Effect of Manufacturing Process on the Corrosion Properties of 304L Stainless Steel Pipe with 8-inch Diameter, 8인치 직경의 304L 스테인리스강관의 부식특성에 미치는 제작공정의 영향

Austenitic stainless steels used in nuclear power plants mainly use pipes made of seamless pipes, which depend on imports. The manufacturing process and high cost are some of the problems associated with seamless pipes. Therefore, in this study, the corrosion characteristics of the seamless pipe and the SAW pipe were assessed to determine the safety and reliability of the SAW pipe in a bid to replace the seamless pipe. Microstructure was analyzed using an optical microscope and the degree of hardness was measured using a Rockwell B scale. Intergranular corrosion resistance was evaluated by ASTM A262 Practice A, C, and E methods. The degree of sensitization was determined using a DL-EPR test. Anodic polarization test was performed in deaerated 1% NaCl solution at 30 ℃ and the U-bend method was used to evaluate the SCC resistance in 0.01 M Na2S4O6 at 340 ℃ and 40% NaOH solution at 290 ℃. Weld metal of the SAW pipe specimen showed relatively high degree of sensitization and intergranular corrosion rate. However, annealing to SAW pipes improved the corrosion properties in comparison to that of the seamless pipe.