The extrusion temperature of industrial aluminum profiles has an extremely important influence on the deformation process of aluminum alloy, the microstructure and properties after deformation, and especially on the microstructure and properties after subsequent heat treatment.
I.The influence of temperature on industrial aluminum profile extrusion
Too low temperature: leads to high deformation resistance and easy to stagnate (especially high magnesium alloy and hard aluminum).
Solution: Preheat the mold (first squeeze 1~2 pieces of soft alloy to heat up), control the ingot temperature (hard aluminum 420~480℃).
Too high temperature: low deformation resistance, but low-speed extrusion is required, otherwise it is easy to crack.
Solution: strictly control the temperature, avoid overheating, and extrude hard aluminum at a low speed.
Key measures:Preheating of mold/extrusion barrel;Low-speed extrusion of hard aluminum;Selecting large-tonnage equipment for high extrusion ratio.
II.The influence of temperature on the microstructure and performance of industrial aluminum profile products
1. Soft aluminum alloys (such as 6061, 6063)
High temperature extrusion (close to melting point): coarse grains → reduced strength and hardness, improved elongation.
Risk: Recrystallization may occur prematurely at high temperatures, and the grains will grow further during subsequent heat treatment, which will deteriorate the mechanical properties.
Suggestion: Control the temperature (such as 450~500℃) to avoid excessively high temperatures.
2. Hard aluminum alloys (such as 2 series, 7 series)
High temperature extrusion: Reduce coarse grain structure and improve mechanical properties (need to be combined with quenching).
Low temperature extrusion: Coarse grain rings are easily formed → performance decreases.
Suggestion: Appropriately increase the extrusion temperature (such as 400~480℃) to ensure uniform deformation.
Key points:Different alloys have different temperature sensitivities, and the process needs to be optimized to avoid abnormal grain growth.
III.Effect of extrusion temperature on surface quality of industrial aluminum profiles
Industrial aluminum profiles extruded in cold state have precise dimensions and good surface finish. As the extrusion temperature of industrial aluminum profiles rises, the surface finish deteriorates overall. For the same aluminum profile product, the temperature of the front section is lower than that of the rear section, and the surface quality of the front section is significantly better than that of the rear section. When the temperature is too high, pitting or pockmarks are likely to occur.
