Cast Iron / Ductile Iron Knife Gate Valve
For cost-sensitive projects and general-purpose applications, cast iron and ductile iron knife gate valves offer a reliable and economical solution. Designed to handle water, wastewater, light slurries, and non-corrosive media, these valves combine the cutting action of a knife gate with the affordability of cast and ductile iron materials.
TOT’s cast iron and ductile iron knife gate valves are built with durable bodies, sharp-edged gates, and versatile seat options. While cast iron provides excellent machinability and low cost, ductile iron offers higher strength, impact resistance, and better performance under pressure. Together, they are widely used in municipal, utility, and light industrial systems.
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Cast Iron / Ductile Iron Knife Gate Valve – Data Sheet
| Parameter | Details |
|---|---|
| Body Material | Cast Iron (GG25 / ASTM A126) / Ductile Iron (GGG40 / ASTM A536) |
| Gate Material | SS304 / SS316 / Duplex / Hardened Alloy |
| Seat Options | EPDM, NBR, PTFE, Metal Seat |
| Packing | PTFE, Graphite, Braided Aramid |
| Pressure Rating | PN6 / PN10 / PN16 / ANSI 150 |
| Face-to-Face | Customizable (MSS SP-81 Standard / ISO Standard) |
| Connection | Wafer / Lug / Flanged |
| Actuation | Manual (Handwheel / Chainwheel), Gear, Pneumatic, Hydraulic, Electric |
Material Comparison: Cast Iron vs. Ductile Iron
| Feature | Cast Iron | Ductile Iron |
|---|---|---|
| Strength | Moderate | High |
| Impact Resistance | Low | High |
| Cost | Lower | Slightly higher |
| Applications | Water, sewage, HVAC | Wastewater, slurry, industrial use |
| Pressure Ratings | PN6 / PN10 | PN10 / PN16 / ANSI 150 |
Key Features
Economical Choice: Affordable alternative to stainless or carbon steel valves.
Reliable Shutoff: Knife-like gate slices through light slurries and solids in suspension.
Material Options: Cast iron for cost efficiency; ductile iron for higher strength and resilience.
Flexible Configurations: Wafer, lug, or flanged ends available.
Versatile Actuation: Manual, gear, pneumatic, hydraulic, or electric operation.
Tested Before Delivery: Hydrostatic and seat tested to international standards.
Materials & Construction
Body Material: Cast Iron (GG25), Ductile Iron (GGG40/50)
Gate Material: Stainless steel (SS304 / SS316) or hardened alloy steel
Seat Options: EPDM, NBR, PTFE, or metal seat depending on application
Packing: PTFE, Graphite, or Braided Aramid for reliable sealing
Coating: Fusion bonded epoxy or epoxy paint for corrosion protection
Sizes & Pressure Ratings
Standard Sizes: DN50–DN1200 (2″–48″)
Pressure Ratings: PN6, PN10, PN16 (limited ANSI 150 available for ductile iron)
Temperature Range: Up to 200°C depending on seat and packing materials
Actuation Options
Manual handwheel or lever
Gear-operated for larger sizes
Pneumatic cylinder for automated systems
Electric actuator for remote operation
Hydraulic actuator for heavy-duty applications
Applications
Cast iron and ductile iron knife gate valves are best suited for:
Water Supply & Distribution – pipelines, pumping stations
Wastewater Treatment – sludge, aeration, grit handling
Municipal & Utility Systems – sewage, irrigation, drainage
Light Industrial Applications – non-corrosive powders, neutral fluids
General Services – HVAC, cooling water, low-pressure systems
Advantages of Cast Iron & Ductile Iron Knife Gate Valves
Low Cost: Significantly more economical than stainless or alloy valves.
Good Mechanical Strength: Ductile iron provides higher pressure resistance and toughness.
Wide Availability: Standard sizes and ratings commonly in stock.
Easy Maintenance: Replaceable seats and packings for long service life.
Coating Options: Epoxy lining extends service life in damp or mildly aggressive environments.
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FAQ – Cast Iron / Ductile Iron Knife Gate Valve
It is a type of knife gate valve with a cast iron or ductile iron body, designed for water, wastewater, and light industrial applications. The sharp-edged gate provides reliable shutoff for fluids with small amounts of solids or suspended particles.
Cast iron is more affordable and suitable for low-pressure, non-shock applications. Ductile iron offers higher strength, toughness, and pressure capacity, making it better for demanding or municipal systems.
Neutral or mildly abrasive fluids such as water, wastewater, sludge, light slurry, powders, and non-corrosive liquids. For corrosive or aggressive chemicals, stainless steel is recommended instead.
The flat gate moves perpendicular to the flow and cuts through media, sealing against a resilient or metal seat. It is primarily designed for on/off isolation, not throttling.
Yes. They can be fitted with pneumatic, electric, or hydraulic actuators, in addition to manual and gear operation.
Cast Iron: Low-cost, general-purpose water/wastewater use.
Ductile Iron: Stronger, higher pressure capability for municipal/industrial systems.
Carbon Steel: For neutral but higher-pressure or more abrasive applications.
Stainless Steel: For corrosive, chemical, or sanitary environments.
Periodic inspection of the seat, gate, and packing is recommended. Epoxy-coated valves should be checked for lining integrity in corrosive service.
