26. Plasma arc overlay welding in the manufacture of heavy nuclear components

In the manufacture of heavy nuclear components, the efficiency and quality of the overlay welding are of great importance. In a BWR reactor for example about 60 % of the total weld metal weight is overlay welding. To enable an accurate inservice inspection of the components a smooth weld surface and regular fusion line are also essential.

As a further development and complement to already existing methods for overlay welding two proce‐ dures utilizing a plasma torch and filler wire («6 1.6 mm) are described. The welding procedures are developed to fulfill the requirements for welding on the quenched and tempered low alloyed steels used for nuclear components. Production welding under normal workshop conditions has been performed with the procedures and the experience gained is related.