NNX-D66 20X9 ET 37 P.C.D 5X108 center hole 63.5 1piece forged wheel (custom 16-24inch and date)   How to improve the quality of gear forging? Hardness is an important quality inspection indicator in the process of gear forging heat treatment. Not only is the hardness test fast, simple, and not damaged forging, but other mechanical properties can also be inferred by the hardness value.   The reasonable determination of the hardness value after thermal treatment will give the forging good use performance, which will have an important role in improving quality and extending durability.