St3 Steel Research Articles

Myrtus communis extract: a bio-controller for microbial corrosion induced by sulphate reducing bacteria

ABSTRACT This study aimed to study the inhibitory effect of the Myrtus communis extract on the microbiologically influenced corrosion (MIC) induced by sulphate reducing bacterial (SRB) consortium in the cooling tower water. The SRB consortium was grown on the surface of the st37 steel and its effects on the surface corrosion were evaluated. The results of electrochemical measurements and microscopic observations revealed that the extract could significantly reduce the corrosion by inhibiting the SRB biofilm formation. The addition of the 0.781 mg ml−1 of the extract into the SRB medium led to a considerable reduction (about seven times) in the corrosion process of the st37 steel and kept it at an almost constant value. Based on Gas chromatography-mass spectrometry analysis, 2-Furancarboxaldehyde, 5-(hydroxymethyl) (42.396%) was the most abundant compound identified in the plant extract. The molecular identification has proved that most population of SRB consortium was related to Desulfovibrio vulgaris species.

The improvement of surface quality characteristics after mechanical treatment by pulse laser radiation

The purpose of this article is to study the possibilities of pulse laser radiation to change the microgeometry of the surface formed by the mechanical treatment. An ordinary sample of carbon structural steel St3 is processed by a pulse laser with an active medium in the form of an yttrium-aluminum garnet alloyed with neodymium ions. The results of a complete factor experiment with three variable parameters of laser radiation modes are described in the article. For each set of parameters, 8 values of the controlled parameter (sample surface roughness) are randomly measured to reduce the final statistical error. Treatment modes reducing the surface roughness by at least 2 times were determined in the article. It was noticed that these treatment modes also do not get a fairly smooth surface without open pores. It may indicate the possibility of more detailed optimization of the treatment mode for a given surface by changing the space, time and energy parameters of the laser pulse.

Bactericidal properties of a combined corrosion inhibitor in the presence of SRB

The bactericidal properties of the combined inhibitor with respect to two types of Desulfovibrio desulfuricans and Desulfomicrobium sulfate-reducing bacteria were studied. The effect of the inhibitor on the number of bacterial cells and the formation of hydrogen sulfide in Postgate nutrient Postgate “B” was evaluated. It has been shown that the combined inhibitor exhibits a bacteriostatic effect on to sulphate-reducing bacteria. It was revealed that the degree of suppression of the number of microorganisms Desulfovibrio desulfuricans at a concentration of the combined inhibitor 100,0 mg/L is higher than Desulfomicrobium. In the latter case, to achieve this effect, 120,0 mg/L concentration of the combined inhibitor is required. The studied combination inhibitor causes the inhibition of hydrogen diffusion in steel St3 in the MI medium saturated with H2S and CO2 separately and together, and also contributes to preserving the ductile properties of the steel St3 after exposure to solutions compared to non-inhibited media.

New software for corrosion research based on IPC series potentiostats

The developed IPC-CorrMeter software is intended for studying corrosion of metals, alloys, and coatings and estimating the efficiency of anti-corrosion protection by emulating the operation of a “Corrosimeter” device in potentiostats of the IPC series that allows implementing well-known and reliable corrosion-electrochemical methods, such as linear polarization resistance, zero resistance amperometry, and potentiometry in the existing serial IPC potentiostats. The advantages of the new software include: a possibility of continuous automatic use of these methods in the study of corrosion processes, obtaining results almost in real time mode, high sensitivity and a wide adjustable range of measurements of the rates of general and pitting corrosion (from 1 nm to tens of mm per year), no absence of any restrictions regarding the RAM size of the device. Quantitative dependences of the general and pitting corrosion rate of steel St3 in water are obtained in the presence of the industrial СARTEС-28B corrosion inhibitor for hydraulic testing of mud pumps. They confirm the reliability, accuracy, high sensitivity, and validity of the IPC-CorrMeter software and equipment for researching metal corrosion and allow evaluating the efficiency of anti-corrosion protection agents, as well as the high efficiency of this inhibitor.

Corrosion inhibition performance of dwarf palm and Cynara cardunculus leaves extract for St37 steel in 15% H2SO4: a comparative study

The inhibition effect of extracts obtained from the commercially insignificant, perennial and overgrowing plants in Tunisia such as Dwarf palm (DP) and Cynara cardunculus (CC) plants leaves against St37 steel corrosion in 15% H2SO4 has been investigated with weight loss experiments (WL) and classical electrochemical methods. The investigations were conducted at the various concentrations of studied extracts, experiment temperature and time. The obtained results were compared with electrochemical impedance spectroscopy (EIS), dynamic electrochemical impedance spectroscopy (DEIS) and surface imaging method outcomes. The results showed that DP and CC extracts exhibit good corrosion inhibitor for St37 steel in 15% H2SO4 solution. From all applied methods, DP extracts approximately showed better inhibition efficiency than CC. The adsorption of the inhibitors was found to obey the Langmuir adsorption isotherm. Results of infrared spectroscopy (FTIR) and physical electronics spectrometry (XPS) analysis strengthen the authenticity of other experimental results by proving that the extract molecules have bonded with the surface of the St37 steel.

Pengembangan alat uji impak charpy di bagian pengereman, berat pendulum, dan skala ukur pada mesin impak charpydi Laboraturium Teknik Mesin Unhasy

The impact test is a test to determine the strength of the material when receiving a load constantly or suddenly. The previous tool did not meet the test requirements, so it required the development of the pendulum weight sector, the measuring scale and the addition of a braking system. Therefore, this research was carried out for the development of previous tools so that the test tools could meet the requirements and the testing of the tools using ST 41 and ST 60 carbon steel specimens. This research is a research and development study using ADDIE (analysis, design, development, implementation and evaluation) as a reference in conducting research. The development of the tool focuses on the pendulum weight to 10.2 kg, replacing the measuring scale and adding a braking system that uses disc brakes. The results of the expert validation questionnaire got a score of 72.63%, the small respondent data questionnaire got a score of 83% and the large-scale respondents got a score of 85%. This shows that the tool gets a decent score. The results of the performance test of the tool using ST 41 carbon steel with an average impact price of 1.02302732 J / mm and carbon steel ST 60 with an average impact price of 1.2422299 J / mm. This study shows that there is an average difference in the impact price between ST 41 carbon steel and ST 60 carbon steel as indicated by the Sig. (2-tailed) value of 0.484 using independent sample test T-test data processing.

Study of the crack resistance and fracture mechanism of steel-aluminum composite material

Steel-aluminum composite materials are widely used in technology due to perfect wedding of their weight efficiency and high mechanical properties. This is the reason for their wide application in the aerospace industry for manufacturing case-type parts of rockets, fuel tanks and elements of aviation armor. The goal of the study is analysis of the crack resistance and the mechanism of fracture of aluminum-steel composite material (20 vol.%) with a density of 2.85 g/cm 3. The matrix component of the material was obtained using a finely dispersed aluminum powder PAP-2. The reinforcing component was made of steel meshes woven from austenitic steel cable (08Kh17N13M2). The transverse bending strength of the obtained material (550 – 600 MPa) was calculated from the maximum load corresponding to the first jump (onset) of the crack nucleating in the matrix. The crack resistance of the composite material at the stage of fracture initiation (estimated using K 1 c parameter) varied from 15 to 30 MPa · m 1/2 . The crack resistance of the composite at the stage of fracture development was described using the specific effective fracture work γ F ranged from 2 × 10 4 to 8 × 10 4 J/m 2 . The latter parameter exceeds by the order of magnitude the value γ F determined for steel St3, aluminum alloy D16T, and titanium alloy VT-5. The high value of γ F (which is an advantage of the obtained composite) is attributed to high-energy-consuming mechanism of the material fracture provided by the increased energy consumption for the destruction of the bridges between the matrix aluminum layers by cutting them off with a cable resulting from the shear stresses, for overcoming the friction forces when pulling cable out of the matrix, and for shifting layered packets formed by diffusion-bonded aluminum scaly particles inside the matrix. The properties of the obtained steel-aluminum composite provide the expediency of using the material for lightweight structural elements operated under mechanical loading.

STUDY OF UNIVERSAL COMBINED INHIBITOR FOR OIL AND GAS INDUSTRY

Using the gravimetric method, the inhibitory efficiency of the combined inhibitor with respect to hydrogen sulfide and carbon dioxide corrosion of St3 steel in model-produced water MI was studied. Corrosion tests were carried out in 0.5 l sealed vessels on St3 samples of size 30×20×1. Gossypol resin + MARZA was used as a multifunctional combined inhibitor. Diesel fuel and kerosene were used as solvent. It has been established that the protective effect of using a multifunctional combined inhibitor in formation water with oil containing hydrogen sulphide and carbon dioxide using kerosene as a solvent ranges from 75 to 96 and for diesel as 80 to 100. The combined inhibitor allows to achieve in the MI medium containing hydrogen sulfide and carbon dioxide in the process of daily testing the corrosion rate of steel is about 0.04 g/ m2∙h only in a concentration of not less than 70 mg/l. However, with an increase in the duration of the test by an order of magnitude, a similar corrosion rate is observed already at an inhibitor concentration of 50 mg/l. The same is characteristic of carbon dioxide and hydrogen sulfide - carbon dioxide solutions. The bactericidal properties of the combined inhibitor with respect to two types of Desulfovibriodesulfuricans and Desulfomicrobium sulfate-reducing bacteria were studied. The effect of the inhibitor on the number of bacterial cells and the formation of hydrogen sulfide in Postgate nutrient medium “B” was evaluated. It has been shown that the combined inhibitor exhibits a bacteriostatic effect on to sulphate-reducing bacteria. It was revealed that the degree of suppression of the number of microorganisms Desulfovibriodesulfuricans at a concentration of the combined inhibitor 100.0 mg/l is higher than Desulfomicrobium. In the latter case, to achieve this effect, 120.0 mg/l concentration of the combined inhibitor is required. The studied combination inhibitor causes inhibition of hydrogen diffusion in steel St3 in the MI medium saturated with H2S and CO2 separately and together, and contributes to preserving the ductile properties of the steel St3 after exposure to solutions compared to non-inhibited media.

Metrological Characteristics of Self-Oscillating Transducers for Track Control Systems

This is a study of the sensitivity and accuracy characteristics of three of the best known types of self-oscillating displacement transducers with flat screens which serve as contactless supports. The screens are made of different metals: cast iron, 45 and St3 steels, 12Kh18N10T stainless steel, brass, dural, and copper. The results of an experimental study are shown graphically and in tables taking into account the mutual position of the self-oscillating displacement transducers, as well as the operating conditions for these transducers as a function of the coordinates of the screens. It is shown that during operation of self-oscillating displacement transducers there is a hysteresis that increases on going from a diamagnetic to a ferromagnetic screen. Experiments show that the sensitivity of self-oscillating displacement transducers depends on the screen material. The effect of fluctuations in the supply voltage in the grid on the accuracy characteristics of self-oscillating displacement transducers is also studied and confirmed. The results of experimental studies can serve as useful reference data, and in a number of cases are necessary for specialists involved in the design of automated track control in various areas of machine building. Questions relating to the need for supply voltage stabilizers, the choice of screen material, etc., are discussed.

The Reinforced Concrete Reinforcement Corrosion Degradation Inhibition with Nitrates of Alkali and Alki-Earth Metals

In order to determine the inhibitory additives concentration influence degree on the corrosion degradation rate, we studied the anode behavior of steel reinforcement made of steel grade St3 in a 10% solution NaCl with and without the inhibitors additives of various concentrations. As inhibitory additives, nitrates of potassium, sodium, magnesium, calcium and zinc were introduced into the aggressive environment, since they are often introduced into concrete compositions to accelerate their hardening. Polarization curves have been obtained for steel reinforcement in an aggressive environment, allowing the corrosion rate calculation. It was established that the introduction of potassium and zinc nitrates in an amount of 0.5% into an aggressive environment has the greatest effect on the corrosion processes’ inhibition. When nitrates of alkali and alkali-earth metals are introduced into an aggressive environment, the change in the reinforcing bars mass made of St3 steel occurs 7-8 times slower. Increasing the concentration to 1 and 1.5% is shown to be impractical, due to the small difference in the effect on the reinforcing steel anodic dissolution. A study on the effect of combining inhibitory additives on the corrosion resistance of steel reinforcement in a 10% solution NaCl was made. It was found that the combined action of inhibitors is less effective than the single effect of additives on the corrosion rate.

Формирование поверхности реза и поверхностное упрочнение при лазерной резке звездочек цепных передач из сталей Ст3 и 30ХГСА

Формирование поверхности реза и поверхностное упрочнение при лазерной резке звездочек цепных передач из сталей Ст3 и 30ХГСА

Material and method selection for increasing the wear resistance of construction machines components

Introduction. The article examines the problem of choosing a material and method for increasing the wear resistance of construction machines elements. The performance of construction machines is affected by the reliability of the parts used. The selection of materials for their manufacture allows to calculate the probability of how such elements will affect its ability to work and productivity.Materials and methods. In the process of determining the material and the method for increasing the wear resistance of construction machines, structural steels with various chemical compositions were selected: lowcarbon 08ps (as a model material), 10, 20.30, St3 and low-alloy steels 09G2S and 10HSND, as well as high-carbon steel 65G and boron steel 30MnB5. The methods as high temperature annealing, normalization, injection and high temperature release, thermocyclic processing, cold plastic deformation, thermocyclic processing of steels after cold plastic deformation were used.Results. During the experiment, it was found that both for low-carbon 08ps, 10, 20, 30, St3, and for low-alloy structural steels 09G2S and 10HSND, as well as for high-carbon steel 65G and for boron-containing steel 30MnB5, an increase in the number of TCT cycles (thermal cycling) leads to an increase in the strength properties of the metal. With an increase in the number of cycles over 3-6, the increase in strength properties slows down significantly. Conclusion. In contrast to heat treatment, TCO allows to identify the positive effect of alloying on strength and plastic properties to a greater extent. At the same time, significantly increasing the strength and plasticity, it is possible to obtain previously unattainable values of the work of destruction of alloy steels in the process of various types of loading. Accordingly, the preliminary preparation of steel for the production of individual elements of machines and mechanisms will increase their strength and wear resistance.

Effect of etching duration on roughness and wettability of different carbon steel substrates

Surface chemistry and morphology play a significant role in affecting the wettability of engineering surfaces. To create functional surfaces that are hydrophobic or superhydrophobic, these properties must be understood and controllable. The purpose of this study is to understand the relationship between surface roughness and contact wettability. For this purpose, samples were prepared by using different steel alloys and etched at different etching durations in a mixed solution. The mixed solution for roughening process was prepared by keeping the molar ratio of nitric acid and hydrogen peroxide constant at 1:1, 1:2 respectively. The steel substrates were then immersed in another mixed solution of stearic acid and N, N′-dicyclohexylcarbodiimide in n-hexane (5 mmol/L) for 24 h to lower the surface energy of steel alloy surfaces after roughening step. The effects of the duration of chemical etching on surface roughness were evaluated by using profilometer and surface contact angles were measured using the sessile drop method. Surfaces were analyzed using scanning electron microscopy. Steel surfaces were changed from hydrophilic to hydrophobic/superhydrophobic. The obtained maximum contact angle was 168.36° for CK40 samples, 161.99° for CK22 samples, and 166.35° for St37 steel samples. The results of this study showed that the surface contact angle was very sensitive to the change of surface roughness, and wettability could be controlled by changing the surface roughness. In addition, the surface roughness values of steel substrates that exhibit superhydrophobic behavior varied according to the steel type.

Solid-state local micro-alloying of thick st37 steel plates with SiC powder using a modified friction hydro-pillar process

Friction hydro-pillar processing is a solid-state process to repair cracks in thick plates, pipes, and vessels. In this study, this process is modified to be used as a solid-state micro-alloying process to make in-depth alloys in steel plates. Alloying is carried out mostly in the liquid phase which results in problems such as dendritic microstructure. Also, there are some restrictions regarding mechanical alloying such as long sintering time. In the present study, The SiC powder was added to St37 steel. A cartridge was drilled in the center of the stud to place the alloying powder. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analyses were used to investigate the powder distribution. Although several agglomerated zones were detected, the results indicate a uniform distribution of the powder. The results also suggest that the SiC was dissolved during the process. Optical microscopic was also utilized to investigate the phase transformation during the process. Due to the high temperatures and strain rate experienced by the stud and the base material during the process, significant changes occur including the formation of Widmanstätten structure. The micro-hardness and tensile properties of the samples were also tested to evaluate their mechanical properties. The highest achieved average micro-hardness and ultimate tensile strength were 395.8 HV and 511.2 MPa, respectively.

Accuracy characteristics of autogenerator transducers for track control systems

The advantages of autogenerator displacement transducers in track control systems of metal – cutting machines, industrial robots, robotic complexes and flexible automated productions, such as high speed and durability of control systems, as well as their disadvantages-the lack of sufficiently complete accuracy characteristics, which affects the efficiency of equipment with track control systems, are considered. Formulated the research problem and described a special experimental setup, which studied the sensitivity of the self displacement transducers three types based on their mutual arrangement and screens of various metals (iron, steel 45, steel St3, 12KH18N10T steel, brass, dural and copper), as well as the conditions of their operation depending on the positioning of screens. The results of experimental data processing are presented, and any dependence of sensitivity on the screen material is not established. The assumption about the randomness and insignificance of the revealed differences is put forward and verified, and it is shown by the Cochran criterion that they are rightfully considered insignificant with a reliability of at least 95 %. The influence of power supply voltage fluctuations in the network on the accuracy characteristics of auto-generator displacement converters is studied and the results of the research are presented. A statistical test was carried out using the student’s criterion, which showed the absence of this influence on the accuracy characteristics. It is noted that hysteresis occurs during the operation of autogenerator displacement transducers and it is experimentally established that in most cases it increases with the transition from a diamagnetic screen to a ferromagnetic one. It is proposed to use the results of the research of precision characteristics in the design and efficient operation of the system limit control on the basis of self converters of displacements of the considered types, addressing issues about the need to use the voltage regulator when selecting screen material, etc.

Protection of carbon steel with superhydrophobic coating against corrosion in NaCl solution

Corrosion and kinetics of partial electrode reactions on carbon steel St3 with superhydrophobic coatings of three types were studied in 0.5 M NaCl and 50 g/L NaCl +400 mg/L H2S solutions. The investigations were carried out on electrodes made of carbon steel St3 with a chemical composition, wt. %: C – 0.20; Mn – 0.50; Si – 0.15; P – 0.04; S – 0.05; Cr – 0.30; Ni – 0.20; Cu – 0.20, and Fe – 98.36. To obtain the type I coating, the metal surface was textured by an IR laser radiation of nanosecond duration followed by chemisorption of fluorobutylsilane out of a solution in n‐decane. To obtain a coating of type II, a nanoscale composite layer consisting of aggregates of aerosil nanoparticles was applied additionally to the outcome of type I method. To obtain a coating of type III, the metal surface after being textured by the infrared (IR) laser radiation of nanosecond duration was followed by chemisorption of fluoroxy silane. The influence of duration τ of the medium corrosive impact on protective effect of the superhydrophobic coating is considered. It was shown that upon reaching a steady state (after 72 h), the corrosion rate of steel with a superhydrophobic coating of I and II types in a 0.5 M NaCl solution is reduced by 23 ± 3 times compared with unprotected samples. Approximately the same picture is characteristic of electrodes with a coating of type III in a solution of 50 g/L NaCl +400 mg/L H2S.

Fatigue Strength Improvement of Low Carbon Steel through Carburizing Process with Coconut Shell Charcoal

The fatigue strength of low carbon steel is a limitation that is often considered in machine construction, especially in rotating component parts. Low carbon steel has special properties that are soft, good welding and good machining, as well as relatively inexpensive prices but have low fatigue strength. For this reason, in this study, a carburizing process was carried out with the media of coconut shell charcoal as a source of carbon and shell powder as a catalyst. The addition of carbon using the carburizing method is relatively easy and does not require a large cost because the materials used are abundant in nature. The carburization process was carried out at 950°C for 4 hours. Furthermore, mechanical properties were tested with hardness, tensile testing and fatigue testing. The carburization process with charcoal media is expected to increase hardness, tensile strength and fatigue strength. Fatigue testing is carried out by the reverse bending method with a load varying 70%, 60%, 50% and 45% of the tensile strength of the material. In addition, microstructure examination and fault surface observation are also carried out to analyze the phenomenon of changes in material structure due to carburization. The hardness value of ST37 steel before carburizing ie 118 HRB increased to 127 HRB after undergoing carburizing treatment. Tensile test results also experienced an increase in which the initial tensile strength value of ST37 steel by 356.66 MPa increased to 541.15 MPa after the carburizing process. Likewise in fatigue testing, the fatigue limit has increased significantly, where the ST37 steel fatigue limit before the carburizing pack is at a stress level of 161 MPa. After experiencing the carburizing pack process the ST37 steel fatigue limits are at a voltage level of 232 MPa.

Research universal combined inhibitor for the oil and gas industry

Using the gravimetric method, the inhibitory efficiency of the combined inhibitor with respect to hydrogen sulfide and carbon dioxide corrosion of St3 steel in model produced water MI was studied. Corrosion tests were carried out in 0,5 liter sealed vessels on St3 samples of size 30х20х1. Gossypol resin + MARZA was used as a multifunctional combined inhibitor. Diesel fuel and kerosene were used as solvent. It has been established that the protective effect of using a multi-functional combined inhibitor in formation water with oil containing hydrogen sulfide and carbon dioxide using kerosene as a solvent ranges from 75 to 96 and for diesel as 80 to 100. The combined inhibitor allows to achieve in the MI medium containing hydrogen sulfide and carbon dioxide in the process of daily testing the corrosion rate of steel is about 0,04 g/m2·h. only in a concentration of not less than 70 mg/l. However, with an increase in the duration of the test by an order of magnitude, a similar corrosion rate is observed already at an inhibitor concentration of 50 mg/l. The same is characteristic of carbon dioxide and hydrogen sulfide - carbon dioxide solutions.

Inhibition effect of Cynara cardunculus leaf extract on corrosion of St37 steel immersed in seawater with and without bleach solution

The inhibition performance of an aqueous extract of Cynara cardunculus leaves on the corrosion of St37 steel immersed in seawater and seawater with bleach was investigated using weight loss measurements, electrochemical methods, and surface characterization techniques. It was found that the extract components acted primarily as a mixed-type inhibitor, and inhibition efficiency increased with increasing inhibitor concentration. Electrochemical impedance spectroscopy (EIS) and dynamic electrochemical impedance spectroscopy (DEIS) confirmed the formation of a protective layer on the metallic surface in both solutions. The adsorption of inhibiting molecules conformed to the Langmuir isotherm model. The thermodynamic parameter values indicated that chemisorption constituted the major contribution to the adsorption process. This result was corroborated by scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analyses. The significant inhibition effect can be related to the large amount of phenolic compounds in the CC aqueous extract as revealed by the Fourier-transform infrared (FTIR) spectrum.

Ni-Cu matrix composite reinforced with CNTs: preparation, characterization, wear and corrosion behavior, inhibitory effects

St37 steel has been used in various industries due to its abundance and low cost. However, the high corrosion rate of steel in acidic environments is one of the limiting factors for its application. In this study, Ni-Cu compos-ite coating reinforced with CNTs was applied on the st37 steel substrate. The extract of the Sarang Semut plant was added to the coating as inhibitory particles and the electrochemical behavior of the coating was investigated. The X-ray diffraction test was performed for phase analysis. Hardness, wear, and dynamic potential polarization tests were performed. Results showed that the presence of CNT particles improved the hardness, tribological performance, and electrochemical behavior of the coating. Also, the presence of Sarang Semut particles acted as a barrier and protected the surface of st37 steel from corrosion. It should be noted that these particles affected the kinetics and thermodynamics of corrosion reactions and were not involved in the reactions.