A hex head cap screw is a six-sided bolt with a washer face on the bearing surface. Hex cap screws are commonly used in OEM applications where precise tolerances are needed. Type 316 steel is an austenitic chromium-nickel stainless steel that contains between two and three percent molybdenum. The molybdenum content increases corrosion-resistance, improves resistance to pitting in chloride ion solutions, and increases strength at high temperatures.