Alloy Steel Round Bar 8620 Cold Finish offers good strength, high case toughness, and good core strength and toughness 8620 is the mostly widely used carburized steel, and the addition of nickel gives it good fatigue resistance and torsional strength It is typically used in gears, cranks, shafting, axles, bushings, heavy duty pins, bolting, springs, hand tools, gears, and many other machinery parts