The use of refractory titanium alloys for the components of structure subjected to increasing temperatures is in full expansion in the air transport. Within the framework of European project HORTIA, aiming to develop and design a conduit of refractory titanium alloy helicopter by associating innovative processes and the industrial constraints, this work relates to the implementation and characterization of Ti6242 and Beta-21 S welded sheets by TIG and C02 laser processes. The determination of the mechanical characteristics in connection with the metallurgical transformations relating to the Ti6242/Ti6242, Beta 2IS /Beta 2lS and Ti6242/Beta2lS assembly configurations allowed a rigorous comparison of the processes and studied materials. The influence of the heat treatment 600°C/8h on the relations structures/mechanical properties was also studied in order to envisage the behaviour of the assemblies under the real service use conditions.