Effect of Dendrite Orientation on SCC of Weld Metal of Nickel-Based Alloy Inconel 182 in PWR Primary Water

The effect of dendrite orientation on stress corrosion cracking (SCC) behavior of weld metal of nickel-based alloy Inconel 182 in simulated pressurized water reactor (PWR) high-temperature primary water was investigated by SCC test. The result show that an extensive interdendritic stress corrosion crack growth zone appeared on the fracture surface of the LT-oriented 182 alloy specimen in the simulated PWR primary water at 320 ℃. Both the average crack growth rate and the maximum crack growth rate of the LT-oriented 182 alloy specimen at 320 ℃ were higher than those of the same sample at 290 ℃, indicating that the stress corrosion crack growth of 182 alloy weld metal was promoted by increasing temperature in the simulated PWR primary water. At 290 ℃, the average crack growth rate, maximum crack growth rate and crack growth zone width ratio of the LT-oriented specimen were greater than those of the TL-oriented specimen, which indicated that cracks were easier to expand along the LT dendrite orientation.