Low-carbon Pipe Steel Research Articles

Crystallographic Features of Phase Transformations in High-Strength Low-Carbon Pipe Steel

Crystallographic Features of Phase Transformations in High-Strength Low-Carbon Pipe Steel

Analysis of Results of Impact Bending Tests of Base Metal Samples and Welded Joints of Pipes From Low-Carbon Pipe Steels

Analysis of Results of Impact Bending Tests of Base Metal Samples and Welded Joints of Pipes From Low-Carbon Pipe Steels

Modeling of necking area reduction of carbon steel in hydrogen environment using machine learning approach

Low carbon and low alloy steel pipes, prevalent in natural gas transmission systems due to their affordability, weldability, and strength, are confronted with significant challenges such as hydrogen embrittlement (HE) when transitioning towards hydrogen energy systems. This necessitates innovative predictive strategies to overcome these hurdles. Most existing research on HE has focused on a limited range of low carbon and low alloy steels under specific experimental conditions and has been constrained by the limitations of experimental facilities. To expand the research scope, our study incorporated seven machine learning (ML) techniques: Random Forest (RF), Decision Tree (DT), Extreme Gradient Boosting (XGBoost), Gradient Boosting (GB), Adaptive Boosting (AdaBoost), Categorical Boosting (CatBoost), and Artificial Neural Networking (ANN). The aim is to predict the HE in terms of the degradation of mechanical properties, specifically the reduction in area. Drawing from tensile test data obtained from 47 distinct low carbon and low alloy steels under pressurized hydrogen gas conditions, we constructed and evaluated a range of ML models, with the aim of identifying the most efficacious one for our study. Our results indicated that the CatBoost ML model offered the best prediction of the reduction in the area of these steels in a hydrogen environment. The CatBoost model provided a low Mean Absolute Error (MAE) of 7.32, Mean Square Error (MSE) of 83.78, Root Mean Square Error (RMSE) of 9.15, and a coefficient of determination (R2) value of 77.62% for the training data and 72.50% for the testing data. Furthermore, the CatBoost model identified hydrogen gas pressure and the steel's ultimate tensile strength as the most influential parameters, contributing 47.4% and 19.2% respectively to the prediction of HE. This research provides valuable insights into the development of advanced materials and infrastructure for efficient hydrogen gas transportation, supporting the broader shift towards a hydrogen-based energy economy.

Modeling of Corrosion Rate Under Two Phase Flow in Horizontal Pipe Using Neural Network

The present study develops an artificial neural network (ANN) to model an analysis and a simulation of the correlation between the average corrosion rate carbon steel and the effective parameter Reynolds number (Re), water concentration (Wc) % temperature (T o) with constant of PH 7 . The water, produced fom oil in Kirkuk oil field in Iraq from well no. k184-Depth2200ft., has been used as a corrosive media and specimen area (400 mm2) for the materials that were used as low carbon steel pipe. The pipes are supplied by Doura Refinery . The used flow system is all made of Q.V.F glass, and the circulation of the two –phase (liquid – liquid ) is affected using a Q.V.F pump .The input parameters of the model consists of Reynolds number , water concentration and temperature. The output is average corrosion rate .The performance of the two training algorithms, gradient descent with momentum and Levenberg-Marquardt, are compared to select the most suitable training algorithm for corrosion rate model. The model can be used to calculate the average corrosion rate properties of carbon steel alloy as functions of Reynolds number, water concentration and temperature. Accordingly, the combined influence of these effective parameters and the average corrosion rate is simulated. The results show that the corrosion rate increases with the increase of temperature, Reynolds number and the increase of water concentration.

Effects of temperature on fatigue crack growth rates of a low-carbon pipe steel in the ductile and ductile-to-brittle transition regions

This study investigated the impact of temperature on Fatigue Crack Growth Rates (FCGR) of low-carbon pipe steel in both the ductile and ductile-to-brittle transition regions. Results showed that the FCGRs decreased as the temperature decreased from the ductile to the ductile-to-brittle transition region, while FCGRs remained consistent within the ductile-to-brittle transition region. The Paris law coefficients, C and m, were also influenced by the temperature change between the ductile region and the ductile-to-brittle transition region. However, the C and m values stayed relatively stable in each region. The m values in the ductile-to-brittle transition region were found to be higher than those in the ductile region, whereas the C values were found to be lower.

Study of 2-Amino-2-Methyl-1-Propanol Effect on Corrosion of Boiler Low Carbon Steel Pipes in Presence of Sodium Sulfite

This paper studies the effect of 2-Amino-2-mthyl-1-propanol (C3H11NO) on corrosion behavior of boiler steel pipes with low carbon content at sodium sulfite (Na2SO3) in the additive mixtures form as oxygen scavengers in the boiler feed water. 
 Experiments were done at temperatures (100 - 150) ºC and pressures (5 - 9) × 101.3 KN/m² in cylinder autoclave with 7.4 ppm dissolved oxygen in used water, then the corrosion rate is measured by weight loss technique and the concentration of dissolved oxygen in feed water was determined before and after the experiment by Winkler method (Titration). 
 This analysis can provide valuable information for mixture scavengers and corrosion behavior on boiler steel pipes with range of used temperature and pressure. The better ratios found is 60 ppm for every one of amine and sulfite, with the best result in decreasing corrosion rate in acceptable way. The above mentioned ratio is optimal and recommended. This opens up the field for formulation synergetic packages of additives as O2 scavengers. 
 Keywords: Oxygen Scavenger, Na2SO3, C3H11NO, Boiler Steel Pipes, NA-Sulfite & 2-Amino-2-mthyl-1-propanor Additive Package

Scanning Tunneling Microscopy of Intermediate Transformation Structures in Electric Arc Surfacing Modified with Titanium Carbonitrides on Pipe Steel

In the present paper, the structure of electric arc coatings modified with nanodispersed titanium carbonitride additives on low-carbon pipe steel is studied using optical, scanning tunneling, and transmission electron microscopy. The obtained “substrate-modified surface” compositions are tested for fracture toughness, and the derived test results are compared with the data for the compositions formed using commercial electrodes. It is found that the introduction of titanium carbonitride nanoparticles with the estimated content from 0.15 to 1 wt% refines the ferrite–pearlite structure. Scanning tunneling microscopy reveals acicular and lamellar structures in local regions of ferrite grains, which, by morphological features, are identified as lower bainite and acicular ferrite. It is concluded that the increase in fracture toughness of the “substrate-modified surface” composition is of a complex nature. First of all, this increase is associated with grain refinement, while the formation of intermediate transformation structures plays a secondary role.

On the Deposition Process of Ceramic Layer Thin Films for Low-Carbon Steel Pipe Protection.

Ceramic thin films with variable thicknesses have been used in many applications. In order to protect the petroleum transportation pipes against the harmful H2S action, two ceramic materials as thin layers are proposed. In this article, pulsed laser deposition (PLD) of ceramic layers by in situ time-resolved optical techniques is investigated. Two ceramic materials were used as targets and real-time monitoring of the PLD process was realized via ICCD fast camera imaging and optical emission spectroscopy. The space–time displacement of the ceramic emissions was analyzed in order to determine the plasma structure and respective kinetic energies. Spectral-resolved investigation allowed the determination of plasma species individual velocities (in the first case: 43 km/s for C ionic species, 11 km/s for Si, from 25 to 5 km/s for atomic species; in the second case: 32 km/s for C ionic species, 11 km/s for W species, and 15 and 53 km/s for neutral species). SEM and AFM techniques were implemented to analyze the resulting ceramic layers showing homogeneous surfaces with characteristic material droplets. The ablation crater also reveals selective ablation during the deposition process. EDX results show that Al/Si is retained in the thin films similar to the target composition.

Timely Application of Deming’s Principle and Cycle in the Production of Low-carbon Steel Pipes and the Improvement of Product Quality on the Project Site

Timely Application of Deming’s Principle and Cycle in the Production of Low-carbon Steel Pipes and the Improvement of Product Quality on the Project Site

Localized Corrosion Occurrence in Low-Carbon Steel Pipe Caused by Microstructural Inhomogeneity.

In this study, the cause of failure of a low-carbon steel pipe meeting standard KS D 3562 (ASTM A135), in a district heating system was investigated. After 6 years of operation, the pipe failed prematurely due to pitting corrosion, which occurred both inside and outside of the pipe. Pitting corrosion occurred more prominently outside the pipe than inside, where water quality is controlled. The analysis indicated that the pipe failure occurred due to aluminum inclusions and the presence of a pearlite inhomogeneous phase fraction. Crevice corrosion occurred in the vicinity around the aluminum inclusions, causing localized corrosion. In the large pearlite fraction region, cementite in the pearlite acted as a cathode to promote dissolution of surrounding ferrite. Therefore, in the groundwater environment outside of the pipe, localized corrosion occurred due to crevice corrosion by aluminum inclusions, and localized corrosion was accelerated by the large fraction of pearlite around the aluminum inclusions, leading to pipe failure.

Corrosion Behavior of Low Carbon Steel Pipe in Condensate Environment

Low carbon steel pipe is widely used in various pipeline applications because it has good mechanical properties. The application of low carbon steel developed generally does not involve corrosion resistance. To find out the behavior of low carbon steel pipe in condensate fluids, the immersion test was carried out. The method for the immersion test is the planned-interval test. The corrosion rate of this steel was determined by weight loss, whereas the corrosivity of the condensate fluids was measured by a multimeter Hach HQ40d. The morphology of corrosion products is characterized by using scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and x-ray diffraction (XRD). The result of immersion of low carbon steel pipe in the condensate fluids shows that the liquid corrosivity and corrodibility of low carbon steel pipe tend to decreases with the length of exposure time. The decrease of metal corrodibility is identical to the lower corrosion rate at a longer exposure time due to the layer a corrosion product formed. The corrosion products during immersion tests are uniform with iron oxide in the form of FeO(OH) and Fe2O3.H2O.
 GRAPHICAL ABSTRACT

Microstructural Evaluation of the High-Frequency Induction Welded Joints of Low Carbon Steel Pipes

Abstract The work presents the results of research on the structure of welded joints in the area of heat affected zone (HAZ). Based on precisely performed metallographic tests, the contribution of individual structural components in the area of welds of pipes welded with the induction method was assessed. The volume fraction of individual structural components in various areas of the heat affected zone, the size of the grain formed in the welding process, as well as its shape coefficients were determined. On the basis of metallographic observations, an attempt was made to describe the course of the pressure induction welding process, taking into account the structural changes, phase changes and the recovering and recrystallization processes taking place in this process.

Formation of Structure and Properties of Low-Carbon Pipe Steel with Ultralow Manganese Content during Thermomechanical Treatment

Formation of Structure and Properties of Low-Carbon Pipe Steel with Ultralow Manganese Content during Thermomechanical Treatment

Metallography of non-metallic inclusions in pipe metal and impact assessment of defect structures on non-destructive testing outcomes

Low carbon steel pipes represent a core component in the gas pipeline system, so it is necessary to improve constantly diagnostic operations and assessment methods of their technical state. Studies on objects operated in diverse conditions within a long period provide reliable data on the real behavior of materials. A key issue is the investigation of characteristics and behavior of products with primarily incorporated defective structures undetected while manufacturing and constructing. It is difficult to forecast the behavior of such defects, in addition, considerably more work need to be done to determine their development, detection methods, and more importantly, their hazards. The reported study investigates the phases, structure and sizes of inclusions detected in the defective pipe metal in the natural gas pipeline. The property that characterizes defects of interest is their concentration within one pipe section in combination with diverse thickness, composition, and location in the pipe wall. Defects are found at various depths, forming one, two and more layers. The difference in structure and phase composition is outlined. The research has pointed out principal inclusions represent fragments of charge materials — fluorite and broken fireclay brick, a number of defects result from casting defects, e.g. gas bubbles and shrinkage holes. Non-destructive ultrasonic testing is implemented; the importance of thickness and structure of inclusions for measurement data has been realized.

Corrosion rate and corrosion behaviour analysis of carbon steel pipe at constant condensed fluid

This study investigates the corrosion rate and corrosion behavior of carbon steel pipe at constant condensed fluid from a geothermal power plant. The corrosion rate of the steel was determined by weight loss analysis, whereas the corrosivity of the condensate fluids was measured by a multimeter Hach HQ40d. The morphology of the corrosion products formed was characterized by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and x-ray diffraction (XRD) analysis. Results showed that the corrosion rate in the liquid part of the condensate fluids is constant during the immersion period when water quality parameters are constant. Meanwhile, the corrosion rate of low carbon steel pipe decreases though with the longer exposure period in the condensate fluid. The decrease of metal corrodibility identical to the lower corrosion rate at a longer exposure time due to the protective corrosion layer formed. The corrosion products during immersion tests identified in the corrosion test were uniform with iron oxide in the form of FeO(OH) and Fe2O3*H2O.

Analysis of Corrosion Breakdown Rate in Low Carbon Steel with Aluminum Coating

This study aims to analyze the corrosion penetration rate of low carbon steel with aluminium coating. The method used is the potentiodynamic method to determine the value of the corrosion rate. The corrosion medium used was HCl. The aluminium used is aluminium frame waste powder. The coating process is by dipping low carbon steel pipes into aluminium frame waste that had been liquefied in the Hot Dip Galvanizing (HDG) method of 700oC and immersion time of 45 seconds. The results of this study show that low carbon steel which has been coated with aluminum frame waste powder has a high corrosion rate which is proven to have a corrosion rate of 18,1808 mm/year. So that the corrosion rate is at an unacceptable level.

Structural nonuniformity: Impact on the cold resistance of low carbon microalloyed steel for building cоnstructions

The nonuniformity of macro- and microstructure of low-carbon microalloyed steel pipes across their wall thickness was estimated comprehensively using optical, scanning and transmission electron microscopy. The texture of the steel was studied by X-ray diffraction analysis. Both the actual and prior austenite structures were analyzed. The possible impact of all peculiarities of the structure, namely, substructure, texture and nonmetallic inclusion as well on the cold resistance of the steel was considered and discussed. The cold resistance of steel was estimated based on the ductile-brittle transition temperature (DBTT) determined in using Сharpy impact tests performed in a wide temperature range (from ambient and subzero temperatures). Correlations between the structural features of samples, which were cut from the near-surface areas of steel pipes and at the pipe-wall midthickness, and the DBTT were found. The high nonuniformity of ductility was demonstrated, which can be characterized by the fact that the DBTT of midthickness areas of pipe wall exceeds that of near-surface areas by 30°. The lower DBTT (the higher cold resistance) corresponds to the steel characterized by thin (less than 20 ​μm) fragmented lath-like bainite bands.

Anticorrosive non-crystalline coating prepared by plasma electrolytic oxidation for ship low carbon steel pipes

A corrosion-resistant non-crystalline coating was fabricated by plasma electrolytic oxidation (PEO) on Q235 low carbon steel for ship pipes. The distribution and composition of chemical elements and phases of PEO coatings were analyzed by an orthogonal experiment, and the formation mechanism of PEO coatings was discussed. The corrosion current densities and corrosion potentials were measured. The results indicated that the formation of a transition layer mainly containing Fe3O4 was crucial for achieving an excellent coating quality. Furthermore, the corrosion current density of coated steel was reduced by 78% compared with the bare steel.

Failure analysis of low-carbon steel pipe clamp of pressure pipe

A real case of breakage of several pipe clamps used in the pressure pipe hanger is investigated. In order to examine the cause of failure, various techniques, including element analysis, mechanical testing, optical and scanning electron microscopy, component analysis, and impact testing were used. It was found that the fractures of the pipe clamps occurred at the transition zone between a straight and arc segments, the finite element analysis has shown that the transition had the highest stress concentration. The surface deformation during pipe clamp manufacturing process caused hardness rising and toughness descending, resulting in surface cracks, Under the combined effect of lower ambient temperature and service stress, the surface cracks expanded rapidly and the pipe clamps fractured finally. Improvements in the molding process and the use of appropriate quality control measures can eliminate this problem.

Effect of Alloying With Molybdenum and Chromium on Low-Carbon Pipe Steel Structure and Properties

The comparative effect of molybdenum and chromium on critical points, structure and strength properties of low-carbon pipe steel after different cooling regimes is studied. It is shown that for the basic chemical composition 0.06%C–1.50% Mn–Cu–Nb–Ti addition of chromium and molybdenum leads to a reduction in Ar3 and Bs critical points for hot-worked austenite decomposition. It is noted that with use of the optimum accelerated cooling regime the difference is overcome between the effect of molybdenum and chromium on dispersion of the structure and strength properties of low-carbon pipe steel of the alloy system 0.06% C–1.50% Mn–Cu–Nb–Ti.