Abstract: A method of welding a sleeve (10) to a tube (20) includes putting onto end portions (11) of the sleeve (10) respective protective elements (40), of a material that cannot be fused with the materials of the sleeve (10) and of the outer coating (24) of the tube (20); applying on each end portion (11) of the sleeve (10) covered by a protective element (40) a respective heat-shrink element (30); supplying each heat-shrink element (30) with a quantity of heat (Q) which by heating it causes it to shrink and compress the respective end portion (11) of the sleeve (10) against the tube (20), where this quantity of heat (Q) is transmitted to the end portion (11) of the sleeve (10) to obtain a welding of the sleeve (10) to the tube (20) and produce a device (1) comprising the tube (20) with the sleeve (10).