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Varied compositions of TiC (Titanium Carbide) and CuNi-Cr (Cupronickel-Chromium) have been examined as coating materials for hydro machinery steel (SS316) using HVOF spraying system. The slurry erosion experiments have been performed to evaluate these coatings' effectiveness among themselves as well as against bare SS316 steel. In regard to this, the effect of different factors affecting the slurry wear of specimens, such as jet velocity, slurry concentration, and impingement angle have been examined. Further, porosity, microhardness, and surface roughness of the specimens have been measured, and the structure of the developed coatings was also analysed using XRD and SEM. Based on the outcomes of the experiments, it was converged that among the different coatings evaluated, 100% TiC based coating has shown significantly higher resistance to erosion in contrast to other candidate coatings which may be due to higher micro-hardness attribute availed by TiC granules. Moreover, as compared with bare SS316 steel, a substantial augmentation in the slurry wear resistance of SS316 steel was observed as contrasted with all the other developed coatings. Ductile mode of failure was noticed for specimen with CuNi-Cr as primary element, which was found to exhibit brittle mode with the increment in TiC percentage. [ABSTRACT FROM AUTHOR]

Several hydro-machinery components such as impellers of the submersible pump and turbine blades generally suffer from slurry erosion during their operation. High-velocity oxy-fuel (HVOF)-sprayed coatings are promising materials to prevent such components from slurry erosion. Moreover, polytetrafluoroethylene (PTFE) is a well-accepted hydrophobic material, which has several attractive properties such as chemical inertness and considerable thermal stability. Therefore, PTFE coating has been explored as a topcoat for a HVOF-sprayed WC-10Co-4Cr coating, with an aim to enhance the performance of the latter and analyzed with different slurry erosion conditions. A slurry erosion test rig was used for experimentation, and the effect of four different erosion parameters, namely average particle size, slurry concentration, impact angle, and velocity of jet, was investigated. A comparative study between PTFE-modified HVOF-sprayed coating and the standalone HVOF-sprayed coating was also done with respect to slurry erosion behavior and hydrophobicity. The overall results indicate that the slurry erosion of the HVOF-sprayed coated SS 316 steel got enhanced after modification by PTFE topcoat. Furthermore, the topcoat of PTFE on HVOF-sprayed coating resulted in a remarkable improvement in hydrophobicity, showing a superhydrophobic behavior, which might have also provided a better slurry erosion resistance to the HVOF-sprayed steel. [ABSTRACT FROM AUTHOR]

There has been rapid incline, in this neoteric era, in the problem of slurry erosion in the hydro machine components and as a result, expensive repairs or replacements may be necessary for the machinery and equipment that could be seriously damaged. In this course of work, for alleviating the problem of erosion in hydro-machineries, Hogonos+50%WC coatings were deposited with the aid laser cladding approach. The impact of laser beam power, torch travel speed, and feeding rate of powder on the clad quality was examined. Cross-sectional coating characterization, XRD analysis, micro hardness and slurry analysis have been done for cladded specimens. Scanning speed has a greater contribution in the increment of hardness as compared to the other built parameters such as laser beam power and feeding rate of powder. Cladded specimens of Hogonas+50%WC have more resistance to slurry erosion as against the un-cladded SS304 steel. There was mixed mode of failure (ductile and brittle) in both cladded and un-cladded specimens. • Hogonas+50%WC clads have been successfully developed using variable laser cladding parameters. • Highest hardness and erosion resistance for clad: 1500 W, 30 g/min, and 1750 mm/min. • Velocity of impact has maximum influence among all slurry erosion parameters. • Mixed mode of ductile and brittle failure has been observed as erosion mechanism for clads. [ABSTRACT FROM AUTHOR]

The current experimental work is focused on development and characterization of HVOF sprayed VC-TiC+CuNi-Cr based coatings on hydro-machinery steel SS316. Empirical correlations for mass loss have been developed with the aid of response surface methodology (RSM) approach. Central composite design (CCD) matrix has been acquired with five different levels over four impingement parameters namely impingement angle, jet velocity, slurry concentration, and exposure time. When compared with bare SS316 steel, a significant increase in the slurry wear resistance of SS316 steel was noticed for different variants of developed coating. Moreover, ductile erosion mode was observed in coatings containing CuNi-Cr as the main component, which was reported to transform into the brittle mode with increasing VC-TiC percentage. [ABSTRACT FROM AUTHOR]

The present work describes the application of High-Velocity oxy-fuel spray process with Ni-20Cr 2 O 3 powder deposition on the various pipeline steels namely SS 202, SS 304, and mild steel. The slurry erosion wear tests were performed on coated and uncoated steels by considering slurry concentration, impact velocity, and erosion time as input parameters. It was concluded that for all materials, rpm (impact velocity of erodent's) influences on erosion wear the most. It was also noticed that the erosion resistance has been improved with SS 202 steel followed by to SS 304 and mild steel. Further, Ni-20Cr 2 O 3 coatings showed maximum enhancement in slurry wear resistance of mild steel, followed by SS 304 steel and SS 202 steel. • Application of High-Velocity oxy-fuel spray process with Ni-20Cr 2 O 3 powder deposition was investigated. • Slurry erosion wear tests were performed on different pipeline steels such as SS 202, SS 304, and Mild steel. • Influence of three parameters namely slurry concentration, impact velocity, and erosion time was investigated. • Ni-20Cr 2 O 3 coatings showed maximum enhancement in slurry wear resistance of Mild steel. [ABSTRACT FROM AUTHOR]

Erosion due to slurry has an indispensable effect on the lifespan and operating efficiency of hydro machine components. To mitigate this effect, laser cladding may prove as a cost-effective choice to improve the surface properties of various hydro machine components. In this research work, a laser cladding of Colmonoy-6 + 50%WC powder on the surface of SS410 steel was deposited using high-power diode laser at optimized levels of operating parameters. The deposited coating was characterized with regard to different mechanical and metallurgical properties. The effect of various factors such as slurry concentration, erodent particle size, impact velocity, and impact angle on slurry erosion behavior of uncoated and laser cladded substrate was analyzed. The Colmonoy-6 + 50%WC cladded specimens exhibited significantly better slurry erosion resistance in comparison with uncoated SS410 steel specimens under all slurry erosion conditions. Impact velocity was observed to be a maximum contributor to slurry erosion, followed by impact angle, average particle size and slurry concentration. The SEM micrographs of eroded cladded surfaces showed signatures of lip formation & fracture sites, micro-cutting, ploughing, and wear marks at a shallow impact angle in Colmonoy-6 pool, however, for normal impact, the existence of cracks in WC particles were observed. • Colmonoy-6 + 50%WC coatings were developed using laser cladding process parameters (scanning speed as 1700 mm/s, laser power 2 kW and powder feed rate 30 g/min). • Impact velocity was found to be most influencing parameter for slurry erosion. • Signatures of lip formation & fracture sites, micro-cutting, ploughing, and wear marks were observed in the pool of Colmonoy-6 at shallow impact angle. • For normal impact, the existence of cracks in WC particles demonstrate brittle failure. [ABSTRACT FROM AUTHOR]