Impact of composition and cold work on SCC of high Si-bearing stainless steel simulating radiation-induced segregation under simulated PWR primary water

• SCC growth of tailored alloys simulating radiation induced segregation is studied. • As-cast tailed alloys show limited local SCC in simulated PWR primary water. • Cold worked tailored alloys show typical IGSCC with different average CGRs. • High-Si raises average CGRs of low-Cr alloys and high Cr inhibit crack growth. • Cold work enhances SCC growth. Thick block alloys simulating radiation-induced segregation effects of compositions at grain boundaries were designed and prepared, and deformation due to irradiation hardening was simulated by cold working treatments. The stress corrosion cracking (SCC) behavior of 17Cr-13Ni-3Si, 13Cr-17Ni, and 13Cr-17Ni-3Si alloys in the as-cast and cold-worked states was studied by crack growth rate (CGR) tests using compact tension specimens in hydrogenated high-temperature water. The fracture surfaces of the three as-cast state simulated alloys showed local SCC indications, while the fracture surfaces of all cold-worked state simulated alloys showed typical intergranular SCC characteristics. In the absence of cold work, the single Si addition has no noticeable effect on SCC propagation. Stress-accelerated grain boundary oxidation acts as the initiation site for intergranular cracks. Cold-worked low Cr alloy with high Si content significantly promotes SCC growth in hydrogenated water. The effect of alloy composition and strain hardening on SCC and its implications for irradiation-assisted SCC were discussed.