Mechanical properties
　　Mechanical properties refer to the properties exhibited by metallic materials under external forces.
　　1. Strength: The ability of the material to resist deformation and fracture under external forces (loads). Material area is stressed by load.
　　2, the yield point (бs): said yield strength, refers to the material in the pull process, the stress on the material reaches a certain critical value, the load will no longer increase the deformation but continue to increase or produce 0.2% L stress value, unit use Newton/mm2 (N/mm2) indicates.
　　3. Tensile strength (бb), also called strength limit, means that the material is subjected to maximum stress before breaking. The unit is expressed in Newtons/mm 2 (N/mm2).
　　4. Elongation (δ): The percentage of the total elongation and the length of the original gauge after the material has been broken.
　　5. Area shrinkage (Ψ) The percentage of the area where the material is stretched and broken, and the maximum area of ​​the section is reduced to the original area.
　　6. Hardness: Refers to the ability of a material to resist the pressure of other harder materials on its surface. Commonly used hardness is determined according to its range of hardness (HBS, HBW) and Rockwell hardness (HKA, HKB, HRC).
　　7. Impact toughness (Ak): The ability of the material to withstand impact loads in Joules/cm 2 (J/cm 2 ).
　　Tensile stress and stage
　　1, Elasticity: εe = σe/E, Index σe, E2
　　, Rigidity: ΔL = P·l/E·F Ability to resist elastic deformation Strength
　　3, Strength: σs - Yield strength ,σb---tensile strength4
　　, toughness: shock absorption work Ak5
　　, fatigue strength: alternating load σ-1< 　　σs6
　　, hardness HR, HV, HB
a.I stage: linear elastic stage, initial stage of stretching, The stress-strain curve is a straight line. The stress limit at this stage is called the material's proportional limit σe.
　　b. Phase II: In the yielding phase, when the stress increases to a certain value, the stress-strain curve shows a horizontal line (with slight fluctuations). During this phase, the stress is almost constant, but the deformation increases dramatically, and the material loses its ability to resist deformation. This phenomenon is called yielding, and the corresponding stress is called yield stress or yield limit, and is expressed by σs.
　　c. Phase III: For the strengthening phase, after yielding, the material enhances its resistance to deformation. The stress corresponding to the highest point of the strengthening phase is called the strength limit of the material. Expressed by σb, the strength limit is the maximum stress that the material can withstand.
　　d. Stage IV: In the necking stage, when the stress increases to the maximum value σb, a certain part of the specimen shrinks significantly and finally breaks at the necking.
　　For low carbon steel σs and σb are the main indicators to measure its strength. Rigidity: △ L = P · l / E · F, the ability to resist elastic deformation. P --- pull, l --- original material length, E --- elastic modulus, F --- cross-sectional area.
　　Process performance
　　refers to those properties that the material can withstand various processing and processing capabilities.
　　Casting performance: refers to the process properties of the metal or alloy for casting, including flow performance, full mold capacity; shrinkage, ability to shrink the volume of the casting when solidified; segregation refers to chemical composition inhomogeneity.
　　Welding performance: refers to the welding of two or more metal materials together through heating or heating and pressure welding of metal materials, and the interface can meet the purpose of use.
　　Top Gas Segment Performance: Refers to the ability of a metal material to withstand upset without cracking.
　　Cold bending performance: refers to the metal material can withstand bending at room temperature without breaking performance. The degree of bending is generally expressed by the ratio of the bending angle α (outer angle) or the diameter d of the bending body to the thickness a of the material. The greater the value of a or the smaller the d/a, the better the cold bendability of the material.
　　Stamping performance: The ability of a metal material to withstand press-deformation without breaking. Stamping at room temperature is called cold stamping. The test method was examined using a cupping test.
　　Forging performance: The ability of a metal material to withstand plastic deformation without breaking during forging.
　　Chemical property
　　Refers to the resistance of a metal material to chemical or electrochemical reactions when it is scanned with surrounding media.
　　Corrosion resistance: refers to the ability of metal materials to resist erosion of various media.
　　Antioxidant: refers to the metal material's ability to resist oxidation at high temperatures.