Custom Flywheels
Engineered for Precision & Balance
We engineer and manufacture heavy-duty custom cast iron flywheels for industrial machinery, diesel engines, and stamping presses. Kurt Foundry delivers fully CNC-machined, porosity-free flywheels directly to your North American facility.
The Foundation of Rotational Stability
Industrial flywheels require immense structural integrity and perfect mass distribution to store rotational energy safely. A minor internal casting defect can cause catastrophic failure at high rotational speeds. Kurt Foundry custom-engineers heavy-duty flywheels to meet your exact dimensional and metallurgical specifications.
We utilize furan resin sand casting to pour medium to massive flywheels weighing up to 5,000 lbs. By combining advanced 3D solidification simulation with in-house 5-axis CNC machining, we guarantee perfect concentricity and strict dynamic balancing tolerances. Our engineering team reviews every CAD file to ensure the hub and web transition areas solidify without internal shrinkage.
Whether you need high-damping custom gray iron castings for heavy stamping presses or high-strength custom ductile iron castings for high-RPM diesel engines, we deliver Ready-To-Assemble components directly to your loading dock. Procurement managers and lead engineers eliminate the middleman and deal directly with the foundry experts.
Flywheel Material Grades & Specifications
| Standard / Grade | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | Common Applications |
|---|---|---|---|---|
| ASTM A48 Class 30 (Gray Iron) | ≥ 207 | N/A (Brittle) | N/A | Standard industrial press flywheels, machine tools, vibration dampers. |
| ASTM A48 Class 40 (Gray Iron) | ≥ 276 | N/A (Brittle) | N/A | Heavy-duty crushers, large compressor flywheels requiring higher strength. |
| ASTM A536 65-45-12 (Ductile Iron) | ≥ 448 | ≥ 310 | ≥ 12 | High-RPM engine flywheels, high-stress rotational applications. |
| ASTM A536 80-55-06 (Ductile Iron) | ≥ 552 | ≥ 379 | ≥ 6 | Severe-duty industrial equipment requiring maximum burst resistance. |
Precision Machining & Perfect Concentricity
A raw casting is useless if the final part wobbles on the drive shaft. We perform all CNC turning, boring, and keyway broaching in-house. This single-source manufacturing approach ensures the final custom flywheel meets strict runout tolerances.
By controlling both the casting process and the final machining, we deliver a perfectly concentric component that requires minimal dynamic balancing before final assembly.
Our Custom Flywheel Manufacturing Process
1. DFM Review & Casting Simulation
We analyze your flywheel CAD model using Magmasoft 3D simulation. We engineer optimized gating and riser systems to feed molten metal directly into the heavy central hub, preventing internal shrinkage porosity.
2. Resin Sand Molding
Our automated molding lines utilize furan resin sand to create exceptionally rigid molds. Understanding the different types of sand used in sand casting allows us to prevent mold wall movement, ensuring the heavy flywheel maintains exact dimensional accuracy during pouring.
3. Spectrometer-Verified Pouring
Before pouring the molten iron, we conduct rigorous spectrometric analysis. We verify the exact Carbon Equivalent (CE) for gray iron or the nodularity rate for ductile iron to guarantee the flywheel meets your specified ASTM standard.
4. Thermal Stress Relief
Heavy flywheels feature thick hubs and thin outer webs, which cool at different rates. We perform controlled thermal stress relief heat treatment to eliminate internal residual stresses, preventing the flywheel from warping during the machining phase.
5. CNC Machining & Inspection
We shot-blast the raw casting and transfer it to our 5-axis CNC machining centers. Our machinists turn the outer diameter, precision-bore the center hole, and cut the keyways. Finally, we verify all critical dimensions using Coordinate Measuring Machine (CMM) inspection.
Uncompromising Quality Control
Flywheels are safety-critical components. We do not guess on quality; we verify every specification before the part leaves our facility. Our in-house laboratory provides the testing and documentation that North American lead engineers demand.
- Ultrasonic Testing (UT): We scan the heavy hub sections to guarantee zero internal voids or shrinkage cavities that could compromise burst strength.
- Spectrometry & MTRs: We provide fully traceable Material Test Reports proving the exact chemical composition of your specific casting batch.
- CMM Dimensional Verification: We measure the machined bore and outer diameter to ensure perfect concentricity and tight runout tolerances.
- Magnetic Particle Inspection (MPI): We check high-stress transition areas for microscopic surface cracks before final packaging.
Frequently Asked Questions
The ideal material depends on your operating speeds and stress requirements. Gray iron (ASTM A48) is the most common choice because it offers excellent vibration damping and is highly cost-effective. However, if the flywheel operates at extremely high RPMs or faces severe impact loads, ductile iron (ASTM A536) provides the necessary tensile strength and ductility to prevent bursting.
The massive central hub of a flywheel cools slower than the outer web, making it highly susceptible to internal shrinkage cavities. We solve this problem by running advanced Magmasoft solidification simulations before cutting any tooling. To understand our approach to feeding molten metal, read more about how sand casting works and how we engineer our risers.
Our heavy resin sand casting lines and floor molding pits allow us to pour custom flywheels ranging from 50 lbs up to 5,000 lbs (2.5 tons) per single piece.
We supply fully CNC-machined flywheels with incredibly tight concentricity and runout tolerances. This precision machining ensures the flywheel is statically balanced and very close to perfect dynamic balance. Most of our OEM customers perform the final fine-tune dynamic balancing after mounting the flywheel to their specific motor assembly.
Yes. We export over 80% of our castings to North America. We package all heavy flywheels in ISPM-15 certified fumigated wooden crates with rust-preventative coatings. We offer Delivered Duty Paid (DDP) shipping, meaning we handle the ocean freight, customs clearance, and trucking directly to your facility.
Ready to Quote Your Custom Flywheel Project?
Send us your 2D drawings and 3D CAD files today. Our foundry engineering team will provide a comprehensive Design for Manufacturability (DFM) review and a competitive direct-factory quote within 48 hours.
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