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Item Enhancing the Flow-Accelerated Corrosion Resistance of X70 API Steel Through Laser Surface Melting in Synthetic Oilfield Water(John Wiley and Sons Inc, 2025) Ajmal, T.S.; Singh, R.K.; Arya, S.B.; Kumar D, S.Hydrodynamic flow conditions play a critical role in piping failure due to sharp variations of the Reynolds number in process and petrochemical industries. The current study aims to enhance flow-accelerated corrosion (FAC) resistance using metallurgy of the surface by utilizing the laser surface melting (LSM) technique. The FAC behavior of API X70 steel in simulated Indian synthetic oilfield water was studied by utilizing a closed-loop corrosion apparatus to simulate the pipeline flow. Electrochemical corrosion experiments (AC and DC methods) were conducted at a constant fluid velocity of 3 m/s in untreated and LSM-treated samples (at 2.5 and 3.0 kW) placed at a 90° pipe elbow. Experimental results showed that LSM-treated samples displayed enhanced resistance to FAC, attributed to changes in surface metallurgy. Additionally, it was observed that the corrosion rate varied within the pipe elbow for the different samples at different locations. © 2024 Wiley-VCH GmbH.Item Meltpool characteristics, microstructure, and corrosion performance of laser-directed energy deposition cladded 316L SS/X70 steel for oilfield applications(Elsevier Ltd, 2025) Singh, R.K.; Arya, S.B.; Nayak, J.In oilfield pipeline transmission, complex geometries such as elbows, reducers, tees, and orifices face significant corrosion risks, especially in aggressive environments where multiphase turbulent flow and chloride ions cause sharp variations in hydrodynamic parameters. This study explores a laser cladding approach to mitigate internal corrosion in these complex geometries. The Laser-Directed Energy Deposition (L-DED) technique, known for its precision and efficiency, is employed to apply corrosion-resistant 316 L stainless steel (SS) over API X70 steel. Key parameters, including laser power and scan speed, were varied across nine combinations to evaluate their effects on melt pool characteristics, microstructure, and corrosion properties of the clads. Results showed that as laser energy increased (higher power and lower scan speed), melt pool dimensions and heat-affected zone (HAZ) thickness also increased, with clad thickness and HAZ ranging from 172 to 504 µm and 159–272 µm, respectively. Cellular and columnar sub-grain structures were present across all process combinations, with sub-grain size increasing at higher laser energy. A notable variation in chromium content was detected, with the clad produced at 500 W and 720 mm/min exhibiting superior pitting and corrosion resistance. This high-energy clad featured 16.3 % chromium and larger sub-grain sizes, facilitating stable passive film formation during corrosion. The optimized clad demonstrated approximately two orders better corrosion performance than the base X70 steel. © 2025Item Enhancing X70 steel durability: Tribo-corrosion resistance through protective laser cladding(Elsevier Ltd, 2025) Singh, R.K.; Bhole, K.B.; Arya, S.B.; Nayak, J.This study investigates the effects of laser surface cladding (L-DED technique) on the tribo-corrosion behavior of API X70 steel in the simulated Indian oilfield water. Using optimized parameters, 500 W laser power, 720 mm/min scan speed, and 4.2 g/min powder feed rate, 316 L SS was successfully clad onto X70 steel without any significant defects. The results showed a significant improvement in corrosion resistance, with the SS clad exhibiting a corrosion rate of 131.3 ?m/year at 20 N, compared to 287.9 ?m/year for the X70 substrate. SEM and 3D profilometer analyses revealed a more stable tribo-layer on the SS clad, with less damage and debris accumulation. These findings highlight the potential of laser cladding to enhance the durability and lifespan of steel components. © 2025 Elsevier Ltd