Plasticity refers to the ability of metal materials to produce plastic deformation (permanent deformation) without damage under load.

2. Performance index analysis of square tube-hardness

Hardness is a pointer to measure the hardness of metal materials. At present, the most commonly used method to measure hardness in production is indentation hardness method, which uses a indenter with a certain geometry to press into the surface of the measured metal material under a certain load, and determines its hardness value according to the indentation degree.

Commonly used methods include Brinell hardness (HB), Rockwell hardness (HRA, HRB, HRC) and Vickers hardness (HV).

3. Analysis of fatigue performance index of square tube

The strength, plasticity and hardness discussed above are all indicators of the mechanical properties of metals under static load. In fact, many machine parts work under cyclic load, and in this case, the parts will fatigue.

4. Performance index analysis of square tube-impact toughness

The load acting on machine parts at great speed is called impact load, and the ability of metal to resist damage under impact load is called impact toughness.