TWI Industrial Member Report Summary 811/2004
Andrea Gregori and Dan Bertaso investigate methods to improve welding, repair and surface deposition of high-value components.
Nickel superalloys are considered extremely difficult to weld and repair because of their susceptibility to heat affected zone (HAZ) and weld metal cracking during fabrication, postweld heat treatment (PWHT) and subsequent operation. Available literature indicates that the reduction of heat input and/or the use of high preheat are required to eliminate cracking during welding of nickel superalloys.
There is little information regarding repair and surface deposition on Waspaloy. This material provides higher strength, operating temperature and oxidation/sulphidation resistance than Alloy 718 for applications including critical stationary and rotating parts of gas turbines. However, it is more susceptible to cracking during welding and PWHT and requires more attention than Alloy 718.
- To apply procedures for minimising cracking during welding and deposition on Alloy 718 and Waspaloy
- To investigate the applicability of TIG and ESD processes for shroud sealing and repairing of single crystal CMSX-10 superalloy blades