| 학회 | 한국재료학회 |
| 학술대회 | 2021년 가을 (11/24 ~ 11/26, 경주 라한호텔) |
| 권호 | 27권 2호 |
| 발표분야 | D. 구조 재료 분과 |
| 제목 | Comparison of the Reheat Cracking Susceptibility of Austenitic Stainless Steels |
| 초록 | Coal fired power plants often have welded joints made up of 347H stainless steel. However, this alloy is known to fail because of reheat cracking. Thus, quantitative evaluation methods are needed as screening measures. In this study, a Gleeble thermo-mechanical simulator was implemented in 347H and Super304H alloy heat-affected zone (HAZ) simulation and stress relaxation testing. In the case of 347H, carbide dissolution in the HAZ reduced the hardness value and promoted grain growth; alternatively, the respective extents of precipitate dissolution and hardness reduction in the nitrogencontaining Super304H were relatively small. The stress relaxation tests were performed at a temperature of 700°C, which was maintained for up to 70 h. Consequently, all 347H specimens fractured within 32 h. Furthermore, the time to rupture substantially decreased as the strain was increased from 5% to 10%, and then to 15%. Additionally, the hardness near the fractured surface increased, and the plastic deformation primarily occurred near the grain boundaries. Conversely, the Super304H specimens did not fracture during the 70-h testing period, as which time their hardness distribution was observed to still be relatively uniform. These results demonstrate that the reheat cracking susceptibility can be quantitatively determined according to the material and strain. |
| 저자 | 이한상, 김범신, 오지은 |
| 소속 | 한전 전력(연) |
| 키워드 | <P>보일러튜브; 용접; 글리블</P> |
