AISI 4140 occupies a mid-range position in the cost spectrum of engineering steels:
Less Expensive Than: High-alloy steels (e.g., 4340 due to nickel, tool steels like H13, stainless steels like 304/316).
More Expensive Than: Plain carbon steels (e.g., 1045, 1144), and low-alloy steels like 4130 (lower Cr/Mo).
Its cost-effectiveness lies in delivering a high-performance profile (strength, hardenability) without the premium price of nickel-alloyed or stainless grades, making it an optimal choice for a vast array of structural and mechanical components.