Alloying elements like nickel, chromium, and molybdenum significantly increase round steel prices. For example, 4140 (chromium-molybdenum) costs 20-30% more than 1045 (carbon steel) due to molybdenum (~30,000/ton)andchromium(8,000/ton) content. 316 stainless (2-3% molybdenum) is 15-20% pricier than 304 (no molybdenum). Even small additions (e.g., 0.1% vanadium in HSLA steel) add 5-10% to costs but improve strength, justifying the price for high-performance applications (e.g., aerospace, oil drilling).