The invention discloses a preparation method of a large-
diameter 6061 aluminum
alloy extruded
pipe for a
new energy automobile. The preparation method sequentially comprises the working procedures of
alloy component optimization,
smelting, melt purification, standing, degassing and deslagging,
casting, homogenizing annealing,
machining and
extrusion. The
alloy comprises the following elements in percentage by weight: 0.6%-0.70% of Si, 0.15%-0.20% of Fe, 0.28%-0.35% of Cu, 0.15%-0.20% of Mn, 0.85%-1.1% of Mg, 0.18%-0.25% of Zn, 0.14%-0.15% of Ti, 0.1%-0.3% of Cr, 0.05% of Ni and the balance of Al, the ratio of Mg to Si is adjusted to be 1.40%-1.53, and a heat treatment process of a cast
ingot is optimized. Meanwhile, in order to ensure that the
pipe meets the precision requirement and the surface quality requirement, a tool, a mold and
extrusion parameters are designed, the aluminum alloy extruded
pipe with good
plasticity,
toughness and rigidity, uniform component distribution and fine
crystal grains is obtained, and therefore the use requirement of a
hydrogen storage pipe of a
new energy automobile is met.