Experimental substantiation of the corrosion rate of pipe steel

2021 ◽  
pp. 407-411
Author(s):  
Михаил Андреевич Белостоцкий ◽  
Анатолий Михайлович Короленок
Keyword(s):  
Corrosion Rate ◽  
Pipe Steel ◽  
Experimental Studies ◽  
Steel Grade ◽  
Electrochemical Protection ◽  
Main Pipelines ◽  
17G1s Steel ◽  
Corrosion Pits ◽  
Corrosive Activity ◽  
Quantitative Indicators

Определяющее значение в развитии дефектности металла труб имеет коррозионный фактор, а также деградация механических свойств трубных сталей в процессе эксплуатации трубопроводов. Авторами приведены результаты экспериментальных исследований по оценке скорости коррозии и склонности к трещинообразованию трубных сталей, наиболее распространенных на длительно эксплуатируемых магистральных нефте- и нефтепродуктопроводах. Разработана методика определения количественных показателей коррозионно значимых параметров для обоснования вывода в капитальный ремонт трубопроводов на основе результатов натурных экспериментальных исследований скорости коррозии фрагментов трубной стали при различных условиях поляризации и коррозионной активности грунта. Объект исследования - фрагменты труб (пластины) 50×50×3 мм, изготовленные из стали марок 09Г2С и 17Г1С. Полученные результаты позволили сформулировать рекомендации по уточнению количественных критериев коррозионно значимых факторов для обоснования вывода трубопровода в капитальный ремонт: 1) необходимо учитывать марку трубной стали (установлено, что сталь 17Г1С на 20-30 % более устойчива к коррозии, чем сталь 09Г2С, особенно в части образования локальных повреждений - язв и питтингов); 2) при значениях удельного электрического сопротивления грунта менее 20 Ом⋅м скорость коррозии возрастает примерно на порядок независимо от марки стали и наличия системы электрохимической защиты. This work presents the results of experimental studies on the assessment of the corrosion rate and the cracking tendencies of pipe steels, most common in the main oil and oil product pipelines that have been used for a significant amount of time. A methodology was developed for determining quantitative indicators of corrosion-significant parameters to justify the overhaul of main pipelines based on the results of field experimental studies of the corrosion rate of pipe steel fragments under various conditions of polarization and corrosive activity of the soil. The object of the study is pipe fragments (plates) with the dimensions of 50×50×3 mm, made of steel with the grades 09G2S and 17G1S. The results made it possible to formulate recommendations for refining the quantitative criteria of corrosion-significant factors to justify the overhaul of the pipeline: 1) it is necessary to take into account the pipe steel grade (it was found that 17G1S steel is 20-30 % more resistant to corrosion than 09G2S steel, especially in the formation of local damages - corrosion pits and pittings); 2) at values of specific soil resistance less than 20 Ohm⋅m, corrosion rate increases by about an order, regardless of the steel grade and the usage of an electrochemical protection system.

The Calculation of the Thickness for Uniform Corrosion and Localized Corrosion in Steel Corrosion

2011 ◽  
Vol 255-260 ◽  
pp. 514-518
Author(s):  
Zheng Yi Kong ◽  
Shan Hua Xu ◽  
Yu Sheng Chen
Keyword(s):  
Corrosion Rate ◽  
Constant Temperature ◽  
Safety Assessment ◽  
Steel Corrosion ◽  
Localized Corrosion ◽  
Power Relationship ◽  
Uniform Corrosion ◽  
Experiment Data ◽  
Temperature And Humidity ◽  
Corrosion Pits

Because of the complexity of corrosion, the law of uniform corrosion and localized corrosion is still not clear,so it is difficult to assess their impact on the structure safety. In order to differ them and find their own law, we obtain a lot of corrosion specimens by ways of constant temperature and humidity, and then detect the size of corrosion pits by roughness tester. After that, the method for calculating the thickness of uniform corrosion and localized corrosion is proposed. Then the method is used to analyze the experiment data. The result indicates the thickness of uniform corrosion and localized corrosion all increase with the rate of corrosion, and they all show a power relationship with corrosion rate, so it will provide a basis for distinguishing them in safety assessment.

scholarly journals The mathematical models for cutting force calculation during structural and corrosion-resistant steels` parts processing

2019 ◽  
Vol 298 ◽  
pp. 00099
Author(s):  
Alexey A. Zhdanov ◽  
Oleg A. Kursin ◽  
Pham Xuan Bach
Keyword(s):  
Mathematical Models ◽  
Cutting Force ◽  
Experimental Studies ◽  
Additional Parameter ◽  
Corrosion Resistant ◽  
Cutting Force Components ◽  
Force Components ◽  
Quantitative Indicators ◽  
Force Calculation ◽  
Thermo Physical Properties

The paper shows that conventional mathematical models for calculating the cutting force components during the turning process, represented in reference guides on engineering, give drastic errors reaching 100 percent or more for various tool-workpiece couples. These errors interfere with applying reference values of the cutting force for any further calculations, equipment selection, workpiece positioning scheme, workpiece deformation value due to the elastic of the technological system elements during processing and etc., because of the insufficient reliability of the results of such calculations. The paper proposes mathematical models obtained as a result of experimental studies, which allow for increasing the accuracy of the calculation of the components of the cutting force by introducing an additional parameter – i.e., the value of thermo EMF of the test running into the calculation formulas. This approach enables to reduce the error in the calculation of the components of the cutting force up to ± 15%. In addition, the need for the development of specific mathematical models for various groups of materials machined is shown, which is due to the peculiarities of contact processes in the machining of various groups of steels, as well as to qualitative and quantitative indicators of the thermo-physical properties of the materials of tool-workpiece contact couples.

scholarly journals Study of corrosion stability of a cement stone in magnesia aggressive environment

Georesursy ◽  
2019 ◽  
Vol 21 (3) ◽  
pp. 73-78 ◽  
Author(s):  
Farit A. Agzamov ◽  
Almaz N. Makhmutov ◽  
Elvira F. Tokunova
Keyword(s):  
Oil And Gas ◽  
Experimental Studies ◽  
Corrosion Damage ◽  
Cement Stone ◽  
Corrosion Mechanism ◽  
Corrosion Stability ◽  
Factors Affecting ◽  
Aggressive Environment ◽  
Mgcl2 Concentration ◽  
Quantitative Indicators

One of the main tasks in the construction of oil and gas wells is to ensure the high quality of well casing. It is especially difficult to get it in wells, in sections of which there are salt-bearing strata. From the salts, the most dangerous are magnesia salts, which can lead to the destruction of the stone based on portland cement within a few months. The report presents the results of experimental studies on the corrosion of cement stone in aggressive magnesia media.The quantitative indicators reflecting the degree of damage to the stone are taken as the thickness of the damaged layer and the coefficient of stone resistance, characterized by the ratio of the ultimate strength of stone samples for compression or bending stored in an aggressive environment to the strength of control samples at the same time of hardening. In the course of the research, the corrosion resistance of the cement stone to the magnesian corrosive environment was assessed, after 8 weeks in a medium with a constant concentration of MgCl2. In addition, the effect of MgCl2 concentration on the cement stone corrosion mechanism was investigated. The use of the palygorskit additive and the reduction of water cement ratio to reduce the porosity of the cement stone and reduce the rate of corrosion damage are proposed. The kinetics and the main factors affecting the corrosion process are considered, and the x-ray structural analysis of corrosion products and unaffected cement stone is carried out.

scholarly journals Effectiveness of the use of sanifying set «SanStim» for disinfection eggs before incubation

2018 ◽  
Vol 20 (83) ◽  
pp. 226-229
Author(s):  
T.I. Fotina ◽  
H.A. Fotina ◽  
I. V. Kovalenko
Keyword(s):  
Growth And Development ◽  
Bacterial Infections ◽  
Guanidine Hydrochloride ◽  
Experimental Studies ◽  
Natural Resistance ◽  
Control Group ◽  
Bactericidal Action ◽  
Source Of Infection ◽  
Wide Range ◽  
Corrosive Activity

The most vulnerable place in poultry farms is incubation, microorganisms are able to survive the entire period of incubation and penetrate through the eggshell, to be the source of infection with embryos, to affect the reduction of the percentage of conditional young birds, growth and development in the early days of cultivation. The accumulated pathogenic microflora negatively affects the state of the immune system of the bird. Contaminated with conditionally pathogenic and pathogenic microflora egg is the main link in the transmission of all bacterial infections. In Ukraine, for the pre-incubation treatment of eggs, sodium hydroxide, formalin, chloramine, persicum C. are used. These agents exhibit bactericidal properties, but are toxic, have corrosive activity and are carcinogens. The «SunTime» kit consists of polyhexamethylene guanidine hydrochloride and a mixture of organic acid salts (lemon, amber, and apple). These substances provide an effective bactericidal action against a wide range of bacteria, are safe for poultry embryos and personnel, have a stimulating effect on the growth and development of the embryo, provide a prolonged bactericidal action. The purpose of the study of the effectiveness of a complex ecologically safe sanitizers set «SunSim», its application for pre-incubation processing of chicken eggs. In experimental studies, two groups were formed, each with n = 250. In order to disinfect the surface of the shell of the incubation egg, two times aerosol treatment of the experimental group using 0.3% of SunStim was carried out, the first time the sanitation of the incubation eggs was carried out before the laying on the incubation cabinet, the exposure was 40 minutes, the second final treatment was carried out on the 18th day of incubation, to extract, a working solution of organic acids (amber, lemon and apple) to stimulate embryonic viability and increase the natural resistance of the embryos. For the control group, formalin was used. After two times of the sanation of the incubation eggs with the SunStim set, the percentage of decontamination of the shell surface of the incubation eggs was 99.1 ± 0.5%. While analyzing the results of the incubation waste category of «dead and drowning» by 3,6% less compared with the control, and the category of «crippled» was not observed. The use of the SunStim set improves the quality of surface treatment of the shell of incubation eggs, increases the incubation eggs output by 4.5-5.0%, the average body weight of the received young animals in experimental groups exceeds control by 4%.

scholarly journals Research on Corrosion Damage Evolution of Aluminum Alloy for Aviation

2020 ◽  
Vol 10 (20) ◽  
pp. 7184
Author(s):  
Zhigang Gao ◽  
Yuting He ◽  
Sheng Zhang ◽  
Tianyu Zhang ◽  
Fei Yang
Keyword(s):  
Aluminum Alloy ◽  
Corrosion Rate ◽  
Early Stage ◽  
Three Dimensional ◽  
Gumbel Distribution ◽  
Corrosion Damage ◽  
Environmental Data ◽  
Evolution Law ◽  
Immersion Corrosion ◽  
Corrosion Pits

Based on the real annual average value of atmospheric environmental data in the Wanning area of Hainan Province in China by selecting 7075 ultra-high-strength aluminum alloy specimens for aviation, a new corrosion solution was designed and the traditional alternate immersion corrosion method of using the alternate immersion corrosion test box was improved to simulate the environment of the internal structure of the aircraft. On this basis, two kinds of corrosion damage parameters, the depth of corrosion pits and corrosion rate, were quickly and accurately obtained by the three-dimensional profile of the specimen and binarization images’ method. The optimal linear regression equation combination of pitting depth and corrosion rate was established, and the dynamic evolution equation of the depth of corrosion pits and corrosion rate was obtained. The results showed that: The depth of corrosion pits in the early stage of corrosion (8 h and 24 h) obeyed the Gumbel distribution and Weibull distribution, respectively, and the later stage (48 h, 72 h, 96 h, and 120 h) conformed to the normal distribution; the depth of corrosion pits’ evolution law was in the form of double straight lines and the corrosion rate evolution law was in the power function form (y = a × xb); and the depth of corrosion pits changed rapidly in the early stage and gradually slowed down in the later stage, while the corrosion rate was just the opposite.

Selection of an inhibitor for corrosion protection of the inter-pipe space of the underwater transition of the “Pavlodar – Shymkent” oil pipeline through the Irtysh river

2020 ◽  
Vol 25 (4) ◽  
Keyword(s):  
Corrosion Rate ◽  
Water Samples ◽  
Corrosion Inhibitors ◽  
Pipe Steel ◽  
Corrosive Environment ◽  
Static Mode ◽  
Oil Pipeline ◽  
Protective Ability ◽  
Irtysh River ◽  
The Irtysh River

The article presents a study of the protection degree of a model inhibiting solution samples in order to select the optimal inhibitor for protecting the annular space of the underwater crossing of the “Pavlodar-Shymkent” main oil pipeline across the Irtysh river built by the pipe-in-pipe method. In order to determine the corrosion rate of pipe steel we used witness coupons made of 17G1S steel similar to the steel of the pipeline in operation. Gravimetric and electrochemical methods were used to study the inhibitory properties of inhibiting solutions consisting of corrosion inhibitors Rancor 1101, CRW 82590, VpCI 337, ForeRP 40, and water from the Irtysh river. We carried out comparative analysis of the corrosion rates of pipe steel and the protection degree of inhibitor solutions at various concentrations. Any of inhibitors in concentrations from 50 to 750 ppm, in static mode, do not provide a protective effect, at which steel 17G1S shows increased resistance in a corrosive environment of water samples from the river Irtysh (reduction of the average corrosion rate to 0.005 mm/year according to GOST). Comparing the protective ability of corrosion inhibitors in a corrosive environment from water samples from r. Irtysh, it has been exhibited that the Baker Hughes inhibitor CRW 82590 shows the best protective ability, in static mode during gravimetric studies 80,38% (500 ppm) and 82,52% (750 ppm), in static mode during electrochemical studies 85,90% (500 and 750 ppm).

Corrosion Conditions Analysis of In-Service ACSR Overhead Lines

2013 ◽  
Vol 446-447 ◽  
pp. 753-758 ◽  
Author(s):  
Yuan Jing Deng ◽  
Jun Chao Yu ◽  
Kai Quan Xia ◽  
Lin Yang
Keyword(s):  
Corrosion Rate ◽  
Corrosion Products ◽  
Operating Environment ◽  
Overhead Lines ◽  
Steel Core ◽  
Core Matrix ◽  
Corrosion Pits

The corrosion conditions of in-service aluminum conductor steel reinforced (ACSR) overhead lines in typical climate were studied by using macroscopic and microscopic methods. According to its operating environment, the corrosion causes were also analyzed. It is found that the corrosion of the outer aluminum stranded conductors is more serious than other parts. And partial corrosion pits have been found on the outer layers of aluminum stranded conductors. While there is no obvious corrosion appeared on the steel core matrix. Additionally, corrosion products can reduce the corrosion rate of aluminum stranded conductors but accelerate corrosion of the steel core. Through this research, more attention should be paid to monitor the aluminum stranded conductors.

Effect of Reeling and pH on the Fatigue Crack Growth Behavior of C-Mn Line Pipe Steels Exposed to Acidizing Environments

2016 ◽  
Author(s):  
Apurva Batra ◽  
Jonathan Bowman ◽  
Weiwei Yu ◽  
Ramgopal Thodla ◽  
Colum Holtam ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Corrosion Rate ◽  
Crack Growth ◽  
Pipe Steel ◽  
Small Scale ◽  
Crack Growth Behavior ◽  
Line Pipe ◽  
Frequency Scan ◽  
Line Pipe Steel

Acidizing treatments are typically performed intermittently during the life of a well. However, more recently there has been a desire to perform an increased number of acidizing treatments in order to improve production. The acidizing treatments typically involve highly corrosive acids, such as hydrofluoric (HF), hydrochloric (HCl) and acetic acid, which are known to cause significant corrosion, but could also lead to environmentally assisted fatigue and fracture. A study was performed to evaluate the effect of cyclic plastic strains associated with reeling installation on the subsequent fatigue crack growth rate (FCGR) behavior of welded C-Mn line pipe steel in acidizing environments. The influence of the pH of the acidizing environment on the FCGR performance was also investigated as part of this study. This paper compares the results of FCGR tests on as-welded (i.e. unstrained) pipe with those from strained and aged welds, as well as quantifying the effect of the pH of the acidizing treatments. Strained and aged welds were obtained by subjecting the as-welded pipe to 4 cycles of full-scale reeling simulation, with each cycle corresponding to 1% strain. Small-scale compact tension (CT) specimens were then extracted from the strained welds and aged at 250°C for one hour to simulate strain aging. FCGR tests were performed in spent acid with corrosion inhibitor on specimens notched in the parent pipe (PP), heat affected zone (HAZ) and weld centerline (WCL) in both the as-welded and strained and aged condition. The majority of the tests were conducted at room temperature (RT) along with a select few tests at elevated temperature (165°F / 74°C). Overall, the results of frequency scan tests indicated that reeling did not have a significant effect on the FCGR behavior of welded C-Mn line pipe steel in spent acid with inhibitor, regardless of which microstructure was sampled. Frequency scan FCGR tests were also performed on strained and aged samples extracted from the intrados side of the strained welds and notched in the PP, HAZ and WCL to investigate the influence of pH on FCGR behavior. Tests were performed in spent acid with inhibitor at RT, with the pH ranging from 3.7 to 6. The observed FCGRs were higher than in air and all microstructures exhibited a frequency dependence (i.e. the FCGR increased with decreasing frequency). At pH = 3.7, the maximum FCGR was approximately 30 times higher than in air and at pH = 5 the FCGR increased to approximately 80 times higher than in air. However, a further increase in pH to 6 produced a decrease in FCGR. The increase in the maximum FCGR is believed to be due to the decrease in corrosion rate with increasing pH leading to reduced crack closure/blunting. However, as the pH increased to around 6, the corrosion rate decreased substantially, which is likely due to a substantial decrease in the concentration of hydrogen being generated, resulting in a lower FCGR. Paris curve FCGR tests were subsequently conducted on strained and aged samples at 0.1Hz.

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