John Deere mower blades are made of abrasion-resistant, high-carbon, nickel-alloy steel. This steel (commonly used for automotive leaf springs) has the hardness to be extremely resistant to wear and breakage. Unlike the lower-carbon blades used by many manufacturers, John Deere blades will withstand sand, stones, or other hard objects with little cracking or chipping. The result is a better cutting job and longer blade life.