Numerical Simulation and Testing of 45 Architecture Steel Welded Based on Gaussian Heat Source

2014 ◽  
Vol 580-583 ◽  
pp. 3187-3191 ◽  
Author(s):  
Jian Bo Ji ◽  
Jin Zhou Zhang ◽  
Lei Zhang
Keyword(s):  
Numerical Simulation ◽  
Heat Source ◽  
Base Metal ◽  
Maximum Stress ◽  
Compressive Strain ◽  
Base Material ◽  
Welding Process ◽  
Welding Temperature ◽  
Welding Position ◽  
Dangerous Section

Using sysweld software based on the Gauss heat source, simulated welding process of 45 steel plate, analysed welding temperature field、stress and strain. The maximum stress value appeared at the initial welding position of junction of base metal and weld. As the most dangerous section, the maximum strain value appeared at the end welding position of the junction of base metal and weld. Compressive strain appeared at the central part of weld and the tensile strain appeared at the junction of base material and weld. The deformation was of upward warping, which is helpful to explore the numerical simulation of welding structure.

Experimental Investigations on Aluminium Ultrasonic Welding Parameters

2014 ◽  
Vol 657 ◽  
pp. 306-310
Author(s):  
Lăcrămioara Apetrei ◽  
Vasile Rață ◽  
Ruxandra Rață ◽  
Elena Raluca Bulai
Keyword(s):  
Microstructural Analysis ◽  
Base Material ◽  
Welding Process ◽  
Ultrasonic Welding ◽  
Experimental Investigations ◽  
Welding Parameters ◽  
Material Structure ◽  
Welding Temperature ◽  
Wide Range ◽  
Made In

Research evolution timely tendencies, in the nonconventional technologies field, are: manufacture conditions optimization and complex equipments design. The increasing of ultrasonic machining use, in various technologies is due to the expanding need of a wide range materials and high quality manufacture standards in many activity fields. This paper present a experimental study made in order to analyze the welded zone material structure and welding quality. The effects of aluminium ultrasonic welding parameters such as relative energy, machining time, amplitude and working force were compared through traction tests values and microstructural analysis. Microhardness tests were, also, made in five different points, two in the base material and three in the welded zone, on each welded aluminium sample. The aluminum welding experiments were made at the National Research and Development Institute for Welding and Material Testing (ISIM) Timişoara. The ultrasonic welding temperature is lower than the aluminium melting temperature, that's so our experiments reveal that the aluminium ultrasonic welding process doesn't determine the appearance of moulding structure. In the joint we have only crystalline grains deformation, phase transformation and aluminium diffusion.

Phenomenological Modeling of Fusion Welding Processes

MRS Bulletin ◽  
1994 ◽  
Vol 19 (1) ◽  
pp. 29-35 ◽  
Author(s):  
S.A. David ◽  
T. DebRoy ◽  
J.M. Vitek
Keyword(s):  
Solid State ◽  
Heat Source ◽  
Base Metal ◽  
Weld Pool ◽  
Welding Process ◽  
Poor Performance ◽  
Consumer Products ◽  
Phase Changes ◽  
Fusion Welding ◽  
Welding Processes

Welding is utilized in 50% of the industrial, commercial, and consumer products that make up the U.S. gross national product. In the construction of buildings, bridges, ships, and submarines, and in the aerospace, automotive, and electronic industries, welding is an essential activity. In the last few decades, welding has evolved from an empirical art to a more scientifically based activity requiring synthesis of knowledge from various disciplines. Defects in welds, or poor performance of welds, can lead to catastrophic failures with costly consequences, including loss of property and life.Figure 1 is a schematic diagram of the welding process showing the interaction between the heat source and the base metal. During the interaction of the heat source with the material, several critical events occur: melting, vaporization, solidification, and solid-state transformations. The weldment is divided into three distinct regions: the fusion zone (FZ), which undergoes melting and solidification; the heat-affected zone (HAZ) adjacent to the FZ, that may experience solid-state phase changes but no melting; and the unaffected base metal (BM).Creating the extensive experimental data base required to adequately characterize the highly complex fusion welding process is expensive and time consuming, if not impractical. One recourse is to simulate welding processes either mathematically or physically in order to develop a phenomenological understanding of the process. In mathematical modeling, a set of algebraic or differential equations are solved to obtain detailed insight of the process. In physical modeling, understanding of a component of the welding process is achieved through experiments designed to avoid complexities that are unrelated to the component investigated.In recent years, process modeling has grown to be a powerful tool for understanding the welding process. Using computational modeling, significant progress has been made in evaluating how the physical processes in the weld pool influence the development of the weld pool and the macrostructures and microstructures of the weld.

Application of FIB/SEM/EBSD for Evaluation of Residual Strains and Their Relationship to Weld Metal Hydrogen Assisted Cold Cracking

2012 ◽  
Author(s):  
W. L. Costin ◽  
I. H. Brown ◽  
L. Green ◽  
R. Ghomashchi
Keyword(s):  
Residual Stresses ◽  
Weld Metal ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Ion Beam ◽  
Base Material ◽  
Welding Process ◽  
Cold Cracking ◽  
Predictive Methods ◽  
Residual Strains

Hydrogen assisted cold cracking (HACC) is a welding defect which may occur in the heat affected zone (HAZ) of the base metal or in the weld metal (WM). Initially the appearance of HACC was associated more closely with the HAZ of the base metal. However, recent developments in advanced steel processing have considerably improved the base material quality, thereby causing a shift of HACC to the WM itself. This represents a very serious problem for industry, because most of the predictive methods are intended for prevention of HACC in the HAZ of the base metal, not in the weld metal [1]. HACC in welded components is affected by three main interrelated factors, i.e. a microstructure, hydrogen concentration and stress level [2–4]. In general, residual stresses resulting from the welding process are unavoidable and their presence significantly influences the susceptibility of weld microstructures to cracking, particularly if hydrogen is introduced during welding [5]. Therefore various weldability tests have been developed over the years which are specifically designed to promote HACC by generating critical stress levels in the weld metal region due to special restraint conditions [4, 6–8]. These tests were used to develop predictive methods based on empirical criteria in order to estimate the cracking susceptibility of both the heat-affected zone and weld metal [4]. However, although the relationship between residual stress, hydrogen and HACC has received considerable attention, the interaction of residual stresses and microstructure in particular at microscopic scales is still not well understood [5, 9–21]. Therefore the current paper focuses on the development and assessment of techniques using Focused Ion Beam (FIB), Scanning Electron Microscopy (SEM) and Electron Backscatter Diffraction for the determination of local residual strains at (sub) micron scales in E8010 weld metal, used for the root pass of X70 pipeline girth welds, and their relationship to the WM microstructure. The measurement of these strains could be used to evaluate the pre-existing stress magnitudes at certain microstructural features [22].

Temperature Distribution of Aluminum Alloys under Friction Stir Welding

2011 ◽  
Vol 264-265 ◽  
pp. 217-222 ◽  
Author(s):  
Ben Yuan Lin ◽  
P. Yuan ◽  
Ju Jen Liu
Keyword(s):  
Numerical Simulation ◽  
Temperature Distribution ◽  
Cross Section ◽  
Base Material ◽  
Welding Process ◽  
Measuring System ◽  
Close Correspondence ◽  
Distribution Profile ◽  
Butt Welding ◽  
Friction Stir

The temperature distribution of 6061-T6 aluminum alloy plates under a friction stir butt-welding was investigated by using experiment and numerical simulation. A real-time temperature measuring system was used to measure the temperature change in the welding process. Vickers hardness profiles were made on the cross-section of the weld after welding. A commercial software of FlexPDE, a solver for partial different equations with finite element method, was used to simulate the experimental welding process of this study. Comparison the experimental and numerical results, the temperature cycles calculated by numerical are similar to those measured by experiment. The temperature distribution profile obtained from the numerical simulation is symmetrical to the weld center and has a close correspondence with the hardness configuration and the microstructure of the weld. The region with the temperature over 300 °C is the zone of softening within the boundaries of base material and HAZ. The regions of 350 °C with minimum hardness are located near the boundary of HAZ and TMAZ. The maxima temperature about 500 °C distributes around the upper part of the weld center. However, the region above 400 °C only matches with the upper half of the weld nugget.

scholarly journals A Study on Vertical Upward Welding of Dissimilar Material and Thickness of Thin Plates Using Novel TIG Welding Process

2019 ◽  
Author(s):  
Ngo Huu Manh ◽  
Nguyen Van Anh ◽  
Murata Akihisa ◽  
Hideno Terasaki
Keyword(s):  
Base Metal ◽  
Heat Input ◽  
Weld Zone ◽  
Welding Process ◽  
Welding Current ◽  
Tig Welding ◽  
Dissimilar Material ◽  
Thin Plates ◽  
Welding Defects ◽  
Welding Position

A study about influence of heat input on welding defects in vertical upward welding position for dissimilar material and thickness using a new variation of TIG welding torch is done with support of advanced inspection methods SEM and EBSD. With vertical upward welding position, control heat input plays an important role to keep the weld stabilization without defects. On the other hand, TIG welding process using a conventional TIG torch (conventional TIG welding process) has low efficiency and it is difficult to control heat input with high accuracy. So, it is considered that using conventional TIG torch is still a challenge for welding thin plates. In this case, a new variation of TIG torch has been developed. This torch used a constricted nozzle to improve plasma arc characteristics. As a result, it can control efficiently the heat input to prevent the excessive or insufficiency for joining thin sheets. For evaluation of welding quality, advanced examination methods SEM and EBSD were applied to directly observe the welding defects. From the results, the formation mechanism of blowhole inside weld zone in case of welding dissimilar material and thickness was discussed. It is pointed out that when sufficient welding current, the change from weld zone to base metal is uniform, no welding defects such as blowhole was seen. However, in case of low welding current, the thinner base metal is insufficient fusion and the change between weld zone and base metal is not uniform. The blowhole was observed at SS400 material side.

scholarly journals Distortion and Mechanical Characteristics of Single-V and Single Bevel Welded Low Carbon Steel

2020 ◽  
Vol 9 (3) ◽  
pp. 704-713
Keyword(s):  
Base Metal ◽  
Room Temperature ◽  
Mechanical Characteristics ◽  
Low Carbon Steel ◽  
Base Material ◽  
Welding Process ◽  
Low Carbon ◽  
Molten Material ◽  
Distinct Process ◽  
Lower Temperature

Welding is a fabrication or sculptural process that joints the materials, usually metals or thermoplastics, by inducing fusion. It is as distinct process from lower temperature metal-joining techniques such as brazing and soldering, to high temperature welding process and this process keep the base metal from melted. In addition, to melt the base metal, a filler material is typically added to the joint to form a pool of molten material that cools at room temperature, forming a joint that is usually stronger than the base material. Pressure may also be used along with heat, or by itself, to produce a weldment. The current study presents the effects of distortion that occurred in single-V and single bevel welded mild steel. It also includes the macro and microstructure analysis, mechanical properties and also the consumable usage along the time needed to complete the bevel and welding process. As a result, single- V is way more safe and reliable to use to withhold large load compare to single bevel.In term of financial, single bevel way more ahead.

The Role of Goldack Double Ellipsoidal Parameters in Temperature Distribution for the GTAW Process

2020 ◽  
Author(s):  
A Karpagaraj ◽  
SURESH KUMAR S ◽  
S Thamizhmanii ◽  
Arun Nelliappan T ◽  
Siva Shanmugam N ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Temperature Distribution ◽  
Heat Source ◽  
Source Parameters ◽  
Welding Process ◽  
Source Model ◽  
Depth Of Penetration ◽  
Factorial Method ◽  
Gtaw Process ◽  
Full Factorial

Abstract Numerical simulation is widely used in all the fields of engineering to predict the results. In welding, various finite element tools are used to predict the bead profile, temperature distribution, joint strength, formability and metallurgical changes etc. With respect to the welding process suitable heat source model has to be assigned for numerical simulation. The most suitable heat source for Gas Tungsten Arc Welding (GTAW) process is the Goldack double ellipsoidal model. This model has few parameters like the width of the weld (a), depth of penetration (b), front profile ellipse (Cf) and rear ellipse profile (Cr). In this research article, the influence of these parameters and their effect on the temperature distribution is focused. For this purpose, based on the full factorial design welding simulations are performed with COMSOL. Later, the grey relational technique was used to find the contribution of these parameters. It was concluded from the full factorial method that; temperature variation is depended on the GTAW welding heat source parameters. At 95% confidence level, the width of the weld showed a major role in controlling the temperature. Moreover, the optimum combination of process variables obtained end with minimum temperature rise at a width of 0.7 mm, depth of 5.7 mm and frontal factor of 4.

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