STEEL GRIPS online - Enhancing corrosion resistance of stainless steel 304 using laser-beam surface treatment

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Dec 4, 2008

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Enhancing corrosion resistance of stainless steel 304 using laser-beam surface treatment
By Ibrahim M. Ghayad, Madiha A. Shoeib, Taha Mattar, and Huda M. Hussain

Stainless steel, corrosion, laser-beam surface treatment

Stainless steel AISI 304 was laser-beam treated to enhance corrosion resistance and improve surface properties. This alloy has many applications in auto industry (car body), as well as in oil and gas industry. Different conditions were applied in the laserbeam surface treatment, namely: laser power density, scan speed, distance between paths, medium gas (air, argon and nitrogen). After laser-beam treatment, the samples’ microstructures were investigated using optical microscope to examine microstructural changes due to laser irradiation. Specimen surfaces were investigated using XRD, SEM and EDAX before and after laser-beam treatment to examine the surface composition changes brought about by laser irradiation.
Results showed that laser irradiation enhances the corrosion resistance of AISI 304 stainless steel to a large extent. Corrosion rates as low as 0.011 m/a for laser-beam treated samples were obtained in comparison to 0.952 m/a obtained for the untreated samples. Superior pitting corrosion resistance was obtained under specific treatment conditions. The enhancement of corrosion resistance depends on the laser irradiation conditions. The corrosion protection afforded by laser-beam treatment is attributed mainly to the grain refinement of the top surface layer. This layer is found to consist of nano-scale grains.

STEEL GRIPS 5 (2007) No. 4, pp 274

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