Steel Weld Research Articles

Research on Mechanical Properties of High‐Manganese Steel Coating Manufactured by Coaxial Powder‐Feeding Laser Cladding

Due to the process complexity of the high‐carbon high‐manganese steel (HMnS) in casting and arc welding, this article propose the coaxial powder‐feeding laser cladding (LC) of HMnS coating using self‐developed HMnS powders. Firstly, high‐carbon HMnS coatings are prepared on the 16Mn substrate using coaxial powder‐feeding LC technology. It has a single austenite phase, without large defects such as pores and cracks. Then, ultrasonic shock peening is used to harden the HMnS coating, and the mechanical properties such as microhardness, impact toughness, wear and tensile properties are measured, which prove that HMnS coating has excellent working hardening, plasticity, toughness, and wear resistance properties. Finally, transmission electron microscopy is used to investigate the coupling effects such as dislocations, multiple twinning, and stacking faults on the HMnS coating after tensile fracture (true strain 39.2%). The deformation strengthening mechanism based on the dynamic Hall–Petch effect is revealed. The research results provide a new method for the preparation of high‐carbon HMnS coatings, and a new idea for expanding the application of high‐carbon HMnS.

Electrochemical Analysis on Intergranular Corrosion of Austenitic Stainless Steel Weld in Molten Nitrate Salt

An investigation of intergranular corrosion (IGC) sensitization in molten nitrate salts of austenitic stainless steel welds of AISI 304, AISI 304H, and AISI321 produced by GTAW with ER 308L and ER 347 fillers was performed. The degree of sensitization (DOS) to IGC was assessed using a double loop electrochemical potentiokinetic reactivation and pitting potential. It was found that DOS levels in weld zones were quite low, not exceeding 15%, while those in HAZs were up to 60% after exposure at 600 °C for 300 h. The low DOS levels were due to low carbide precipitation. However, another cause of DOS was the delta-ferrite to sigma transformation in weld zones. Linear sweep voltammetry was used to quantify the sigma phase.

Effects of laser power on the microstructure, mechanical properties, and corrosion resistance of welded joints in dissimilar laser welding of 05Cr17Ni4Cu4Nb stainless steel and HR-2 stainless steel

Effects of laser power on the microstructure, mechanical properties, and corrosion resistance of welded joints in dissimilar laser welding of 05Cr17Ni4Cu4Nb stainless steel and HR-2 stainless steel

Exploring Through-Thickness Residual Stress Distribution in Double V-Groove Multipass Welds of High-Strength Low-Alloy Steel and the Impact of Mechanical Restraints

Exploring Through-Thickness Residual Stress Distribution in Double V-Groove Multipass Welds of High-Strength Low-Alloy Steel and the Impact of Mechanical Restraints

On the evolution of root weld microstructure and properties during automatic girth welding of high strength pipeline steel

ABSTRACT Properties of root weld are important for service safety of pipelines, while microstructure and properties of root weld would alter due to heat affect of following welding passes. Evolution of root weld microstructure and properties during automatic girth welding of X80 pipeline was studied. Microstructure of the original root weld primarily consists of acicular ferrite (AF) and side-plate ferrite (SPF), and it is mostly affected by hot pass and first filling pass weld, after which SPF and AF coarsened significantly and some interlock ferrite combined with each other. During subsequent welding, no significant microstructural changes was found. However, impact toughness of root weld slightly increased after hot pass and first filling pass in spite of microstructure coarsening. In contrast, hardness of root weld notably dropped due to microstructure coarsening of hot pass and first filling pass, and then it was retrieved in following welding passes due to tempering effect.

Study on microstructure and sliding wear behavior of similar and dissimilar welded joints produced by laser-arc hybrid welding of wear-resistant steels

Study on microstructure and sliding wear behavior of similar and dissimilar welded joints produced by laser-arc hybrid welding of wear-resistant steels

Stress Corrosion Cracking of Stainless Steel Weldments in Nuclear Power Plants

Stress Corrosion Cracking of Stainless Steel Weldments in Nuclear Power Plants

Mn vaporization control and stress-induced martensite transformation in high-manganese steel welds under different laser keyhole conditions

Vaporization modeling of high-Mn steel during laser welding, along with the effects of Mn vaporization on the tensile properties at room and cryogenic temperatures, were investigated for various laser defocusing (LD) conditions. The LD10 exhibited a full penetration keyhole, while LD20 showed a partial penetration keyhole. The vaporization modeling based on computational fluid dynamics (CFD) analysis confirmed that a significant Mn flux occurred in LD20, which corresponded with the most substantial loss of Mn observed in the partially penetrated weld. The room temperature tensile testing showed a slight increase in the yield strength and a minor reduction in tensile elongation for LD20, which could be attributed to the stress-induced ε-martensitic transformation. In cryogenic tensile testing, LD20 exhibited a higher yield strength with more martensitic transformation, including some stress-induced α′-martensitic transformation observed. Through the vaporisztion modeling, significant Mn vaporization in LD20 was found to decrease the stacking fault energy, which enhanced stress-induced martensite transformation and yielding stress during tensile deformation at 110 and 298 K.

Ultrasonic Total Focusing Method Technology in Carbon Steel Butt Weld Application

Carbon steel butt welds are widely used in aircraft carrier, shipbuilding, railway, aerospace and other industries. As a new technology of ultrasonic non-destructive testing, Total Focusing Method (TFM) technology is a method of image reconstruction in which the value of each constituent datum of the image results from focused ultrasound. TFM may also be understood as a broad term encompassing a family of processing techniques for image reconstruction from full matrix capture (FMC). This paper compares resolution and focus between TFM and conventional phased array technology, by using phased array test block type B. The paper also introduces the testing system, including equipment, probe, wedge, calibration block as per ASME, PC analysis software, for detection of 21mm thickness carbon steel welds. In order to improve the defect detection ability, a customized software on board was designed based on TFM technology, and an appropriate propagation mode was adopted for different types of defects, such as longitudinal cracks on surface, lack of fusion, porosities, slag inclusions. The test results showing that compared with conventional phased array technology, the defect information such as length and depth detected by TFM are nearer to the actual situation, and the shape is closer to the physical one. TFM technology has more advantages in quantitative and qualitative capabilities in testing carbon steel butt welds, and can meet the requirements of on-site testing.

Effect of Submerged Arc Welding (Saw) Parameters on Aisi 1020 Steel

Abstract: This research investigates the Submerged Arc Welding (SAW) process applied to AISI 1020 steel plates (450 mm x 300 mm, 12 mm thickness). A V-groove shape was prepared for welding using Tungsten Inert Gas (TIG) rooting. To achieve optimal results, welding parameters such as current, voltage, and travel speed were optimized. Following this experimentation phase, parameter selection was guided by a comprehensive literature review. Microstructure observations for the welded bead, HeatAffected Zone (HAZ), and base metal were then reviewed in the existing literature, highlighting this study's unique focus on parameter optimization. The findings provide valuable insights for industries relying on welded components, enhancing quality and reliability in AISI 1020 steel welding applications.

Influence of adjustable ring modes on molten pool behavior and microstructure of Al–Si coated boron steel in fiber laser welding

The influence of adjustable ring modes on the phase transition and microstructural evolution in conduction mode laser welding of Al–Si coated boron steel was investigated. Distinct geometric variations and molten pool behavior were observed through a ring-shaped beam effect. The ring beam introduced by ring-beam-mode (RBM) and dual-beam-mode (DBM) laser welding inhibited Al segregation into the fusion zone (FZ). The ring beam caused the Al molten particles to be driven towards the outer boundaries of the weld pool. A ring-beam-mode (RBM) and a dual-beam-mode (DBM) laser welding inhibited Al segregation into the FZ, resulting from a minimal temperature gradient and extension of the solidification time. Phase transition calculations demonstrated that a mount of residual ferrite within the FZ is significantly correlated with the Al concentration at specific temperature points, indicating a predominant role of a central-beam-mode (CBM) FZ in δ-ferrite formation. The RBM and DBM effectively suppressed Al segregation into the FZ, leading to a reduction in ferrite formation and the development of a refined microstructure characterized by a uniform and high density of geometrically necessary dislocations. Electron backscattered diffraction (EBSD) analysis revealed a higher proportion of low-angle grain boundaries in the RBM and DBM, attributed to the unique thermal distribution induced by the ring beam. These findings highlight the critical role of beam mode in tailoring the microstructure and properties of laser welds in Al–Si coated boron steel.

Experimental Investigation of Temperature Field, Fusion Zone Microstructure and Mechanical Properties During Dissimilar Laser Welding of Nickel-Base Alloy and Duplex Stainless Steel

Experimental Investigation of Temperature Field, Fusion Zone Microstructure and Mechanical Properties During Dissimilar Laser Welding of Nickel-Base Alloy and Duplex Stainless Steel

Optimization of the Thermokinetic Method for the Control of Weld Decay in AISI 304L and AISI 316L Stainless Steel Weldment

This study investigates the control of weld decay in AISI 304L/316L alloy weldments for liquefied natural gas (LNG) and cryogenic environments using the Tungsten Inert Gas (TIG) welding technique. Weldment samples were thermokinetically treated at 1050, 1100, and 1150°C and cooled in five mediums: Water, Salt, Natural Air, Salt with annealing, and Water with annealing, to retain carbon and chromium in solid solution at approximately 30°C. Furthermore, evaluation methods based on metallography i.e. optical microscopy (OM), Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDX), Wear Test (i.e. wear rate and wear track) and electrochemical corrosion potential measurements were adopted. An experimental design table was developed using the design expert software 13.0. This helped develop a predictive mathematical model for ascertaining the optimum operating service conditions of the material. From the results, the optical microscopy analysis revealed that the control sample exhibited a more irregular pattern than others. Results showed that the control sample had a more irregular structure, while air-cooled samples exhibited smoother surfaces, indicating better bonding. SEM revealed a coarse surface with uneven particle distribution post-heat application. The predominant elements were Iron (Fe), Chromium (Cr), and Nickel (Ni). Corrosion potential varied between -0.5 to 0.15 V, demonstrating wave-like behaviour over time. Wear analysis indicated that lower coefficients of friction correlate with better wear resistance. Finally, response surface methodology (RSM) revealed that increasing temperature proportionally increased yield and corrosion rates. While the identified optimal values for Temperature are (1112.68°C), Material (316L), and Quenching Medium (SQ+SA), resulting in specific values such as Wear Rate (5.76896E-06), Coefficient of friction (0.224254), Corrosion Rate (0.395566), and Weight of Heat-Treated Sample (14.7797). The study enhances understanding of the mechanisms affecting welding and contributes to optimizing welding procedures for improved mechanical properties and corrosion resistance.

Effect of Precipitation Behavior and Deformation Twinning Evolution on the Mechanical Properties of 16Cr–25.5Ni–4.2Mo Superaustenitic Stainless Steel Weld Metals

Effect of Precipitation Behavior and Deformation Twinning Evolution on the Mechanical Properties of 16Cr–25.5Ni–4.2Mo Superaustenitic Stainless Steel Weld Metals

Characterization of physical metallurgy of quenching and partitioning steel in pulsed resistance spot welding: A simulation-aided study

This study mainly focuses on the microstructure evolution of QP980 steel during resistance spot welding and its influence on the mechanical performance of resistance spot welds which is a critical influencing factor on the quality of body-in-white at the service condition. It is observed that the thermomechanically engineered microstructure of QP980 steel changes to form metastable phases such as martensite in the fusion zone and the heat affected zone due to rapid cooling induced by the thermal cycle of the welding. A finite element modeling of the welding process was used to predict the weldment heat distribution, thermal history and microstructure evolution in different welding zones. The modeled thermal history of the weldments shows that the peak temperature in the four-pulse resistance spot welding is delayed because of pulsed welding conditions and holding times between the welding pulses. This heat management approach in pulsed welding prevents void formation. The modeled thermal history and rapid heating, and cooling conditions are discussed here to predict the microstructure evolution and transformation in the fusion and reheated zones. The modeled results were helpful in the prediction of the microstructure at different weld zones. Then the strategic links between the microstructure and mechanical performance of the welded alloy are discussed thoroughly. The microhardness profile of the weld is discussed from a microstructural point of view to disclose the physical metallurgy of the welds. Softening phenomena were not observed in the sub-critical heat affected zone.

Structure and properties of the welded joint during arc welding of low-carbon steel under a layer of flux obtained from metallurgical slag of electric steelmaking

The results of the study of the influence of the thermophysical properties of the welding flux obtained by processing man-made waste of electric steelmaking (metallurgical slag) on the structure and properties of welded butt joints of thin-sheet low-carbon steel, with automatic arc welding on ceramic linings, are presented. Welding modes have been established using the developed flux, contributing to the achievement of seam sizes according to GOST8713–79, C4 joints, compliance with the mechanical properties of joints close to the base metal and ensuring a minimum level of welding deformations and stresses.

A novel dissimilar resistance spot welding of Ti6Al4V alloy and 316L stainless steel via copper as interlayer by using optimal electrodes

A novel dissimilar resistance spot welding of Ti6Al4V alloy and 316L stainless steel was performed via copper as interlayer by using optimal electrodes. A significant improvement in nugget morphology being of less defects was achieved with increasing the copper interlayer thickness from 50 μm to 400 μm. Thinner interfacial reaction layers at both the nugget/titanium interface and the nugget/stainless steel interface and finer equiaxed dendritic grained structure at the inner nugget were formed with copper interlayer thickness of 300 μm compared with those without interlayer. The formation of TiCu and Ti2Cu was facilitated with the incorporation of Cu into the nugget, which effectively inhibited the formation of the brittle Ti–Fe intermetallic compounds including Fe2Ti. The nugget in the welded joint with copper interlayer in 300 μm thickness exhibited a far lower microhardness than that of the interlayer-free welded joint, and the average microhardness reduced to 604 HV in the inner nugget, which was about 36% lower than that of the interlayer-free welded joint. The tensile shear load of the welded joint exhibited an increased tendency with increasing interlayer thicknesses from 50 μm to 300 μm, and the maximum tensile shear load of 6.3 kN was obtained with the interlayer thickness of 300 μm, which was ∼97% higher than that of the interlayer-free welded joint. The welded joint with copper interlayer exhibited hybrid ductile and fragile fractured characteristics. The work would provide a facile and cost-effective method to achieve a reliable welded joint of Ti alloy and stainless steel.

Flux-bound TIG welding on UNS S32760 super duplex stainless steel using activating fluxes

In this article, the effect of activating flux powders viz., Silicon Dioxide (SiO2), Chromic Oxide (Cr2O3), Titanium Dioxide (TiO2) and Vanadium Pentoxide (V2O5) on Flux-Bound TIG (FB-TIG) welding of UNS S32760 Super Duplex Stainless Steel (SDSS) is investigated. Also, conventional TIG welding is done for a comparative study with the FB-TIG welds. The macrographs of the welds are obtained to analyze the depth, width and aspect ratio. The depths obtained with all the fluxes are found to be superior relative to the conventional TIG welds. The highest penetration of 6 mm is obtained for V2O5 welds. Then the microstructure and composition of the welds are analyzed using Optical Microscopy and Area-Mapping analysis. The authors observed the presence of three forms of austenite viz., Grain Boundary Austenite, Intragranular Austenite and Widmanstatten Austenite in the weldment zones. The micro-hardness profiles of the welds are also analyzed, and the profiles obtained with all the FB-TIG welds are found to be relatively smoother without any abrupt variations. Through this investigation, it is delineated that FB-TIG welding can increase the overall productivity in the welding of SDSS, as the penetration obtained is up to thrice relative to the conventional TIG welding.

Numerical simulation and modeling of the trielectrode-coupled corrosion mechanism at the laser-welded interface of N80 steel

Laser welding, a prevalent technique in automotive structure manufacturing, can introduce compositional disparities and stresses within the weld zone, exacerbating corrosion complexity at the weld interface. This paper develops a triple galvanic corrosion model for N80 steel welds under stress conditions, leveraging the COMSOL software for simulations. The findings demonstrate that, within the elastic stress range, an elevation in stress intensifies the overall electrode surface potential, ultimately transitioning into plastic stress and fostering a more negative potential. This, in turn, amplifies the cathode-anode potential difference, rendering the material more susceptible to corrosion. The deeper the depression between the weld zone and the heat-affected zone, the higher this potential difference becomes, exacerbating the corrosion risk. Under stress, the corrosion rate markedly surpasses that observed in unstressed conditions. During the 160 day corrosion period, the weld seam and heat affected zone undergo a transition from plastic strain to elastic strain, while the base metal zone experiences both plastic strain and elastic strain simultaneously. This dynamic strain evolution leads to temporal variations in the stress-induced cathode-anode potential differences. In comparison to stress-free corrosion scenarios, the impact of stress on the cathode-anode potential difference initially intensifies, yet this effect tapers off over time.

Correction: Optimizing Advanced High-Strength Steel Welds: The Role of Regional Pre-heating in the Heat-Affected Zone

Correction: Optimizing Advanced High-Strength Steel Welds: The Role of Regional Pre-heating in the Heat-Affected Zone