1.What are the commonly used sheet metal materials?
Commonly used sheet metal materials mainly include the following:
1.1 Cold Rolled Sheet: The grade is SPCC, which is the most basic material in sheet metal fabrication and is widely used. This material is often used as a base material for other materials, but it is important to note that it is more prone to rust.
1.2 Electro galvanized sheet: The grade is SECC, which is also widely used. It is obtained by electroplating cold rolled sheets, which is a chemical reaction process.
1.3 Hot-dip galvanized sheet: The brand name is SGCC, which is also widely used. It is the cold rolled plate into the molten zinc liquid heating, so that the zinc layer attached to the plate, which is a physical change process.
1.4 Hot Rolled Sheet: The brand name is SPHC, which belongs to the lower end of the material, easy to rust, and the thickness is usually more than 3 mm. This material is often used for hinge products.
1.5 SD steel plate: this is a very good rust and corrosion resistance of the plate, such as air conditioning outdoor unit mounting bracket is made of this material.
1.6 Stainless steel and stainless steel: they are alloy materials, typical grades SUS304 and SUS430, rust and corrosion resistance is very good, the appearance is also very beautiful. Therefore, they are often used to make appearance parts, such as door shells of refrigerators and stove tops of gas stoves.
1.7 Aluminum-zinc-plated sheet: it looks like a kind of electro-galvanized sheet, but there is one more metal aluminum element inside, so the surface is more polished and beautiful, and is often used to do the appearance of parts, such as some models of refrigerator back steel plate.
1.8 Aluminum or aluminum alloy plate: can also be called aluminum sheet, its low density, good corrosion resistance. For example, the water catch pan of the refrigerator and the fins of the evaporator are made of this material.
2.What is the price of sheet metal material?
In the case of the same thickness, the prices of sheet metal materials are arranged from low to high: hot rolled sheet, cold rolled sheet, hot galvanized sheet, electro galvanized sheet, SD steel sheet, stainless steel, stainless steel.
Moreover, for the same material, generally speaking, the greater the thickness, the lower the price.
In the cost of sheet metal parts, the material cost usually accounts for 60% to 70%, sometimes even higher.
Therefore, it is important to design a reasonable structure, and it is also important to improve the material utilization rate. If the material utilization rate is low, there may even be a situation where the product price is still lower than the scrap price.
3. Purpose of Sheet Metal Surface Treatment
Since some sheet metal materials themselves do not have the ability to prevent rust and corrosion, they have to undergo surface treatment to achieve the purpose.
The purpose of surface treatment has two main categories:
3.1 To improve the service life of products in harsh environments. Refers to: anti-rust and anti-corrosion ability.
3.2 To obtain the desired surface effect or function. Refers to: to meet the product’s appearance requirements.
4. Sheet metal commonly used surface treatment process
4.1 Zinc plating:
It is the use of electrolysis, the formation of uniform, dense, combined with a good metal or alloy deposition layer on the surface of the parts of the process.
Compared with other metals, zinc is relatively cheap and easy to coat a metal, is a low-value corrosion-resistant plating layer. It is widely used to protect steel parts, especially against atmospheric corrosion, and for decorative purposes. Plating techniques include tank plating (or hanging plating), roll plating (suitable for small parts), automatic plating and continuous plating (suitable for wire and strip).
They are categorized into four main groups according to the plating solution:
The zinc plating industry is a polluting industry. Although it is widely used and inexpensive, zinc plating products do not comply with ROHS standards, so try not to use electroplated products in product design.
4.2 Chrome plating
The process principle is the same as galvanizing.
Compared with the traditional zinc plating: the chromium coating has extremely strong corrosion resistance, 7-10 times that of zinc plating, and the surface is beautiful, but the cost is higher
Currently the most advanced chrome plating process called DACROMET, is a revolutionary high-tech metal surface treatment process, the whole process without pollution.
4.3 Powder spraying
The powder is polarized, under the action of electric field force, uniformly attached to the surface of the product with opposite polarity. It is a physical change.
Powder spraying process principle:
Electrostatic powder spraying: mainly through the electrode will paint (powder) polarization, and then the object to be sprayed with the opposite charge, under the action of the electric field force, the powder is uniformly attached to the surface of the object.
Characteristics of the powder spraying process:
Powder electrostatic spraying will not cause atmospheric pollution, powder can be recycled to reduce the cost of material consumption, film performance superior acid resistance, alkali resistance, salt corrosion resistance is better, adhesion is also higher.
4.4 Electrophoresis
Electrophoretic coating in the role of cathode and anode, charged paint ions move to the product surface, deposition to form a coating. It belongs to chemical change.
The process principle of electrophoresis:
Electrophoretic coating in the cathode and anode, applied to the role of voltage, charged paint ions move to the cathode, and with the cathodic surface of the alkaline action generated by the formation of insoluble substances, deposited on the surface of the workpiece.
Characteristics of electrophoretic surface treatment process:
Electrophoretic paint film has the advantages of fullness, uniformity, flatness and smoothness of the coating. The hardness, adhesion, corrosion resistance, impact performance and penetration performance of the electrophoretic paint film are obviously superior to those of other coating processes.
The common electrophoretic color is black, and other colors are also available.
4.5 Immersion molding
Products in the molten material, heating, heated metal and the surrounding molten material combined to form a certain thickness of the surface material. Belong to the physical change.
The process principle of dip molding:
Metal dip molding is a new type of technical treatment process way for metal surface anti-corrosion, dip molding is a heating process, metal preheating, dipping material, curing. In the dip, the heated metal sticks to the surrounding material, the hotter the metal, the longer the dip, the thicker the material.
The process characteristics of dip molding:
Wide range of applications: rich colors, good protection, excellent cold insulation and resistance to acid and alkali.
