الفهرس 
Introduction and ObjectivesOnly 14 pages are availabe for public view
 |  | from | 89 |  |  |
| | | from | 89 | | |
Abstract
Austenitic stainless steels are the most popular grades of stainless steels because of their excellent formability, corrosion resistance and weldability. One of the important maintenance and repair processes is repair welding. In the metal industry, the volume of repair and maintenance is more than that of the manufacturing.There is no limitation in the number of repairs in the welding procedures such as API-1104 and ASME section IX. The references found that the number of weld repairs is limited are: DNV-OS-F101, and GB50236-98 standards. In the DNV-OS-F101 Appendix C, sub-section G 300 it is expressed ‘‘Weld seams may only be repaired twice in the same area’’. According to the GB50236-97 and GB50236- 98 standards, no more than two repair welds should be performed in the same area.
This study aims to evaluate the changes in microstructural, mechanical and corrosion behavior of AISI 316 stainless steel under repeated repair welding. Shielded metal arc welding (SMAW) applied in this study was performed using AWS E316L-16 filler metal. Weld samples with one, two, three and four repairs in the same area were prepared, to determine the changes in microstructure, tensile properties, micro hardness and corrosion resistance. The corrosion behavior in a 5% NaCl solution at room temperature was evaluated using the weight loss method (for 3 and 6 days) and potentiodynamic polarization curves. Hardness of the heat affected zone decreased as the number of repairs increased. For first and second repairs, the mechanical properties are gradually decreased. After the second repair, a significant decrease in yield stress, ultimate strength and % elongation compared into the values of base metal is observed. Finally, the corrosion test results show that the repaired specimens exhibit significant corrosion following immersion in a 5% NaCl solution. The rate of the corrosion increases with an increasing number of weld repairs.