1. Plasticity
Plasticity refers to the ability of a metal material to undergo plastic deformation (permanent deformation) without damage under load.

2. Hardness
Hardness is a measure of the hardness of a metal material. At present, the most commonly used method for measuring hardness in production is the indentation hardness method, which presses the surface of the metal material to be tested under a certain load with a certain geometry of the indenter, and determines the hardness value according to the degree of being pressed.
Commonly used methods are Brinell hardness (HB), Rockwell hardness (HRA, HRB, HRC) and Vickers hardness (HV).

3. Fatigue
The strength, plasticity, and hardness discussed above are all indicators of the mechanical properties of the metal under static load. In fact, many machine parts work under cyclic loading, under which conditions parts can fatigue.

4. Impact toughness
The load acting on the machine at a large speed is called the impact load, and the ability of the metal to resist damage under the impact load is called impact toughness.

5. Strength
Strength refers to the property of a metal material against damage (excessive plastic deformation or fracture) under static load. Since the action mode of the load is tensile, compression, bending, shearing, etc., the strength is also divided into tensile strength, compressive strength, bending strength, shear strength and the like. There is often a certain relationship between various strengths, and tensile strength is generally used as the most basic strength indicator.