scholarly journals Protection enhancing of threaded connections of light-alloy drill pipes against contact corrosion

2021 ◽  
Vol 225 ◽  
pp. 03003
Author(s):  
Vladimir Malyshev ◽  
Mikhail Gelfgat ◽  
Arseniy Scherbakov ◽  
Alexey Alkhimenko

When using light-alloy drill pipes (LAIDP) with steel tool joints, the development of contact corrosion is observed under certain operating conditions. The value of corrosion mainly depends on the difference in electrochemical potential (ECP) of the contacting metals. One of the effective methods for increasing the corrosion resistance of aluminum alloys is the micro-arc oxidation (MAO) method. This is an electrochemical process in combination with micro-arc-discharges phenomena at the anode-electrolyte border, which allows forming ceramic coatings of aluminum oxides on the surface, including its high-toughness and wear-resistant phase - α-Al2O3 (corundum). MAO-technology is a highly efficient and environmentally friendly process. At the forming of such a coating on the threaded part and in the tool joint zone of the pipe, a barrier for contact corrosion between the steel tool joint and the surface of the aluminum pipe is created. In this work, contact corrosion on samples in a pair of 1953T1 aluminum alloy - 40KhN2MA steel in a 5% NaCl solution at 80 °C was investigated. The data obtained showed the effectiveness of using protective MAO-coating to reduce contact corrosion and increase the reliability of the tool joint threaded connection of LAIDP.

Author(s):  
Marcelo Igor Lourenc¸o ◽  
Theodoro A. Netto ◽  
Neilon S. Silva ◽  
Paulo Emi´lio Valada˜o de Miranda ◽  
Joa˜o Carloes Ribeiro Pla´cido

Experimental program and numerical analyses were carried out to investigate the fatigue mechanisms of aluminum drill pipes designed and manufactured in compliance with ISO 15546. Material mechanical properties, including S-N curve, were determined through small-scale tests on specimens cut from actual drill pipes. Full-scale experiments were also performed in laboratory. Initially, the tool-joint assembly procedure was actually performed to monitor the resulting strain/stress level in selected points of the aluminum pipe. Three full-scale aluminum drill pipe specimens were then fatigue tested under combined cyclic bending and constant axial tension. In parallel, a finite element model of the tool-joint region, where two drill pipe specimens failed in the fatigue tests, was developed. The model was first used to reproduce the tool-joint assembly. Then, the physical experiments were simulated numerically in order to obtain the actual stress distribution in this region. Good correlation between full-scale and small-scale fatigue tests was obtained by adjusting the strain/stress levels monitored in the full-scale tests in light of the numerical simulations.


Author(s):  
Vadim Tikhonov ◽  
Danila Davydov ◽  
Rudolf Alikin ◽  
Mikhail Gelfgat

Aluminum alloys continue to be among the promising materials for manufacture of drill pipes and risers for deepwater and ultra-deepwater environment. Steel tool-joints attached to aluminum alloy pipes increase the number of make-ups and break-outs. Currently, aluminum drill pipes (ADP) are assembled by “cold” or “hot” methods. By the first method, the pin and box are screwed on the pipe with a “sufficiently” high specified make-up torque. By the second method, the pin and box of the tool joint are heated and screwed on the ends of the pipe without effort. After cooling, the shrinkage of the tool joint units creates a reliable permanent threaded “pipe – tool joint” connection. The first method is easier than the second one; however the comparative strength of these ADP connections has not been enough clear. The paper presents the results of comparative strength analysis of both types of connection after assembly at applying tensile load and alternating bending load. The theoretical aspect of the study includes a detailed FEA of “hot” and “cold” assembly connections at applying tensile load and alternating bending load with SCF evaluation. The experimental data are presented as the results of tensile testing of small-scale specimens, removed from different aluminum pipe sections that were heated during “hot” assembly. Finally, full-scale specimens of both types of connections were tested for tensile capacity and fatigue. The comparative strength of both types of connections is concluded.


Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1546
Author(s):  
Árpád Imre-Lucaci ◽  
Melinda Fogarasi ◽  
Florica Imre-Lucaci ◽  
Szabolcs Fogarasi

This paper presents a novel approach for the recovery of lead from waste cathode-ray tube (CRT) glass by applying a combined chemical-electrochemical process which allows the simultaneous recovery of Pb from waste CRT glass and electrochemical regeneration of the leaching agent. The optimal operating conditions were identified based on the influence of leaching agent concentration, recirculation flow rate and current density on the main technical performance indicators. The experimental results demonstrate that the process is the most efficient at 0.6 M acetic acid concentration, flow rate of 45 mL/min and current density of 4 mA/cm2. The mass balance data corresponding to the recycling of 10 kg/h waste CRT glass in the identified optimal operating conditions was used for the environmental assessment of the process. The General Effect Indices (GEIs), obtained through the Biwer Heinzle method for the input and output streams of the process, indicate that the developed recovery process not only achieve a complete recovery of lead but it is eco-friendly as well.


Author(s):  
Sergey Grigoriev ◽  
Igor Kondratsky ◽  
Boris Krit ◽  
Valery Ludin ◽  
Varvara Medvetskova ◽  
...  

Abstract Magnesium alloys are now widely used for various purposes due to their unique properties despite the significant disadvantage associated with low corrosion resistance. The plasma-electrolytic oxidation (PEO), which allows the formation of ceramic coatings on the surface of magnesium alloys, is the most advanced and effective method for their protection. But firstly, PEO process of magnesium alloys has some difficulties, and secondly, PEO coatings affect the thermophysical characteristics of the modified materials, in particular they reduce thermal diffusivity. The presented work is devoted to the development of the technological parameters for formation of protective coating on the ultra-light alloy Mg-8Li-1Al-0.6Ce-0.3Y by the PEO method. The results analyses of electrolytes acidity and specific electrical conductivity before and after PEO process and also investigation data of the coatings structure and surface morphology are presented. An integral assessment of the ability of thermal diffusivity and corrosion resistance of the modified alloy was made. Studying of protective and thermophysical characteristics of the obtained coating showed that it provides a sufficiently high corrosion protection, despite the relatively small thickness, and the presence of pores and slightly (not more than 5%) reduces the thermal diffusivity of the magnesium ultra-light alloy.


2014 ◽  
Vol 567 ◽  
pp. 44-49 ◽  
Author(s):  
Gan Chin Heng ◽  
Mohamed Hasnain Isa

Electrochemical process is one of the most effective methods to enhance sludge disintegration. In this study, Ti/RuO2 anodes were prepared by Pechini’s method and the electrode surface morphology was characterized by FESEM and EDAX. The effects of various operating conditions were investigated including initial pH value of sludge, sludge concentration, electrolysis time and current density. The study showed that the removal efficiencies of TS, VS, TSS and VSS increased with the increase of pH in the alkaline range, electrolysis time and current density but decreased with the increase of initial sludge concentration. The application of electrochemical process using Ti/RuO2 electrodes enhanced the sludge disintegration for possible subsequent biological treatment.


1977 ◽  
Vol 12 (5) ◽  
pp. 530-532
Author(s):  
V. I. Pokhmurskii ◽  
A. M. Prishlyak ◽  
A. T. Levchenko ◽  
K. M. Gil'man

2018 ◽  
Vol 2018 (7) ◽  
pp. 19-25
Author(s):  
Андрей Паренко ◽  
Andrey Parenko ◽  
Константин Макаренко ◽  
Konstantin Makarenko

In connection with a relatively high cost of drill pipes large companies loss caused by rejection achieves tens millions of rubles. And at the same time it is necessary to take into account that the tool-joint thread rejection does not mean at all unworthiness to operation a drill pipe itself as having restored an inter-lock it is possible to continue the operation of a res-tored product. In such a way, one of the priority direc-tions at major repair of drill pipes is a restoration of interlock geometrical joints. In this paper there is considered a technology for repair of a worn thread in an interlock of drill pipes and its updating at the expense of electric contact weld deposition used into an upset groove. The method of-fered allows keeping a pipe without its shortening at repair at the expense of additional metal application directly upon a thread area and decreasing a thermal impact area and also increasing operation properties of a restored pipe.


2021 ◽  
Vol 9 ◽  
Author(s):  
Timothy A. Barckholtz ◽  
Heather Elsen ◽  
Patricia H. Kalamaras ◽  
Gabor Kiss ◽  
Jon Rosen ◽  
...  

Molten Carbonate Fuel Cells (MCFCs) are used today commercially for power production. More recently they have also been considered for carbon capture from industrial and power generation CO2 sources. In this newer application context, our recent studies have shown that at low CO2/H2O cathode gas ratios, water supplements CO2 in the electrochemical process to generate power but not capture CO2. We now report the direct Raman observation of the underlying carbonate-hydroxide equilibrium in an alkali carbonate eutectic near MCFC operating conditions. Our improved electrochemical model built on the experimental equilibrium data adjusts the internal resistance terms and has improved the representation of the MCFC performance. This fundamentally improved model now also includes the temperature dependence of cell performance. It has been validated on experimental data collected in single cell tests. The average error in the simulated voltage is less than 4% even when extreme operating conditions of low CO2 concentration and high current density data are included. With the improvements, this electrochemical model is suitable for simulating industrial cells and stacks employed in a wide variety of carbon capture applications.


2018 ◽  
Vol 18 (1) ◽  
pp. 21-27
Author(s):  
Alina I. Shakirova ◽  
Rustem A. Ismakov ◽  
Akhtyam Kh. Agliullin ◽  
Nikolai K. Tsenev

Special aluminum alloys appear to be promising materials for manufacture of high-strength light-alloy drill pipes (HSLADP) that can be used in areas with a severe climate and challenging geology. The effect of using light-alloy drill pipes (LADP) depends directly on the properties of the aluminum alloys from which such pipes are made. As the wells become deeper and horizontal wellbores get longer, use of LADPs becomes more relevant. Since light-alloy pipes are 2.8 times softer than steel pipes, LADPs offer the same performance as steel drill pipes of the lowest strength grade even in the case of rotary drilling. The materials from which such pipes are made have a number of unique advantages: extra light weight in the drill mud, allowing the coefficient of sliding friction between the pipe surface and the borehole wall to be reduced; high corrosion resistance in aggressive media with A high concentration of hydrogen sulfide and carbon dioxide; and high magnetic inductive capacity that allows LADPs to be used as a housing for MWD (measurement while drilling) and LWD (logging while drilling) telemetry systems during well-drilling operations. This study suggests methods for industrial production of submicrocrystalline (SMC) structure in aluminum alloys with the help of severe plastic deformation. Through the example of model aluminum-lithium alloys 1420 (Al-Mg-Li-Zr) and 1460 (Al-Сu-Li-Zr), the researchers demonstrate that SMC structure helps significantly increase resistance to wear and reduce the rate of corrosion depending on the pH value. The research team also states that severe plastic deformation methods may be used to develop highly promising technologies for manufacture of high-strength LADPs with advanced strain-stress properties for use during operations in the Arctic.


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