1. The analysis of plasticity of square pipe

Plasticity refers to the plastic deformation(permanent deformation) of metal material under the action of the load, which can not be damaged.

2. The analysis of hardness of square pipe

Hardness is a measure of softness and hardness of metal materials. The most commonly used hardness measurement in the production is the press method, which uses indenters with a certain geometric shape to press the surface of tested metal materials and obtains its hardness based on the pressing degree. The commonly used methods are Brinell hardness (HB), Rockwell hardness (HRA, HRB, HRC), Vickers hardness (HV) and so on.

3. The analysis of fatigue of square pipe

The strength, plasticity, and hardness which we discussed above are the mechanical properties of the metal under static load. In fact, many machine parts are working under cyclic loading, which will lead to fatigue.

4. The analysis of impact toughness of square pipe　　

The load acting on the part at a high speed is called impact load, and the ability of resisting the damage under the impact load is called impact toughness.

5. The analysis of strength of square pipe

Strength refers to the damage resistance of metal material under static load(excessive plastic deformation or fracture). There are different ways for the load, including stretch, compression, bending and shear. So strength is also classified into tensile strength, compressive strength, bending strength, shear strength. There is a certain connection between the different strengths, and we often use tensile strength as the most basic indicator.