316 stainless steel hex cap screws are manufactured to meet or exceed ASTM F593C. 316 series stainless steel differs from 18-8 by its molybdenum content (2-3%) and a higher nickel content (10-14%). 316 stainless steel has greater corrosion resistance than 18-8 as well as superior strength at high temperatures.Star Stainless Screw Co.