Corrosion Acceptance Testing of Weld Metals for Nuclear Service

Corrosion Acceptance Testing of Weld Metals for Nuclear Service

by

 J R Crum and S M Gosnay

Special Metals Corporation

and

S J Kiser and Dr Rengang Zhang

Special Metals Welding Products Corporation 

ABSTRACT

Intergranular corrosion tests such as ASTM G28, Practices A and E and RCCM MC1300 are often used to verify the resistance of nickel alloys to intergranular corrosion.  The inherent differences in wrought products and weld metals can cause differences in test results for these two materials.   A weld metal cast structure, which is also less homogenous than wrought metals, is often measured against commonly used wrought metal acceptance criteria that are difficult for welding products to pass regardless of weld quality.  Intergranular corrosion test results for Ni-Cr-Fe weld metals are correlated with chromium content and intergranular carbide precipitation.  Finally, effects of these variables on actual service performance in environments such as nuclear power plant high-purity water are compared with measured acceptance test corrosion rates.