Plasticity refers to the ability of metal materials to produce plastic deformation without being damaged under load.
Hardness is a measure of the hardness of metal materials. At present, the most commonly used method for measuring hardness in production is the indentation hardness method, which uses an indenter of a certain geometric shape to press into the surface of the metal material to be tested under a certain load, and the hardness value is determined according to the degree of indentation.
Commonly used methods are Brinell hardness (HB), Rockwell hardness (HRA, HRB, HRC) and Vickers hardness (HV) and other methods.
The strength, plasticity, and hardness discussed above are all indicators of the mechanical properties of metals under static load. In fact, many machine parts are working under cyclic loads, under which conditions the parts will fatigue.
The load acting on the machine at a very large speed is called impact load, and the ability of metal to resist damage under impact load is called impact toughness.
Strength refers to the ability of metal materials to resist damage (excessive plastic deformation or fracture) under static load. Since the load acts in the form of tension, compression, bending, shearing, etc., the strength is also divided into tensile strength, compressive strength, flexural strength, and shear strength. There is often a certain relationship between various strengths. Generally, tensile strength is often used as the super basic strength indicator in use.