Definition of class and grade in bolt and nut
Bolts and nuts are made of different materials based on their application and the environment they are used in. these materials vary from low carbon alloy class 4.6 and 5.6, average carbon alloy class 8.8 and high carbon class 10.9 and 12.9. Other materials such as stainless steel 304 and 316 and titanium are also used to manufacture bolts and nuts. The mentioned classes and grades in American standard system which are 2, 5 and 8 are the most important factor to determine the tensile, resistance, sheering stress, tension and the physical strength of bolts and nuts. The higher these numbers, the stronger and yet crunchier the bolts and nuts are.