How does cast iron’s resistance to bending fatigue compare to stainless steel?

Cast iron and stainless steel are widely used in engineering and construction, but their resistance to bending fatigue differs significantly. Cast iron, known for its high compressive strength and vibration damping, tends to perform well under static loads but is more brittle and less resistant to repeated bending stresses. In contrast, stainless steel, particularly austenitic grades like 304 or 316, exhibits superior fatigue resistance due to its ductility and ability to withstand cyclic loading without cracking.

The graphite flakes in cast iron create stress concentration points, making it prone to fatigue failure under dynamic loads. Stainless steel’s homogeneous microstructure and corrosion resistance further enhance its longevity in high-stress environments. For applications requiring repeated flexing or impact, stainless steel is generally the better choice, while cast iron excels in scenarios where rigidity and damping are prioritized. Engineers must consider these differences when selecting materials for components subject to bending fatigue.