This study conducted by Xinfeng Li et al. in 2024 addresses the critical issue of hydrogen embrittlement (HE), a significant threat to alloys exposed to hydrogen-containing environments. The research focuses on the role of microstructural interfaces, such as grain boundaries (GB), twin boundaries (TB), and matrix/nano-precipitate interfaces (coherent, semi-coherent, and incoherent), in determining HE susceptibility. These interfaces play a crucial role in the material's response to hydrogen. The study reviews hydrogen-GB interactions (dominant HE mechanisms, crystallographic features of hydrogen-assisted intergranular cracking, and strategies for enhancing HE resistance through GB segregation and GB engineering), hydrogen-TB interactions (the effect of deformation/pre-existing twins on HE susceptibility, four types of TB-related cracking mechanisms, and improving HE tolerance by controlling pre-twins, gradient twins, and twin orientations), and hydrogen-precipitate interactions (hydrogen capacity, hydrogen trapping sites, hydrogen activation energy, and the effect of nano-precipitates on HE). The correlation between HE susceptibility, active HE mechanisms, and their synergy (HELP + HEDE model) with these three types of interfaces is comprehensively summarized and discussed. Additionally, strategies for improving HE resistance through the control of these microstructural interfaces in metallic alloys are proposed.

#HydrogenEmbrittlement #GrainBoundary #TwinBoundary #NanoPrecipitate #HELP_HEDE

For a detailed review, you can access the related study here.

This study conducted by M. Koçak et al. in 2008 presents a Fitness-For-Service (FFS) procedure for the fracture-based assessment of flaws in welded metallic structures and components. The study provides a roadmap that includes the information required for assessment, fracture analysis, reporting of results, and specific fracture assessments. Data quality directly influences the sophistication and accuracy of the analysis. The procedure features a hierarchical structure that allows users to expend minimal effort to achieve acceptable results. Qualitative and quantitative guidance is provided based on the effects of brittle fracture and plastic collapse. These methods can be used to determine the acceptability of specific conditions, the value of critical parameters, safety margins against failure, or the probability of failure.

#FractureAssessment #WeldFlaws #FFS #MetallicStructures

For a detailed review, you can access the related study here.

Bulletin / Circular by Welding Research Council, Inc., 1976

Hydrogen-induced cracking occurs in either the heat-affected zone microstructure or weld metal when four factors interact simultaneously. These factors are defined as (1) presence of hydrogen, (2) welding stresses, (3) a susceptible microstructure, and (4) a low temperature. Hydrogen can be introduced during welding from base and filler materials or external contaminants. With modern steelmaking processes, hydrogen levels have been significantly reduced, particularly in applications within the nuclear industry, where the hydrogen content in weld metal is strictly controlled. However, eliminating hydrogen entirely from initial metallic materials remains challenging. The possibility of introducing hydrogen still exists, for instance, through improperly dried welding fluxes.

Welding stresses are unavoidable and can only be minimized before welding by considering joint geometry, fit-up, external restraint, and the yield strength of the weld metal. The heat-affected zone microstructure depends on the steel composition, hardenability, and post-weld cooling rate, which in turn is influenced by weld heat input, preheating, and thickness. Among these factors, preheat temperature and post-weld holding time are the most controllable during fabrication. Thus, effective preheat control is crucial for reducing hydrogen concentrations (if present) during welding and heat treatment.

#HydrogenInducedCracking | #PressureVesselSteels | #PostweldHeatTreatment | #Preheating | #WeldingTechnology

For a detailed review, you can access the study here.

Bulletin / Circular by Welding Research Council, Inc., 1988

The subcommittee on Pressure Vessel Steels of JPVRC published a study report in 1981 titled "Application of Controlled Rolled Steel Plates for Tank and Pressure Vessel." The data in this report were primarily obtained from line pipe steels with high strength and toughness, based on Nb or Nb-V alloy systems. While the base plate exhibited superior toughness, the toughness of the welded joints was not always sufficient for low-temperature service pressure vessels. Toughness testing was required at temperatures not lower than -20°C.

Over the past five years, low-temperature service steel plates have faced new challenges. The design and fabrication of Arctic offshore structures, icebreaking ships, and pressure vessels for liquefied gas have increased the demand for steel plates with a tensile strength of 500 MPa. These steels needed high toughness not only in the base plate but also in the welded joints, along with compatibility for high heat input welding and preheating-free welding. During this period, both Japanese steel manufacturers and fabricators developed new processes. The steelmakers introduced the Thermo-Mechanical Control Process (TMCP), incorporating accelerated cooling techniques in plate rolling. They have also developed new low-temperature steels meeting these demands. Fabricators, on the other hand, have implemented highly efficient welding technologies. Extensive collaboration between these groups has resulted in a wealth of valuable data on the practical use of these steels and welding methods.

Currently, TMCP has been approved for structural steel production by major ship classification societies, JIS, and ASTM. JIS G 3115 and G 3126 define standard specifications for steel plates used in pressure vessels for intermediate and low-temperature service. ASTM A 841 is the standard for TMCP-produced pressure vessel steel plates and is under discussion as API standard 2W. The specifications and requirements of JIS and ASTM standards are summarized in Table 1.

The new initiative of the JPVRC Pressure Vessel Steels Subcommittee aims to review TMCP and provide unified insights on TMCP steels for structural applications in low-temperature environments. This report compiles the latest data from Japanese steel manufacturers and fabricators on TMCP steels.

#PressureVesselSteels | #TMCP | #LowTemperatureSteels | #WeldingTechnology | #StructuralSteels

For a detailed review, you can access the study here.

Developed by the Electric Power Research Institute (EPRI) and first deployed in 1989, FatiguePro is a widely used fatigue monitoring software that assists with the aging management of nuclear power plants.

The Stress-Based Fatigue (SBF) module in FatiguePro has historically used a single stress term for calculating fatigue usage factors. This simplified approach was chosen not only due to computational limitations at the time but also because conventional stress cycle counting algorithms, which effectively handle random and ordered stress histories instead of idealized transient definitions, are typically limited to a single stress term. However, the United States Nuclear Regulatory Commission (NRC), in Regulatory Issue Summary RIS 2008-30, raised concerns about this simplified approach.

While EPRI will continue to maintain FatiguePro, it is expected that new fatigue monitoring software will be developed by vendors that do not use FatiguePro’s simplified approach.

This report establishes the technical basis for the newly developed multiaxial SBF technology, which addresses the concerns raised by the NRC. It also serves as a requirements specification for SBF computations in fatigue monitoring software and provides a detailed rationale for various technical decisions made during development.

The SBF methodology described in the report includes automatic calculations of environmentally assisted fatigue, in line with applicable regulatory guidance and the latest industry consensus on fatigue calculation methods.

#FatigueAnalysis | #FatiguePro | #NuclearEnergy | #EnvironmentalFatigue | #FatigueMonitoring

For a detailed review, you can access the study here..

Compiled by J.F. Knott and P.A. Withey, this book focuses on the significant advancements in fracture mechanics, evolving from a theoretical foundation to practical applications in component design, service inspection, and safe material usage. The primary objective of this publication is to introduce readers to the concepts of fracture mechanics through a series of WORKED EXAMPLES, demonstrating how fracture toughness values are derived and how this information can be used to prevent failures in service. The book is designed not for experts in fracture mechanics but for those who wish to learn about the subject and its applications.

#FractureMechanics | #MaterialScience | #Engineering | #StructuralIntegrity | #FractureToughness

For a detailed review, you can access the study here.

In this study conducted by Marwah Sabah Fakhri and colleagues, the resistance spot welding (RSW) process for aluminum (Al) and copper (Cu) materials was investigated. Using the Finite Element Analysis (FEA) method, the optimal welding parameters for both similar (Al-Al) and dissimilar (Al-Cu) joints were determined, and the weld nugget diameter was calculated both numerically and experimentally.

Mechanical Properties:

The tensile force results from numerical modeling were compared with experimental findings.

The shear tensile force was measured at 690 N for dissimilar joints and 780 N for similar joints.

Crack Behavior and SIF:

Crack propagation and the Stress Intensity Factor (SIF) were numerically simulated.

Fatigue loading was determined as 414 N (Al-Cu) and 468 N (Al-Al), corresponding to a percentage of the tensile force.

The SIF solutions were validated against existing theoretical models from Pook and Zhang in the literature.

Optimal Parameters:

The optimal welding parameters were determined as:

Welding current: 14,000 A

Electrode force: 8,800 N

Welding time: 1 second

Crack propagation was analyzed under a stress ratio of R = 0.1 and an initial crack length of 0.1 mm.

It was observed that cracks primarily developed near the Heat-Affected Zone (HAZ) surrounding the weld nugget diameter.

The numerical analysis results were found to be consistent with experimental data and existing theoretical SIF solutions.

For a detailed review, you can access the related study here.

The 69th issue of the Welding in the World journal has been released! This edition features significant articles covering the latest research in welding and joining technologies. Here are some of the highlighted topics from this issue:

Studies on Multiple Weld Repairs of M250 Maraging Steel for Solid Motor Casing

P. Manikandan, K. Jalaja, Govind Bajargan

Comparison of Microstructure and Mechanical Properties in Friction Stir Welding of Similar and Dissimilar Aluminum Alloys

Jianhui Wu, Tao Sun, Yifu Shen

Prediction of Ferrite Content in Duplex Stainless Steel Weld Metal: WRC '92 Estimates and Practical Measurements

Lukas Quackatz, Elin Marianne Westin, Sten Wessman

Effect of Silane-Doped Argon Shielding Gases in Gas Metal Arc Welding for S355

Kai Treutler, Philipp Neef, Volker Wesling

Microstructural Studies on Stellite 6 Coating Under Long-Term Aging

Xiaozhou Zhang, Rong Liu, Fadila Khelfaoui

Strength and Embrittlement Mechanisms in Additively Manufactured and Laser-Welded Inconel 718 Superalloy

Atef Hamada, Sumit Ghosh, Antti Järvenpää

Fatigue Performance of HFMI-Treated Transverse Stiffeners

J. Schubnell, M. Burdack, M. Farajian

Unsupervised Machine Learning for Detecting Local Stresses in Fatigue Analysis of Welded Joints

Mehdi Ghanadi, Manoranjan Kumar, Zuheir Barsoum

This issue includes a total of 19 research articles, covering the latest innovations and developments in welding engineering and joining technologies.

For a detailed review, you can access the 69th issue of the journal here.

This study by Jorge Luis García-Jacomino et al. investigates the effects of nitrogen (N₂) atmosphere on the welding parameters (current and voltage) and the properties of filler materials used in self-shielded flux-cored arc welding (FCAW) for hardfacing operations. The study evaluates three different filler materials used for the reclamation of parts exposed to severe wear:

A filler wire with high chromium content.

A filler wire alloyed with both high chromium and niobium.

A filler wire with lower chromium content and titanium alloying.

Research Findings

Welding Parameters and Gas Protection:

The nitrogen (N₂) gas protection changed the welding parameters in filler metal deposition processes performed with a welding machine operating in constant voltage mode. These changes had a significant impact on the mechanical properties and microstructure of the filler materials.

Microstructure and Mechanical Properties:

Optical microscope analysis confirmed the effects of the N₂ atmosphere on the filler material, showing that the operating behavior during the welding process and the microstructure of the filler material were altered.

The effects of N₂ exhibited different characteristics for each of the three wires used.

This study highlights the impact of using nitrogen gas as an additional protective gas, demonstrating its influence on welding operations and the properties of filler materials, contributing to hardfacing processes designed to resist severe wear.

For a detailed review, you can access the related study here.

This study by P. A. Lazarev et al. investigates the effects of Self-Propagating High-Temperature Synthesis (SHS) and pressing methods in the production of Ti–Al–Mg/Ti-based metal–intermetallic materials. The system, composed of elemental powders, was prepared using exothermic synthesis under 10 MPa pressure, and then the hot product was pressed under 250 MPa pressure.

Findings:

Microstructure and Transition Zone:

The SHS pressing process created an inseparable bond between the metal and intermetallic layers.

The transition zone thickness was found to be at least 15 μm.

Energy dispersive analysis (EDA) revealed that Mg was predominantly found in intergranular layers, indicating that full reaction diffusion did not occur between the Ti–Al and Al–Mg layers.

Mechanical Properties:

The microhardness of Ti–Al grains was measured at 5820 MPa, while the Al–Mg-based matrices showed a microhardness of 3980 MPa.

The hydrostatic density was 3.3 g/cm³, and porosity was below 13%.

The porosity of the Ti–Al–Mg alloy obtained by SHS pressing was reduced by a factor of three.

The study highlights the effectiveness of the SHS pressing process in producing Ti-based metal-intermetallic materials with improved microhardness and reduced porosity, though full reaction diffusion between the layers was not achieved.

For a detailed review, you can access the related study here.

This study by Yang Tao et al. investigates the effects of aging conditions on the microstructure and mechanical properties of the Heat-Affected Zone (HAZ) in welded joints of Al–Mg–Si–Cu alloys. The study examined extrusions treated with T4, T5, and T6 heat treatments and analyzed the mechanisms behind the observed softening in the HAZ region.

Findings:

HAZ I:

Hardness increase was linked to the solution hardening mechanism.

In the T4 and T5 conditions, precipitate phases dissolved into the matrix.

In the T6 condition, the insoluble Q phase remained.

HAZ II:

Decrease in hardness was attributed to the limited precipitation of β'' and Q' phases in the T4 condition.

In the T5 and T6 conditions, the dissolution of β'' phase followed by precipitation of Q' and Q phases was the main cause of softening.

HAZ III:

In this region near the base metal, hardness gradually recovered.

This study provides theoretical guidance for the development of high-strength and heat-resistant aluminum alloys by understanding the mechanisms behind the hardness changes in the HAZ under different aging conditions.

For a detailed review, you can access the related study here.

Pavel Doubek et al. conducted a study focusing on determining the geometric parameters of internal defects in protective layers applied via laser cladding on S960 high-strength steel and investigating their effects on fatigue behavior.

In the study, materials such as aluminum bronze, hard chrome, cobalt alloy, and stainless steel were applied to S960 steel using laser cladding technology. Experimental work involved analyzing the morphometric parameters of internal defects at the interface between the two materials using X-ray microtomography. The obtained data were then evaluated in terms of their impact on fatigue behavior during three-point bending tests.

For a detailed review, you can access the related study here.

Editor: Eduardo Valencia Morales
This book aims to bring together a series of articles that present new ideas arising from significant advancements in the understanding of steel over the past few decades. The book discusses the relationship between the structure, composition, and properties of steel, and how these are influenced by environmental factors such as stress, temperature, and strain.

Main topics covered in the book include:

• New approaches and uses of stainless steels
• Behavior of different steel types under environmental factors
• New structural concepts for understanding fatigue processes
• Insights into the mechanisms of strength and toughness in micro-alloyed steels
• Tempering kinetics of low-alloy steels, analyzed using the modified Avrami approach

Each chapter contains an updated reference list to allow readers to delve deeper into specific topics.

For a detailed review, you can access the related study here.

This study by S. Daneshpour et al. investigates the effects of overload on fatigue crack propagation in the welding of aerospace-grade aluminum alloy 2139-T8 sheets using laser beam welding. Using experimental methods and finite element (FE) analyses, the fatigue crack behaviors in 3.2 mm thick welded panels were compared with those of homogeneous base materials.

Crack Tip Plasticity:

Crack tip plasticity in homogeneous M(T) specimens was determined using the Irwin method.

The plastic strain at the crack tip under single overload was calculated for both homogeneous and welded specimens using finite element analysis.

Overload and Crack Delay:

Crack delay caused by overload in the welded specimens was explained using the Wheeler Model.

The crack tip plastic region size was calculated in the welded specimens using the maximum plastic region expansion.

Results:

Single overload resulted in larger fatigue crack delay in welded specimens compared to the base metal.

However, after periodic multiple overloads, the crack delay in low-strength welds was shorter than in the base metal.

This study highlights the effects of overload on fatigue crack propagation in laser-welded joints and demonstrates the applicability of the Wheeler Model for heterogeneous welded structures.

For a detailed review, you can access the related study here.

This study by Marwah Sabah Fakhri et al. investigates the welding of aluminum (Al) and copper (Cu) materials using the Resistance Spot Welding (RSW) process. Using Finite Element Analysis (FEA), the optimal welding parameters for similar (Al-Al) and dissimilar (Al-Cu) joints are determined, and the weld nugget diameter is calculated both numerically and experimentally.

Mechanical Properties:

• Tensile force results were compared between numerical modeling and experimental findings.
• For dissimilar joints, the tensile shear force was measured at 690 N, while for similar joints, it was 780 N.

Crack Behavior and SIF:

• Crack propagation and Stress Intensity Factor (SIF) were numerically simulated.
• The fatigue load was determined as a percentage of the tensile force: 414 N for Al-Cu and 468 N for Al-Al.
• SIF solutions were validated against existing solutions, such as those by Pook and Zhang.

Optimal Parameters:

• The optimum parameters for the process were found to be:

14,000 A welding current

8,800 N electrode force

1-second welding time • Crack progression was examined with a stress ratio of R = 0.1 and an initial crack length of 0.1 mm. • Cracks were observed to generally develop near the heat-affected zone (HAZ) around the weld nugget diameter.

The numerical analysis results align well with experimental data and existing theoretical SIF solutions.

For a detailed review, you can access the related study here.

This study by Mishra, P et al. focuses on the optimization of weld seam properties using Electron Beam Welding (EBW). EBW is considered one of the most precise welding techniques, as it creates a small Heat-Affected Zone (HAZ) by focusing on the weld area with a high depth-to-width ratio.

Research Scope:

The study optimizes parameters such as weld depth and geometry on Nimark 300 maraging steel, commonly used in aerospace sensing applications.

Optimization Tools:

• The study uses the Taguchi optimization tool to determine weld depth and geometry.
• Further analysis is performed using ANOVA (Analysis of Variance).
• Mathematical modeling results are compared with theoretical predictions to validate the findings.

Results:

• Maximum Weld Depth: 50 kV, 6 mA current, 300 mm/min welding speed.
• Maximum Seam Width: 60 kV, 6 mA current, 600 mm/min welding speed.

This study successfully demonstrates the optimization of machine parameters to enhance weld quality, and the alignment of theoretical results with experimental data.

For a detailed review, you can access the related study here.

This study by Liu, S et al. investigates the application of a Ni-Fe-Cr alloy brazing method to increase the bond strength between WC-Co and low-carbon steel (LCS). The process was conducted in a furnace at 1180°C under an argon atmosphere.

Research Findings:

Bonding and Mechanical Properties:

• XRD, SEM, and EPMA analyses were conducted to examine the WC-Co/LCS interface, confirming the absence of cracks or pores and ensuring a strong metallurgical bond.
• The shear strength of the bonded material was measured to be approximately 321-328 MPa, showing a significant improvement compared to values obtained using Ag-Cu-Zn-Cd, Cu-Zn, Cu-Ni-Al, Ag-Cu-Zn + Ni/Mn, and Ag-Cu-In-Ti filler materials.

Diffusion and Phase Transformations:

• EPMA analyses revealed that Fe, Cr, and Ni diffused from the Ni-Fe-Cr alloy into WC-Co, with distances of 802-815 µm, 803-817 µm, and 632-641 µm, respectively.
• Initially, WIC formed at the sharp corners of WC, which then reacted with Fe and Cr to form M6C and M7C3 phases.

Industrial Applications:

• This method was applied in the production of cylinder sleeves for vertical mills, resulting in a 1.9 times increase in the service life of these parts.

For a detailed review, you can access the related study here.

This study by Gourav Rao investigates the tensile properties of dissimilar metal weld joints (DMWJ) between modified 9Cr-1Mo ferritic steel (P91) and 316LN stainless steel (SS 316LN), which are used in liquid metal-cooled fast breeder reactors (LMFBR).

Material Selection and Joint:

• P91 steel is preferred in steam generators due to its creep resistance and resistance to stress corrosion cracking.
• SS 316LN is used in piping systems due to its excellent oxidation resistance and superior creep strength.
• The joint between these two materials is made using nickel-based filler materials such as Alloy 82 and Alloy 182.

Temperature and Mechanical Properties:

• The mechanical properties of the DMWJ were evaluated at room temperature (RT) and 550°C.
• Tensile tests showed heterogeneous mechanical properties across the DMWJ. Specifically, the tensile properties at high temperature (550°C) were significantly lower compared to the values at RT.

Microstructural Effects:

• The complex microstructures developed in the joint regions contributed to changes in mechanical properties.
• Microstructure and microhardness analyses provided a detailed understanding of these changes.

This study provides valuable insights into the reliability and integrity of DMWJ connections operating at high temperatures.

For a detailed review, you can access the related study here.

This study by Ankur Bansod investigates the effect of different filler materials used in welded joints of 430 ferritic stainless steel (FSS) formed by the Tungsten Inert Gas (TIG) welding method. The TIG welding method is commonly preferred for ferritic stainless steel due to its ability to produce high-quality, clean, and precise welds.

Research Details:

This study analyzes the effects of 310 (austenitic) and 410 (ferritic) filler materials on the welded joints.

Microstructural Findings:

The 310 filler material led to a columnar microstructure in the weld.

The 410 filler material caused the formation of a ferritic (acicular ferrite) microstructure, along with martensite and austenite phases.

Mechanical Properties:

Weld samples with 410 filler material exhibited superior mechanical properties compared to those with 310 filler material.

Significant effects of filler material were observed in microhardness, chromium-nickel equivalent ratio, and tensile strength.

These findings emphasize the importance of selecting the appropriate filler material to achieve the desired microstructural and mechanical properties in weld joints.

#mechanicalproperties | #fillermaterial | #microstructure | #weldjoints

For a detailed review, you can access the related study here.

Editor: J. R. Davis

Welding is one of the most important processes in the manufacturing of metallic structures. However, the relationship between welding metallurgy and corrosion is crucial for ensuring the longevity and reliability of these structures. This book, edited by J. R. Davis, thoroughly addresses the corrosion of welded joints.

Content of the Book:

Hydrogen-Induced Cracking: Cracks that occur in steel welded joints due to the effects of hydrogen.

Sensitization and Intergranular Corrosion: Types of corrosion resulting from sensitization in stainless steel welded joints.

Sulfur Stress Cracking: A critical issue seen in steel welded joints used in pipelines.

Microbiologically Induced Corrosion: Types of corrosion triggered by microorganisms in welded joints.

Stress Corrosion Cracking: Cracks caused by stress corrosion in welded joints of various alloys.

Materials Covered:

The book extensively covers ferrous materials, including carbon steels and stainless steels.

It also provides a comprehensive analysis of non-ferrous metals, such as high-nickel alloys, aluminum alloys, and titanium alloys.

Industrial Applications and Testing:

The book also explores the impact of welding corrosion in various industries, the methods used for monitoring and testing this corrosion.

#weldments | #corrosion | #metallurgy | #stresscorrosion | #hydrogencracking

For a detailed review, you can access the related study here.
 

This study by J. Besson et al. focuses on an important industrial issue concerning the safety assessment of welded structures and joints. The research investigates the effect of plastic incompatibility by analyzing a simple diffusion-bonded two-material joint. The study involves the joining of ferritic and austenitic steels, representing components of nuclear pressure vessels.

Experimental Methods:

Tests were conducted using smooth and notched tensile specimens, Charpy V-notch specimens, and single-edge notched bend specimens.

Tests were performed on both homogeneous and two-material samples.

Notch and Interface Effect:

In deep notched specimens, the effect of the distance between the notch root and the interface on crack initiation and propagation direction was investigated.

Numerical Models:

Elasto-plastic finite element simulations were used to model the tests.

Crack initiation was determined according to the "local approach to fracture" procedure, based on the Rice and Tracey criterion.

This study provides a detailed analysis of the effects of plastic incompatibilities at the material interface on crack behavior, contributing to the safety assessment of nuclear pressure vessel components.

#crackinitiation | #ferriteaustenitejoint | #fractureanalysis | #finiteelementmodeling | #localapproach

For a detailed review, you can access the related study here.
 

This study by Abhishek Tripath et al. investigates the friction stir processing (FSP) of AZ31 magnesium alloy in different cooling environments (air, liquid nitrogen, and water), both experimentally and numerically.

Microstructure and Grain Refinement:

During the process, different cooling environments caused the grain size in the mixing zone to refine to varying degrees.

In the water environment, the grain size, which was initially 48 µm, was refined to 3 µm.

Macrostructure and Mixing Zone Sizes:

Significant differences were observed in the mixing zone sizes and temperature profiles, depending on the cooling environment.

Finite Element Analysis:

The numerical analysis of FSP effectively reflected the experimental observations regarding the mixing zone sizes and temperature profiles.

This study examines the effects of different cooling environments on FSP and reveals changes in both micro and macro structural properties of the AZ31 magnesium alloy.

#frictionstirprocessing | #grainrefinement | #finiteelementanalysis | #coolingmediums | #AZ31magnesiumalloy

For a detailed review, you can access the related study here.

This study by Lozica Ivanovic investigates the effects of two different welding procedures on the impact toughness and hardness distribution in welded joints of high-strength low-alloy (HSLA) steels.

Welding Procedures:

Both procedures used the MAG (Metal Active Gas) welding method for filler and cover passes.

First procedure: Root passes were performed using the MMA (Manual Metal Arc) method.

Second procedure: Root passes were carried out using the MIG (Metal Inert Gas) method.

Experimental Findings:

In both procedures, the fracture energy values of the welded samples were lower compared to the base metal. This indicates that the welding process caused some deterioration in the mechanical properties of HSLA steel.

It was noted that welding parameters should be carefully selected to minimize these negative effects.

This study emphasizes the need to optimize welding technologies and provides a comparative analysis of the effects of different welding methods on the mechanical properties of HSLA steels.

#HSLAsteels | #impacttoughness | #microhardness | #weldingprocedure | #Vbuttweld

For a detailed review, you can access the related study here.

This study by Uğur Gürol et al. investigates the mechanical and ballistic performance of an innovative sandwich joint design used in welded connections of armor steels. Armor steels are particularly known for their mechanical and ballistic performance in the production of armored vehicles. However, welding with austenitic stainless steel (ASS) wires can result in a decrease in ballistic performance due to material incompatibility. This issue was addressed through a sandwich layer design in which low-hydrogen ferritic (LHF) filler layers are placed between the softer ASS weld layers.  

Experimental Findings:

Mechanical Properties: Hardness, tensile strength, and Charpy V-notch impact tests were conducted. Impact toughness in the WM and HAZ regions was measured at 31.4 J and 65 J, respectively, which are higher than the 20 J measured for the base material.

Ballistic Performance: The penetration depth (DoP) was found to be 7.2 mm, and the penetration width (WoP) was 12.5 mm. These values improved the weld zone's resistance to ballistic threats while maintaining mechanical integrity.

Microstructural Analyses:

Stereo, optical, and scanning electron microscopy analyses revealed that the sandwich structure design optimized the toughness and ductility properties.  

This innovative sandwich joint design offers an effective method for enhancing ballistic performance and strengthening weak areas in welded connections of armor steels.  

#armorsteels | #sandwichjoints | #mechanicalproperties | #ballisticperformance | #weldingdesign

For a detailed review, you can access the related study here.

This study by Agata Wieczorska et al. examines the operating parameters and welding conditions used in the Submerged Arc Welding (SAW) of S355JR structural steel. The study was conducted on samples welded in compliance with the PN-EN 15614 standard.

Research Findings:

The variation in weld penetration depth based on different welding parameters applied to the samples was analyzed.

Based on the results, linear energy for the welding parameters was calculated.

Key Points:

Penetration Depth: The depth of the weld pool was evaluated as a critical parameter influencing weld quality.

Linear Energy and Penetration: The study revealed the relationship between welding parameters and linear energy, offering key insights for optimizing penetration.

This study provides valuable data on penetration depth and linear energy calculations for S355JR steel joints welded using the SAW method.

#SAW | #structuralsteel | #penetration | #linearenergy | #depthoffusion

For a detailed review, you can access the related study here.

This study by Manjarekar S.S et al. focuses on optimizing the parameters of the Submerged Arc Welding (SAW) process. SAW is a widely used, established, and high-quality automated welding method for metal joining operations.

SAW Process Mechanism:

SAW involves generating an arc between a continuously fed electrode and the workpiece, melting the metal in the joint area while supplying additional filler material. The process is conducted under a granular flux covering.

During the process, heat effects depend on the electric arc, type of flux, and the thermal field within the workpiece. These factors are key to analyzing and optimizing the SAW process.

Features of the Study:

Tools such as RSM (Response Surface Methodology), ANOVA, MINITAB software, and S/N ratio were employed to optimize SAW parameters.

The thermal field of copper was analyzed to evaluate the effects of thermal conditions on different metallic materials.

This study provides significant insights into improving the efficiency of the SAW process and optimizing weld quality.

#SAW | #weldingoptimization | #thermalanalysis | #RSM | #ANOVA

For a detailed review, you can access the related study here.

This study by N.D. Jadhav et al. focuses on determining the optimum weld bead geometry for the Submerged Arc Welding (SAW) process to improve the quality of welded joints.

Scope of the Study:

Input parameters such as welding current, welding voltage, welding speed, and stick-out were evaluated.

Outputs such as weld bead width and reinforcement were identified as response variables.

Methodology and Findings:

An experimental approach using a two-level factorial design was adopted.

A mathematical model was developed through multiple regression analysis, which was used to determine the effects of input parameters on the outputs.

Results:

Current and stick-out showed a positive effect on reinforcement.

Speed and stick-out negatively affected weld bead width.

This study provides valuable insights for optimizing weld quality by analyzing the relative effects of welding parameters on the outputs.

#SAW | #sensitivityanalysis | #weldbeadgeometry | #multipleregression | #optimisation

For a detailed review, you can access the related study here.

This study, conducted by Rudra Pratap Singh et al. , focuses on optimizing the Submerged Arc Welding (SAW) process to achieve high-quality weld joints in thick metal materials.

Input Parameters:

Key input parameters influencing weld quality in the SAW process include welding current, welding voltage, wire feed rate, and carriage travel speed.

Research Methodology:

In the study, 16 welded joints were trained using artificial neural networks (ANN) implemented in a C++ program. Additionally, nine welded joints were used for testing and validation.

The program was designed to predict the optimum values of workpiece hardness based on known input parameter values (current, voltage, feed rate, and travel speed).

Results and Findings:

A sensitivity analysis was performed to evaluate the effects of input parameters on weld hardness.

The input parameter values required to achieve optimum hardness were successfully predicted.

This study demonstrates that artificial neural networks can be an effective method for optimizing hardness values in welding processes.

#SAW | #hardnessoptimization | #artificialneuralnetworks | #processparameters | #sensitivityanalysis

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This study by Hambal Iqbal et al. compares the use of cored and solid wires in variants of the Wire Arc Additive Manufacturing (WAAM) process, specifically gas metal arc (GMA) and plasma transferred arc (PTA), for 2.25Cr-1Mo steel.

Experimental Studies:

Bead-on-plate trials were conducted for both WAAM processes, evaluating different shielding gas combinations and cored wire usage.

Heat input and deposition rate were analyzed to assess the effects of shielding gases.

Arc behavior was monitored using a process camera, and weld pool morphologies and dilution rates were compared.

Results and Findings:

Heat Input: Cored wire usage provided lower heat input; shielding gas selection introduced variability in heat input.

Microstructure and Hardness:

Bainitic/martensitic microstructures were observed in samples produced with both cored and solid wires.

The PTA process yielded higher hardness values compared to GMA. Additionally, solid wire usage provided slightly higher hardness than cored wire.

Shielding gas selection had a significant effect on hardness.

EDS Analyses:

Element distribution and segregation showed similar results for both wire types.

This study highlights the effectiveness of cored and solid wire applications in WAAM processes, detailing how shielding gas selection and heat input affect microstructural and mechanical properties.

#WAAM | #GMAW | #PTA | #coredwire | #microstructure

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Winston Revie and Herbert H. Uhlig

This book serves as a comprehensive reference on the fundamental principles of corrosion science and engineering. Corrosion management is critically important for the effective and efficient use of materials in addressing today’s three major global challenges: energy, water, and air.

Key Topics of the Book:

Corrosion Management and Applications:

The role of corrosion control in high-pressure steel pipelines, the design and operation of nuclear power plants, and nuclear waste management.

Protective strategies for metals and alloys such as steel, aluminum, magnesium, and titanium.

The impact of environmental regulations like the EPA Lead and Copper Rule on corrosion control.

From Fundamentals to Specific Applications:

Fundamental scientific tools such as Pourbaix diagrams, thermodynamic and kinetic analyses.

New alloys, protective coatings, and technologies used in various industries.

Current Technologies and Research:

Modern measurement methods such as galvanic series, critical pitting temperatures (CPT), and critical pitting potentials (CPP).

Corrosion of steel reinforcements in reinforced concrete structures and durability demands in nuclear reactors.

Target Audience:

This book is designed as a textbook for students who need foundational knowledge of corrosion science and engineering. It is also a starting point and reference resource for researchers and engineers.

#corrosioncontrol | #metallurgy | #materialscience | #corrosionengineering | #naturalresources

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This study, conducted by D. R. G. Achar et al., examines the effects of dissolved nitrogen in ferritic steel weld metals on toughness and strain aging embrittlement. The study evaluated nitrogen content ranging from 80 to 210 ppm (wt) in C-Mn steel weld metals produced using the manual metal arc (MMA) method.

Research Methods:

Samples were tested under four different post-weld conditions:

As-welded (untreated),

Stress-relieved,

Artificially strain-aged,

Both artificially strain-aged and stress-relieved.

Microstructure and Microhardness: Quantitative metallography and low-load microhardness analyses were applied to assess microphases.

Findings:

Detrimental Effect of Nitrogen: High nitrogen content significantly reduced the toughness of C-Mn steel weld metals, especially under strain-aging conditions.

Microstructural Changes: A reduction in the amount of acicular ferrite was observed alongside an increase in primary ferrite and secondary phase ferrite content. A notable increase in the microhardness of acicular ferrite was also recorded.

Stress Relief Heat Treatment: For weld metals with low nitrogen content, stress-relieving only provided limited improvement, changing fracture behavior from brittle to ductile or semi-ductile.

Comparison of Test Results: Crack tip opening displacement (CTOD) test and Charpy test results showed similar trends in nitrogen's impact on toughness. However, the fracture mechanics approach yielded more conservative results.

This study highlights the detrimental effects of nitrogen content on the microstructure and mechanical properties of weld metals, emphasizing the importance of controlling nitrogen levels.

#ferriticsteel | #weldtoughness | #strainageing | #fracturemechanics | #nitrogeneffects

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