Several common surface treatments for sheet metal processing are: wire drawing, sandblasting, baking paint, powder spraying, electroplating, anodizing, screen printing. As the surface of some sheet metal materials does not have the ability to resist rust and corrosion, it is necessary to carry out effective surface treatment. The surface treatment of sheet metal parts can improve the service life of products in harsh conditions, or to achieve specific surface effects or functions.
Sheet metal processing materials in the cold rolling plate, hot rolling plate is less corrosion resistant, it is easy to occur oxidation reaction, and the deepening of corrosion. Causes the sheet metal processing workpiece to lose performance or scrap. Therefore, it is necessary to achieve the purpose of corrosion and rust prevention through surface treatment. Which which which sheet metal processing surface craft has?
Introduction to surface treatment technology of sheet metal machining workpiece:
1. Wire drawing
The so-called sheet metal wire drawing refers to placing the material between the pipe of the wire drawing machine and pipe it with sand belt. This pipe can be driven by a motor to pipe the material through the pipe and draw a series of marks on the surface of the material. Besides draw silk also call wipe grain! This kind of surface treatment craft commonly used material: it is aluminous material commonly, stainless steel sheet just considers to use the surface treatment way of brushed wire.
2. Sand blasting
Through the sandblasting machine of the wind will hit the sand on the surface of the workpiece, the formation of a layer of dense pits on the surface of the workpiece, the main role is to remove the dirt on the surface of the workpiece, rust, increase the adhesion of the surface of the workpiece, prepare for the subsequent surface treatment. This surface treatment process commonly used materials: cold rolled plate, hot rolled plate, aluminum and so on.
3. The spray paint
Generally refers to liquid spraying, his process has two kinds: liquid baking paint and self-drying spray paint, self-drying is sprayed at room temperature can be naturally cured, the cost is lower, but the effect can not compare with baking paint. Paint color effect will be better, paint film thickness is relatively thin, suitable for some precision products, the cost is higher. This surface treatment process commonly used materials: cold rolled plate, hot rolled plate, etc.
Sheet metal surface treatment painting process
Step 1: the base layer of sheet metal processing products shall be derusted, such as sandblasting, phosphating, etc.
Step 2: epoxy zinc-rich primer for sheet metal processing products, mainly used as anti-rust primer for steel structure and steel products, the coating film has good physical and chemical properties, easy construction and good supporting properties.
Step 3: sheet metal processing products epoxy micaceous iron oxide intermediate paint: with epoxy zinc-rich primer, make long-term anti-corrosion coating transition layer, the effect to enhance the sealing properties of the composite coating and anticorrosion, and can also be used as anticorrosion primer. The coating strength, has the good adhesion and closeness, and QianHouDao coating compatibility is good. It is divided into: epoxy resin and curing agent, the mother of ferric oxide and antirust paint, etc.
Step 4: sheet metal processing products do surface layer. It can be used as epoxy asphalt topcoat, chlorinated rubber topcoat, acrylic and polyurethane topcoat, fluorocarbon topcoat, etc.
4. Plastic spraying (also known as powder spraying)
It means that the powder is polarized, under the action of electric field force, uniformly adhere to the product surface with opposite polarity. Spray features: wear-resisting, corrosion resistance is better, the film is thicker, suitable for cabinets, equipment category of relatively thick products, the cost is lower, plastic powder can be recycled. This surface treatment process commonly used materials: cold rolled plate, hot rolled plate, etc.
Electrostatic powder spraying is mainly to polarize the coating (powder) through the electrode, and then the object to be sprayed will have opposite charge, and the powder will adhere to the surface of the object uniformly under the action of electric field force.
5. Electroplating
Through chemical reaction, attach a layer of other metal on the surface of the material, to increase the corrosion resistance of the metal, and to achieve a certain beautification of the appearance, is a common surface treatment. Such as: galvanizing, nickel plating and so on. Mainly colorful zinc, blue and white zinc, black zinc, chrome plating. This surface treatment process commonly used materials: cold rolled plate, hot rolled plate, etc.
Sheet metal surface treatment plating process
Types of plating:
Galvanized: 1. Cyanide galvanized 2. Zincate galvanized 3. Chloride galvanized 4. Sulfate galvanized
B. chrome plating c. gold plating d. copper plating e. nickel plating f. other metal plating
6. Anodizing
Oxidize the metal on the surface of the workpiece to form a dense protective film on the surface of the workpiece and increase the corrosion resistance of the workpiece. Generally, there are two ways: chemical oxidation and anodic oxidation. It is a common surface treatment, usually with primary color anodizing and black anodizing. This surface treatment process commonly used materials: aluminum.
7. Screen printing
Screen printing on the surface of materials on a variety of signs of the process, generally there are flat screen printing and pad printing two ways, the main principle and camera film imaging principle, is also a process of exposure. Usually used in trademark, use sign, warning sign, etc.
8. Phosphating
Phosphating is a common pretreatment technology, which belongs to chemical conversion film treatment in principle. It is mainly used for phosphating steel surface, and non-ferrous metal (such as aluminum and zinc) parts can also be used for phosphating.
The main purpose of phosphating is to provide protection to the base metal and prevent the metal from being corroded to some extent. Used as primer before painting to improve adhesion and corrosion resistance of paint film; It plays a role in reducing friction and lubrication in cold metal processing. This surface treatment process commonly used materials: cold rolled plate, hot rolled plate.
9. Jinsu
The product is heated in a molten material and the heated metal is combined with the surrounding molten material to form a surface material of a certain thickness. According to the use of different raw materials can be divided into liquid immersion (coating) plastic and powder immersion (coating) plastic. Such as: our daily use of clothes hangers, pliers, scissors on the rubber cover, water valve wrench and so on. This surface treatment process commonly used materials: cold rolled plate, hot rolled plate.
Sheet metal surface treatment impregnation process
Metal impregnation is a new technology of anti-corrosion on metal surface. In the dip, the heated metal sticks to the surrounding material, the hotter the metal, the longer the dip time, the thicker the material thickness
10. Common surface treatment process of stainless steel
Drawing, polishing: according to the complexity of stainless steel products and user requirements of different conditions can be used for mechanical polishing, chemical polishing, electrochemical polishing and other methods to achieve mirror luster.
Sandblasting, scratches, whitening treatment: stainless steel in the process of processing, after the coil, binding, welding or artificial surface fire heating treatment, the production of black oxide skin. This hard gray black oxide is mainly composed of NiCr2O4 and NiF EO4 components, which were removed by hydrofluoric acid and nitric acid in the past. However, this method costs a lot, pollutes the environment, is harmful to the human body, and is highly corrosive, so it is gradually eliminated.
At present, there are two main treatment methods for oxide skin:
1, sandblasting (pellet) method: the main method is to use spray micro glass beads, remove the surface of the black oxide skin.
2.The chemical method: use a pollution-free pickling passivation paste and cleaning liquid with inorganic additives at room temperature. So as to achieve the purpose of whitening stainless steel color. After treatment it basically looks a dull color. This method is suitable for large and complex products.
Staining method: chemical oxidation staining method; The electrochemical oxidation staining method; The ion deposition oxide staining method; Of high temperature oxidation staining method; 5. The gas phase pyrolysis coloring method.
Other surface treatment methods such as baking paint, enamel, and so on, for the chassis cabinet sheet metal processing products are not commonly used.
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