2.9. Locking By a Lock Nut. 2.10. Locking By Spring Washer. 2.11. Screw Pin Locking. In this article, you will learn about the types of nuts and bolts. A bolt contains two parts a shank and head. The cylindrical portion of the bolt is known as the shank. Stainless steel 304 - As the most common material, SS 304 is a designation for a bolt, nut, washer or other hardware. Stainless steel 316 - SS 316 features high resistance to corrosion than SS 304, but more expansive than others. Beside stainless steel, carbon steel is also a common choice for hardware like bolts, nuts, washers, blind rivets.