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Mechanical properties and common terminology of aluminum alloy
- Mechanical properties and common terminology of aluminum alloy
-
Mechanical properties and common terminology of aluminum alloy
haomeialu > 02-25-2018, 06:50 AM
1, the intensity
Strength is the ability of metal materials to resist permanent deformation and fracture under external forces. It is commonly used in engineering to indicate that the strength of metal material has yield strength and tensile strength.
Yield strength is the limit of yield when metal materials yield, which is the stress of resistance to microplastic deformation.
The delta S = Fs/AO
Fs-- the maximum external force (N) when the sample yields the yield phenomenon
AO-- the original sectional area (mm2)
Delta S- yield strength (Mpa)
Tensile strength refers to the maximum stress the metal material can bear before pulling out.
FO-- the maximum external force before fracture (N)
AO-- the original sectional area (mm2)
Delta b- tensile strength (Mpa)
2. Elongation
The elongation ratio mainly measures the plastic properties of the material, i.e. the properties of permanent deformation without fracture.
The delta = (L - L0)/L0 * 100%
The delta - elongation
L0-- the original length of the sample.
L-- the length of the specimen after tensile fracture.
3, hardness
The ability of metal materials to resist the pressure of other harder objects is called hardness, or the resistance of the material to local plastic deformation. Therefore, hardness and strength have a certain relationship. According to the determination method of hardness, the most commonly used hardness values are
1) brinell hardness (code HB), (2) rockwell hardness (HRC); HRB), (3) vickers hardness (code HV), (4) weber hardness (code name HW). There is a certain conversion relationship between each hardness index, such as rockwell hardness HRC and brinell hardness HB: 1HRC is approximately 0.1hb.
4. Fatigue strength
Metal materials in the long-term repeated stress or under the action of alternating stress (stress generally are less than the yield limit of the delta S strength), the significant deformation occurs fracture phenomenon called fatigue or fatigue fracture.
5. Elastic modulus.
This is material on the elastic limit stress sigma and strain within the scope of the delta (corresponding to the stress deformation) ratio, expressed in E, unit of MPa (MPa) : E = sigma/delta tg = alpha type of alpha for tensile test curve o - E line and horizontal axis o - Angle x. Elastic modulus is the index that reflects the rigidity of metal materials (the ability to resist elastic deformation when metal materials are stressed is called rigidity).
6. Internal stress
The force on the sectional area of an object is called stress. Stress is called the working stress caused by external force, under the condition of without external force known as the internal stress of balances the object interior stress (such as stress, thermal stress, residual stress after the machining process of the... Etc.).
7. Stress annealing.
Stress annealing is also known as low temperature annealing (or high temperature tempering). This annealing is mainly used to eliminate residual stresses in castings, forgings, welding parts, hot rolled parts, cold drawing pieces and so on. If these stresses are not eliminated, the material will cause deformation or crack in the subsequent machining process after a certain period of time.
8. Solid solution heat treatment.
The alloy is heated to a high temperature single phase zone constant temperature, so that the excess phase is fully dissolved in the solid solution and then quickly cooled to obtain the heat treatment process of the supersaturated solid solution. Objective: to dissolve various phases in alloy, strengthen solid solution, improve toughness and corrosion resistance, stress and softening, so as to continue processing or forming.
9. Aging treatment
The metal workpiece after quenching should be kept at room temperature or high temperature to improve the metal heat treatment process. The aging treatment at room temperature is natural aging; The aging treatment at higher temperature is artificial aging. In mechanical production, the casting is usually placed at room temperature for a long time in order to stabilize the casting size. This measure is also known as aging. But this limitation does not belong to metal heat treatment process.
10. Conductivity and conductivity.
The resistance value of the unit cross-sectional area and the unit length metal conductor is called the volume resistivity (the resistivity), also known as the resistivity, denoted by the symbol P, and the unit is ohm. Mm 2/ m; The reciprocal of the volume resistivity is called the volume conductivity (the conductivity), also known as the conductivity factor, and the unit is msi /m (MS/m). The percentage of the conductivity of the sample and the ratio of a standard value is called the conductivity of the sample.
In 1913, the international annealing copper standard was determined: the use of the annealed copper wire with a density of 8.89 g/cm, with a length of 1 m, a weight of 1g and a resistance of 0.15328 ohm as the measurement standard. Under the temperature of 200 c, the resistance coefficient of the annealed copper wire is 0. 0172411 ohm. Was/m (or conductivity of 58.0 MS/m) determined to be 100% IACS (international standard annealed copper), the conductivity of the its him any material (% IACS) are available under the type of computing: conductivity (% IACS) = 0.017241 / P * 100% or conductivity (% IACS) = P / 58.0 * 100%.
11. SGS report
SGS is a third-party certification body, on the material chemical composition and mechanical properties for the third party inspection report, it can make management system certification, such as inspection, also can do product certification (can send CE, GS certificate), moreover is a chemical test. It usually takes 7 working days to do SGS chemical test.
Misunderstanding of SGS report:
A, "SGS report" is only test report, namely test report, not the ROHS certificate issued by SGS institution.
B. The "SGS report" is only responsible for the reliability of the data of the test items mentioned in the samples, but not in accordance with the ROHS directive.
C. The "SGS report" is permanent and valid for the data of the test items mentioned in the sample.
D, "SGS report" is not only "lead-free test".
E, "SGS" is the abbreviation of Societe Generale DE Surveillance S.A., which is translated as "general public license bank", and "SGS report" is not the only agency required to be tested by ROHS directive; There is also the report of ITS report, CQC report.
F and "SGS report" not only carry out the 6 items required by ROHS directive, but also carry out "environmental hazardous substances" detection, safety test and others listed in national regulations; SGS does not equal RoHS. The place to fill RoHS cannot be filled into SGS.