Microstructure and properties of laser welding Ni-based alloy/austenitic stainless steel with filler wire for nuclear reactor pump can end sealing

Abstract

The current study investigates the microstructure and properties of laser welding involving Hastelloy C-276 and 304 stainless steel with filler wire, which is closely related to nuclear reactor pump can end sealing. The experimental results indicate the presence of an unmixed zone (UZ) and a small amount of Mo-rich secondary phase in weld seam, and microstructure of UZ is composed of austenite and ferrite phases. Laser welding enhances the ratio of low-angle misorientation and the uniformity of elements macro-distribution. The end sealing property of nuclear reactor pump can is characterized by anti-peel property of weld joints. The welded joint has local fracture and through fracture in the test of anti-peel property. The weld with local fracture exhibits superior anti-peel property. The joint crack starts at the bottom of the UZ. The anti-peel property of the welded joint is 239.6 ± 4.7 N/mm and mainly related to the weld penetration. The corrosion property of welded joints is determined by the elements of the weld, and the welded joints showcasing a better integral corrosion property than that of 304 base metals. Laser welding Ni-based alloy/austenitic stainless steel with filler wire has significant technical advantages for end sealing of nuclear reactor pump can.

Keywords

• Ni-based alloy
• Dissimilar metal laser welding
• Anti-peel property
• Filler wire