Browsing by Author "Shariff, S.M."

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    Comparative study of diode laser welding of solid-solution/precipitation-strengthened Fe-Ni-Cr-based superalloys
    (Taylor and Francis Ltd., 2025) Kumar, H.; Banerjee, K.; Aqeel, M.; Shariff, S.M.
    This study investigates autogenous diode laser welding of two differently strengthened Fe-Ni-Cr superalloys: solid-solution strengthened Incoloy 800 and precipitation-strengthened Incoloy A286. Effects of laser power, welding speed, and defocusing distance on weld bead geometry, microstructure, and mechanical properties were comprehensively analyzed. Butt weld joints produced with optimum and similar heat input conditions achieved joint efficiencies comparable to their base metals. Microstructural analysis of fusion zone revealed columnar dendrites of ?-(Ni,Fe) in both alloys, with A286 showing segregation of Ti, Cr, and Mo intermetallics at interdendritic regions, while Incoloy 800 exhibited refined columnar/equiaxed dendrites with chromium carbides and Fe-Ni-Ti intermetallics. Mechanical testing indicated enhanced yield strength but reduced impact toughness and marginal hardness gain in A286 welds, whereas Incoloy 800 welds maintained similar hardness to the base material. Overall, the study demonstrated utilization of fiber-coupled diode laser welding for producing butt-joints in both superalloys, supporting their potential adoption in high-temperature applications. © 2025 Taylor & Francis Group, LLC.
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    Effect of hydrodynamics and laser surface melting on erosion-corrosion of X70 steel pipe elbow in oilfield slurry
    (Elsevier Ltd, 2022) Ajmal, T.S.; Arya, S.B.; Maurya, P.; Shariff, S.M.
    Erosion-corrosion (EC) is a significant cause of pipeline failure in the petrochemical industry. The influence of laser surface melting (LSM) on the EC of API X70 steel was investigated with simulated oilfield slurry (1.5 wt% silica sand). The slurry was circulated continuously in a closed-loop apparatus at 3 m/s velocity and EC tests were performed using electrochemical corrosion and weight loss measurements for the untreated and LSM (2.5 kW) samples located at a 90⁰ pipe elbow. Since the erodent particle velocity and the flow rate are low, the EC was dominated by corrosion. LSM samples exhibited higher EC resistance and hardness due to the surface metallurgy alteration and the EC rate varies within the pipe elbow. The primary reasons for the severe EC rates of electrodes placed at the downstream side of the elbow's extrados (outer face) are the secondary flow effect and higher sand concentration. © 2022 Elsevier Ltd