Cast VS Forged What Will Survive? Crankshafts Explained Like You’ve Never Seen! Is Forged Worth it??

Added: 2026-05-05

Engine crankshaft material selection follows the principle of 'no more or less than you need' based on power requirements: cast iron (20,000-40,000 PSI tensile strength) is suitable for low-power applications up to 240 HP; cast steel (5140 or 4340, 60,000-140,000 PSI) handles 400-700 HP; and forged steel (4340, 140,000-200,000+ PSI) is reserved for extreme applications exceeding 1,000 HP. Nodular/ductile cast iron, invented in the 1960s by adding magnesium, replaced forged steel for most OEM applications because it offers sufficient strength (60,000-100,000 PSI) at lower cost. The key distinction between iron and steel is carbon content: cast iron contains 2-4% carbon making it brittle, while steel is refined with lower carbon content (around 0.4% for 4340) providing better ductility and strength.