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This paper aims to depict the erosion performance of two HVOF-coated micron layers (Colmonoy-88 and Stellite-6) on pump impeller steel (SS-410) by using Taguchi's method. Taguchi's array (L16) was used to optimize the erosion wear (in terms of weight loss) by using four influencing parameters such as rotational speed, solid concentration, average particle size and time which were varied at four different levels.

The experiments were carried out by using a Ducom slurry tester with rotational speed in the range of 750-1,500 rpm, solid concentration of 35-65 per cent by weight, time period of 75-210 min and average particle sizes in the range of < 53 to 250 µm. Bottom Ash with a nominal size range of < 53 to 250 µm was used as erodent. The process parameters were optimized by using Taguchi's method. The ANOVA method was used to validate the results given by Taguchi's method.

The results revealed that the presence of both carbides and borides and the additional presence of Cr in Colmonoy-88 coating enhancing the slurry erosion resistance of Colmonoy-88 coating. Moreover, the chromium and tungsten carbide particles help in increasing the bond strength between the coating and the substrate material. Further, it was also found that the time was the most dominant factor as compared to other factors.

The very less work has been reported on optimization of erosion wear response of Colmonoy-88 and Stellite-6 coatings by using different design of experiment techniques. Further, the erosion wear mechanism of both coatings has been studied by using image j analysis software.

This study aims to deal with development and performance analysis of high-velocity oxy-fuel (HVOF) thermally sprayed Mo₂C-based WC-CoCr (tungsten carbine cobalt chrome) (Co-10% and Cr-4%) cermet coating deposited on the pump impeller steel 316 L.

In this work, a study was carried out by modifying the conventional WC-CoCr powder with a small addition of molybdenum carbide (Mo₂C). Reinforcement was done by 1–4 wt.% addition of Mo₂C feedstocks in WC-CoCr powder by using a jar ball mill process. The design of experiment was implemented for optimization of the percentage of Mo₂C feedstock. L16 (4 × 4) orthogonal array was used to design the experiments for erosion output for the input parameters namely velocity, particle size, concentration and Mo₂C proportion.

Results show that the Mo₂C-based WC-CoCr coating provides better microhardness as compared to conventional WC-CoCr coating. The present study also reveals that the deposition of conventional WC-CoCr coating has improved the wear resistance of SS 316 L by 9.98%. However, the slurry erosion performance of conventional WC-CoCr coating was improved as 69.6% by the addition of 3% Mo₂C.

WC-CoCr coatings are universally used for protecting the equipment and machinery from abrasion, erosion and corrosion. So, the 3% Mo₂C-based WC-CoCr can be useful in power plants and various industries like mining, chemical, automobile, cementing and food processing industries.

A new HVOF coating has been developed by the addition of Mo₂C feedstock in WC-CoCr powder (Co 10% and Cr 4%) and the percentage of Mo₂C feedstock was optimized to improve the tribological behavior of WC-CoCr coating.

Bituminous‐epoxy Coating. Of all the protective systems developed over the last few years, none has shown such promise as those of the epoxy resin group. Exposure to acids, alkalis and immersion in oils and spirits leaves them relatively unaffected and they will resist conditions which would strip a normal paint film in a matter of hours. Coal tar pitch coatings, on the other hand, possess an unequalled resistance to moisture and humid conditions.

Pitting Pitting is possibly the most expensive form of corrosion, in that one small hole can result in the failure or destruction of a process or plant. By its very nature it is a localised form of attack, the diameter of the resultant pit being approximately the same as its depth. Some materials are very prone to pitting—the pits are so close that the surface resembles a roughened specimen. The most important factor, that of pit depth, is sometimes referred to in terms of ‘pitting factor’. This relates the ratio of deepest pit to average metal penetration, the latter being derived from the weight loss of the specimen. Uniform corrosion has a pitting factor of unity.

CUTTING FLUIDS function by providing lubrication and cooling, and naturally where the latter is the predominant requirement cutting fluids based on water are used. Soluble oil emulsions are the most common type, but in recent years there has been a revival of interest in aqueous solutions as alternatives, and sufficient experience in their use has been accumulated to warrant a review of their present status.

Binder jetting is one of the essential additive manufacturing methods because it is cost-effective, has no thermal stress problems and has a wide range of different materials. Using binder jetting technology in the industry is becoming more common recently. However, it has disadvantages compared to traditional manufacturing methods regarding speed. This study aims to increase the manufacturing speed of binder jetting.

This study used adaptive slicing to increase the manufacturing speed of binder jetting. In addition, a variable binder amount algorithm has been developed to use adaptive slicing efficiently. Quarter-spherical shaped samples were manufactured using a variable binder amount algorithm and adaptive slicing method.

Samples were sintered at 1250°C for 2 h with 10°C/min heating and cooling ramp. Scanning electron microscope analysis, surface roughness tests, and density calculations were done. According to the results obtained from the analyzes, similar surface quality is achieved by using 38% fewer layers than uniform slicing.

More work is needed to implement adaptive slicing to binder jetting. Because the software of commercial printers is very difficult to modify, an open-source printer was used. For this reason, it can be challenging to produce perfect samples. However, a good start has been made in this area.

To the best of the authors’ knowledge, the actual use of adaptive slicing in binder jetting was applied for the first time in this study. A variable binder amount algorithm has been developed to implement adaptive slicing in binder jetting.

The purpose of this paper is to focus on the structural integrity of the rainwater propeller pumps installed in the municipal wastewater treatment plant (WTP).

A numerical analysis is performed to determine the maximum shear stress on the fasten bolts. The rainwater propeller pump is examined in operation at normal conditions and when one blade is progressively blocked.

The failure mechanism of the rainwater pump impeller is determined.

The fibbers and wastes are discharged together with rainwater during storms with these types of pumps to avoid the flood of the WTP. Several catastrophic events have occurred in service due to the fibbers clog the gap between the impeller blades and the pump casing. The clogging process is partially understood so actual technical solutions deal with effects rather the main causes.

The operation time of all seven rainwater pumps installed in Timisoara’s WTP is investigated. Climate changes in Banat region and new waste properties found in the wastewater require appropriate technical solutions. A technical solution is proposed based on these investigations to extend the operation time and to diminish the operation and maintenance costs.

These large pumps are installed in the urban sewage centralised system implemented in the most cities. The access to the sewerage network is a requirement of any community, regardless of the social status.

The fracture surfaces of both fastening bolts of the rainwater pump impellers produced in service are examined. As a result, it has been identified that the catastrophic events are due to the brittle fracture of both fasten bolts between the impeller blades and the pump hub, respectively. The catastrophic events of the rainwater propeller pumps are directly correlated to the clog level of the impeller. The numerical simulation is performed to determine the maximum shear stress on the fasten bolts. The case with pump operating at normal conditions is performed identifying its vulnerabilities to clog conditions. Next, one impeller blade is progressively blocked considering three time stop scenarios associated with different clog levels. Conclusively, the operating time of the rainwater pump up to the catastrophic failure is correlated to the clog level of the impeller.

Most chemical pumps on the market today were designed 20 to 30 years ago, in the days of shaft sealing by gland packing. Their characteristics include small diameter shafts, with the packing acting as a third bearing to support the overhang; high pressure in the seal chamber; and excessive shaft end‐play.

After six years' arduous service, it has been estimated that eight cooling‐water pumps at a U.K. power station are in such good condition that they will outlast the life of the station itself. This follows the introduction of Ni‐Resist Type 2 austenitic cast iron (containing 20% nickel) for the pump casings and covers, and Type 316 nickel stainless steel for the impellers. The pumps handle salty silt‐laden water and those first installed, made of non‐alloyed cast iron, had to be replaced after only ten years' service — during which time they frequently had to be repaired by welding. Since the changeover to Ni‐Resist and stainless steel, repairs to casings and impellers have become a thing of the past. The power station is situated at Uskmouth on the tidal estuary of the rivers Usk and Severn, just outside Newport, Wales, where the rise and fall of each tide — about 43ft (13m) — is one of the largest in the world. The pumps were made by Allen Gwynnes Pumps Limited, Bedford, and the Ni‐Resist casings and covers were cast by Glenfield and Kennedy Limited, Kilmarnock, Scotland.