Soil Corrosion Research Articles

Estimation of Aquifer Protective Capacity, Soil Corrosivity and Dar-Zarrouk Parameters in Kaura Area of Kaduna State, Nigeria

This study presents an estimation of aquifer protective capacity, soil corrosivity and Dar-Zarrouk parameters for Kaura area of Kaduna State in northern Nigeria. Electrical resistivity sounding data and borehole pumping test data obtained from 20 locations within the LGA were obtained and used for this study. The geoelectric data exhibited curve types generally consisting of H, HA, KH or K-A-H types from which five-layer lithology were delineated across the entire study area. Well yield varies from 16 – 400 litres/min, pumping rate ranges from 16 to 140 l/min, drawdown varies from 1 – 22m, while specific capacity ranged from 1 – 95 litres/min. The aquifer protective capacity characterization was based on values of longitudinal unit conductance of the overburden, and 35% of the locations showed good protective capacity, while the remaining 65% exhibited moderate protective capacity. From the soil corrosivity evaluation, the upper soil layers were classified as moderately corrosive at one location, four locations were marked as slightly corrosive, while the remaining locations were found to be practically non-corrosive. Based on thicknesses and resistivities of the overburden layers, Dar-Zarrouk parameters were determined. The reflection coefficient ranged from 0.29 to 0.92, resistivity contrast occurred between 0.35 to 25.38, while the coefficient of anisotropy ranged from 0.70 to 3.84 with mean value of 1.57. Values above 1.0 are generally considered high and they occurred more toward the western part of the area than the middle and eastern parts. Both the longitudinal unit conductance map and coefficient of anisotropy map were generated for the area.

Corrosion effects on the granular nano mechanical properties of buried cast iron

Considerable research reported in literature shows that corrosive soil degrades the bulk mechanical properties of buried cast iron pipes due to cracks anddegradation of microstructure. The nanomechanical properties of the grains of cast iron pipes can also be affected by the corrosion before bulk mechanical properties. However, the influence of soil corrosivity on the nanomechanical properties at the granular level is remained unresolved to date. This paper addresses this gap and presents the nanomechanical measurements performed on the corroded cast iron specimens and the maximum degradation was quantified.Specimensafter 545 days of burial in corrosive soil conditions were tested by nanoindentation for determining the degradation of their nanomechanical properties. The analysis of the test results showed a significant reduction in the nano elastic and nano hardness of the grains of the cast iron due to the diffusion of hydrogen from the surrounding corrosive soil environments. The high corrosion rates were found proportional to inducing the maximum degradation of the nano elastic modulus of the grains. A relation for the prediction of maximum degradation of the nano elastic modulus of the grains as a function of corrosion rates, pH and moisture content of the clay soil was also developed. The finding of the current research is significant as it shows that apart from bulk mechanical properties, the nanomechanical properties of cast iron grains can be degraded by corrosive environments which in turn can affect the service life. Furthermore, understanding the mechanical science of the degradation of the grains can assist in manufacturing sustainable ferrous pipes resistive to corrosion soils.

Combine Shot Penning (SP) and Ultrasonic Impact Treatment (UIT) for Soil Corrosion Buckling Strength Enhancement of AA 2014-T4

The aim of this work is to investigate the effect of soil corrosion on the critical buckling load of circular columns made of 2014-T4 aluminum alloy. In this work, 24 specimens were used and buried in the soil for 120 days. The samples divided into two groups (12 columns with corrosion before shot penning (SP) and ultrasonic impact treatment (UIT), and 12 columns with corrosion after combined surface treatments (SP+UIT)). The experimental1results revealed1that the corrosion negatively1affects the mechanical properties1of the material, and the1reduction percentage (R%) for1ultimate tensile strength (UTS) and1yield strength (YS) was (1.95% and 4.57%) respectively. After combined surface treatments (SP+UIT) for the corroded columns, the ultimate1tensile strength (UTS) and yield1strength (YS) were improved with (2.42%, and 2.87%) respectively. Perry-Robertson, Rankine, and ANSYS were used to estimate the critical buckling load (Pcr) and compare it with the experimental results. Rankine and Perry's formulas have been achieved a good agreement with the experimental without and with (1.5) factor of safety respectively. While ANSYS gave satisfactory prediction with a safety factor of (2.2, and 2.7) and (1.9, and 2.7) for long and intermediate columns before and after (SP+UIP) respectively.

Corrosion of cast iron pipelines buried in Fraser River silt subject to climate-induced moisture variations

Experiments were carried out to characterise the influence of soil water retention properties on the corrosion of a cast iron specimen buried in Fraser River silt. The corrosion rates were measured at different degrees of saturation using standard corrosion tests, along with separate water retention tests for the Fraser River silt. Building on previous work on this topic, a numerical model solving moisture flow, oxygen diffusion, electrical conductivity and their coupled influence on metallic corrosion in unsaturated soil was developed. The experimental data and preliminary numerical modelling results were then used as inputs to a field-scale numerical model to examine climate-induced moisture migration around a pipeline and the resulting levels of corrosion. The time-dependent corrosion mass loss and the resulting loss in pipe wall thickness of a buried pipeline were modelled, and it was demonstrated that the cyclic climatic variations predominantly perturb the corrosion rates during the initial cycles, and subsequently a gradual corrosion rate arises depending on general climatic conditions. Further analysis of the influence of electrical resistivity on the levels of corrosion revealed that a decrease in resistivity due to effects such as seawater intrusion or naturally saline soils may result in a significant increase in the levels of localised corrosion.

Impact of Soil Characteristics and Moisture Content on the Corrosion of Underground Steel Pipelines

External corrosion of underground steel structures is a major environmental and economic burden. The severity of such detriment depends on many factors that encompass: soil properties, moisture content, total soluble salts, the presence of microorganism, and method of metal protection. The investigative endeavor put forth bestows prime attention to the effect of soil attributes and moisture loading on the corrosion of submerged steel structures. The exposure to four discrete soil types (saline, clay, calcareous and sand) was explored in this study. Electrochemical linear polarization measurements were deployed as a means of assessing corrosion performance. The results revealed corrosion event severities endured by steel to be strongly underpinned by soil overall characteristics and moisture content in the vicinity. Corrosion potentials were found to possess more negative values with rising soil moisture content. The corrosion rate was rendered consistently peaking in coincidence with 20% (by wt.) moisture contents pertinent to sand, and with a corresponding 25% content in clay, saline and calcareous soils. The corrosivity of soil at the critical soil moisture content increases in the order: calcareous < clay < saline < sand. Scanning electron microscope observations confirmed the existence of corrosion product (loose and porous) with evidence of pitting attack. EDX analysis proved that the corrosion product was mainly composed of iron oxide. Plate counts revealed the absence of bacteria which warrants the exclusion of any microbial detriment as a contributing factor that might underpin corrosion.

Biological resistance of polymeric pipeline materials

Currently, the problems of biodeterioration are becoming crucial in assessing the durability of buildings and structures for various purposes. Metal, reinforced concrete, polymer, and other products and structures, including the pipelines for water and gas supply, water disposal, etc., are subject to biodeterioration. Biodeterioration processes in construction are considered in many scientists and specialists’ works. From their works it follows that changes in the properties of pipeline materials as a result of microbiological corrosion can lead to a shutdown of facilities, accidents. Materials are exposed to biological and mechanical influences in natural conditions, therefore, the need to study various factors: the chemical composition of the materials used, density, temperature range, and the field of these materials’ use of relevant.The article presents the studies’ results of soil corrosion of samples from polymer pipes. The descriptions of pipeline materials from different manufacturers are given., The samples were selected for the research from thermoplastic polymers based on polyethylene and polypropylene, including those reinforced with fiberglass. The samples were aged in various layers of soils belonging to the groups of chernozems and loams. Methods for assessing the materials’ accreting degree by microorganisms are given. In the course of the research, the species composition of microorganisms accreting on the samples during the tests was established; the data on changes in the samples’ mass content are revealed. The results can be used to assess the biological resistance of pipeline materials.

Comparison of AC Corrosion of X80 Steel in Real Soil, Soil Extract Solution, and Simulated Solution

Corrosion of X80 steel induced by alternating current (AC) in acidic red soil (ARS), acidic red soil-extracted solution (SES), and acidic red soil-simulated solution (SSS) has been investigated. Corrosion of the steel coupons is dramatically aggravated by AC. The kinetic relationship between the corrosion rate (CR) and the AC density (JAC) in the three testing media all follows a model function, CR= αJAC + β. Grey relational analysis shows that the correlation coefficient between corrosion rates with JAC in SES and ARS is 0.614; however, the coefficient between those in SSS and ARS is only 0.484, which indicates that SES is more suitable for the evaluation of soil corrosion than SSS.

Potensi korosivitas pada tanah endapan dataran banjir sungai Citarum di Karawang, Jawa Barat

Corrosion is the biggest problem for equipment that utilised metal, including infrastructure. Corrosion is degradation of metal quality due to the chemical reaction of a metal with the surrounding environment, including soil. Important indicators that contribute to the classification of the rate of corrosivity in soils are water content, pH, types of minerals, soil resistivity values and other chemical-physical parameters. The research area is in Anggadita Village, Klari District, Karawang Regency, West Java Province. Drilling and sampling locations are approximately 300 meters from the Citarum river. The article aimed to investigate between physical and chemical characteristics (soil texture, type of resistivity, pH) of weathered sediments of the Citarum river flood plain to the classification of soil corrosivity. Soil classification in the study area is fine grained and classified into silt with high plasticity (MH-ML) and clay with high plasticity (CH). The results of the analysis of the distribution of potential soil corrosivity in the study area indicate that the level of soil corrosivity is at a high level of corrosive to very high corrosive

Role of Mexican Clay Soils on Corrosiveness and Stress Corrosion Cracking of Low-Carbon Pipeline Steels: A Case Study

This work analyzed the physicochemical effect of different types of Mexican clay soils on corrosion and stress corrosion cracking (SCC) behavior in contact with X60 and X65 steels. Four soils were obtained from the right of way land in southern Mexico at 1.5 m depth close to pipelines. Two soils were from the state of Oaxaca (SO1 and SO2), and two others from the state of Veracruz (SV1 and SV2). Physicochemical and textural analysis of soils was performed and correlated to SCC susceptibility and corrosion mechanism. It was observed that soil texture might be related to corrosivity. A texture index (ratio between sand and silt + clay), which was seen to have a relationship with the corrosive tendency of soils, was estimated. It showed that soil with a higher index (SV1) has a higher corrosion rate. Electrochemical impedance spectroscopy and polarization curves were performed and correlated to the corrosion rate and the SCC susceptibility of steels. Steels exposed to SV1 soil exhibited a higher corrosion rate related to a higher content of chlorides and acid pH than those seen in other soils, which resulted in the pitting of such steels. Two types of corrosion were observed. Soils from SV1 and SV2 generated pitting, and soils from SO1 and SO2 produced general corrosion. Inclusions caused pitting in the gauge section of X60 and X65 steels exposed to SV1 soil by anodic dissolution. Galvanic coupling between inclusions and the base metal and dissolution of the inclusions might have enhanced the nucleation of pits at these sites. SCC susceptibility was evaluated using slow strain rate tests (SSRT). After SSRT, the fracture surfaces were analyzed through scanning electron microscopy. The SCC index obtained from SSRT indicates that X60 and X65 steels exhibited good resistance to SCC. A highly corrosive soil, such as SV1, causes the formation of pits instead of cracks, which is attributed to the dissolution process; however, lower SCC indexes were obtained for this system. The higher corrosion resistance of X60 steel is related to a more homogenous microstructure and a higher content of elements, such as Ni and Cr, than those of X65 steel that decrease the corrosion rate.

Fracture toughness degradation of cast iron due to corrosive mediums

Corrosion induced degradation of fracture toughness in buried cast iron pipes is a serious concern for structural integrity and smooth operation of buried pipes. External corrosion of pipes is fundamentally governed by the corrosivity of soil which may vary depending on the type of soil and its specific properties. While the corrosion assessments of pipes buried in soil can provide realistic behaviour, the investigations of pipe corrosion in simulated soil solutions are becoming popular due to simplicity. Limited studies are reported in the literature using simulated soil solution for determining the effect of corrosion on the fracture toughness of cast iron specimens. However, it is important to evaluate the outcomes based on the solutions benchmarking against the corrosion from the realistic soil environment. This study investigates the corrosion of cast iron specimens in both the acidic soils and the simulated soil solutions of the same varying pH for 365 days. The fracture toughness testing of the corroded specimens taken out from both the real and simulated soil solutions was performed at 180 and 365 days, respectively. The fracture toughness (KQ) values of the corroded specimens of the two soil mediums were compared and correlated statistically. Moreover, relations for the variation in KQ of specimens as a function of corrosion rates, and pH with time were developed for soil and simulated soil solution. The findings of this research have practical applications for the predictions of the service life of buried cast iron pipes.

Beijing-Tianjin-Hebei carbon steel soil corrosion rate map based on BP-GIS

Beijing-Tianjin-Hebei carbon steel soil corrosion rate map based on BP-GIS

Utilization of waste spent alumina catalyst and agro-waste rice husk ash as reinforcement materials with scrap aluminium alloy wheel matrix

In this study, an attempt was made to utilize waste products from industries to develop composite materials. In the present study, car scrap aluminium alloy wheels (SAAWs) was used as matrix material. Waste rice husk ash (RHA) was collected from a rice mill to utilize as a primary reinforcement material. Spent alumina catalyst (SAC) waste was used as a secondary reinforcement material. SAC was collected from the oil refinery industry. These wastes produced lots of soil and air pollution. However, by utilizing these wastes, some environment pollutions can be reduced. Car scrap aluminium alloy wheels (SAAWs) based composite material was developed using RHA as primary reinforcement material and SAC as a secondary reinforcement material by stir casting technique followed by squeeze pressure on the universal testing machine (UTM) in mushy zone. Microstructure behaviour shows a uniform distribution of RHA and SAC in a recycled aluminium alloy matrix. Mechanical properties such as hardness, ductility, compressive strength and tensile strength were improved using RHA and SAC as reinforcement material simultaneously in SAAWs matrix material. Thermal expansion behaviour, soil degradation test and corrosion loss were also observed to see the effect of agro-waste RHA and SAC in recycled aluminium alloy.

Microstructure and long-term corrosion of archaeological iron alloy artefacts

The smithing skills of craftsmen in the western Mediterranean during the early Iron Age can be determined by studying the microstructure of oxidised iron items. While some ghost structures have already been identified in dense corrosion products, their formation has not always been explained. Four objects from southern France were analysed using optical microscopy, X-ray diffraction, micro-Raman spectroscopy and field-emission scanning electron microscopy coupled with energy dispersive spectroscopy and electron backscatter diffraction. The role of microstructure, grain boundaries, cracks, species diffusion through oxides in soil corrosion and the initial microstructure are discussed. An additional parallel degradation mechanism (graphitisation) was experimentally revealed.

Microbiologically influenced corrosion: a review of the studies conducted on buried pipelines

AbstractBuried pipelines are essential for the delivery of potable water around the world. A key cause of leaks and bursts in these pipelines, particularly those fabricated from carbon steel, is the accelerated localized corrosion due to the influence of microbes in soil. Here, studies conducted on soil corrosion of pipelines' external surface both in the field and the laboratory are reviewed with a focus on scientific approaches, particularly the techniques used to determine the action and contribution of microbiologically influenced corrosion (MIC). The review encompasses water pipeline studies, as well as oil and gas pipeline studies with similar corrosion mechanisms but significantly higher risks of failure. Significant insight into how MIC progresses in soil has been obtained. However, several limitations to the current breadth of studies are raised. Suggestions based on techniques from other fields of work are made for future research, including the need for a more systematic methodology for such studies.

Statistical analysis of spatial distribution of external corrosion defects in buried pipelines using a multivariate Poisson-lognormal model

It is well recognised that the severity of pipeline external corrosion is highly related to the corrosivity of the surrounding soil environment. However, in practice, the explicit effects of the soil corrosivity variables on the spatial distribution of external corrosion defects are largely unknown. This paper presents a novel modelling and predicting approach for pipeline external corrosion defect count data in terms of spatial patterns using on a multivariate Poisson-lognormal (MVPLN) model. The MVPLN model can account for the over-dispersion and unobserved heterogeneity of the defect count data, as well as consider the stochastic correlation between corrosion defects with different spatial patterns. The developed model is applied to a pipeline inspection dataset consisting in-line inspection (ILI) data and corresponding soil corrosivity measurements. Its performance is validated by using cross-validation. A comparison study shows that the MVPLN model provides superior modelling results for the spatial distribution of external corrosion defects over the commonly used univariate count data models. In addition, the obtained model coefficients of the soil corrosivity measurements are discussed, and their estimated impacts on the spatial patterns of corrosion defects are verified qualitatively. The potential application to assess the corrosion severity of non-piggable pipeline segments is further demonstrated.

Impact factor analysis, prediction, and mapping of soil corrosion of carbon steel across China based on MIV-BP artificial neural network and GIS

Q235 carbon steel is one of the most widely used carbon steels, and soil corrosion and failures of it caused accidents, casualties, and great financial losses. Corrosion of Q235 carbon steel differed in spatial because of spatial variation in soil environmental factors. However, the national scale spatial pattern of soil corrosion of Q235 carbon steel across China has not been explored. The values of 12 impact factors, corrosion rate, and pitting corrosion rate at 25 sites covered all soil types in China were collected. Mean impact value (MIV) algorithm and back propagation artificial neural network (BP ANN) were combined and applied in the impact factor analysis. Prediction models for corrosion rate and pitting corrosion were developed based on BP ANN. The proposed prediction models and information about soil properties with high resolution (1 km × 1 km) were used in the prediction of corrosion rate. Based on geographical information system (GIS), the national scale spatial pattern of soil corrosion of Q235 carbon steel across China were analyzed. The water content and pH were of the largest influence (|MIV| > 0.522) on both corrosion rate and pitting corrosion rate. For prediction models of corrosion rate and pitting corrosion rate, the predicted values were close to the measured values. Corrosion rates were of higher spatial differences, ranged from 0.632 to 5.181 g/(dm2·a). Pitting corrosion rates in the northeast were higher than other areas, which might be caused by higher values of total salt content, organic matter, and total voidage. Average corrosion rate in soil type 1 (1.161 mm/a) was nearly two times of that in soil type 2 (0.610 mm/a) and over three times of that in other types, indicating that corrosion rate varied largely among different soil types. The importance of 12 impact factors of corrosion of Q235 carbon steel were evaluated, and the national scale corrosion rate and pitting corrosion rate in China were predicted and mapped for the first time. Both pitting corrosion rates and corrosion rates were of strong spatial variation.

Cathodic protection on stuctures of carbon steel using sacrificial anode methode for corrosion control

The pipes for land or sea are generally made of carbon steel and susceptible to corrosion. Cathodic protection can be used to control metal corrosion in water and soil. Cathodic protection is a metal surface protection system bypassing adequate direct current to the metal surface and converting sacrificial anode area on the metal surface into cathodic region. The aim of this research was to study the effect of cathodic protection in controlling the corrosion rate of carbon steel and determine the best immersing time for sacrificial anode in 25,000 ppm sodium chloride solution to protect the cathode. Zinc was used as the sacrificial anodes for the cathodic protection. Then, the effect of immersion time (10, 20, and 30 days) and distance of the anode from the cathode (1, 2, and 3 cm) were investigated. The best protection for corrosion was obtained at immersion time of 10 days and electrode distance of 1 cm, allowing corrosion rate of 0.694 mpy with an efficiency of 81.8%.

The effects of Cl−and direct stray current on soil corrosion of three grounding grid materials

PurposeThe purpose of this paper is to study the effects of Cl−and direct stray current on the soil corrosion of three grounding grid materials.Design/methodology/approachThe electrochemical corrosion properties of three grounding grid materials, which include the Q235 steel, Q235 galvanized flat steel and copper, were measured by means of the weak polarization curve method and electrochemical impedance spectroscopy; the corrosion rate of specimens was calculated using the weight loss method; and the specimen surfaces were characterized using the scanning electron microscopy, energy-dispersive spectroscopy and X-ray diffraction analysis.FindingsResults showed that both factors, Cl−and direct stray current, can accelerate the corrosion rate of grounding grid materials. The magnitude of DC stray current density affected the mass transfer type and response frequency of the anode and cathode reaction of grounding materials, while the Cl−contents of the soil only affect the mass transfer rate of the electrode material from the electrochemical impedance spectroscopy diagrams. The electric field generated by the DC stray current caused Cl−directed migration. The larger the DC stray current density, the greater the diffusion process and the greater the weight loss rate of the grounding grid materials that would have a logarithmic relationship with the Cl−content at the same DC stray current density. The corrosion resistance of the three materials is copper &gt; Q235 galvanized flat steel &gt; Q235 flat steel.Originality/valueThe paper provides information regarding the relationship among Cl−, direct stray current and corrosion of three grounding grid materials by means of electrochemical impedance spectroscopy. Meanwhile the weight loss rate is the logarithmic relationship with the Cl−content, which is useful for understanding the corrosion mechanism of Q235 steel, Q235 galvanized flat steel and copper under the condition of Cl−and direct stray current in soil.

A Classification Approach for Corrosion Rating of Soil to Buried Water Pipelines: A Case Study in Budhanilkantha-Maharajganj Roadway Areas of Nepal

The present study was focused to estimate six characteristics of soil specimens taken from 0.3 to 1.5 m sampling depth of six sampling sites of Budhanilkantha-Maharajganj roadsides using standard methods, and was assessed their corrosive nature to the buried-metallic pipelines using an empirical corrosion rating model. The estimated soil pH, moisture, resistivity, redox potential (ORP), chloride and sulfate ions were 6.4-7.9, 7-45%, 4.5 × 103-45.5 × 103 Ohm. cm, 317-514 mV (SHE), 12-86 ppm, and 40-294 ppm, respectively, in all the soil sample specimens. The experimental results indicated that the soils could be rated as mildly corrosive to less corrosive groups to the buried galvanized-steel and cast iron pipes in the study areas. A good positive or negative correlation coefficient between resistivity, moisture, chloride and sulfate contents implies that these soil parameters have an equal contribution to the rating of soil corrosivity. A polyethylene-sheet wrapping (i.e., encasement) around the galvanized-steel and cast iron water pipelines or the use of non-conducting materials of gravel/sand around the burying ground could be sufficient for the extension of their life up to 50 years or more. The empirical model is successfully applied for the corrosion rating of soil samples and could be progressive in the future for soil corrosion rating of soils to the underground waterworks. Present findings would be insightful and suggestive in making the corrosive land maps of the studied areas which would be helpful for the potable water pipeline works in other urban areas of Nepal.

黄土高原土壤团聚体稳定性及抗蚀性能力经度变化特征

黄土高原土壤团聚体稳定性及抗蚀性能力经度变化特征