To support the use of new production methods for the nuclear industry it is important to develop an understanding of the primary water stress corrosion cracking (PWSCC) susceptibility compared to the wrought material that it is looking to replace. This paper presents the results to date from a stress corrosion cracking (SCC) crack growth rate testing programme for hot isostatically pressed (HIP) Alloy
625 in conditions representing the primary circuit of a pressurised water reactor (PWR). SCC crack growth rates were measured for different heats of HIP Alloy 625 under a range of temperatures and stress intensity factors to generate data for comparison with wrought Alloy 625 material. Testing was performed using 12.5mm (0.5 inch) compact-tension (CT) specimens manufactured from wrought and HIP Alloy 625. Direct current potential drop (DCPD) monitoring was used to measure
PWSCC crack growth rates, with transitioning to constant load performed in line with established best practice. Results have shown the PWSCC crack growth rates of cold worked HIP Alloy 625 to be a factor of ~10-300 times faster than equivalently worked wrought material. However, if the difference in material properties are accounted for this factor reduces significantly.