Steel shot, a material resulting from the unique heat treatment process applied to specific materials, varies in size, specifications, and most importantly, hardness. The latter serves as a crucial benchmark for assessing the quality of steel shot.
There are two primary methods used to measure the hardness of steel shot:
Brinell Hardness (HB):
This technique involves applying a hardened steel ball of a defined diameter to the surface of the test specimen under a controlled load (p). After maintaining this pressure for a set duration, the load is removed, and the resulting indentation's area is measured. The smaller the indentation, indicative of greater resistance to plastic deformation, translates to higher hardness. The Brinell hardness value is inversely proportional to the indentation size and is denoted as "HB."
2.Rockwell Hardness (HRC):
Rockwell hardness testing entails pressing a steel ball or diamond indenter vertically into the surface of the test piece under specified external loads, creating an indentation. The depth of this indentation is then measured, and the Rockwell hardness (HR) is calculated using the formula HR=(K-H)C, where K and C are constants. In simpler terms, a shallower indentation corresponds to a higher HR value and, consequently, a harder material. Specifically, when using a diamond cone indenter with a 120° vertex angle under a 150kg test load, a material with a Rockwell hardness of HRC signifies an indentation depth of 0.08mm.