On the Weldability of Inconel 600 Alloy

• Main Authors: Chun-Hui Yang, 楊竣揮
• Other Authors: Jong-Ning Aoh
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/72266046574263891230

碩士 === 國立中正大學 === 機械系 === 89 === Inconel 600 is a solid-solution strengthened nickel-based alloy. It is applied extensively in the steam piping system in the power plant. Fracture or cracks are often observed in the weldments of Inconel 600. Failure may arise from the inadequate welding process which results in earlier damages in the weldment as well as in the heat affected zone. In this work, weldability of Inconel 600 was studied by using Varestraint Test and by conducting manual and automatic welding on Inconel 600 with different filler metals and welding process parameters. The result indicated that the Inco 82 weld metal possessed better mechanical properties than the Inco 62 weld metal. Higher current may result in grain coarsening in the weld metal and in the HAZ. Too high heat input also results in migration of precipitates on the grain boundaries. The results of hot-ductility test revealed that higher heat input (12KJ/cm) resulted in a delay in ductility recovery during cooling, a larger crack susceptible region and brittle temperature range. Varestraint test results showed that hot cracks in the fusion zone often propagated into HAZ at higher heat input. The quality of the welding is therefore deteriorate. Higher crack susceptibility was observed at higher welding current if heat input remained at the same level. Suggestions of GTAW welding procedure for Inconel 600 have been made according to the results obtained from the Varestraint test and the other welding evaluations.