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The material selection of sanitary grade fittings has a decisive impact on their service life, corrosion resistance, and compliance. At present, the mainstream material is austenitic stainless steel, among which 316L stainless steel has excellent resistance to chloride pitting and crevice corrosion due to its high molybdenum content (2-3%), making it the preferred choice in the food and pharmaceutical industries. Its carbon content is less than 0.03%, effectively reducing the risk of carbide precipitation during the welding process and ensuring the corrosion resistance of the weld area. In contrast, although 304/304L stainless steel has a lower cost, it is prone to corrosion in salt containing or weakly acidic media, and its applicability is relatively limited.

Except for 316L, higher performance alloy materials may be used under certain special working conditions. For example, duplex stainless steel (such as 2205) combines high strength and excellent stress corrosion cracking resistance, making it suitable for marine environments or high chloride ion concentration systems; Super austenitic stainless steel (such as 904L) and nickel based alloys (such as Hastelloy C276) are used for extreme corrosion conditions, and although expensive, they cannot be replaced in specific strong acid and oxidant environments. Non metallic materials such as food grade silicone or PTFE lined fittings are mainly used for conveying sensitive media or as flexible connecting sections, with good chemical inertness and shock absorption effects. All materials that come into contact with the medium must pass relevant safety certifications to ensure that no harmful substances are released. From a manufacturing perspective, the processability, welding performance, and surface treatment adaptability of materials also need to be evaluated simultaneously to ensure the consistency and reliability of the finished product. Through systematic material comparison, optimal solutions can be provided for different application scenarios.