaptability to the shape and size of products.
The hot dip galvanizing process is favored by people because of its low plating cost, excellent protection properties and beautiful appearance, which is widely used in automobiles, construction, home appliances, chemicals, machinery, petroleum, metallurgy, heavy industry, transportation, electric power, marine engineering, etc.
Surface Treatment Dacromet
Dacromet is a new type of surface treatment technology.
Compared with the traditional electroplating process, Dacromet is a “green electroplating”.
Its advantages are as follows:
1. Superior corrosion resistance: The thickness of Dacromet coating is only 4-8μm, but its anti-rust effect is more than 7-10 times that of traditional electrogalvanizing, hot-dip galvanizing or paint coating.
2. No hydrogen embrittlement: Dacromet’s treatment process determines that Dacromet does not have hydrogen embrittlement, so Dacromet is very suitable for the coating of stressed parts.
3. High heat resistance: Dacromet can resist high temperature corrosion, and the heat resistance temperature can reach above 300℃.
4. Good bonding force and recoating performance: Dacromet coating has good bonding force with metal substrate, and has strong adhesion with other additional coatings. The treated parts are easy to be sprayed and colored, and combined with organic coatings. The force even exceeds that of the phosphating film.
5. Good permeability: Due to the electrostatic shielding effect, the deep holes, slits and inner walls of pipe fittings are difficult to be electroplated with zinc, so the above parts of the workpiece cannot be protected by electroplating. Dacromet can enter these parts of the workpiece to form a dacromet coating.
6. No pollution and public nuisance: Dacromet does not generate waste water and waste gas that pollute the environment in the whole process of production, processing and workpiece coating, and does not need to treat three wastes, which reduces the treatment cost.