Preparation method of aluminium alloy composite pipe

The invention provides a preparation method of an aluminium alloy composite pipe, comprising the following steps of: firstly fusing and refining an aluminium alloy external layer, preheating a core material aluminium alloy rod in a heat treatment furnace to the temperature from room temperature to 620 DEG C, placing into a die or a crystallizer, centering; introducing the alloy melt into the die or the crystallizer by a casting tool to clad the core material aluminium alloy rod, taking out an ingot after the external alloy layer is solidified, so as to obtain an aluminium alloy composite ingot blank; making the aluminium alloy composite ingot blank to an extrusion specification dimension, heating to 400-500 DEG C, and filling into an extruder for extruding so as to prepare a composite pipe blank; and finally drilling the head of the composite pipe blank and carrying out multi-pass drawing by using a drawing machine to prepare the composite pipe material of different specifications. According to the invention,