【Haichuan Chemical Valve Management】Series of Posts–Stop Getting It Mixed Up! Quick reference for CF8/CF8M/CF3/CF3M materials

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Proper management of valves is the foundation for stable operation. Everyone is welcome to engage in discussions and share insights on this series of posts: 【HaiChuan Chemical Valve Management】 series of posts: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=5719309 ---------------------------------------------------------------- Disclaimer: The content contained in this article is intended solely for technical exchange and reference purposes only; it does not constitute any form of professional engineering advice, design basis, or operational guidance. ----------------------------------------------------------------------------------- CF8, CF8M, CF3, and CF3M are all austenitic cast stainless steels per the ASTM A351 standard, and are commonly used in castings such as valves, pump bodies, and flanges. Their composition is comparable to that of forged stainless steels 304/304L/316/316L; the key differences lie in the carbon content and the presence of molybdenum. I. Quick reference for grade meanings: C: Casting; F: Austenitic; 8: Carbon ≤ 0.08% (normal carbon); 3: Carbon ≤ 0.03% (ultra-low carbon); M: Contains Mo (molybdenum, 2.0%–3.0%). II. Material correspondences and compositions (ASTM A351). III. Key differences and selection criteria: CF8 vs CF3. CF8: Carbon ≤ 0.08%, corresponding to 304; suitable for applications subject to normal corrosion, as well as for castings that are not welded or can be treated by solution treatment. CF3: Carbon content ≤0.03%, corresponding to 304L; it offers greater resistance to intergranular corrosion, making it suitable for thick-walled welded parts in applications where no post-weld heat treatment is required. CF8M vs CF3M CF8M: Carbon ≤0.08%+Mo, corresponding to 316; resistant to moderate corrosion and chloride ions. CF3M: Carbon ≤0.03% + Mo; corresponds to 316L. Offers welding resistance, intergranular corrosion resistance, and pitting resistance – the ideal choice for harsh environments such as seawater, chemical industries, and LNG applications. IV. Typical Applications (Valves/Pumps/Chemical Equipment): CF8: General water, nitric acid, food applications, and low-temperature conditions. CF8M: Acetic acid, phosphoric acid, medium chloride environment. CF3: Welded structure, large cross-section, no post-weld heat treatment. CF3M: Seawater, brine, chlorinated acidic media, offshore engineering, desulfurization units.