As a key control component in industrial piping systems, the material selection of butterfly valves directly impacts equipment reliability, service life, and operational safety. In complex and diverse operating environments (such as corrosive media, high temperatures and pressures, or fluids containing particles), the appropriate material matching not only improves valve performance but also significantly reduces maintenance costs. WEIZIDOM, drawing on years of experience, systematically introduces butterfly valve material classification, characteristics, and selection strategies, and incorporates practical testing methods to provide a scientific basis for project selection.
Carbon steel: Nominal pressure PN ≤ 32.0 MPa, temperature range -30 to 425°C, suitable for non-corrosive media such as water, steam, and petroleum products. WCB (cast carbon steel), 20/25 (high-quality carbon steel).
Ductile iron: Has a tensile strength superior to gray cast iron (PN ≤ 4.0 MPa, -30 to 350°C), suitable for media such as oil and air, but should avoid strong acid environments. It is commonly used in water supply and drainage systems.
304 stainless steel: Resistant to nitric acid and organic acids, meets FDA standards, and is suitable for applications requiring high hygiene standards, such as food processing and pharmaceuticals.
316 stainless steel: Contains molybdenum, which improves resistance to chloride ion corrosion and is suitable for chemical industry, seawater treatment and coastal environments.
Alloy steel (such as duplex steel): Resistant to high temperature, high pressure and strong corrosion (such as concentrated sulfuric acid and hydrofluoric acid), but with higher cost.
WEIZIDOM can provide butterfly valves of various types including carbon steel butterfly valves, stainless steel butterfly valves, ductile iron butterfly valves, and fluorine-lined butterfly valves. We can also customize butterfly valves made of other materials according to customer needs.
CPVC (chlorinated polyvinyl chloride): Resistant to strong acids, alkalis, and salts, suitable for water treatment and chemical piping, operating temperature ≤95°C.
UPVC/PP (polypropylene): Resistant to mild corrosion, low cost, mostly used in drainage and ventilation systems.
Alumina ceramics: Wear-resistant and heat-resistant (≤600°C), suitable for fluids containing particles (such as slurry).
Fluoro-lined/rubber-lined: Lined with PTFE or EPDM for improved corrosion resistance, but with lower pressure-bearing capacity.
Rubber
EPDM (ethylene propylene diene monomer): Resistant to water, steam, and weak acids and alkalis, operating temperature ≤120°C, suitable for municipal water pipes and the food industry. NBR (nitrile rubber): Excellent oil resistance, suitable for petroleum product pipelines.
Fluororubber (FKM): Resistant to strong acids, strong alkalis, and high temperatures (≤200°C), commonly used in the chemical industry.
Plastics
PTFE (polytetrafluoroethylene): Excellent corrosion resistance, suitable for acidic and alkaline media, but prone to creep at high temperatures (≤150°C).
Fluororubber-coated PTFE: Combining the advantages of both materials, it offers enhanced temperature and corrosion resistance.
Stainless Steel Overlay: Resistant to high temperatures and pressures (≤425°C), with strong pressure-bearing capacity. Suitable for steam and oil pipelines.
Carbide: Excellent wear resistance, hardness of HRC60 or above. Suitable for fluids containing particles (such as slurry).
Ceramic (zirconia): High-temperature resistance up to 600°C, strong corrosion resistance, zero leakage. Suitable for extreme operating conditions (such as hydrofluoric acid).
Corrosive media: Prefer CPVC, 316 stainless steel, or fluorine-lined butterfly valves.
High temperature and high pressure: Choose a triple-eccentric hard-seal alloy steel butterfly valve.
Particle-containing fluids: Ceramic seals or metal hard seals resist wear.
Visual and Label Inspection
Nameplate Identification: Check the material code (e.g., WCB, 304SS, CPVC, etc.) and standard (ASTM/GB) marked on the valve body nameplate.
Surface Characteristics
Stainless steel (304/316) is silvery white and non-magnetic or weakly magnetic;
Cast iron (HT200) has a dull gray surface with visible pinholes;
Plastic (CPVC/UPVC) is lightweight and produces a dull sound when tapped.
Spectroscopic Analysis (Rapid On-site Testing)
Use a portable X-ray fluorescence spectrometer (XRF) to analyze metal composition, for example, to confirm whether chromium and nickel content match 316 stainless steel standards.
Laboratory Chemical Testing
Verify alloy composition using an acid etching test or energy dispersive spectroscopy (EDS), for example, to distinguish duplex steel (such as 2205) from standard stainless steel.
