Erosion Corrosion Characteristics Research Articles

Study on metal corrosion behavior of heat-affected zone of oil pipeline

Due to the influence of welding technology, a series of non-uniform and continuous heat-affected zones formed by welding seams is the weakest link of pipeline steel. Compared with the X70 steel, the heat-affected area is in the form of coarse acicular and massive ferrite, granular bainite, and a small amount of pearlite, with weak strength and corrosion resistance. Therefore, this paper simulated the heat-affected zone of the high-strength steel welding seam by the Gleeble 3500 thermal/force simulation testing machine for two heat cycles. Taking Shengli crude oil as the experimental medium, the metal corrosion morphology of heat-affected zones at different temperatures and transmission rates during hot oil transportation was analyzed through immersion experiment and corrosion morphology characterization. The results show that the increase in temperature and flow rate will increase the overall corrosion rate of the metal in the heat-affected area. In the range of 30∼50°C, pitting corrosion was the main corrosion feature of the metal, and in the range of 50∼70°C, the corrosion morphology of the metal changed from pitting corrosion characteristics to comprehensive corrosion characteristics. In the range of the flow rate studied (1∼4 m/s), the metal in the heat-affected area was mainly the overall corrosion rate, and the metal surface showed the erosion-corrosion characteristics along the flow rate direction.

Experimental Study on the Erosion-Corrosion Characteristics of Desulfurization Slurry on Stainless Steel Pipe Materials.

The recovery of low-grade waste heat from power plants greatly benefits energy conservation and emission reduction during electricity generation, while the waste heat utilization directly from desulfurization slurry is a significantly promising method to deeply recover such low-grade energy and has been developed in practical application. However, the pipe materials are subjected to erosion and corrosion challenges due to the high level of solid compositions and the presence of harmful ions, such as Cl-1, which requires further evaluation under the condition of slurry heat exchange. The present study aimed at an experimental study on the erosion-corrosion characteristics of desulfurization slurry on three types of stainless steel, including type 304, 316L, and 2205. Both mass loss and micromorphology features were analyzed with possible mechanisms elucidated. The erosion-corrosion rate is weak at low temperatures, while the increase in the slurry temperature clearly promotes its rate. The influence of the temperature on the corrosion resistance of 304 is much greater than that of 2205. With an increase in duration time, the weight loss rate of stainless steel in the desulfurization slurry declines, and the changing trend of metal mass slightly slows down. The present study offers a better understanding of the erosion-corrosion behaviors of three types of stainless steel under flow and heat transfer conditions of a desulfurization slurry.

Optimizing material selection: A study of erosion-corrosion performance in homogeneous and carbide-containing materials

Erosion-corrosion is a major factor contributing to material loss and reduced useful life of hydro-transport equipment. The combined effect of erosion and corrosion is responsible for high degradation rates. In oil sand mining, materials from different classes are used for various applications depending on the severity of degradation. In this research, we assessed the erosion-corrosion characteristics of four uniform materials (pipeline and abrasion-resistant steels) as well as five materials containing varying types and quantities of carbide (chrome white iron and WC-based overlay). The materials underwent erosion-corrosion testing within a slurry container (comprising 3.5 wt% NaCl + 35 wt% natural silica sand) at a temperature of 45 °C. Under the test conditions, it was found that matrix wear influences the extent of carbide degradation for all carbide-containing materials. To provide good erosion-corrosion resistance, the surrounding matrix that supports the carbide must have sufficient wear and corrosion resistance. This study also identifies the dominant wear mechanisms for both uniform and carbide-containing materials.

An investigation on wear and cavitation erosion-corrosion characteristics of the TiC modified Fe-based composite coating via laser cladding

Fe-based composite coating, modified with TiC ceramic particles, has been successfully manufactured on 304 stainless steel substrate by laser cladding technique in this paper. The phase distribution and microstructure of composite coating are carefully studied via some advanced techniques such as XRD, SEM, EDS and EBSD, meanwhile, the microhardness, wear resistance, electrochemical performance and cavitation corrosion resistance of composite coating and substrate are systematically tested. The obtained results reveal that the as-cladded composite coating is mainly composed of α-Fe, (Cr,Fe)7C3 and TiC. The introduction of TiC particles refined the microstructure inside the dendrites, at the same time the different forms of TiC particles are dispersively distributed in the composite coating. It is found the high microhardness is beneficial for the wear resistance of the coating. Compared with the matrix and some common engineering materials, although no obvious passivation zone is observed, the composite coating also exhibits superior electrochemical performance. Combining the excellent electrochemical and mechanical properties of the coating, the cavitation corrosion resistance of the composite coating has been significantly enhanced. A cavitation erosion resistance mechanism for composite coating has been proposed.

Experimental Investigations on Erosion-Corrosion Characteristics of HVOF-Sprayed WC-10% Ni Coatings Deposited on Aluminum Alloy

The current work investigates the erosion-corrosion behaviour of thermally sprayed tungsten carbide-10% nickel (WC-10% Ni) coatings placed on the AA6061 aluminum alloy. The AA6061 aluminum alloy was coated with tungsten carbide –10% nickel coatings utilising a high-velocityoxy-fuel (HVOF) spray method. The microstructure and hardness of thermally sprayed coatings were examined using a scanning electron microscope (SEM) and a Vickers hardness tester. The slurry erosion-corrosion wear tests were carried out by varying the parameters of the slurry erosion process, such as testing time, slurry content, slurry speed, and impinging particle size, on the erosion testing equipment. The data demonstrated that when slurry concentration, slurry speed, and impinging particle size increased, so did the slurry erosion-corrosion wear loss. The wear processes of uncoated and thermally sprayed tungsten carbide –10% nickel have been examined using SEM and a 3-D confocal microscope.

Effect of Silicon Addition on Erosion-Corrosion Characteristics of High-Tensile Brasses

Effect of Silicon Addition on Erosion-Corrosion Characteristics of High-Tensile Brasses

Effect of Manganese on Synergistic Erosion–Corrosion Characteristics of A890 7A Hyper Duplex Stainless Steels

Effect of Manganese on Synergistic Erosion–Corrosion Characteristics of A890 7A Hyper Duplex Stainless Steels

Experimental and numerical simulation of erosion-corrosion of 90° steel elbow in shale gas pipeline

Coexistence of the solid particle erosion and acid liquid corrosion is common in shale gas gathering and transportation pipelines. It is conceivable that the synergistic effect of erosion and corrosion accelerates the pipeline damage process. In this research, a novel experimental device is designed to study the erosion-corrosion characteristics of 90° steel elbow in the gas-liquid-solid three-phase flow. A total of 28 group experiments are designed including 4 gas velocities, 3 liquid pH values, and 150 μm average sand particles. Moreover, a numerical simulation model is built based on the FLUENT code to predict the erosion-corrosion behavior. Experimental and simulation results show that the most severe erosion-corrosion region of the pipe bend occurs at the axial angle of the elbow between 20° and 50° and at the radial angle of the elbow between −45° and 45°. At the bottom of the elbow and the outer wall surface close to the outlet, the synergistic effect of erosion and corrosion accelerates the wear of the pipeline, but the opposite phenomenon exists at the position of the elbow with an axial angle of 50–70°.

Slurry Erosion-Corrosion Characteristics of As-Built Ti-6Al-4V Manufactured by Selective Laser Melting.

Erosion and erosion–corrosion tests of as-built Ti-6Al-4V manufactured by Selective Laser Melting were investigated using slurries composed of SiO2 sand particles and either tap water (pure water) or 3.5% NaCl solution (artificial seawater). The microhardness value of selective laser melting (SLM)ed Ti-6Al-4V alloy increased as the impact angle increased. The synergistic effect of corrosion and erosion in seawater is always higher than erosion in pure water at all impact angles. The seawater environment caused the dissolution of vanadium oxide V2O5 on the surface of SLMed Ti-6Al-4V alloy due to the presence of Cl− ions in the seawater. These findings show lower microhardness values and high mass losses under the erosion–corrosion test compared to those under the erosion test at all impact angles.

Erosion Corrosion Behavior of Aluminum in Flowing Deionized Water at Various Temperatures.

To optimize the operating temperature and flow velocity of cooling water in a high voltage direct current (HVDC) thyristor valve cooling system, the erosion corrosion characteristics of aluminum electrodes in deionized water at various temperatures were studied. With increasing water temperature, the corrosion current of the aluminum electrode gradually increases and the charge transfer impedance gradually decreases, thus, the corrosion of aluminum tends to become serious. The aluminum electrode in 50 °C deionized water has the most negative corrosion potential (−0.930 V), the maximum corrosion current (1.115 × 10−6 A cm−2) and the minimum charge transfer impedance (8.828 × 10−6 Ω), thus, the aluminum corrosion at this temperature is the most serious. When the temperature of deionized water increases, the thermodynamic activity of the ions and dissolved oxygen in the deionized water increases, and the mass transfer process accelerates. Therefore, the electrochemical corrosion reaction of the aluminum surface will be accelerated. The corrosion products covering the aluminum electrode surface are mainly Al(OH)3. With increasing water temperature, the number of pits and grooves formed by corrosion on the aluminum surface increased. In this paper, the molar activation energy Ea and the equilibrium constant K of the aluminum corrosion reaction with various temperatures are calculated. This clarifies the effect of temperature on the aluminum corrosion reaction, which provides a basis for protecting aluminum from corrosion. The results of this study will contribute to research that is focused on the improvement of production techniques used for HVDC thyristor valve cooling systems.

Erosion Corrosion Characteristics of Al5052-O and Al6061-T6 Aluminum Alloys with Flow Rate of Seawater

Erosion Corrosion Characteristics of Al5052-O and Al6061-T6 Aluminum Alloys with Flow Rate of Seawater

Experimental Study on Erosion⁻Corrosion of TP140 Casing Steel and 13Cr Tubing Steel in Gas⁻Solid and Liquid⁻Solid Jet Flows Containing 2 wt % NaCl.

To study the erosion–corrosion characteristics of TP140 casing steel and 13Cr tubing steel in oil fields, we performed gas–solid and liquid–solid jet flow experiments to control particle addition, jet angle, and flow velocity and measure erosion and corrosion components. Meanwhile, we used a standard three-electrode system to study the changes in electrochemical parameters on a metal surface in a two-phase flow containing 2 wt % NaCl. Results showed that erosion is mainly dominated by the flow velocities and impact angles of particles, and corrosion rate is mainly affected by liquid flow rate. The erosion rates of the two materials increase with flow velocity, and the critical angle of maximum erosion rate exists. Meanwhile, flow velocity growth increases the current density on the TP140 surface while reducing the corrosion potential of 13Cr, but the effect of the angle on the two parameters is relatively small. The uniform corrosion of TP140 increases the erosion rate in the range of 10–20%, and the pitting of 13Cr increases the erosion rate in the range of 30–90%, indicating that the interaction between the erosion and corrosion of stainless steel is obvious.

Erosion-corrosion behaviour of aluminum alloy 6063 hybrid composite

Aluminum alloy 6063 (AA6063) composite with varying proportion of snail-shell-ash (SSA) and silicon carbide (SiC) reinforcement has been developed by stir-casting. Hardness and erosion-corrosion characteristics of the composite were studied. Erosion-corrosion behaviour of the composite was studied in a mono-ethylene glycol (MEG)-water environment with 20% v/v of ethylene glycol and 0.1g/L silica sand particles using a re-designed miniature submerged impinging jet rig. SEM-EDX of the as-cast composites showed the presence of the particulates distributed in the matrix. The hardness of the aluminum alloy was enhanced up to a maximum value (with the addition of 7.5wt % SiC+7.5wt % SSA). However, hardness values declined when (10wt % SSA+10wt % SiC) was used as reinforcing phase. Erosion-corrosion studies showed that erosion component dominates the total material loss and the composite with highest hardness displaying better erosion-corrosion resistance. Also, addition of MEG to the slurry resulted in lower erosion-enhance corrosion and total material loss due to erosion-corrosion. SEM images of the damaged composite showed that the damage mechanism is dominated by ploughing and indentation.

Erosion-corrosion characteristics of spark plasma sintered pure nickel in simulated mine water

This study estimates the impact of shear stress and solid particles on the erosion-corrosion behaviour of spark plasma sintered pure nickel in simulated mine water. Rotating cylinder electrode system was employed to carry out the erosion-corrosion tests by weight-loss and electrochemical measurements. Corroded coupons were examined with the aid of microscope to assess the surface morphology. The gravimetry data was inconsistent with both weight gain and weight loss recorded. The impact of the hydrodynamic parameters was correlated with the pitting resistance and re-passivation behaviour of the sintered nickel, while the morphology results showed minimal general attack and severe localised corrosion.

Cavitation Erosion-Corrosion Characteristics of HVOF Sprayed Fe–Cr–Ni–C–Si Coating for Cu Alloy

Cavitation Erosion-Corrosion Characteristics of HVOF Sprayed Fe–Cr–Ni–C–Si Coating for Cu Alloy

Influence of microstructure on the erosion and erosion–corrosion characteristics of 316 stainless steel

The economic impact of surface damage and component failure arising from solid particle impact in the UK has been estimated in 1997 at around £20 million [1]. The additional complexity associated with erosion in a corrosive environment such as that encountered in the chemical and hydro-carbon extraction industries can significantly accelerate surface wear and material loss. In this study, surface material response of a stainless 316 alloy subject to erosion and erosion–corrosion was investigated by focused ion beam (FIB) and transmission electron microscopy (TEM) techniques. Samples tested in a slurry pot apparatus using 1% uncrushed silica at 7m/s for 60min, both in water and 3.5% NaCl solution. Site specific FIB–TEM lamellas showed that solid particle impact resulted in extensive crater and lip formations and a martensitic phase transformation at the surface. The presence of a corrosive fluid resulted in preferential dissolution of the martensitic phase, reducing the work hardening behaviour and promoting greater elongation to failure and thus higher erosion–corrosion rates. These results are discussed in light of the extensive literature on solid particle impact and corrosion by considering the influence of nano-scale phase changes which can often only be observed using transmission electron microscopy.

An investigation of the erosion–corrosion characteristics of ductile cast iron

The erosion–corrosion wear characteristics and mechanism of martensitic ductile cast irons with different alloying compositions in quartz slurries with different pH values were determined and analysed. The results indicated that the erosion–corrosion wear resistance of martensitic ductile cast iron would be increased not only with the pH values of the slurry and the erosion angle, but also with the addition of copper, nickel and chromium elements, respectively. A few of eutectic carbides would appear in the microstructures of ductile cast iron when the chromium element is added into this cast iron. However, these carbides would harm the erosion–corrosion wear resistance of this cast iron in acidic slurry. The addition of Ni, Cu, Cr elements and increase of Si element content would be helpful to improve the erosion–corrosion wear resistance of this cast iron in neutral and alkaline slurry, especially for chromium. Because the hardness of ductile cast iron could be remarkably increased by the occurrence of carbides when the chromium element was added. The erosion–corrosion mechanisms of the martensitic ductile cast irons were dominated by particles erosion wear in alkaline and neutral slurries, and by the interaction of particle erosion wear and medium corrosion in acidic slurry.

The erosion–corrosion behaviour of high velocity oxy-fuel (HVOF) thermally sprayed inconel-625 coatings on different metallic surfaces

The minimization of cost and the enhancement of reliability of rotating and stationary fluid machinery equipment that are subjected to highly erosive and corrosive environments is mandatory in the oil and gas production industries. This can be achieved by minimizing the material damage resulting from the combination of solid particle impingement and corrosion. The high velocity oxy-fuel (HVOF) process is one method of producing metallic coatings to protect metallic surfaces from high temperature, wear, and corrosive environments. Stainless steel components coated with Inconel-625 are very common in the oil/gas industry. In this study, the erosion–corrosion characteristics of HVOF thermally sprayed Inconel-625 powder coatings were evaluated when applied on three different metallic surfaces: (a) plain stainless steel (SS), (b) spot-welded stainless steel (SW-SS), and (c) a composite surface of stainless steel and carbon steel welded together (C-SS-CS). These coated surfaces were tested in a jet impingement rig under two fluid conditions: (i) free from added solids, (ii) containing 1% silica sand. Weight loss measurements were used to provide a measure of the amount of material loss that each coated surface experienced, and the influence of time during impingement testing was taken into consideration. The surface morphology and the elemental composition of the coating before and after the erosion–corrosion test were examined using the SEM and EDS techniques. The results indicated that the coating over both spot-welded and plain stainless steel surfaces exhibited a similar degree of weight loss. However, the coating on the composite surface experienced a greater degree of weight loss. Microscopic observations of the fracture surfaces showed that the metal removal of the tested surface was concentrated around the unmelted and the semi-melted particles of the deposit.

Erosion–corrosion behaviour of high-velocity oxy-fuel Ni–Cr–Mo–Si–B coatings under high-velocity seawater jet impingement

In this paper, erosion–corrosion characteristics of self-fluxing Ni–Cr–Mo–Si–B coatings deposited onto carbon steel (BS970 EN8) and stainless steel (UNS S31603) substrates using a commercial high-velocity oxy-fuel (HVOF) thermal spray process are reported. The coatings were studied in as-sprayed, vacuum-sealed (by polymer impregnation) and vacuum furnace fused conditions. In addition, comparisons of the HVOF coatings were made with an uncoated wrought stainless steel (UNS S31603). The erosion–corrosion characteristics were assessed under the influence of a high-velocity single-phase artificial seawater jet (without added solids), impinging perpendicularly onto the coating surface at 72 ms −1 flow velocity. Anodic polarisation tests were performed at both 18 and 50 °C to assess the in situ corrosion performance. Using static seawater results as a reference, the effects of the impinging flow on both the electrochemical response and the damage mechanisms are discussed in this paper. The application of cathodic protection (CP) reduced the extent of deterioration. The study showed the effect of sealing by polymer impregnation did not significantly alter the erosion–corrosion behaviour of the sprayed coating. However, there was an improvement in erosion–corrosion durability afforded by the post-fusion process. The mechanisms by which the improved performance of fused coatings is achieved are discussed.

Cavitation erosion–corrosion characteristics of laser surface modified NiTi shape memory alloy

In the presented work, the cavitation erosion–corrosion behavior of a nearly equiatomic NiTi alloy subjected to hot rolled, laser surface melting and laser gas nitriding (LGN) was investigated. Results show that the tested samples are very resistant to erosion damage. Secondary phases and inclusions are harmful to the erosion resistance of the alloy, and the interface between particles and matrix initiates the crack formation and material removal. A clean, compact microstructure with ultrafine grain, high work hardening ability and fatigue strength contributes to the improved resistance to cavitation erosion–corrosion of the laser surface melted NiTi alloy. The high resistance to erosion of the LGN sample is attributed to the high hardness of the TiN surface layer.