Can you assist in redesigning parts for enhanced fatigue resistance?
Yes, Neway offers comprehensive engineering support to assist clients in redesigning cast or machined parts for enhanced fatigue resistance. Fatigue failure is one of the most common and critical failure modes in metal components subjected to cyclic stress, particularly in automotive, aerospace, and industrial equipment applications. By applying advanced design strategies, material optimization, and casting simulation, Neway helps clients extend product life and prevent fatigue-related failures.
We integrate fatigue design principles early in the die casting design process, enabling our customers to reduce stress concentrations, optimize load paths, and select appropriate materials and surface treatments for their operating conditions.
Understanding Fatigue in Cast Components
Fatigue is the progressive and localized structural damage that occurs when a material is subjected to repeated loading and unloading. Most fatigue cracks initiate at geometric discontinuities or surface imperfections, especially in areas with stress concentrations or casting defects.
Key factors affecting fatigue life include:
Cyclic stress amplitude and frequency
Microstructure and porosity of the casting
Surface roughness and residual stress
Part geometry, wall transitions, and notches
Environmental exposure (e.g., corrosion fatigue)
Design Best Practices to Improve Fatigue Resistance
Design Strategy | Purpose | Benefit |
|---|---|---|
Add Fillets at Stress Concentrations | Reduce notch sensitivity and redistribute stress | Lowers peak cyclic stress by up to 50% |
Use Uniform Wall Thickness | Avoid hot spots and porosity due to uneven cooling | Enhances structural consistency and grain integrity |
Eliminate Sharp Corners | Prevent crack initiation under cyclic loading | Increases fatigue strength and surface durability |
Optimize Rib and Boss Geometry | Provide support without creating rigid transitions | Minimizes flexural stress and prevents microcracks |
Apply Surface Treatments | Strengthen outer layer and reduce crack propagation | Increases fatigue life by up to 2–5x |
Improve Alloy Selection | Use materials with fine grain and low inclusion levels | Enhances resistance to crack initiation and growth |
Geometry Optimization and Simulation
Neway uses CAD-based optimization and casting simulation tools to:
Identify and reduce stress risers in high-load zones
Predict internal porosity locations that could become fatigue initiators
Evaluate and improve wall transitions, fillet radii, and thickness distribution
These optimizations are integrated into our tooling design to ensure that aluminum die castings and zinc die cast parts meet fatigue performance targets without overengineering.
For instance, increasing a fillet radius from 0.5 mm to 2 mm can reduce localized stress concentration factors (Kt) by more than 30%, significantly improving fatigue performance.
Material and Process Selection
Material properties such as yield strength, ductility, and inclusion content greatly affect fatigue life. Neway helps clients choose the most suitable alloy for fatigue-critical applications:
A356-T6 aluminum: heat-treated for high fatigue strength (~150 MPa endurance limit)
Zamak 5: suitable for low-to-moderate fatigue applications, good damping properties
C95500 aluminum bronze: offers outstanding fatigue and corrosion resistance in harsh conditions
Post-casting processes such as heat treatment and hot isostatic pressing (HIP) can also be considered for parts requiring enhanced internal integrity.
Surface Treatment Solutions for Fatigue Resistance
Surface quality plays a key role in fatigue performance. Neway recommends treatments that increase surface hardness, minimize micro-defects, and introduce beneficial compressive stress:
Shot peening: improves fatigue life by inducing compressive stress layer
Hard anodizing: increases surface hardness and crack resistance in aluminum parts
PVD coatings: protect from surface wear, reducing microcrack initiation points
Polishing or brushing: removes machining marks or flash that serve as crack initiators
Each method is tailored to the alloy and application requirements to maximize endurance without sacrificing dimensional tolerance.
Application Case Example
A client manufacturing a suspension linkage originally designed with sharp corner transitions and inconsistent wall thickness experienced premature fatigue cracking after 300,000 load cycles. Neway’s engineering team performed a geometry redesign, added fillets, balanced wall sections, and selected A356 with T6 heat treatment. After implementing these changes, the component passed 1,000,000 cycles with no signs of fatigue.
Conclusion
Enhancing fatigue resistance requires a holistic redesign approach, including geometry refinement, material optimization, simulation analysis, and post-processing. Neway supports customers from concept to production, applying industry best practices and precision tooling to deliver high-performance, fatigue-resistant parts. Whether you're modifying an existing part or developing a new component, our design and simulation capabilities ensure long-lasting durability and mechanical integrity.
