The corrosion of alloys based on Fe,Co and Ni containing 15 and 30 wt-% Nb was studied at 700℃in H<sub>2</sub>-H<sub>2</sub>S mixtures providing 10<sup>-8</sup
The dieless hydroforming of spherical vessels from combination frustum shells is put forward in thepresent paper,and the forming process is developed by means o