TY - GEN
T1 - Development of compressive residual stresses in underwater PTA welds
AU - Feng, Z.
AU - White, R. A.
AU - Willis, E.
AU - Solomon, H. D.
PY - 1999
Y1 - 1999
N2 - The repair of nuclear reactor internals can generally best be done underwater to take advantage of the shielding that the water provides, and to eliminate the need to remove the fuel. These advantages prompted a study of underwater plasma transfer arc (PTA) welding. It was found that there was actually a benefit to performing the welding underwater. Rather than the typical tensile residual stresses that are developed in the weld and heat affected zone, HAZ, (which promotes stress corrosion cracking, SCC, and corrosion fatigue), the underwater welds exhibited compressive stresses, or at least greatly reduced tensile stresses. This paper aims at explaining why this is the case. Welding under water produces a significant difference in the temperature distribution. In conventional welding the poor heat conduction out from the face of the plate being welded, results in the surface being hot relative to the interior of the plate. Welding underwater reverses this gradient because of the good heat conduction into the water. This temperature distribution difference is modeled using finite element analysis, FEA, and is used to demonstrate, through FEA, why these compressive stresses develop.
AB - The repair of nuclear reactor internals can generally best be done underwater to take advantage of the shielding that the water provides, and to eliminate the need to remove the fuel. These advantages prompted a study of underwater plasma transfer arc (PTA) welding. It was found that there was actually a benefit to performing the welding underwater. Rather than the typical tensile residual stresses that are developed in the weld and heat affected zone, HAZ, (which promotes stress corrosion cracking, SCC, and corrosion fatigue), the underwater welds exhibited compressive stresses, or at least greatly reduced tensile stresses. This paper aims at explaining why this is the case. Welding under water produces a significant difference in the temperature distribution. In conventional welding the poor heat conduction out from the face of the plate being welded, results in the surface being hot relative to the interior of the plate. Welding underwater reverses this gradient because of the good heat conduction into the water. This temperature distribution difference is modeled using finite element analysis, FEA, and is used to demonstrate, through FEA, why these compressive stresses develop.
UR - http://www.scopus.com/inward/record.url?scp=0033489148&partnerID=8YFLogxK
U2 - 10.1002/9781118787618.ch79
DO - 10.1002/9781118787618.ch79
M3 - Conference contribution
AN - SCOPUS:0033489148
SN - 0873394755
SN - 9780873394758
T3 - Proceedings of the Ninth International Symposium on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors -
SP - 757
EP - 766
BT - Proceedings of the Ninth International Symposium on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors -
A2 - Bruemmer, S.
A2 - Ford, P.
A2 - Was, G.
PB - Minerals, Metals and Materials Society
T2 - Proceedings of the Ninth International Symposium on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors -
Y2 - 1 August 1999 through 5 August 1999
ER -