In the machinery manufacturing industry, mechanical parts are generally used in environments with normal temperature and pressure, and in non-strange corrosive media. During use, each part will be subjected to different loads. The ability of a metallic material to resist failure under load is called its mechanical properties (or physical and mechanical performance).
The mechanical properties of metallic materials are the primary basis for part design and material selection. Different types of applied loads (e.g., tension, compression, torsion, impact, cyclic loading, etc.) will require different mechanical properties from metallic materials. Commonly used mechanical properties include: strength, plasticity, hardness, impact toughness, resistance to repeated impacts, and fatigue limit.
1.Strength Strength refers to the ability of a metallic material to resist failure (excessive plastic deformation or fracture) under static load. Since loads can be applied in the form of tension, compression, bending, and shear, strength is also divided into tensile strength, compressive strength, bending strength, and shear strength. There are often certain relationships between these strengths, but tensile strength is generally used as the most basic strength indicator in practice.
2. Plasticity: Plasticity refers to the ability of a metallic material to undergo plastic deformation (permanent deformation) without breaking under load.
3. Hardness: Hardness is an indicator of the softness or hardness of a metallic material. Currently, the most commonly used method for measuring hardness in production is the indentation hardness test. This method uses an indenter of a specific geometry to press into the surface of the metal material under a certain load, and the hardness value is determined based on the degree of indentation. Commonly used methods include Brinell hardness (HB), Rockwell hardness (HRA, HRB, HRC), and Vickers hardness (HV).
4. Fatigue: The strength, plasticity, and hardness discussed above are indicators of the mechanical properties of metals under static loads. In reality, many machine parts operate under cyclic loads, under which conditions fatigue can occur.
