Papers by Keyword: Erosion

Abstract: In view of the combined effect of the load and the corrosive environment on the downhole tubing and the need for the selection of downhole tubing materials, the study on the pitting corrosion, crevice corrosion, erosion corrosion, high temperature and high pressure simulation of corrosion, galvanic corrosion, resistance to sulfide stress corrosion cracking SSC, resistance to hydrogen induced cracking, stress corrosion cracking test under simulated working conditions for TC27 titanium alloy was carried out. Furthermore, the corrosion performance was evaluated by the test results and evaluation standards such as GB/T 18590-2001, SY/T 7394-2017, GB/T 15748-2013. The results show that TC27 have excellent resistance to pitting corrosion, crevice corrosion and erosion corrosion under the corrosive environment of NaCl and H₂S. The alloy also has excellent corrosion resistance and crack resistance under high-intensity environments such as high temperature and high pressure, and has good overall performance, which can effectively meet the needs of anti-corrosion performance of downhole tubing materials in different corrosive environments.

Abstract: Material choices for liquid lead bismuth spallation target are some of austenitic stainless steel, ferrite martensitic steel and cold-worked austenitic stainless steel. In order to ensure materials resistance to irradiation and corrosion as well as compatibility with lead bismuth, it is appropriate to lower the incident proton current density and the process temperature, in which temperature range engineering design can control to work, especially in ADS (Accelerator-Driven nuclear transmutation System) concept. The lower limit temperature is determined from the physical melting temperature and the engineering efficiency of the steam generator involved in process control. The material related issues for liquid lead bismuth are mass loss by impinging secondary flow, wettability at the device interface for ultrasonic waves application, detachable control of the slag in the flowing system, stabilized electrical resistance between the material and the liquid lead bismuth interface. Electromagnetic fluid analyses show how flow rate relates electrical resistivity of flow channel material.

Abstract: The article is devoted to the analysis of the internal structure and properties of a copper-graphite coating applied to a copper electrode. The article provides a calculation of the transient contact resistance of electrodes with a coating obtained using plasma spraying technology. Copper-graphite powder with high arc resistance was used as a spraying substance. Coated electrodes were tested for erosion resistance by an arc at currents of several kiloamperes. The aim of the work is to determine the effect of the composition and internal structure of the coating on the transient processes in the contact gap.

Abstract: The study of fatigue behavior of aluminum alloy 6063 exposed to periodic fatigue stresses was studied in laboratory conditions under the two conditions of the presence of the first indentation in the first test, then the presence of the phenomenon of erosion in the second test resulting from the projection of pure water Jet on samples of the same metal used in The first test. The purpose of these tests was to estimate the practical life of these samples and the resulting accumulation by using upward and downward variable stresses. A mathematical model was built to calculate the life of the samples in the above conditions, and the results of the estimated life of the samples calculated by the model showed a large convergence with the results of the estimated life of the samples practically calculated. So this mathematical model can be used to estimate the life of samples made of different minerals under these same conditions, after knowing the (S-N) curve for each metal and the amount of the value of the fatigue notch factor (Kf), which can be calculated from special tables without referring to performing practical tests for them.

Abstract: This study focuses on the effect of deposition time and heat treatment on Ni₃Al coatings with respect to mechanical and microstructural properties of the material. Air plasma spraying technique was employed to deposit Ni₃Al on hot work tool steel samples for different deposition times i.e. 15-45 seconds. The coated samples were then heat treated at 900 °C for 20 to 100 hours at an interval of 20 hours each. The characterization tools such as X-Ray diffraction (XRD), optical and scanning electron microscopy (SEM) were used to study the homogeneity, phases formed and structure of coatings. All the coatings showed lamellar structure with distinctive boundaries along with the presence of some porosity and oxide particles. The XRD analysis of as prepared samples showed characteristic peaks of Ni₃Al whereas of heat treated samples revealed NiO formation that increased with increasing heat treatment time. Micro-hardness and wear resistance measurements of the coated layer showed that they were increasing with the deposition time due to formation of more thick and dense layers. Formation of NiO, due to heat treatment imparted greater hardness and wear resistance to the coating. Moreover, the SEM study of heat-treated samples showed presences of alumina and spinel phases which were confirmed by energy dispersive spectroscopic analysis.

Abstract: In this work, feather-column 7YSZ thermal barrier coatings (TBCs) were prepared by plasma spray-physical vapor deposition (PS-PVD). The anti-particle erosion test was carried out at room temperature to study the erosion behavior and failure mechanism of PS-PVD TBCs. The results showed that the particle erosion process of the PS-PVD TBCs experienced three stages of high-rate, medium-rate and slow-rate erosion. In order to improve the particle erosion resistance of the PS-PVD TBCs, different thicknesses of dense-layered coatings were prepared on the surface of the PS-PVD TBCs by air plasma spraying (APS). The effect of dense-layered thickness on the erosion behaviour of PS-PVD TBCs was discussed. Experimental results showed that, as the thickness of the dense-layered increased, the erosion resistance of the PS-PVD TBCs enhanced. When the thickness of the dense-layered coating was 5μm, it was not obvious upon the influence on the erosion failure behavior of the PS-PVD TBCs. In the case of a 10μm dense-layered coating, the erosion resistance performance of the PS-PVD TBCs improved by about 30%. While the erosion resistance performance of the PS-PVD TBCs increased almost 4 times when the thickness of the dense layer reached 20μm.

Abstract: In the present work a detailed microstructural investigation of Cobalt based microwave cladding on S-355 stainless steel was carried out. The experimentations were carried out in a home based domestic microwave oven. This article clears the circumstances of clad formation during microwave hybrid heating. The solidification texture and grain structure of the developed clad scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy, and measurement of Vicker’s microhardness. Cobalt based clads developed with an approximate thickness of 1 mm without interfacial cracking. The microstructure of clad clearly illustrated excellent metallurgical bond with S-355 substrate and found dominantly fine cellular grains. Iron and cobalt were recognized inside the cells while chromium was ascertained segregated around the cell boundaries. The average microhardness of the cobalt based clad was observed in the range of 402±60 HV.

Abstract: This paper describes the existing methods for determining the corrosion-erosion wear of materials, and describes a technique developed to assess the stability of oilfield pipes for corrosion-abrasive wear. The results of comparative tests on this method of steels 13HFA and St20 are presented.

Abstract: Now a days natural fibers are progressively projected as a choice of conventional synthetic fibers which causes an adverse impact on the surroundings. Rise within the utilization of environment-friendly natural fibers as reinforcement for the manufacture of lightweight, low-cost polymer with excellent mechanical, thermal and tribological properties can be made globally. One such material of interesting material being presently used is basalt fiber, which is the most-efficient and provides important properties over Carbon fibers, Glass fiber, and some other fibers. In this attempt, an effort made to showcase the tribological properties achieved for application in specific wear conditions like abrasive, sliding and erosion of basalt fiber reinforced polymer composites.

Abstract: In the paper, the resistance of concrete to the erosive effect of water from a water jet was monitored. The tests were performed on concrete without the addition of fibres and on concrete with the addition of polypropylene fibres and steel fibres. The water flow hit the concrete surface at an angle of 90°. The water flow rate was 1.1 l/min and the water pressure was 80 MPa. After blasting the concrete with water jet, no cracks in the concrete were observed and the intended rugged surface relief was created. Steel fibres remained firmly anchored into the cement matrix.