scholarly journals Microstructure and Performance Analysis of Welded Joint of Spray-Deposited 2195 Al-Cu-Li Alloy Using GTAW

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1236
Author(s):  
Chuanguang Luo ◽  
Huan Li ◽  
Yonglun Song ◽  
Lijun Yang ◽  
Yuanhua Wen
Keyword(s):  
Spray Deposition ◽  
Welding Process ◽  
High Strength ◽  
Fine Crystal ◽  
Factors Affecting ◽  
Gas Tungsten Arc ◽  
Welding Thermal Cycle ◽  
Gtaw Process ◽  
And Performance ◽  
Grain Misorientation

High-strength aluminum alloy fabricated using spray deposition technology possesses many advantages, such as fine crystal grains, low component segregation, uniform microstructure, and small internal stress. In this study, spray-deposited 2195 Al-Cu-Li alloy in forged state was used and welded using the gas tungsten arc welding (GTAW) process to test and verify the features of the fusion joint. Quantitative analysis was carried out to evaluate the relationship between the local microstructures and performances of the fusion joint, which was composed of four zones: weld metal, fusion zone, heat-affected zone, and base metal. The characteristic quantities of each zone, including recrystallized grain fraction, grain sizes, grain misorientation angle, and Vickers hardness, and their distributions were considered as the key factors affecting the performance of the joint because of welding thermal cycle impact on the fusion joint. To recognize the metallurgical characteristics of spray-deposited alloy 2195, a statistical algorithm based on the concept of the Hall–Petch relationship was proposed to validate the actual test results, which include the correlation effects of both the filler wire and welding process. The correlation between the microstructures and performances of several characteristic quantities were evaluated by integrating the above characteristic information of the fusion joint under the strong coupling of multiple factors. Thus, the advantages of weldability of spray-deposited alloy 2195 using GTAW could be understood in detail.

Investigation of Residual Stresses Distribution in Titanium Weldments

2014 ◽  
Vol 777 ◽  
pp. 171-175 ◽  
Author(s):  
Shao Pin Song ◽  
Anna M. Paradowska ◽  
Ping Sha Dong
Keyword(s):  
Residual Stresses ◽  
High Performance ◽  
Weight Ratio ◽  
Welding Process ◽  
High Strength ◽  
Naval Research ◽  
Office Of Naval Research ◽  
And Performance ◽  
Superior Corrosion Resistance ◽  
The University

Titanium and its alloys have increasingly become a material of choice for applications in high-performance structures due to their superior corrosion resistance and high strength-to-weight ratio. However, in contrast to conventional steel alloys, there exist little design and manufacturing experience in the heavy fabrication industry with large welded structures made of titanium materials. In addressing the above concern, the University of New Orleans funded by Office of Naval Research (ONR) initiated program on investigation of manufacturability and performance of a titanium mid-ship section. The uniqueness of this program is its focus upon a representative full-size mid-ship section upon which relevant scientific and technological challenges are simulated and experimentally validated. This paper reports the measurements of residual stresses using neutron diffraction in titanium T-joints. The residual stresses were measured using Engin-X at ISIS (UK) and the Kowari Strain Scanner at ANSTO (Australia). This experimental research was used to validate our in house predictions and significantly improved the knowledge and understanding of the welding process of titanium alloys.

Ambient Temperature Temperbead Welding Using the Underwater Laser Beam Welding Process

2010 ◽  
Author(s):  
Bruce Newton
Keyword(s):  
Laser Beam ◽  
Ambient Temperature ◽  
Laser Beam Welding ◽  
Welding Process ◽  
Nuclear Industry ◽  
High Quality ◽  
Gas Tungsten Arc ◽  
Class 1 ◽  
Gtaw Process ◽  
Underwater Laser

Ambient temperature temperbead welding using the Machine Gas Tungsten Arc Welding (GTAW) process is widely accepted in the nuclear industry. GTAW machine ambient temperature temperbead welding, addressed in ASME Code Case N-638, has been used to repair ASME Class 1 components in numerous safety related applications. Underwater laser beam welding (ULBW) is gaining increasing industry recognition as a method for producing high quality welds in high radiation environments. Since ULBW enables high quality weld deposition in underwater environments, the process enables water to serve as a radiation moderator, reducing personnel exposure levels. ULBW’s advantages go beyond radiation exposure reductions, and this paper will provide the reader a better understanding of the ULBW process’s capabilities and properties. A recently formed ASME Task Group is preparing a new Code Case that will delineate specific requirements and essential variables governing use of ULBW to repair ASME Class 1 components. In addition, this Code Case will provide specific rules for use of the ULBW process for ambient temperature temperbead welding. Extensive testing has been performed to demonstrate ULBW’s capabilities with regard to ambient temperature temperbead welding in an underwater environment, and this paper summarizes testing and test results. It also provides a technical summary of the new Code Case, it’s requirements, and summarizes several of the bases for these requirements.

Weldability of High-Mn Austenitic Twinning-Induced Plasticity (TWIP) Steel Microalloyed with Nb

MRS Advances ◽  
2017 ◽  
Vol 2 (62) ◽  
pp. 3899-3908 ◽  
Author(s):  
I. Mejía ◽  
H. Hernández-Belmontes ◽  
C. Maldonado
Keyword(s):  
Heat Affected Zone ◽  
Twip Steel ◽  
Research Work ◽  
Welding Process ◽  
X Ray Diffraction ◽  
Austenite Stability ◽  
Gas Tungsten Arc ◽  
Solution Condition ◽  
Gtaw Process ◽  
Arc Welding Process

ABSTRACTThe objective of this research work is to study the weldability of a Nb microalloyed TWIP steel through welding nuggets generated by Gas Tungsten Arc Welding process. Weldability was examined by microstructural changes in the fusion zone (FZ) and heat affected zone (HAZ) using light optical metallography (LOM), segregation in the nuggets was evaluated using elemental mappings of chemical analysis by Scanning Electron Microscopy and Electron Dispersive Spectroscopy (SEM-EDS), phase transformations were evaluated using X-ray diffraction (XRD) and the hardness properties were examined using Vickers microhardness testing (HV25). Experimental results show that microstructure of welding nuggets consists of austenitic dendritic grains in the FZ and equiaxed grains in the HAZ. FZ width and HAZ grain growth tend to increase as the heat input increases. Additionally, the studied Nb-containing TWIP steel showed segregation in the FZ, where Mn and Si segregated in the interdendritic regions, while Al and C preferentially segregated in dendritic areas. In general, the data obtained by XRD indicated that GTAW process did not affect austenite stability. Finally, the welding nuggets of studied TWIP steel showed lower microhardness values than the as-solution condition (starting condition). However, the heat affected zone showed hardened areas, which are associated with NbC precipitation hardening.

Validation of Fabricability for ITER TF Coil Structures

2011 ◽  
Author(s):  
Yutaka Chida ◽  
Masahide Iguchi ◽  
Hideo Nakajima ◽  
Koichi Oosemochi ◽  
Kenichiro Niimi ◽  
...  
Keyword(s):  
Welding Process ◽  
High Strength ◽  
Superconducting Magnet ◽  
Full Scale ◽  
Angular Distortion ◽  
Magnet System ◽  
Energy Agency ◽  
Superconducting Magnet System ◽  
Gtaw Process ◽  
Coil Winding

The ITER superconducting magnet system consists of 18 Troidal Field (TF) coils, 6 Central Solenoid (CS) modules, 6 Poloidal Field (PF) coils and 18 Correction coils. The Japan Atomic Energy Agency (JAEA), acting as the Japan Domestic Energy Agency (JADA) in the ITER project, is responsible for the procurement of 9 TF coil winding packs (WP), structures for 19 TF coils, (including one spare), and assembly of the WP and the coil structures for 9TF coils [1]. TF coil structures, which support large electromagnetic force generated in TF coils under the cryogenic temperature (about 4K), are the mega welding structures composed of coil case and support structures made of heavy thickness high strength and high toughness stainless steel. JAEA started the study on welding trials for the materials to be used since 2008 and have been demonstrating of full scale mock-up model fabrication for main sub-components since 2010. This paper introduces the results on welding trials and status of full scale mock-up model fabrication before fabricating actual products. Enough weld joint performance was obtained with the base metal of JJ1 (FMJJ1 specified by JSME (The Japan Society of Mechanical Engineers) Code [2] and is developed in Japan) and SS316LN (FM316LN specified by JSME Code), and also their combination using JJ1 filler wire (FMYJJ1 specified by JSME Code and is developed in Japan) by narrow gap GTAW process. Welding deformation such as angular distortion between outer plate and side plates of U-shape segment could be controlled and minimized by using effective restraint jig in trial manufacturing of 1m long leg. Validity of welding technology and manufacturing design are confirmed during full scale mock-up model fabrication. And also investigations such as UT (ultrasonic test) and effective welding process for rationalization have been performed.

Development of New Weld Heat Input and Dilution Equations for Gas Tungsten Arc Welding: Part 1

2013 ◽  
Author(s):  
Jonathan K. Tatman ◽  
Steven L. McCracken ◽  
Trevor G. Hicks
Keyword(s):  
Heat Input ◽  
Arc Welding ◽  
Filler Metal ◽  
Welding Process ◽  
Gas Tungsten Arc Welding ◽  
Power Ratio ◽  
Gas Tungsten Arc ◽  
Welding Part ◽  
Gtaw Process ◽  
Gas Tungsten

Predicting weld dilution for machine gas tungsten arc welding (GTAW) is a challenge due to the number of variables associated with the welding process. Proper heat input and power ratio controls are critical in many welding applications to control weld dilution, such as for dissimilar metal welds where low weld dilution is necessary to prevent solidification cracking or for cladding where weld dilution is minimized to maintain corrosion resistance of the clad material. This paper discusses the preliminary development and validation of improved weld dilution, heat input, and power ratio equations for the GTAW process. The new equations incorporate power added for the hot wire GTAW process, filler metal material properties, and the heat used to melt the filler metal when added to the GTAW process. The weld dilution equation was validated by comparing calculated dilution values to measured values from bead-on-plate weld trials performed on a variety of filler metals and substrates. Results of the testing and validation along with limitations of the new equations are discussed.

scholarly journals Effect of Current on Mechanical Properties and Microstructure of Aluminum 6061 with Gas Tungsten Arc Welding Process

Kapal ◽  
2020 ◽  
Vol 17 (3) ◽  
pp. 107-113
Author(s):  
Tarmizi Tarmizi ◽  
Kevin Daniel Sianturi ◽  
Irfan Irfan
Keyword(s):  
Mechanical Properties ◽  
Arc Welding ◽  
Gas Flow ◽  
Welding Process ◽  
Butt Joint ◽  
Gas Tungsten Arc Welding ◽  
Welding Parameters ◽  
Gas Tungsten Arc ◽  
Gtaw Process ◽  
Gas Tungsten

Aluminum 6061 is an aluminum alloy that is widely used in various industrial fields, which heat treatable. However, it can be joined using a welding process. Aluminum joining using the Gas Tungsten Arc Welding (GTAW) process has become the option to produce good quality joints. This research aims to get optimum welding parameters by knowing the mechanical properties and microstructure of the welding results. The GTAW process uses a 25-volt voltage, Argon protective gas flow rate of 15 liters per minute with filler rod ER 5356 with 2.4 mm diameter and electrodes tungsten 2.4 mm in diameter. This process uses a single V butt joint and groove angle of 60° with variations in the current of 100, 110 and 120 A. The results indicate that specimens with a variety of current of 110 A give better results in the absence of defects, have a tensile strength of 152 MPa, and get a hardness value of 87.55 HV, which is the highest compared to the other two specimens. Whereas specimens with the current variation of 100 and 120 A have defects in the weld area. The optimum parameters of the 6061 aluminum GTAW process with a thickness of 6 mm using a current of 110 A bring on better outcomes and mechanical properties than the use of currents of 100 and 120 A.

Distortion control in multi pass dissimilar GTAW process using Taguchi ANOVA analysis

2018 ◽  
Vol 7 (3) ◽  
pp. 1140 ◽  
Author(s):  
Harinadh Vemanaboina ◽  
G Edison ◽  
Suresh Akella
Keyword(s):  
Welding Process ◽  
Fractional Factorial ◽  
Inconel 625 ◽  
Filler Wire ◽  
Gas Tungsten Arc ◽  
Distortion Control ◽  
Gtaw Process ◽  
Continuous Current ◽  
Arc Welding Process

The present study is to observe the distortion development in the weldment of Inconel 625 to SS316L multipass weldments. In this work two-level factors such as welding process, filler wire and root gap were employed with L4 orthogonal array. The welding has been carried out with continuous current and pulsed current gas tungsten arc welding process implementing ERNiCrMo-3 and ERNiCr-3 fillers rods respectively. The fractional factorial experimentation was analysis of variances (ANOVA), it was carried out to observe the critical parame-ter which influence distortion caused in the weldments. The quality of welds has been evaluated by X-Ray Radiography test. The results show that welding process and filler wire are contributing more in the distortion.  

scholarly journals Formability of Medium Mn Steel Welded Joints

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 706
Author(s):  
Yang Cao ◽  
Bo Wang ◽  
Lin Zhao ◽  
Yun Peng ◽  
Minlin Zhong ◽  
...  
Keyword(s):  
Welded Joints ◽  
Welded Joint ◽  
High Strength ◽  
Welding Parameters ◽  
Factors Affecting ◽  
Gas Tungsten Arc ◽  
Deformation Limit ◽  
Medium Mn Steel ◽  
Erichsen Cupping Test ◽  
Mn Steel

In this study, a new-generation high-strength and high-ductility medium Mn steel (0.1C-5Mn-Fe) for the automotive industry was joined by the fiber laser and gas tungsten arc welding (GTAW) methods. Formability testing of the welded joints was done by the Erichsen cupping test and finite element (FE) analysis. The results showed that the formability of medium Mn steel welded joints was sensitive to the welding parameters and inferior to that of the base metal (BM). The hardening zone (HZ) was formed in the welded joint, which was composed of the fusion zone and two symmetrical parts of the heat-affected zone. The width of the HZ was one of the primary factors affecting the formability of the welded joints, while the tensile strength and ductility of the HZ were secondary factors. FE simulation of the Erichsen cupping test results indicated that the forming strain of the welded joint with narrow HZ concentrated on the BM, while the forming strain of the welded joint with wide HZ concentrated on the HZ. The HZ strain reached the deformation limit first due to its weak ductility; therefore, the welded joint with wide HZ had the worst formability. It was also observed that adopting high-velocity and high-laser power welding could greatly improve the formability of the welded joint as a result of reducing the width of the HZ.

scholarly journals Modeling of workers’ learning behavior in construction projects using agent-based approach

2018 ◽  
Vol 25 (4) ◽  
pp. 559-573 ◽  
Author(s):  
Behzad Mahjoubpour ◽  
Farnad Nasirzadeh ◽  
Mahmoud Mohammad Hosein Zadeh Golabchi ◽  
Maryam Ramezani Khajehghiasi ◽  
Mostafa Mir
Keyword(s):  
Influencing Factors ◽  
Construction Projects ◽  
Welding Process ◽  
Steel Structure ◽  
Learning Behavior ◽  
Content Type ◽  
Factors Affecting ◽  
Agent Based ◽  
Social Ability ◽  
And Performance

Purpose Learning as the way in which labor acquire new knowledge and skills has important strategic implications for the competitive advantage of an organization. The purpose of this paper is to present an agent-based modeling (ABM) approach to investigate the learning behavior of workers. The effect of interactions among different workers as well as the factors affecting the workers’ learning behavior is assessed using the proposed ABM approach. Design/methodology/approach For this purpose, the processes through which the competency value of worker is changed are understood and the workers’ learning behavior is modeled, taking account of various influencing factors such as knowledge flow, social ability to teach and forgetting factor. Findings The proposed model is implemented on a real steel structure project to evaluate its applicability and performance. The variation in the competency value of different workers involved in the project is simulated over time taking account of all the influencing factors using the proposed ABM approach. Practical implications In order to assess the effect of interactions among welders as well as the welders’ characteristics on their learning behavior, the competence value of different welders is evaluated. Originality/value This research presents an ABM approach to investigate the workers’ learning behavior. To evaluate the performance of the proposed ABM approach, it was implemented on a real steel structure project. The learning behavior of different welders (agents) was simulated taking account of their interactions as well as the factors affecting the welders’ learning behavior. The project involved the welding of a 240-ton steel structure. The initial project duration was estimated as 100 days. In this project, it has been planned to execute the welding process using three different welders namely welder A, B and C.

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