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Passivation

Metal surface passivation treatment is a common method of metal surface treatment, which aims to change the chemical properties of the metal surface to form a protective layer with good corrosion resistance and wear resistance, thereby improving the corrosion resistance and service life of metal materials. This article will introduce the principles, common methods, and application fields of passivation treatment.

1. The principle of passivation treatment

Metal materials are prone to oxidation reactions in the atmosphere, producing metal oxides, which can lead to metal corrosion. And passivation treatment forms a dense oxide film on the metal surface, blocking the contact between the metal and the external medium, thereby playing a protective role for the metal. This type of oxide film can reduce the activity of the metal surface, making it less prone to oxidation reactions under certain conditions, thereby improving the corrosion resistance of the metal.

2. Common passivation treatment methods

1) Acid pickling passivation: This is one of the most common passivation treatment methods. By immersing metal materials in a dilute acid solution, the metal surface reacts with acid to form a dense oxide film. Common acids include nitric acid, phosphoric acid, and sulfuric acid. The acid pickling and passivation method is suitable for surface treatment of metal materials such as iron, copper, and aluminum.

2) Electrochemical passivation: This method utilizes the principle of electrochemistry to apply an external current to the metal surface, causing an oxidation-reduction reaction to occur on the metal surface, generating a dense oxide film. This method has the advantages of good passivation effect and simple operation, and is suitable for different types of metal materials.

3) Chemical deposition passivation: This method involves depositing a layer of metal compound on the metal surface to form a protective thin film. Common chemical deposition passivation methods include galvanizing, chromium plating, and nickel plating.

3. The application areas of passivation treatment

Passivation is widely used in various fields, especially in the manufacturing industry, playing an important role. The following are several common application areas:

1) Automotive manufacturing industry: For the manufacturing of automotive components, passivation treatment can improve their corrosion resistance and extend their service life. For example, metal components such as the chassis and body of a car often undergo passivation treatment to enhance their corrosion resistance.

2) Electronic and electrical industry: In the manufacturing process of electronic and electrical appliances, metal components often require passivation treatment to improve their corrosion resistance and conductivity. For example, metal contacts and circuit boards in electronic products can be passivated to increase their stability and reliability.

3) Construction industry: In the manufacturing of building structures and equipment, metal materials often require passivation treatment to improve their corrosion resistance and service life. For example, steel structures, pipelines, etc. can be treated with passivation to prevent corrosion.

4) Aerospace field: In the manufacturing process of aerospace vehicles, metal materials need to have good corrosion resistance and wear resistance. Therefore, passivation treatment has important application value in this field, which can improve the service life and safety performance of aircraft, rockets, etc.

Different passivation treatment methods have wide applications in different application fields. In practical applications, appropriate passivation treatment methods should be selected based on the characteristics and specific requirements of metal materials to achieve the best results.

Electronic Industry Sheet Metal Parts

Sheet metal fabrication pays an important role in electronic industry. From big parts like metal cabinet, chassis, housing, brackets to small parts like terminal, USB connectors, contact chip etc, we can see sheet metal parts everywhere. The consumer electronics industry has witnessed tremendous growth in recent years and precision sheet metal fabrication has provided a guarantee for the updating and replacement of electronic industry products.

Consumers are now pursuing smaller, thinner, and lower energy consuming electronic devices, which can be achieved through precision sheet metal production. Our factory uses advanced materials, machines, and processes to manufacture micro electronic products and also big electronic parts shell, which not only ensure the firmness, accuracy, and precision of the products, but also enhance the aesthetics of electronic products through powder coating, anodizing, electroplating, and other surface treatment.

Electronic Metal Parts Manufacturing Capabilities

At Shanghai Yixing Technology, we have complete range of equipment like flat laser cutting machine, 3D laser cutting machine, hydraulic press, deep drawing machine, punching machine, shearing machine, CNC bending and welding machines to combine all the sheet metal fabrications like metal bending, metal stamping, progressive die stamping, welding and also surface treatment for one stop sourcing.

Some electronic components can be very small in size but complex in structure. Our facility has been very professional in progressive die stamping for these small components. Progressive die stamping is ideal for big volume production and at the same time ensures cost effective and great accuracy.

How Yixing Technology Produce Electronic Metal Parts

First of all, we select the correct material grade based on the drawing materials. We will strictly control the inspection of incoming materials and material storage. We will require the mill factory to provide raw material certificates and ask a third party to test the chemical composition of the materials. Our own inspectors will conduct visual inspection (mainly looking for surface defects, scratches and rust), thickness and size inspection of raw materials.

We will then evaluate the production process based on the design of the customer's drawings, which is generally divided into the following steps:

1. Cutting

We can use laser cutting, plasma cutting, flame cutting and water cutting, etc. for blanking. Cutting is usually the first step in sheet metal production.

2. Punching

According to the design requirements, punch holes in the cut metal plate to facilitate subsequent bending and forming.

3. Bending and forming

Bending and forming the punched metal plate, we usually use equipment such as bending machines and stamping machines.

4. Welding

For sheet metal parts that need to be joined together, welding is most common assembly method. Commonly used welding methods include argon arc welding, laser welding, etc.

5. Surface treatmen

The surface of sheet metal parts needs to be treated to enhance its corrosion resistance, wear resistance and aesthetics, such as powder coating, chrome plating, anodization, electroplating and other treatments.

In agricultural machinery, sheet metal parts are widely used in casings, buckets, lawn mowers, seeders, harvesters, irrigation equipment, etc. These parts usually require precise design before they fit together to form a complete agricultural machine. Sheet metal parts have the characteristics of simple structure, beautiful appearance and light weight, which can improve the overall performance of agricultural machinery.

metal stamping for agriculture

Agriculture Machinery Metal Parts Manufacturing Capabilities

Equipped with complete range of production machines like flat laser cutting machine, 3D laser cutting machine, four column hydraulic press(100t-1000t), deep drawing machine(46t-80t), punching machine(60t-630t), shearing machines, bending machines, industrial robot welding machine, gas shielded welding machine, argon arc welding machine etc, Shanghai Yixing Technology has very strong capabilities in agriculture machinery sheet metal parts fabrication.

The sheet metal parts used in agriculture machinery need to be very strong, durable and corrosion resistant because of its high intensity work environment. We ensure that the material grade and thickness meet the drawing requirements (usually welding parts are S355 and above).

To ensure the high quality welding strength, we will do magnetic particle testing, ultrasonic testing, or radiographic testing. The chemical composition and mechanical properties of the material will also be sent for third-party testing. The appearance of agricultural machinery is also very important, usually done by powder coating or spray painting. We will strictly test the thickness, hardness, glossiness, adhesion, etc. of the coating.

Sheet Metal Fabrication for Sale

What are the commonly used materials for agricultural machinery sheet metal parts?

1. Commonly used materials for agricultural machinery sheet metal parts

Commonly used materials for the production of agricultural machinery sheet metal parts include: cold-rolled plates, hot-rolled plates, steel plates, aluminum plates, etc. These materials have good rigidity and toughness and can meet the hardness and durability requirements of agricultural machinery during use.

2. Characteristics and scope of application of each material

1) Cold rolled plate

The cold-rolled plate has a smooth surface, good formability and strong corrosion resistance, and is suitable for the production of agricultural machinery casings, heat insulation layers and other parts.

2) Hot rolled plate

There is iron oxide scale on the surface of the hot-rolled plate, which has poor formability. However, the material has high strength and is suitable for the production of large structural parts such as agricultural machinery and machine tools.

3) Steel plate

Steel plates have good formability, high hardness and strength, and are suitable for steel structural components such as agricultural machinery bodies and carriages.

4) Aluminum plate

Aluminum plates are light in weight, have both hardness and toughness, are corrosion-resistant and have good thermal conductivity. They are suitable for the production of agricultural machinery casings, wheel hubs and other parts.

3. Application of different materials in the production of agricultural machinery sheet metal parts

1) Agricultural machinery casing production: Cold-rolled plates and aluminum plates are commonly used materials for making agricultural machinery casings. Cold-rolled plates are corrosion-resistant and have good formability; aluminum plates are light in weight, have strong oxidation resistance, and have excellent effects.

2) Production of thermal insulation layer of agricultural machinery: Cold-rolled plate is the most commonly used material for making thermal insulation layer. It is widely used in the manufacturing process of agricultural machinery because of its good formability and excellent corrosion resistance.

3) Manufacturing of agricultural machinery and machine tools: Hot-rolled plate is the best material, its strength and hardness are better than other materials, and it is suitable for agricultural machinery and machine tool parts with relatively complex structural design.

4) Production of agricultural machinery bodies and carriages: Steel plates are the most commonly used materials for making agricultural machinery bodies and carriages. They have low production costs, good stiffness and strength, and have high load-bearing capacity for agricultural machinery during transportation and operations.

In the modern medical industry, sheet metal products are an indispensable part. Medical device sheet metal product processing is an important manufacturing process that can provide high-quality medical equipment and appliances for hospitals and medical institutions, and provide better healthcare services for patients.

The application of medical device sheet metal processing is very wide, mainly involving medical equipment, medical devices, medical appliances and other fields. Sheet metal processing technology can manufacture medical devices of various shapes and sizes, such as operating tables, surgical lamps, surgical instrument racks, etc. These devices can help doctors perform surgeries and treatments more effectively. Medical sheet metal products can also be used to manufacture medical equipment, such as stretchers, wheelchairs, beds, etc. These tools can provide a more comfortable nursing environment and help patients recover.

Medical Metal Parts Manufacturing Capabilities

The advantage of medical sheet metal product processing is its precision and reliability. As an experienced sheet metal factory in China, we follow the strict quality control system, use well trained engineers and workers, use state of the art equipment to ensure our sheet metal parts have the best precision and accuracy.

We have decades of experience in manufacturing sheet metal parts for medical industry. Because of its complexity in design and aesthetics in appearance, medical device has high requirements on factories, and almost all processes will be involved, such as laser cutting, CNC bending, precision stamping, deep drawing, welding, surface treatment, etc. We already have a deep understanding of medical devices and can meet our customers' quality requirements.

How Yixing Technology Produce Medical Metal Parts

How to make medical device can be mainly divided into below four parts:

Part 1: Cutting Materials

Laser cutting is one of the most common cutting methods in sheet metal processing. Firstly, according to the size specifications of the finished sheet metal parts, stainless steel and other sheets are laser cut into the required dimensions for backup. This process is collectively referred to as cutting.

Part 2: Bending

Bending is the process of CNC bending the finished material according to the size specifications of the sheet metal workpiece. It will be prepared for the next step of sheet metal welding. Take patient transfer device as example, the main parts are square tubes. We use press brake or pipe bending machine to do the precise bending.

Part 3: Welding

Welding can be divided into two methods: manual welding or robot automatic welding. It is a process of welding finished materials based on the cut, bent or formed sheet metal parts. It is combining two or more types of the same or different types of sheets. Shanghai Yixing Technology can do TIG and MIG welding. Material selection and welding quality is the most important because it will influence the load bearing capacity and whether the machine can do straight line rolling. We pay attention on every detail.

Part 4: Surface Treatment

There are many surface treatment we can do such as sandblasting, anodization, polishing, powder coating, electrophoretic paint, hot-dip galvanizing, electroplating or others. For the patient transfer device, the main surface treatment is powder coating. The minimum coating thickness is more than 60um and we do 100 grid test and salt spray test to check the adhesion and corrosion resistance.

Patient transfer device is a complicated design and more process will be involved which is not listed above like riveting, threading, printing, heat treatment, assembly with motors and other plastic parts and hammock.

What are Common Marine Grade Metals?

When metal is exposed to water or moisture, marine-grade metal may be needed to prevent the material from failing under the conditions. To be considered marine grade, the material must be able to resist the corrosive effects commonly found in water environments. To achieve this, special alloying elements are added to these grades to prevent corrosion.

Marine grade metals include:

Carbon and alloy steel

Aluminum

Stainless steel

Copper

Bronze

Brass

Galvanized steel

Carbon and alloy steel

Most carbon steel is not suitable for marine environments, however, there are several marine-grade carbon steels available. AH36, DH36, and EH36 are all examples of commonly used marine-grade carbon steel approved by the Bureau of Shipping. Compared to ASTM grades, these grades will have slightly more alloying elements such as manganese and chromium, which helps achieve greater strength and greater corrosion resistance. Alloy steel also comes in marine grades. Grades such as MD, ME, MF, MG provide the strength that common alloy steels are known for and are approved by the Bureau of Shipping for shipbuilding applications.

Applications: Structural shipbuilding and other offshore structural applications

Aluminum

There are several different grades of aluminum suitable for marine conditions. Marine grade aluminum, in most cases, is limited to grades 5XXX and 6XXX. Grade 5052 is an excellent marine grade when formability is required. If strength is more of a concern, level 5083 is a good choice. 6061-T6 is an all-around popular aluminum grade also commonly used in marine applications. It has very good corrosion resistance and is precipitation hardened. In most cases, these grades have additional chromium and manganese to help protect them from corrosive marine conditions.

Applications: Structural shipbuilding, hulls, boat lifts, docks and other offshore structural applications

Stainless steel

All grades of stainless steel have some degree of corrosion resistance, however, several grades are more suitable than others for use in marine environments. Grade 316 is probably the most commonly used grade of stainless steel in marine applications. It contains more molybdenum than other austenitic stainless steels, which helps resist pitting and other corrosive effects of salt water. Grade 304 is another marine grade stainless steel, although it has less molybdenum than grade 316, making it a less ideal choice in chlorine-rich environments.

Applications: Marine accessories, marine fasteners and marine structures

Copper

There are several copper-nickel alloys suitable for marine applications. Examples include C70600, which contains nickel and manganese to help resist corrosion. C71500 is also able to withstand marine conditions and is similar in composition to the C70600 alloy, except that it contains more nickel in its chemical composition.

Applications: Water pipes, desalination equipment, marine accessories, fasteners, valves and pumps

Bronze

Silicon bronze alloys such as C65500 and aluminum bronze alloys such as C95400 are more resistant to marine environments than other bronze alloys. Alternatively, Phosphor Bronze Alloy C51000 is another common grade suitable for marine applications.

Applications: Propellers, propeller shafts, pipes and marine fasteners

Brass

Navy brass, or naval brass as it is commonly called, comes in a variety of alloys. Alloys C46200 and C46400 have zinc and tin added to make the brass alloy corrosion-resistant in wet and even underwater applications. Alloys C48200 and C48500 are similar except that they contain more lead in their chemical compositions.

Applications: Pipes, Marine Fittings, Marine Fasteners and Pumps

Galvanized steel

Galvanized steel is suitable for certain marine environments. Zinc coatings generally perform better at the low temperatures of fresh water than in salt water. Salt water contains chloride, which causes zinc to corrode quickly. High temperatures will cause corrosion to occur faster.

Application: Marine structures

Marine Metal Parts Manufacturing Capabilities

Shanghai Yixing Technology has produced sheet metal components for marine industry for more than 20 years. The most important factor we need to consider for marine industry parts is the corrosion resistance because the seawater and marine environments are much more corrosive than normal environments. How to ensure the durability of the product and corrosion resistance is very important. We are very serious in material selection. Not only do we use the marine grade material, but also we will choose the top 3 mill factory in China like Baosteel, Wuhan Iron and steel etc. Equipped with most advanced machines, we can make qualified sheet metal parts for marine industry.

How Yixing Technology Produce Marine Metal Parts

Take the gangway production as an example:

The gangway is a device that connects the ship hull to the dock and allows people to get on and off the ship. The gangway process technology mainly includes two aspects: gangway manufacturing and gangway installation. Gangway manufacturing is an important part of gangway process technology.

In gangway manufacturing, the first step is to select the appropriate material. Commonly used materials for gangways include aluminum alloy, steel and fiberglass. Aluminum alloy gangways are lightweight, corrosion-resistant, and suitable for all parts of ships; steel gangways have a stable structure and strong load-bearing capacity, and are suitable for heavy-load ships; fiberglass gangways have the advantages of light weight, corrosion resistance, and fatigue resistance, and are suitable for general ships.

Secondly, design and drawing are required in the manufacturing of gangway. Based on actual needs and usage requirements, designers will design the function, shape, size, etc. of the gangway and produce detailed drawings. Information such as the size, material, and processing requirements of each component will be marked on the drawing to facilitate processing and manufacturing by workers.

Then, the processing and manufacturing of the gangway are carried out. The manufacturing process of the gangway includes blanking, bending, welding, cutting, drilling and other processes. During the processing process, precise operations are required according to the drawing requirements to ensure that the quality and size of the gangway are accurate. At the same time, surface treatment is also required, such as spraying anti-corrosion paint, painting, etc., to improve the corrosion resistance and aesthetics of the gangway.

Gangway installation is another important link in gangway technology. During the installation of the gangway, the position needs to be measured and marked first. According to the design requirements and actual conditions, the construction personnel will measure and mark the dock and ship to determine the location of the gangway installation.

Then, fix and install the gangway. There are many ways to fix the gangway, the most commonly used ones are welding fixation and bolt fixation. For large ships and heavy-duty ships, welding is usually used to ensure the stability of the gangway; for light ships, bolts are usually used to facilitate replacement or disassembly.

Finally, the ramp is tested and accepted. After the installation of the gangway is completed, testing and acceptance are required to ensure the safety and reliability of the gangway. The test content includes the load-bearing capacity test of the gangway, wind resistance test, etc. The acceptance includes inspection and measurement of all parts of the gangway to ensure that the gangway meets the design requirements and relevant standards.

Laser Cutting

Laser cutting has obvious advantage such as high precision, high speed and low cost compared with other traditional cutting method. Shanghai Yixing Technology provides professional laser cutting service for all industries. Thickest material can be 20mm for carbon steel and 14mm for stainless steel.

What is Laser Cutting?

Laser cutting is an efficient and economical cutting process. It is the use of a high density laser beam to irradiate a workpiece, causing the irradiated material to vaporize and melt, while using high-speed airflow to blow away the material, in order to cut the workpiece out. It leaves edges with high-quality surface finish. Industrial laser cutting machines are generally used to cut flat materials as well as structural and pipeline materials. Laser cutting is a mainstream technology known for its accuracy, efficiency, and versatility.

Laser Cutting Material

Laser cutting machine can cut metals, plastic, wood, leather and even cardboard. Below is the summary of the metal material we can cut. The material and its thickness choice is highly dependent on the machine parameters.

Material

Grade

Aluminium

2024, 5052, 5754, 6061, 6063, 1060 et

Carbon Steel

SPCC, HRS, SAPH440 etc

Stainless Steel

201, 301, 304, 316 etc

Cold or Hot Dip Galvanized Steel

DC01+Z100, S220GD+Z100, DX51D+Z100, DC01+Z275, S220GD+Z275, DX51D+Z275 etc

ZINCALUME Steel

DC01+AZ150

Advantages of Laser Cutting in Shanghai Yixing Technology

In Shanghai Yixing Technology, we will use the most suitable laser cutting equipment like 3D laser cutting machine 1500W and flat laser cutting machine 2000W according to the material and design shape and also other external suppliers resource to fully meet customers' demands.

We provide accurate and fast laser cutting services for all industries like automobile, agriculture, solar industry etc. There are hundreds of materials we can laser cut and we do not set minimum order QTY so as to relieve customers’ financial pressures. We are friendly to new start project with small quantities.

We have professionally trained engineer who can fully control the beam intensity, thermal output, and duration during the laser cutting process. Therefore, our laser cutting process is highly reliable and helps to significantly avoid errors and reduce material waste.

FAQ of Laser Cutting

What is the thickest flat sheet you can laser cut?

We offer different thickness specifications for different laser cutting materials. The laser cutting equipment parameters will decide what thickness we can cut.

For aluminum, the thickest flat sheet we can laser cut is around 10mm.

For stainless steel, the thickest flat sheet we can laser cut is around 14mm.

For carbon steel, the thickest flat sheet we can laser cut is around 20mm.

How long does it take to laser cut materials?

Laser cutting is one of the most efficient cutting method that can cut steel materials very fast. This ensures that various cutting projects will be completed very quickly while at the same time save material costs. With precise laser cutting machines in Shanghai Yixing Technology, we can provide faster lead times and reasonable pricing for customers.

For aluminum, our cutting speed is around 0.3~0.45m/min.

For stainless steel, our cutting speed is around 0.4~0.5m/min.

For carbon steel, our cutting speed is around 0.3~0.5m/min.

How accurate is your laser cutting service?

Our laser cutting service can cut material with a precision of +/- 0.002 inches and a positional accuracy of +/- 0.004 inches. This high precision makes laser cutting an ideal choice for industries that require complex and detailed cutting. For example, precision parts of serrated teeth used in the manufacturing and even production of medical devices.

The accuracy of laser cutting machines is mainly affected by the following factors:

1. Laser beam quality

The better the quality of the laser beam, the smaller the focused spot, and the higher the cutting quality and accuracy.

2. Optical system

High precision and high-quality optical systems can significantly improve the accuracy of laser cutting machines. During the operation of the laser cutting machine, the optical system guides the laser beam very close to the workpiece, ensuring the accuracy and stability of the laser beam, thereby achieving high-precision processing.

3. Machine accuracy

Machine accuracy is also one of the key factors affecting the accuracy of laser cutting machines. The laser cutting machine needs to have a high-precision positioning system, including the workbench, guide rail, servo motor, sensor, and other parts that must ensure accuracy in order to ensure the processing accuracy of the laser cutting machine.

4. Cutting parameters

Different materials and thicknesses require different cutting parameters, such as laser power, spot diameter, gas flow rate, cutting speed, etc. Adjusting these parameters can effectively affect the accuracy of cutting.

Hot-dip Galvanizing

What is the difference between hot-dip galvanizing and cold galvanizing?

1. Concept analysis

Hot-dip galvanizing: also called hot galvanizing. It is an effective method of metal anti-corrosion. It melts zinc ingots at high temperatures, puts in some auxiliary materials, and then immerses the metal structural parts in a galvanizing bath. In it, a layer of zinc is attached to the metal components to achieve the purpose of anti-corrosion. The advantage of hot-dip galvanizing is that it has strong anti-corrosion ability and the galvanized layer has good adhesion and hardness, thus achieving the purpose of anti-corrosion.

Cold galvanizing: It is electro-galvanizing. The amount of zinc applied is small, only 10-50g/㎡. It is a process that uses electrolysis to attach a metal film to the surface of metal or other material parts. The process of forming a uniform, dense, and well-bonded metal layer can prevent corrosion, improve wear resistance, conductivity, reflectivity, and enhance aesthetics.

2. Differences in reaction methods

Hot-dip galvanizing is a chemical treatment and is an electrochemical reaction. Hot-dip galvanizing makes the molten metal react with the iron matrix to produce an alloy layer, thereby combining the matrix and the coating.

Cold galvanizing is a physical treatment. It just brushes a layer of zinc on the surface, so the zinc layer is easy to fall off. Hot dip galvanizing is often used in building construction.

3. Process differences

Hot-dip galvanizing involves degreasing, pickling, dipping, and drying the workpiece, then immersing it in the molten zinc solution for a certain period of time and then lifting it out.

Cold galvanizing uses electrolytic equipment to degrease and pickle the workpiece and put it into a solution composed of zinc salts, and connect it to the negative electrode of the electrolytic equipment; place a zinc plate opposite the workpiece and connect it to the positive electrode of the electrolytic equipment, and turn on the power, using the directional movement of current from the positive electrode to the negative electrode, a layer of zinc will be deposited on the workpiece.

4. Differences between galvanized finished products

Differences in galvanized finished products: The surface of hot-dip galvanizing is not as delicate and bright as cold galvanizing, and the coating is uniform. However, the thickness of the zinc layer is dozens of times that of cold galvanizing. The anti-corrosion performance is also dozens of times that of electroplated zinc.

Hot galvanizing, also known as hot-dip galvanizing, involves removing oil and rust from the steel workpiece to present a dirt-free, wetted surface. The workpiece is immediately immersed in a plating bath where the zinc has been heated and melted in advance to form a layer of zinc on the surface of the workpiece. zinc plating method.

Cold galvanizing is to hang the workpiece that has also been degreased and rusted, showing no dirt and infiltration, onto the cathode in a special electroplating tank, and the anode is zinc. When the DC power supply is turned on, the zinc ions on the anode migrate to the cathode and are discharged on the cathode, so that the workpiece is coated with a layer of zinc. The coating of hot-dip galvanizing is thicker, generally 30-60 microns, and the coating has higher anti-corrosion capabilities.

Electro-galvanized, the surface of the workpiece is smooth and flat, but because the coating is relatively thin, electro-galvanized is generally within 5-30 microns, so the anti-corrosion time will be relatively short. They are all used for rust prevention of indoor parts, such as chassis bottoms, panels, small-size fasteners, etc.

In suburban environments, the standard hot-dip galvanized rust-proof thickness can be maintained for more than 50 years without repair; in urban or offshore areas, the standard hot-dip galvanized rust-proof layer can be maintained for 20 years without repair;

5. Differences in uses

Hot-dip galvanizing: suitable for long-term rust prevention of steel parts for outdoor work, such as highway fences, power towers, large-size fasteners and other relatively "rough" workpieces. Earlier iron water pipes were also hot-dip galvanized.

Electro-galvanizing: It is used to prevent rust of indoor parts, such as the bottom of the casing, panels, small-size fasteners, etc.

6. Price difference

The galvanizing process is faster than other coating application methods and eliminates the time required to paint on site after installation.

Low treatment costs: The cost of hot-dip galvanizing for rust prevention is lower than the cost of other paint coatings;

In general, the cost of hot-dip galvanizing is lower than applying other protective coatings. The reason is simple. Other protective coatings such as sandblasting and painting are labor-intensive processes. On the contrary, the process of hot-dip galvanizing is highly mechanized and tightly controlled. Construction inside.

Cold galvanizing can only be plated on one side, while hot dip galvanizing must be fully galvanized. And hot-dip galvanizing generally has a thicker galvanized layer than cold galvanizing, so the price of hot-dip galvanizing is higher than that of cold-dip galvanizing.

7. Environmental issues

Hot-dip galvanized square and rectangular pipes emit less pollutants, mainly waste acid from pickling workpieces.

The pollutants of cold galvanizing mainly include waste acid from pickling workpieces, waste electroplating liquid, waste passivation liquid, etc. The types and quantities of emissions are much greater than those of hot-dip galvanizing.