A pipe according to the present disclosure comprises: a hollow tube body in which fluids of different temperatures pass through the inside and outside thereof; and a coating layer which is provided on an external surface of the hollow tube body, and which has an alloy comprising an amorphous phase, wherein the alloy comprises Fe, and comprises at least one or more first component selected from the group consisting of Cr, Mo and Co, and at least one or more second component selected from the group consisting of B, C, Si and Nb.