ALFRED W KLEIN
Engineers in Pittsburgh, PA

5034190, Jul 23, 1991

Apr 8, 1988

7/183260

George Economy - Murrysville PA
Richard J. Jacko - Forest Hills PA
Fredric W. Pement - Pittsburgh PA
Alfred W. Klein - Pittsburgh PA

Westinghouse Electric Corp. - Pittsburgh PA

G01N 1700

422 53

Both an improved method and apparatus for determining, on an accelerated basis, the susceptibility of a nickel-based alloy to suffer stress corrosion cracking within a steam generator environment is disclosed herein. The method generally comprises the steps of subjecting a mechanically stressed specimen of the alloy to a mixture of steam and hydrogen at a temperature of between about 365. degree. C. to 435. degree. C. , wherein the partial steam pressure is between about 10. 4 MPa to 30. 4 MPa, and the partial hydrogen pressure is between about 32 kPa to 500 kPa. The improved testing apparatus of the invention generally comprises a vessel for containing a stressed specimen and a pressurized atmosphere formed of steam and hydrogen, and an inlet cell for injecting a selected amount of hydrogen into the pressurized atmosphere of the vessel which includes a diffusion membrane which is permeable to hydrogen but impermeable to the remainder of the pressurized atmosphere. The inlet cell has a tubular housing having a wall formed from a thin layer of hydrogen permeable palladium-silver alloy. The tubular housing contains a gas permeable sponge formed by sintered particles of stainless steel to prevent the thin layer of palladium-silver alloy used in the hydrogen diffusion membrane from imploding in response to the pressure within the vessel.