Composite tube and manufacture method thereof

The invention discloses a composite tube and a manufacture method thereof. The composite tube comprises a base tube (1) and a corrosion-resistant alloy liner tube (2) mechanically combined in the base tube, wherein a corrosion-resistant alloy surfacing layer (3) is arranged at the inner circumference of the end part of the base tube, the inner end face of the corrosion-resistant alloy surfacing layer (3) is connected with the end face of the corrosion-resistant alloy liner tube (2), and the axial length of the corrosion-resistant alloy surfacing layer (3) is not less than the distance between the end face of the corrosion-resistant alloy liner tube (2) and the end face of the base tube (1). The manufacture method comprises the following steps of: S1, mechanically combining the corrosion-resistant alloy liner tube (2) in the base tube (1); S2, removing the corrosion-resistant alloy liner tube (2) (with certain length) at the end part of the composite tube; and S3, forming the corrosion-resistant alloy surfacing layer (3) on the inner circumference of the end part of the base tube (1) from inside to outside in a surfacing manner from the end part of the corrosion-resistant alloy liner tube (2). According to the composite tube, the problems of large welding difficulty, low welding qualified rate and low speed of the dual-metal mechanical composite tube are solved.