The near net shape component parts are cut using oxy-fuel cutting. These are then EB welded, with each join being made in a single pass, and inspected. The fabrications are machined before heat treatment by a full quench and temper. A final machining operation gives the component its final shape and they are then inspected again using dye penetrant inspection. The component is then given a Ni-Cu or Inconel overlay by hot wire TIG cladding, after which the valve component is assembled.
Although the fabrication process has not been widely employed, the development has demonstrated the possibilities of adopting the EB welding process as an alternative to existing production methods.
For information about TWI’s capabilities please email contactus@twi.co.uk