Production process and technology of aluminum profiles for solar energy

The pillars, tie rods, supporting legs, etc. of solar panel frames and their supporting structures are new markets for the application of aluminum alloy materials and have been promoted and applied globally.

1. Introduction

Solar energy is a new type of inexhaustible pollution-free green energy. The pillars, tie rods, supporting legs, etc. of its solar panel frames and their supporting structures can be extruded and manufactured with the most economical and durable aluminum alloy materials at present. It is a new market for the application of aluminum alloy materials and has been promoted and applied globally.

2. Optimize the design and manufacturing of aluminum profile extrusion dies

The extrusion die is an important tool to ensure the shape and dimensional accuracy of solar photovoltaic aluminum profile products. The design and manufacturing quality of the extrusion die is an important guarantee for achieving high-quality, high-yield, low-consumption, high-efficiency and low-cost extrusion production. Therefore, in order to produce high-precision photovoltaic aluminum alloy profiles, it is necessary to optimize the design and manufacturing of the extrusion die.

2.1 Use advanced extrusion die manufacturing equipment

High-precision and advanced extrusion die processing equipment is a prerequisite for ensuring the qualification of metal extrusion dies. Therefore, advanced mold processing equipment should be used to produce photovoltaic aluminum alloy profiles, such as CNC, slow wire cutting, three-axis machining center, EDM center, etc. to improve the processing accuracy and performance of the mold.

2.2 Reasonable arrangement of mold holes

In order to ensure the good symmetry of photovoltaic aluminum profiles and improve production efficiency and yield rate, the arrangement of mold holes must comply with the principle of central symmetry and adopt a symmetrical arrangement of multiple mold holes. In the process of designing the mold, try to design the bridge position on the non-decorative surface of the profile to avoid defects.

2.3 Optimize the design of the working belt of the extrusion die

The working belt is the part that stabilizes the product size and ensures the surface quality of the product. When designing the length of the mold working belt, try to minimize the drop, make the length change gentle, and use the obstruction angle and the flow promotion angle to reduce the metal flow rate, so as to achieve the purpose of uniform metal flow and improve the surface quality of the profile.

3. Chemical composition control

The use of 6063 aluminum alloy has become an important choice for the production of high-precision photovoltaic aluminum alloy profiles. 6063 aluminum alloy Al-Mg-Si is a heat-treatable strengthened aluminum alloy. The alloy strengthening phase is Mg2Si. It has good extrusion performance and low quenching sensitivity, good high-temperature plasticity, wide quenching temperature range, and low critical quenching speed. Within the composition range of 6063 aluminum alloy, different values of chemical composition will result in different material properties. When the range of chemical composition is large, the performance difference will fluctuate within a large range, so that the comprehensive performance of the profile will be difficult to control. In order to ensure the precision of photovoltaic aluminum alloy profiles, the chemical composition of the alloy must be determined strictly in accordance with the enterprise control standards.

4. Melting, casting and ingot homogenization process

4.1 Melting and refining process

Use a rotary heat storage melting furnace for melting, and the melting temperature is 720-760℃. At a temperature above 720℃, high-purity nitrogen is blown into the refining agent for 15min, and the amount of refining agent is 0.08% of the weight of the melt. After refining, electromagnetic stirring is performed for 15min, and the aluminum liquid is allowed to stand for 20-30min. Sampling inspection strictly controls the chemical composition of the aluminum alloy solution so that the material can achieve the required mechanical properties.

4.2 Casting process

A semi-continuous direct water cooling casting method is used. The direct water cooling method has a high cooling intensity and a fast cooling speed, which refines the casting structure and increases the density of the structure, thereby improving the mechanical properties and heat treatment effect of the ingot. Control the casting temperature to 710-730℃, the casting speed to 50-70mm/min, and the cooling water pressure to 0.1-0.3MPa. In order to reduce the tendency of hot cracks and improve the chemical composition of the alloy, online addition of aluminum titanium boron wire is adopted, and the addition speed is 1700-2000mm/min.

4.3 Homogenization of cast rod structure

In order to reduce and eliminate the intracrystalline segregation of the ingot and improve the inhomogeneity of its chemical composition and organizational structure, the aluminum alloy cast rod is homogenized. The technical conditions for control are to heat the cast rod to 540-550℃, keep it warm for 8-10h, and cool it with strong wind and water mist after it is taken out of the furnace. After homogenization annealing, cooling should be accelerated to ensure the uniformity of color after anodizing.

5. Control of process and technical conditions for extrusion and aging process

The process and technical conditions for extrusion, online quenching and aging of 6063 aluminum alloy profiles are to control the heating temperature of the cast rod: 440-480℃; mold heating temperature: 450-480℃, mold heating time is less than 5h; extrusion barrel heating temperature 460-500℃; extrusion speed: 12-18m/min; discharge port temperature 510-550℃; cooling method is online air cooling or water mist cooling; aging treatment is performed after online quenching of extruded profiles: control temperature is 200±5℃, insulation time: 3h. The combination of solid solution treatment of 6063 aluminum alloy and extrusion process can avoid grain growth and improve the physical and mechanical properties of profile products.