In order to use metal materials more rationally and give full play to their functions, it is necessary to grasp the performance (use performance) of the parts and components made of various metal materials under normal working conditions and the performance of the materials during the hot and cold processing. (Process performance).
The use properties of materials include physical properties (such as specific gravity, melting point, electrical conductivity, thermal conductivity, thermal expansion, magnetism, etc.), chemical properties (durability, corrosion resistance, oxidation resistance), and mechanical properties are also called mechanical properties.
The process performance of a material refers to the ability of the material to adapt to cold and hot processing methods.
(1) Mechanical properties
Mechanical properties refer to the characteristics of metal materials under external force.
1. Strength: The ability of the material to resist deformation and fracture under external force (load). The unit area of the material is called stress by load.
2. Yield point (бs): It is called the yield strength, which means that when the stress on the material reaches a certain critical value during the stretching process, the load no longer increases and the deformation continues to increase or produce 0.2%L. Hour stress value, the unit is expressed in Newton/mm2 (N/mm2).
3. Tensile strength (бb) is also called strength limit, which refers to the maximum stress that a material can withstand before it breaks. The unit is expressed in Newton/mm2 (N/mm2).
4. Elongation (δ): The percentage of total elongation to the original gauge length after the material is stretched and broken.
5. Reduction of area (Ψ) After the material is stretched and broken, the maximum reduced area of the section is the percentage of the original section area.
6. Hardness: refers to the ability of the material to resist the pressure of other harder objects. Commonly used hardness is measured according to its range of distribution hardness (HBS, HBW) and Rockwell hardness (HKA, HKB, HRC).
7. Impact toughness (Ak): The ability of the material to resist impact load, in Joule/cm2 (J/cm2).
(2) Process performance
Refers to those properties of the material’s ability to withstand various processing and processing.
8. Casting performance: refers to some process performances of whether a metal or alloy is suitable for casting, mainly including flow performance, ability to fill the mold; shrinkage, the ability to shrink the volume when the casting solidifies; segregation refers to the unevenness of chemical composition.
9. Welding performance: refers to the characteristics of welding two or more metal materials together by heating or heating and pressure welding methods, and the interface can meet the purpose of use.
10. Top gas section performance: refers to the performance that metal materials can bear upsetting without breaking.
11. Cold bending performance: refers to the performance of metal materials that can withstand bending without breaking at room temperature. The degree of bending is generally expressed by the ratio of the bending angle α (external angle) or the bending center diameter d to the material thickness a. The larger a or the smaller d/a, the better the cold bendability of the material.
12. Stamping performance: the ability of metal materials to withstand stamping deformation without breaking. Stamping at room temperature is called cold stamping. The inspection method is tested by cupping test.
13. Forging performance: the ability of metal materials to withstand plastic deformation without breaking during forging.
(3) Chemical properties
Refers to the resistance of metal materials to chemical or electrochemical reactions when they are in contact with the surrounding medium.
14. Corrosion resistance: refers to the ability of metal materials to resist corrosion by various media.
15. Oxidation resistance: refers to the ability of metal materials to resist the generation of oxide scale at high temperatures.