Corrosion-Resistant Castings Manufacturers

Which factors are most critical when selecting corrosion-resistant casting materials

In the modern industrial field, corrosion-resistant castings are widely used in many industries such as chemical, petroleum, metallurgy, and waste incineration, especially those that need to face harsh environments and corrosive media. How to choose suitable corrosion-resistant casting materials is not only directly related to the service life of the product, but also to the production efficiency and economic benefits of the enterprise.
Working environment and the nature of corrosive media
When selecting corrosion-resistant casting materials, the first thing to consider is the environment in which it will be used. Different corrosive media have different effects on castings. One of Wuxi Dongmingguan’s main products is castings for waste incinerators. Such castings are usually faced with the combined effects of high temperature, high pressure and corrosive gases. Therefore, when selecting corrosion-resistant materials, the type and concentration of corrosive media must be analyzed first. For example, substances such as chlorides and sulfides have a faster corrosion rate, and special attention needs to be paid to the corrosion resistance of castings.
The company mainly serves the heat treatment, petrochemical, and metallurgical industries, which are usually faced with harsh conditions such as high temperature corrosion and high sulfur environments. Therefore, when selecting materials, it is necessary to consider their corrosion resistance in high temperature environments. For example, materials such as high-alloy cast iron and high-corrosion-resistant alloy steel are often preferred.
Chemical composition and alloy design of materials
The chemical composition of corrosion-resistant materials is crucial to their corrosion resistance. In the material selection process, the appropriate alloy composition should be selected according to the corrosion environment. For example, alloy compositions such as high chromium alloys and molybdenum alloys have strong corrosion resistance, especially in acidic and chloride media. With many years of experience, Wuxi Dongmingguan provides a series of high-alloy centrifugal cast pipes, which are typical high-chromium alloy materials. They have shown excellent performance in chemical corrosion environments and have been widely recognized by customers.
In addition, alloy design also needs to take into account the mechanical properties of the material, especially its performance in stress corrosion environments. Certain corrosive environments may induce stress corrosion cracking (SCC). In this case, it is crucial to select alloys with good stress corrosion resistance.
Processing technology and surface treatment of castings
The production process of corrosion-resistant castings, including casting technology and surface treatment, will affect the final corrosion performance of the material. At Wuxi Dongmingguan, we use technologies such as precision casting, centrifugal casting and resin sand casting, which ensure the structural density of the castings, thereby reducing porosity, reducing the penetration of corrosive media and extending the service life of the castings.
The surface treatment of the castings also affects the corrosion resistance, especially when facing the erosion of marine environments and chemicals. Surface treatments such as spraying, passivation, and anodizing can effectively increase the surface corrosion resistance of castings. For the high-alloy centrifugal casting pipes and heat treatment fixture series produced by Wuxi Dongmingguan, we usually use advanced surface protection treatment to ensure its long-term stable operation in highly corrosive environments.
Adaptability to temperature and pressure conditions
When selecting corrosion-resistant materials, their performance under high temperature and high pressure conditions must also be considered. For example, in the metallurgical industry, changes in temperature and pressure can significantly affect the corrosion resistance and mechanical properties of the material. The heating furnace bottom rollers and paper machine roller series castings produced by Wuxi Dongmingguan usually need to face high temperature operating environments, so the high temperature corrosion resistance of the material is particularly important. In order to ensure that these castings will not fail due to corrosion at high temperatures, we selected high-alloy materials containing elements such as molybdenum and chromium, which can provide excellent corrosion and oxidation resistance in high temperature environments.
Wear and impact resistance of materials
In some application scenarios, castings must not only have corrosion resistance, but also good wear and impact resistance. One of Wuxi Dongmingguan's products is a grate series for waste incinerators. These castings need to withstand continuous wear and impact, so the materials are not only required to be corrosion-resistant, but also wear-resistant and high-strength. For such high-demand castings, high-temperature resistant materials containing a large amount of cemented carbide are usually selected, which can effectively improve their wear and impact resistance.

How corrosion-resistant castings cope with erosion by different chemical media

In modern industry, corrosion-resistant castings are key components for harsh working environments, especially in chemical engineering, metallurgy, petrochemicals, waste incineration and other industries. The corrosiveness of chemical media is often variable, including acidic, alkaline, high chloride, high sulfur and other corrosive environments. How to choose the right casting material to deal with different chemical media corrosion directly affects the durability and safety of the equipment.
Understand the corrosion characteristics of chemical media on castings
Different chemical media have different ways of corroding castings, so it is necessary to fully understand the corrosion characteristics of various chemical media when selecting materials. Common corrosive media include acidic solutions, alkaline solutions, chlorides, sulfides, etc.
Acidic media: Acidic solutions such as sulfuric acid and hydrochloric acid can accelerate the dissolution of metals. Casting materials need to have strong acid corrosion resistance. High chromium alloys and molybdenum-containing alloy materials usually have strong acid resistance and can maintain good corrosion resistance in acidic media.
Alkaline media: Alkaline solutions such as sodium hydroxide are less corrosive to some materials, but there is still a threat to the corrosion of alloy materials such as stainless steel. When castings encounter alkaline media, they need to have good stability to avoid alkaline corrosion.
Chloride: Chloride (such as sodium chloride solution) is a typical substance that causes stress corrosion cracking (SCC), especially in high temperature environments. For this environment, castings must be made of high-alloy materials that are resistant to chloride corrosion.
Sulfide: Sulfide media are usually present in high-temperature environments, such as in smelting and chemical processes. Casting materials need to pay special attention to resistance to sulfidation corrosion, especially high-sulfur alloy castings in this regard.
Material selection and response strategies for Dongmingguan castings
Wuxi Dongmingguan's corrosion-resistant casting materials use a series of high-performance alloys to ensure excellent durability in different corrosive environments. According to the characteristics of different corrosive media, Dongmingguan adopts different alloy designs and processing strategies.
High-alloy cast iron: Dongmingguan uses high-chromium alloy cast iron in the production process. This material exhibits excellent corrosion resistance when facing acidic media (such as sulfuric acid and hydrochloric acid), especially in high-temperature environments. It can effectively resist acid corrosion. This material is widely used in key components in high-temperature and highly corrosive environments such as grates and heating furnace bottom rollers of waste incinerators.
Molybdenum-containing alloys: For chloride environments (such as marine environments or chemical media containing chlorides), Dongmingguan uses molybdenum-containing alloy castings. Molybdenum can significantly improve the alloy's resistance to chloride corrosion. Wuxi Dongmingguan's high-alloy centrifugal cast pipe series is widely used in equipment that requires chloride corrosion resistance, such as radiation tubes, heat treatment fixtures, etc., and can work stably in chloride corrosion environments for a long time.
Sulfur-resistant alloy: For castings that handle sulfur-containing gases or high-sulfur environments, Dongmingguan uses high-sulfur corrosion-resistant alloys, especially when casting easy-to-cut high-sulfur centrifugal cast pipes, which can effectively resist sulfide corrosion. This alloy material is commonly found in key parts such as heat exchangers and furnace tubes in metallurgy, petrochemical and other industries, and can significantly improve the service life of equipment.
Dongmingguan's production process
In order to better cope with the corrosion of different chemical media, Dongmingguan uses a variety of advanced casting technologies and surface treatment processes in the production process. These processes can ensure that the surface of the casting is dense and uniform, reduce the generation of pores and cracks, and thus improve the corrosion resistance of the casting in harsh environments.
Precision casting: Through precision casting (such as investment casting, EPC lost wax casting process), Dongmingguan's castings can achieve high dimensional accuracy and surface finish, reducing surface defects of castings, which is crucial to improving corrosion resistance. Precision casting can form a dense oxide film on the surface of the casting, further improving corrosion resistance.
Centrifugal casting: Dongmingguan also uses centrifugal casting technology, which is particularly suitable for casting large high-alloy castings. During the centrifugal casting process, the metal liquid solidifies in a high-speed rotating mold, which can effectively eliminate pores and shrinkage holes, ensuring that the surface of the casting is smooth and defect-free. The high-alloy centrifugal cast pipe produced by this process performs particularly well in dealing with highly corrosive environments.
Surface treatment: Dongmingguan also performs surface treatment on castings based on specific application environments. Common treatment processes include spraying, passivation, anodizing, etc. These surface treatment processes can enhance the resistance of the casting surface to corrosive media and extend its service life.