Details

Autor(en) / Beteiligte

• Fu, Yunlong
• Guo, Ning
• Zhou, Cheng
• Wang, Guanghui
• Feng, Jicai

Titel

Investigation on in-situ laser cladding coating of the 304 stainless steel in water environment

Ist Teil von

• Journal of materials processing technology, 2021-03, Vol.289, p.116949, Article 116949

Ort / Verlag

Amsterdam: Elsevier B.V

Erscheinungsjahr

2021

Quelle

Access via ScienceDirect (Elsevier)

Beschreibungen/Notizen

• [Display omitted] •Underwater laser cladding coating of the 304 stainless steel was prepared in water environment in situ.•The high-density aerosol particles decreased the laser power density and reduced the stability of cladding process.•The water interaction on coating formation, grain, microstructure and corrosion performance was investigated.•The grain size decreased overall and the number of equiaxed grain dropped compared with in-air coating.•The increasing ferrite content caused the corrosion resistance of underwater coating reduced. The 304 stainless steel coating was prepared successfully in water environment directly through an in-situ underwater laser cladding technique utilizing an underwater gas-shielding laser cladded nozzle, and the interaction mechanism of water on cladding coating formation, grain morphology and size, microstructure and corrosion performance was investigated. For underwater laser cladding, the high-density aerosol particles decreased the laser power density and reduced the stability of cladding process, causing the conduction mode of molten pool and decreasing the wettability of molten metal. In underwater laser cladding coating, columnar dendrites nucleated near the fusion line and track band and grew up along the opposite direction of maximum temperature gradient whilst equiaxed grains formed in the center region; besides, the grain size decreased overall and the number of equiaxed grain dropped owing to the water cooling effect compared with in-air coating. For in-air and underwater cladding coatings, the solidification mode of molten metal was ferrite-austenite mode and the ferrite mainly distributed in the austenite matrix with skeleton shape. Attributed to the higher cooling rate, a small amount of lathy ferrite was observed in underwater cladding coating, and the ferrite content increased within the overlap region of tracks, causing the corrosion resistance of coating reduced.