Investigation on the Preparation Technology of Large-size Stress Corrosion Cracks of Nuclear-grade Stainless Steel

316L austenitic stainless steel small-size sample was pre-developed, and the stress corrosion cracking parameters of prefabricated large-size sample was preliminarily determined. The results showed that 3.5% (mass fraction) NaCl solution, -1.2 V (vs. SCE) applied potential, reducing the strain rate and prolonging the polarization time were conducive to the occurrence of stress corrosion and reduced the elongation after fracture. On this basis, after a holding load of 100 kN for 24 d, a slow strain rate test was carried out at a strain rate of 0.5×10^-6 s^-1, and a crack with a length of more than 25 mm could be successfully produced on a large-size sample. And the elongation after fracture of the large size sample was only 12%.