6063/T5 Aluminum Pipe
6063 aluminum alloy is widely used in the construction of aluminum doors, windows, and curtain wall frames. It is a common aluminum alloy model.
Product Description
6063 aluminum alloy
6063 aluminum alloy is widely used in the construction of aluminum doors, windows, and curtain wall frames. It is a common aluminum alloy model.
- Chinese name: 6063 aluminum alloy
- Use: Building aluminum doors, windows, and curtain wall frames
- Composition: AL-Mg-Si
Introduction
In order to ensure that doors, windows and curtain walls have high wind pressure resistance, assembly performance, corrosion resistance and decoration performance, the requirements for the comprehensive performance of aluminum alloy profiles are far higher than the standards for industrial profiles. Within the composition range of 6063 aluminum alloy specified in the national standard GB/T3190, different values of the chemical composition will result in different material characteristics. When the chemical composition has a large range, the performance difference will fluctuate in a large range. , So that the comprehensive performance of the profile will be out of control.
Chemical composition
The chemical composition of 6063 aluminum alloy has become the most important part of the production of high-quality aluminum alloy building profiles.
erformance impact
6063 aluminum alloy is a medium-strength heat-treatable and strengthened alloy in the AL-Mg-Si series. Mg and Si are the main alloying elements. The main task of optimizing the chemical composition is to determine the percentage of Mg and Si (mass fraction, the same below).
1.The role and influence of 1Mg Mg and Si form the strengthening phase Mg2Si. The higher the content of Mg, the more the amount of Mg2Si, the greater the heat treatment strengthening effect, the higher the tensile strength of the profile, and the higher the deformation resistance. Increased, the plasticity of the alloy decreases, the processing performance deteriorates, and the corrosion resistance deteriorates.
2.1.2 The role and influence of Si The amount of Si should enable all Mg in the alloy to exist in the form of Mg2Si phase to ensure that the role of Mg is fully exerted. As the Si content increases, the alloy grains become finer, the metal fluidity increases, the casting performance becomes better, the heat treatment strengthening effect increases, the tensile strength of the profile increases, the plasticity decreases, and the corrosion resistance deteriorates.
3.Selection of conten
4.2. Determination of the amount of 1Mg2Si
5.2.1.1 The role of the Mg2Si phase in the alloy Mg2Si can be dissolved or precipitated in the alloy with changes in temperature, and exists in the alloy in different forms: (1) Dispersed phase β'' Mg2Si phase precipitated in solid solution Dispersive particles are an unstable phase that will grow up with increasing temperature. (2) The transition phase β'is an intermediate metastable phase formed by the growth of β'', which will also grow with the increase of temperature. (3) The precipitated phase β is a stable phase formed by the growth of β'phase, which is mostly concentrated in grain boundaries and dendrite boundaries. The strengthening effect of Mg2Si phase is when it is in the β'' dispersed phase state, the process of changing the β phase to β'' phase is the strengthening process, and vice versa is the softening process.
2.1.2 Selection of the amount of Mg2Si The heat treatment strengthening effect of 6063 aluminum alloy increases with the increase of the amount of Mg2Si. When the amount of Mg2Si is in the range of 0.71% to 1.03%, its tensile strength increases approximately linearly with the increase of the amount of Mg2Si, but the deformation resistance also increases, making processing difficult. However, when the amount of Mg2Si is less than 0.72%, for products with a small extrusion coefficient (less than or equal to 30), the tensile strength value may not meet the standard requirements. When the amount of Mg2Si exceeds 0.9%, the plasticity of the alloy tends to decrease. The GB/T5237.1-2000 standard requires that the σb of the 6063 aluminum alloy T5 profile is ≥160MPa, and the T6 profile σb≥205MPa, which is proved by practice. The tensile strength of the alloy can reach up to 260MPa. However, there are many influencing factors for mass production, and it is impossible to ensure that they all reach such a high level. Comprehensive considerations, the profile must be high in strength to ensure that the product meets the requirements of the standard, but also to make the alloy easy to extrude, which is conducive to improving production efficiency. When we design the strength of the alloy, we take 200MPa as the design value for the profile delivered in the T5 state. It can be seen from Figure 1 that when the tensile strength is about 200 MPa, the amount of Mg2Si is about 0.8%. For the profile in the T6 state, we take the design value of the tensile strength as 230 MPa, and the amount of Mg2Si is increased to 0.95. %.
2.1.3 Determination of Mg content Once the amount of Mg2Si is determined, the Mg content can be calculated as follows: Mg%=(1.73×Mg2Si%)/2.73
2.1.4 Determination of Si content The Si content must meet the requirement that all Mg forms Mg2Si. Since the relative atomic mass ratio of Mg and Si in Mg2Si is Mg/Si=1.73, the basic Si amount is Si base=Mg/1.73. However, practice has proved that if the Si base is used for batching, the tensile strength of the produced alloy is often low and unqualified. Obviously it is caused by insufficient amount of Mg2Si in the alloy. The reason is that the impurity elements such as Fe and Mn in the alloy rob Si. For example, Fe can form an ALFeSi compound with Si. Therefore, there must be excess Si in the alloy to compensate for the loss of Si. Excess Si in the alloy will also play a complementary role in improving the tensile strength. The increase in the tensile strength of the alloy is the sum of the contributions of Mg2Si and excess Si. When the Fe content in the alloy is high, Si can also reduce the adverse effects of Fe. However, since Si will reduce the plasticity and corrosion resistance of the alloy, the Si excess should be reasonably controlled. Based on actual experience, our factory believes that it is better to choose the amount of excess Si in the range of 0.09% to 0.13%. The Si content in the alloy should be: Si%=(Si base + Si over)%
Control range
3.1 The control range of Mg Mg is a flammable metal, which will be burnt during the smelting operation. When determining the control range of Mg, the error caused by burning should be considered, but it should not be too wide to prevent the alloy performance from getting out of control. Based on experience and the level of our factory's ingredients, smelting and laboratory tests, we have controlled the fluctuation range of Mg within 0.04%, the T5 profile is 0.47% to 0.50%, and the T6 profile is 0.57% to 0.50%. 60%.
3.2 The control range of Si When the range of Mg is determined, the control range of Si can be determined by the ratio of Mg/Si. Because the factory controls Si from 0.09% to 0.13%, Mg/Si should be controlled between 1.18 and 1.32.
3.3 The selection range of the chemical composition of the 36063 aluminum alloy T5 and T6 state profiles. If you want to change the alloy composition, for example, if you want to increase the amount of Mg2Si to 0.95%, so as to facilitate the production of T6 profiles, you can move Mg up to a position of about 0.6% along the upper and lower limits of Si. At this time, Si is about 0.46%, Si is 0.11%, and Mg/Si is 1.
3.4 Concluding remarks According to our factory's experience, the amount of Mg2Si in 6063 aluminum alloy profiles is controlled within the range of 0.75% to 0.80%, which can fully meet the requirements of mechanical properties. In the case of a normal extrusion coefficient (greater than or equal to 30), the tensile strength of the profile is in the range of 200-240 MPa. However, controlling the alloy in this way not only has good plasticity, easy extrusion, high corrosion resistance and good surface treatment performance, but also saves alloying elements. However, special attention should be paid to strictly control the impurity Fe. If the Fe content is too high, the extrusion force will increase, the surface quality of the extruded material will deteriorate, the anodic oxidation color difference will increase, the color will be dark and dull, and Fe will also reduce the plasticity and corrosion resistance of the alloy. Practice has proved that it is ideal to control the Fe content within the range of 0.15% to 0.25%.
Chemical composition
|
Si |
Fe |
Cu |
Mn |
Mg |
Cr |
Zn |
Ti |
Al |
|
0.2~0.6 |
0.35 |
0.10 |
0.10 |
0.45~0.9 |
0.10 |
0.10 |
0.10 |
Margin |
Mechanical properties:
- Tensile strength σb (MPa): ≥205
- Elongation stress σp0.2 (MPa): ≥170
- Elongation δ5 (%): ≥7
Surface corrosion
The corrosion behavior of 6063 aluminum alloy profiles caused by silicon can be prevented and controlled. As long as the purchase of raw materials and alloy composition are effectively controlled, the ratio of magnesium to silicon is ensured within the range of 1.3 to 1.7, and the parameters of each process are strictly controlled. , To avoid segregation and liberation of silicon, try to make silicon and magnesium form a beneficial Mg2Si strengthening phase.
If you find this kind of silicon corrosion spots, you should pay special attention to the surface treatment. In the process of degreasing and degreasing, try to use weak alkaline bath fluid. If the conditions are not allowed, you should also soak in the acid degreasing fluid for a period of time. Try to shorten it as much as possible (the qualified aluminum alloy profile can be placed in the acid degreasing solution for 20-30 minutes, and the problematic profile can only be placed for 1 to 3 minutes), and the pH value of the subsequent washing water should be higher (pH>4, control Cl- content), prolong the corrosion time as much as possible in the alkali corrosion process, and use nitric acid luminescence solution when neutralizing the light. When sulfuric acid anodizes, it should be energized and oxidized as soon as possible, so that the dark gray corrosion points caused by silicon are not obvious , Can meet the requirements of use.
Detail Display
Post time: Nov-28-2022