Producing Control Of The Welding Mark At Aluminium Extrusion

Extrusion' s welding marks happen at the quadratic form extrusion, especially at the curtain wall use profile, that produced with hollow die. Once under surface treating, the black or white banding mark damages the aesthetic function of the profile. But this is pervasive problem in manufacture of aluminium extrusions and effect to company' s honor negatively.This study subject focuses on the extrusion die for curtain wall use. During the experiment, about 40 sets die were redesigned, the old dies were reprocessed, a new composition of 6063 alloy was dispensed for fulfill the special mechanical requirement of curtain wall and optimized the produce technique. In the nearly one year produce practice,The author thinks the target of experiment was reached and shares his experience at below:(1) The optimizing die design for mark-free extrusion includes layouting the die bore properly, enlarging the volume of welding room and improving the structure of flow distribution bridge.(2) The old dies should be redesigned or repaired in order to reach the requirements of the optimized technique.(3) Decreasing the extruding temperature, controlling the outlet operating temperature between 490~ 510 ℃ and enforcing the outlet quenching can improve the welding mark situation.(4) Adjusting the content of Mg and Si in 6063 alloy to 0.6% and 0. 45% respectively and then aging at 170 ℃ for 5h can make the mechanical properties improve 5~10% and reach T6' s requirement.(5) Increasing the extrusion ratio to 30~80 can improve the welding quality.