Abstract
The current study reports the successful preparation of Ni/TiN coatings via laser melting deposition (LMD) for repairing the shaft of an electric submersible pump (ESP). The surface morphology, microstructure, phase composition, microhardness, shear strength, and wear resistance were investigated using a scanning electron microscope (SEM), X-ray diffractometer (XRD), microhardness meter, shear strength test machine, and friction and wear tester. Among the three coatings, the Ni/TiN coating deposited at 1.5 kW processed fine grains with an evenly dispersed and compact structure. The Ni/TiN coating revealed a face-centered cubic (f c c) lattice that exhibited diverse orientations due to the laser powers. The Ni/TiN coating deposited at 1 kW had the lowest average microhardness of 768 HV, while the Ni/TiN coating deposited at 1.5 kW had the highest average hardness of 843 HV. The shear displacements of the Ni/TiN coatings obtained at 1, 1.5, and 2 kW were 0.68, 0.54, and 0.61 mm, respectively. The Ni/TiN coating deposited at 1.5 kW had the lowest friction coefficient among all coatings, with an average value of only 0.44. Additionally, the Ni/TiN coating deposited at 1.5 kW exhibited the highest wear resistance. The presence of Ni, Ti, N, Cr, and Fe elements on the surface of the shaft of the ESP, indicated that the LMD technology had successfully repaired the shaft.
Highlights
The 40Cr steel (GB/T17107-2018) is generally used for manufacturing the shaft of an electric submersible pump (ESP) [1]
The Ni/Titanium nitride (TiN) coating deposited at 1 kW had an average microhardness of 768 HV, the lowest of the three coatings, but the Ni/TiN coating deposited at 1.5 kW had a maximum average microhardness of 843 HV
Ni/TiN coatings were fabricated by using laser melting deposition, and some conclusions were listed as follows: (1) The Ni/TiN coating deposited at 1 kW exhibited a coarse morphology with large TiN particles
Summary
The 40Cr steel (GB/T17107-2018) is generally used for manufacturing the shaft of an electric submersible pump (ESP) [1]. During a long-term operation, the shaft of the ESP is prone to wear and corrosion due to sand particles, acid liquid, poor lubrication, and other factors [2–4]. Some repair methods, such as electrospark deposition, brushing electrodeposition, plasma arc deposition, and laser melting deposition can be used to refabricate the shaft when it is worn or corroded [5–8]. The LMD approach was successfully used to fabricate reduced activation steels by An et al [10]. They found that the grain sizes in the upper layers were larger than those in the substrate. They found that laser power could affect the microstructure, phases, and composition of the steel
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