Stainless steel castings have a wide range of applications, such as in mechanical manufacturing for manufacturing components, connectors, gears, etc; Used in aerospace for manufacturing engine components, gas turbine blades, etc; Used in automobile manufacturing to manufacture engine cylinder blocks, exhaust pipes, etc; Used in the petrochemical industry to manufacture chemical equipment, pipelines, etc.

Some stainless steel castings have good high-temperature stability, which can maintain their strength and structural stability in high-temperature environments, and are suitable for high-temperature process fields such as oil refining, coal-fired power generation, aerospace, etc. Stainless steel castings have certain machinability and can be further processed and manufactured through casting, forging, welding, mechanical processing and other processes to meet the production needs of parts with different shapes, sizes and precision requirements.

How to improve the corrosion resistance of stainless steel castings?

Optimize chemical composition

Reasonable control of chromium content: Chromium is a key element for stainless steel to achieve corrosion resistance, and generally the higher the chromium content, the stronger the corrosion resistance. On the premise of ensuring other properties of stainless steel castings, appropriately increasing the chromium content can promote the formation of a denser and more stable passivation film on its surface, thereby effectively resisting the erosion of corrosive media.

Adding alloying elements: In addition to chromium, adding appropriate amounts of nickel, molybdenum, copper, nitrogen and other alloying elements can also help improve the corrosion resistance of stainless steel castings. For example, nickel can expand the austenite phase region, improve the toughness and corrosion resistance of stainless steel; Molybdenum can enhance the corrosion resistance of stainless steel in reducing media; Copper can enhance its corrosion resistance in certain specific media; Nitrogen helps to refine grain size, enhance the strength and corrosion resistance of stainless steel.

Improve casting process

By using precision casting techniques such as investment casting and lost foam casting, stainless steel castings with high dimensional accuracy and good surface quality can be obtained. These processes can reduce the surface roughness of castings, decrease surface defects and porosity, making it difficult for corrosive media to stay and penetrate on the surface of castings, thereby improving corrosion resistance.

Control the solidification process: Optimizing the solidification process of stainless steel castings, such as using reasonable pouring temperature, cooling rate and other parameters, can achieve uniform and fine grain structure in the castings. Uniform organization helps to improve the quality and stability of passivation film formation, reduce local corrosion caused by uneven organization, and enhance overall corrosion resistance.

Avoiding casting defects: Strictly control each link in the casting process to prevent defects such as porosity, shrinkage, inclusions, etc. These defects can damage the integrity of the casting surface, become the starting point of corrosion, and accelerate the corrosion process. By optimizing the melting process, strengthening the quality control of molding sand, and designing the casting structure reasonably, measures can be taken to effectively reduce casting defects and improve corrosion resistance.

Heat treatment process

Solution treatment: Solution treatment is performed on stainless steel castings, which involves heating the castings to high temperatures and holding them for a period of time, followed by rapid cooling. Solid solution treatment can fully dissolve alloying elements in austenite, forming a single austenite structure and improving the corrosion resistance and toughness of stainless steel. Meanwhile, solution treatment can also eliminate casting stress and reduce the risk of stress corrosion cracking.

Stabilization treatment: For stainless steel castings containing stabilizing elements such as titanium and niobium, stabilization treatment can form stable carbides with carbon, avoiding the formation of chromium carbide by the combination of carbon and chromium, thereby preventing chromium depletion at grain boundaries and improving the intergranular corrosion resistance of stainless steel.

Aging treatment: Aging treatment can cause alloy elements in stainless steel castings to precipitate and form dispersed strengthening phases at a certain temperature, thereby improving the strength and hardness of the castings. Meanwhile, appropriate aging treatment can also help improve the corrosion resistance of stainless steel, especially for some precipitation hardening stainless steel castings, aging treatment is an important means to improve their comprehensive performance.

The production process of stainless steel castings includes mold design, raw material preparation, melting and casting, cleaning and slag removal, heat treatment, and surface treatment. Among them, mold design is a key link that directly affects the quality and shape accuracy of castings. Raw material preparation includes selecting suitable stainless steel materials and adding appropriate amounts of alloying elements to ensure that the castings have good performance. Smelting casting is the process of heating raw materials to a molten state and then pouring them into a mold for casting, ultimately forming castings of the desired shape.

Strictly control various process links in casting production, such as melting temperature, pouring speed, cooling speed, etc., to ensure the uniformity of the structure and stability of the castings. At the same time, quality monitoring is carried out on processes such as shell making and model manufacturing to ensure the dimensional accuracy and surface quality of castings.