Carbon Steel Weld Research Articles

Rotary Friction Welding of Low Carbon Steel

Rotary Friction Welding of Low Carbon Steel

Improvement of Weld Bead Characteristics in Gas Metal Arc Welding of SA515 Carbon Steel by Applying Alternating Shielding Gas Flow Technique

Improvement of Weld Bead Characteristics in Gas Metal Arc Welding of SA515 Carbon Steel by Applying Alternating Shielding Gas Flow Technique

Metallurgical and mechanical properties evolution in cusp-magnetic field-assisted GTAW of low carbon steel

In this work, magnetic field-assisted autogenous gas tungsten arc welding (GTAW) of low carbon steel has been studied. The external magnetic field was generated by custom made rectangular shaped samarium cobalt permanent magnets which were arranged in a manner to generate a cusp-type magnetic field (CMF). The impact of CMF on the morphology and microstructural evaluation of the weld joints were examined prudently using optical microscope, Field-emission scanning electron microscope and X-Ray Diffraction technique. The experimental results exhibited that the CMF assisted GTAW produce joints with better mechanical and metallurgical properties compared to conventional GTAW. In CMF assisted welds, width of weld beads was reduced by an average of 4% and depth of penetration was increased by 13%. Temperature measurement on the work piece showed a significant amount of temperature decrease for the same amount of heat input under the influence of the CMF. An improvement in grain refinement was observed in the heat-affected zone (HAZ) adjacent to fusion boundary by 12% and HAZ adjacent to base metal by 15% compared to conventional GTAW, which in turn promoted a considerable increase in hardness. The tensile properties in CMF assisted welds were enhanced by 3% and 8%, respectively, for an increase of heat inputs from 0.34 to 0.45 kJ mm−1.

Failure analysis of the leakage in girth weld of bimetal composite pipe

A bimetal mechanically-composite pipe leaked at the entrance of processing station. The failure location was the 6o'clock direction of the girth weld connecting the gathering pipe and pipe in the station. In order to figure out the root cause of the failure, a series of experiments were carried out. The macroscopic analysis and metallographic test results show that the leakage point is located at the 6o'clock direction of the girth weld, the root welding and the base pipe of the bimetallic composite pipe are corroded, resulting in perforation. The end of the bimetallic composite pipe is not seal-welded, the girth weld has misalignment and at 6o'clock, the root weld was concave, and the wall thickness of the root weld and the lining is<1.5 mm. The FeCl3 pitting corrosion test results of the girth weld show that the pitting corrosion resistance of the root weld is lower than that of the liner and pure stainless-steel pipe. The galvanic corrosion test shows that the galvanic corrosion grades of weld-pure material, weld-liner, carbon steel-weld, carbon steel-liner are all severe corrosion, and the galvanic corrosion of carbon steel-weld is the most serious. The root cause of the failure of girth weld puncture leakage: the end of the bimetallic composite pipe is not seal-welded. At 6o’clock, the girth weld has misalignment, and the root weld is concave, resulting in that the thickness connecting the root weld and the liner being small. In the medium environment containing Cl- and CO2, local corrosion occurs, and then the medium enters the base pipe and the liner interlayer, and the galvanic corrosion aggravates the corrosion of the base pipe. To avoid the reoccurrence of such failure, the mitigation measures were proposed.

Investigating the mechanical properties and fusion zone microstructure of dissimilar laser weld joint of duplex 2205 stainless steel and A516 carbon steel

Laser welding of dissimilar A516 low carbon steel and duplex stainless steel was conducted to evaluate the effect of fiber laser welding parameters (e.g., laser power, welding speed, nozzle distance and beam deviation) on the responses of tensile strength, depth of the melt pool, microstructure, temperature near the melt pool and melt pool hardness. The maximum tensile strength of 500 MPa and 18 percent elongation were obtained at the laser power of 400 W, welding speed of 300 mm/min and the focal point. The absorbed power of laser and linear speed of welding had the most notable impact on the tensile strength of the weld. The fusion zone microstructure was composed of a combination of ferrite–austenite distribution from duplex stainless steel (DSS) based on different cooling and heating cycles. During the nucleation process, ferrite grains were transformed to austenite grains from different areas of the fusion zone. Also, the weld fusion zone microstructure at A516 side was composed of fully martensitic structure, according to the higher heat input upper critical temperature of steel (AC3), thereby leading to rapid cooling. The EDS analysis also showed that the Fe percentage was continually reduced at the fusion line from A516 to DSS, although Ni and Cr were distributed at the fusion zone with some minor changes of weight percentage. Therefore, Cr and Ni had a crucial effect on elemental alloy composition in this laser welding process. The ductility of the A516 fracture surface with bigger and deeper fracture dimples was caused by applying higher laser energy density, which effectively improved the fracture ductility of the welded samples.

Analysis of weld seam characteristic parameters identification for laser welding of dissimilar materials based on image segmentation

Welded joints of dissimilar materials increase the flexibility in design and manufacturing process greatly and, hence, have been widely used in aerospace, rail transportation, and other related industries. Due to the difference in physical and chemical properties of dissimilar materials, the formed weld during laser welding is different from that of the same material welding. The geometric morphology of the formed weld is an important factor affecting the welded joints performance. Therefore, an identification method of weld seam characteristic parameters is proposed in this paper for evaluating the welding quality by image segmentation in the laser welding of low carbon steel (Q235) and stainless steel (316L). The region of interest of the weld metallograph from experimental observation is defined, converted into grayscale image and then denoised by filter. The weld is segmented by the seeded region growing method with initial seed automatic selection. The weld seam characteristic parameters including the weld area, left weld width, right weld width, and weld penetration in the laser welding of dissimilar materials are identified based on the segmented image. The obtained results are validated by the experimental measurements of weld and good agreement between them has been found. The identified weld seam characteristic parameters are adopted for assessing weld fusion status, depth-to-width ratio, and symmetry quantitatively. The results indicate that the proposed method is reasonable and feasible for the weld quality evaluation to improve the laser welding quality of dissimilar materials in practical production.

Comparisons of laser and laser-arc hybrid welded carbon steel with beam oscillation

Laser welding and laser-arc hybrid welding of Q235 steel with and without beam oscillation were carried out, the weld formation, microstructure and mechanical properties were investigated. It was found that the width of the heat affected zone (HAZ) increased by beam oscillation during laser welding, while decreased during laser-arc hybrid welding. The side-plate ferrite (FS) increased by the beam oscillation, while the blocky ferrite (FB) was broken up and the proeutectoid ferrite (FP) was reduced. Moreover, the beam oscillation was beneficial to improve the elongation rate from 6.8% to 7.6% for laser welds and 8.3% to 9.8% for hybrid welds, while decrease the micro-hardness of the welds by 85 HV10 for the laser welds and 10 HV10 for the hybrid welds. Finally, the variation in width of HAZ was illustrated according to the heat distribution of the laser source, arc column and oscillating behavior of the laser beam. The relation between microstructure and mechanical properties was established, according to the stirring effect of the oscillated laser beam within the molten pool, and the solidification theories.

Microstructure evolution and microhardness of thermal-simulated HAZ in Fe–Mn–Al–C steel

The microstructure evolution and microhardness of Fe–Mn–Al–C steel heat-affected zone (HAZ) were investigated systematically using the weld thermal simulation technique. The results illustrated that the microstructure in HAZ with different peak temperatures (600, 800, 1000 and 1300°C) and heat inputs (10, 20 and 30 kJ cm–1) mainly consisted of ferrite and austenite. When the peak temperature was 1300°C, there are many high-angle grain boundaries which may inhibit crack propagation. With the increase in heat input, κappa carbide precipitation increased, the grain size became finer and microhardness increased. The microhardness was 438 HV when the peak temperature was 1300°C at 30 kJ cm–1. Highlights The welding of high carbon, high aluminium and low-density steel was simulated. The HAZ was composed of austenite and a small amount of high-temperature δ-ferrite. The proportion of high- and low-angle grain boundaries has a great influence on the mechanical properties. The welding heat input was 30 kJ cm–1, the grain size of the HAZ decreased and microhardness was the largest.

Application of Unconstrained Cobalt and Aluminium Metal Powders in the Alloying of Carbon Steel in Submerged Arc Welding: Thermodynamic Analysis of Gas Reactions

The application of cobalt and aluminium powders in unconstrained format, not as metal powder in tubular wire nor as pre-alloyed powder, is used in this work to simplify weld metal alloying. The objective of this study is to demonstrate the application of unconstrained cobalt and aluminium powders in Submerged Arc Welding SAW to alloy the weld metal and to control the weld metal oxygen content. Aluminium powder is used to control the oxygen potential at the weld pool-slag interface in order to prevent oxidation of cobalt. The results presented here show that with the addition of Aluminium powder, 70% yield of Cobalt was achieved from the cobalt powder to the weld metal. The carbon steel base-plate material and weld wire materials combination were alloyed to 5.3% Co and 4.2% Al, whilst controlling the weld metal total oxygen content to 230 ppm. Thermodynamic analysis is applied to investigate the possible chemical interaction reactions between Co and Al compounds, as well as the role of the reactions on Co yield to the weld pool. The application of unconstrained metal powders ensures productivity gains in the overall SAW process because the time consuming and expensive manufacturing of alloyed wire and alloyed powder are eliminated.

Electrochemical behavior of friction stir welded joint of ultra-low carbon steel

In this study, friction stir welding of ultra low carbon steel was performed at tool rotational speeds in the range from 300 to 750rpm with 150rpm increments at 60mm/min fixed traverse speed. Throughout study was performed on macro and micro structures in order to determine the several welded zones for example stir zone, thermo-mechanically affected zone, and heat-affected zone. Microhardness profiles were performed along the welded joint's cross section and the utmost hardness was obtained at stir or nugget zone as compared to the other zones of the welded joints. The hardness values on the stir zone decreases with rise in tool rotating speed. Electrochemical study was investigated in 3.5%NaCl electrolyte solution. Corrosion rate is maximum (~27MPY) at 300 rpm stir zone and minimum value (~0.3 MPY) obtained at heat affected zone at 750rpm welded sample.

Prediction of Percentage Dilution in AISI 1020 Low Carbon Steel Welds Produced from Tungsten Inert Gas Welding

The objective of this study is to predict the percentage dilution in AISI 1020 low carbon steel welds produced from tungsten inert gas welding using Artificial Neural Networking (ANN) approach. The regression plot showed R = 0.9992 as progress of training, R = 0.99865 as progress of validation and R = 0.85285 as progress of the training test. This led to overall correlation coefficient (R) of 0.90007 which signified that ANN is a robust tool for predicting the percentage of weld dilution. To test the reliability of the trained network, the ANN model was employed to predict its own value of percentage dilution using the same input parameters generated from the central composite design. Based on the observed and the predicted values of percentage dilution, a regression plot of outputs was thereafter generated, and r2 value of 0.9876 was obtained which led to the conclusion that the trained network can be used to predict percentage dilution beyond the limit of experimentation. There was proximity in the results obtained, as both the experimental and predicted weld dilution fell between 44.5-71.55%. Hence, prediction adopted in this study can be applied in actual scenario without fear of inacuracies.

Aluminium Assisted Nickel Alloying in Submerged Arc Welding of Carbon Steel: Application of Unconstrained Metal Powders

Nickel alloying of carbon steel is used to enhance steel strength and toughness. Nickel alloying of the weld metal via solid weld wire presents several difficulties as highlighted previously, such as work hardening of the solid weld wire in manufacturing and feeding through the SAW wire feeding mechanism, and expensive and time consuming manufacturing of multiple weld wire formulations. The application of nickel and aluminium powders in unconstrained format, meaning not as fluxed cored wire or as metal cored wire, is used to simplify weld metal alloying. Al powder is used to control the oxygen potential at the weld pool-molten flux interface. The results presented here show that the addition of Al powder to the weld metal enhances Ni yield to the weld metal, at 85%, compared to pre-alloyed powder Ni yields of 57–78% as applied in previous work. Carbon steel was alloyed to 6.9% Ni and 3.7% Al. Thermodynamic analysis is applied to elucidate the chemical interaction between Ni and Al, and its effects on Ni yield in the weld pool. Overall process productivity gains stem from weld metal alloying from unconstrained metal powders because the expensive and time consuming step of manufacturing alloyed wire and alloyed powder is eliminated.

Finite Element Analysis and Experimental Investigation on Effect of Process Parameters in Plasma-Assisted Friction Stir Welding of Low Carbon Steel

Finite Element Analysis and Experimental Investigation on Effect of Process Parameters in Plasma-Assisted Friction Stir Welding of Low Carbon Steel

In Situ Modification of CaF2-SiO2-Al2O3-MgO Flux Applied in the Aluminium-Assisted Transfer of Titanium in the Submerged Arc Welding of Carbon Steel: Process Mineralogy and Thermochemical Analysis

Flux formulations are specified to target chemical and physico-chemical parameters. Chemical parameters set flux element transfer behaviours and weld metal oxygen contents. Physico-chemical parameters such as slag viscosity, surface tension and melting range are targeted to ensure an acceptable weld bead profile and surface appearance. Slag detachability is an important physico-chemical property required to ensure high welding productivity, smooth weld bead surface and no slag entrapment. Here, bead-on-plate welding tests were made with and without metal powder additions, including aluminium powder as a de-oxidiser. Difficult slag detachability was observed in weld runs made with metal powder additions. Mineralogy of the post-weld slags, and thermochemical calculations, show that the flux was modified due to the aluminothermic reduction of MnO and SiO2 from the slag to form alumina. Increased quantities of spinel phase were identified in the post-weld slag samples, at the weld pool–slag interface. The combined effect of increased slag viscosity, from increased spinel in the slag, and lowered weld pool solidus temperature, resulted in the formation of a rough bead surface morphology, which, in turn, caused mechanical fixation of the slag to the weld bead. Flux modification to higher CaF2 content should ensure that higher quantities of spinel phase can be tolerated in the slag.

Microstructure and Corrosion Resistance of Fusion Welding Zone for Duplextubes Welded with Q345R Tube Sheet under Different Welding Currents

Duplextubes are widely used in oil and gas storage and transportation, the nuclear industry, and other fields, but the welding quality of metals is an important factor affecting the use of equipment. In order to study the welding quality of S10C steel/Incoloy 825 duplextubes and Q345R tube sheet based on gas tungsten arc welding technology with a filler of ER50-6 carbon steel welding wire, the microstructure and grain size of fusion welding zone of duplextubes and tube sheet under welding currents of 150 A, 160 A, and 170 A were studied by optical microscopy and scanning electron microscopy. At the same time, the corrosion behavior of fusion welding zone after the welding was investigated in 3.5 wt.% NaCl solution by potentiodynamic polarization and electrochemical impedance spectroscopy. The results show that the metallurgical structure of the fusion welding zone was mainly composed of δ-ferrite and retained austenite. The grain size in the fusion welding zone increased with the increase of the welding current. The corrosion resistance of the fusion welding zone welded with a high welding current of 170 A was better than that with low welding currents. However, the pitting corrosion resistance of fusion welding zone with the lowest welding current of 150 A was better than that with high welding currents. This study can provide a preliminary exploration for the manufacture and applicability of duplextubes air coolers.

Effect of Heat Treatment Temperature on Tensile Strenght through Welding of Mild Carbon Steel

This study aims to explain how much the tensile strength of mild steel welding without heat treatment and with heat treatment and to explain how much influence the variation of heat treatment temperature of mild steel welding results on the tensile strength. The method used is the experimental method, namely by conducting experiments in the laboratory, taking data directly on the object to be observed then recording the required data in the form of the initial length of the specimen, the length of the specimen after breaking, the diameter of the initial specimen, the diameter of the specimen after breaking and maximum load. The results showed that the tensile strength value of the mild steel welding without heat treatment was 27.07 kgf/mm2, the tensile strength of the specimen welded by heat treatment at a temperature of 5000C was 29.08 kgf/mm2, at a temperature of 6000C was 35.17 kgf/mm2 and at 7000C the tensile strength is 40.06 kgf/mm2.

Analisa Pengaruh Kuat Arus Terhadap Kekuatan Tarik Dan Bending Sambungan Las Kampuh V Menggunakan Las SMAW Dengan Elektroda E6013 Pada Pengelasan Baja Karbon Rendah

Strong current in welding is something that has always been a problem in the welding process. High currents can cause penetration of the welded material, whereas low currents can cause shallow penetration. The purpose of the study was to determine the effect of current on the tensile and bending strength of V seam welded joints using SMAW welding with E6013 electrodes on low carbon steel welding. The research method used is to make a seam on a steel plate with an angle of 60 degrees and then weld it with a different current. The current used is 70, 90, 110 amperes with an electrode diameter of 2.6 mm. The samples that have been welded are then formed into tensile and bending test specimens. The results showed that the highest average tensile stress was 518.310 MPa at a welding current of 110 amperes. The highest average tensile strain is 34.00% at a welding current of 70 amperes. The highest average elastic modulus is 0.01864 GPa at a welding current of 110 amperes. For bending testing at 70 amperes, the fb1 specimen has cracks in the weld metal area with a crack length of 1.00 mm and the fb2 specimen has 0.50 mm cracks, while the 90 amperes fb1 specimen has 1.00 mm cracks, and fb2 specimens have 0.50mm crack. Current 110 amperes fb1 specimen has a crack of 4.70 mm, and fb2 specimen has a crack of 3.00 mm. From the results of the study, a good welding current for a plate with a thickness of 7.5 mm with an E6013 electrode with a diameter of 2.6 mm is at a current of 90 amperes.

Experimental Investigation of TIG Welding Parameters and Weld Joint Strength for Carbon Steel - SA516GR70 Material based on Taguchi Method

This study focuses on experimental study of mechanical characterisation for the carbon steel material SA516GR70, steel alloy welds through tungsten inert gas (TIG) welding process used for the applications of pressure vessel and heat exchanger. Current work describes the preparation of test coupons which is used for sample preparation of tensile, bending and hardness test. Welding process parameters optimization is carried out using Taguchi method for the carbon steel weld material to improve the properties. Using the orthogonal array, experiments are setup and weld joint obtained is used for mechanical testing. Graphs are obtained from the full factorial design using the Mini tab software which is helpful in studying the effects of the parameters on properties. Interpretation of the statistic for various parameters is analysed and the coefficients are determined. Main effects plot, interaction plot and residual plots are plotted which reveal that model fits the data with the average acceptance level of 91.85%.

RETRACTED: Phased array ultrasonic test signal enhancement and classification using Empirical Wavelet Transform and Deep Convolution Neural Network

In the recent past, Non-Destructive Testing (NDT) has become the most popular technique due to its efficiency and accuracy without destroying the object and maintaining its original structure and gathering while examining external and internal welding defects. Generally, the NDT environment is harmful which is distinguished by huge volatile fields of electromagnetic, elevated radiation emission instability, and elevated heat. Therefore, a suitable NDT approach could be recognized and practiced. In this paper, a novel algorithm is proposed based on a Phased array ultrasonic test (PAUT) for NDT to attain the proper test attributes. In the proposed methodology, the carbon steel welding section is synthetically produced with various defects and tested using the PAUT method. The signals which are acquired from the PAUT device are having noise. The Adaptive Least Mean Square (ALMS) filter is proposed to filter PAUT signal to eliminate random noise and Gaussian noise. The ALMS filter is the combination of low pass filter (LPF), high pass filter (HPF), and bandpass filter (BPF). The time-domain PAUT signal is converted into a frequency-domain signal to extract more features by applying the Empirical Wavelet Transform (EWT) algorithm. In the frequency domain signal, first order and second order features extraction techniques are applied to extract various features for further classification. The Deep Learning methodology is proposed for the classification of PAUT signals. Based on the PAUT signal features, the Deep Convolution Neural Network (DCNN) is applied for further classification. The DCNN will classify the welding signal as to whether it is defective or non-defective. The Confusion Matrix (CM) is used for the estimation of measurement of performance of classification as calculating accuracy, sensitivity, and specificity. The experiments prove that the proposed methodology for PAUT testing for welding defect classification is obtained more accurately and efficiently across existing methodologies by providing numerical and graphical results.

Effect of Process Parameters on Interfacial Temperature and Shear Strength of Ultrasonic Additive Manufacturing of Carbon Steel 4130

Abstract Ultrasonic additive manufacturing (UAM) is a solid state manufacturing process capable of producing near-net-shape metal parts. Recent studies have shown the promise of UAM welding of steels. However, the effect of weld parameters on the weld quality of UAM steel is unclear. A design of experiments study based on a Taguchi L16 design array was conducted to investigate the influence of parameters including baseplate temperature, amplitude, welding speed, and normal force on the interfacial temperature and shear strength of UAM welding of carbon steel 4130. Analysis of variance (ANOVA) and main effects analyses were performed to determine the effect of each parameter. A Pearson correlation test was conducted to find the relationship between interfacial temperature and shear strength. These analyses indicate that a maximum shear strength of 392.8 MPa can be achieved by using a baseplate temperature of 400°F (204.4°C), amplitude of 31.5 μm, welding speed of 40 in/min (16.93 mm/s), and normal force of 6000 N. The Pearson correlation coefficient is calculated as 0.227, which indicates no significant correlation between interfacial temperature and shear strength over the range tested.