Abstract
Due to its excellent resistance to corrosive environments and its superior mechanical properties, the Ni-based Hastelloy C-276 alloy was chosen as the material of the stator and rotor cans of a nuclear main pump. In the present work, the Hastelloy C-276 thin sheet 0.5 mm in thickness was welded with filler wire by a pulsed laser. The results indicated that the weld pool geometry and microstructure were significantly affected by the duty ratio, which was determined by the pulse duration and repetition rate under a certain heat input. The fusion zone area was mainly affected by the duty ratio, and the relationship was given by a quadratic polynomial equation. The increase in the duty ratio coarsened the grain size, but did not obviously affect microhardness. The weld geometry and base metal dilution rate was manipulated by controlling pulsed parameters without causing significant change to the performance of the weld. However, it should be noted that, with a larger duty ratio, the partial molten zone is a potential weakness of the weld.
Highlights
The Ni-based Hastelloy C-276 alloy is widely used in chemical processing and the nuclear industry, and as marine engineering components such as pumps, valve parts, and spray nozzles, due to its excellent resistance to corrosive environments and its superior mechanical properties [1,2]
Li et al [4] investigated the effects of plate thickness and the annealing process on the microstructure and properties of the Hastelloy C-276 welding line by GTAW, and the grain coarsened with the increase in plate thickness
The 0.4-mm-thick Hastelloy C-276 thin sheet was welded by GTAW without filler metal, and both the heat affected zone (HAZ) and a secondary phase were detected
Summary
The Ni-based Hastelloy C-276 alloy is widely used in chemical processing and the nuclear industry, and as marine engineering components such as pumps, valve parts, and spray nozzles, due to its excellent resistance to corrosive environments and its superior mechanical properties [1,2]. The 0.4-mm-thick Hastelloy C-276 thin sheet was welded by GTAW without filler metal, and both the heat affected zone (HAZ) and a secondary phase were detected. It was found that the mixed zone of the weld contained a number of brittle phases, and there performed a series of studies about the laser welding of 0.5‐mm‐thick Hastelloy C‐276 thin sheets was a tendency of the NiTi to absorb elements from the Hastelloy C-276. The results indicated that, by using a precise without filler wire, and the MZ was found to be of much finer grains, and the element segregation was control of the pulse energy and the dilution rate, sound welds could be obtained. The trend of the brittle phase's formation was weakened, no HAZ was found, and the Reports about arc welding Hastelloy C‐276 thin sheets with thicknesses of 0.5 mm or less are mechanical properties were comparable to the as-received alloy.
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