scholarly journals SEM and XRD Characterisation of Fusion Lines Obtained on Austempered Ductile Iron by Laser Beam Welding without Preheating

2021 ◽  
Vol 13(62) (2) ◽  
pp. 1-8
Author(s):  
I.C. MON ◽  
Mircea Horia ȚIEREAN ◽  
Liana Sanda BALTEȘ
Keyword(s):  
Laser Beam ◽  
Laser Welding ◽  
Heat Affected Zone ◽  
Welding Speed ◽  
Ductile Iron ◽  
Laser Power ◽  
Laser Beam Welding ◽  
Xrd Analysis ◽  
Austempered Ductile Iron ◽  
Melted Zone

This study highlights the weldability of austempered ductile iron (ADI) using laser welding. SEM, EDS and XRD analysis were performed on fusion lines, heat affected zone (HAZ) and melted zone (MZ). Welding speed (Ws) and laser power (P) were varied. The heat affected zone is composed of graphite, perlite and martensite; the melted and solidified zone contains graphite, ferrite and cementite. XRD results are in accordance with SEM micrographs.

Effect of Laser Welding on the Mechanical Properties AISI 1018 Steel

MRS Advances ◽  
2017 ◽  
Vol 2 (64) ◽  
pp. 4031-4039 ◽  
Author(s):  
M. A. Carrizalez-Vazquez ◽  
M. Alvarez-Vera ◽  
A. Hernández-Rodríguez ◽  
J. M. Orona-Hinojos ◽  
Gabriel Sandoval-Vázquez ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Laser Welding ◽  
Fusion Zone ◽  
Heat Affected Zone ◽  
Welding Speed ◽  
Laser Power ◽  
Steel Plates ◽  
Welding Joints ◽  
Welding Processes

AbstractLaser welding processes offer significant advantages such as high welding speed, narrow heat affected zone and quality of the welding joint. In this study, the process parameters of laser power and welding speed were modified for AISI 1018 steel plates of 8 mm thickness and compared using finite element method. The results of cross-section microstructure, heat affected zone and fusion zone were characterized. The grain refinement was affected as the parameters were modified. Tensile and microhardness tests were performed to determine the mechanical properties of the welding joints. Microhardness increased in fusion zone and decreased in heat affected zone. Tensile test showed ductile fracture in heat affected zone of the welding joints. The simulated profiles were compared with the experimental observations showing a reasonable agreement.

scholarly journals Development of laser welding of high strength aluminium alloy 2024-T4 with controlled thermal cycle

2020 ◽  
Vol 326 ◽  
pp. 08005
Author(s):  
Mete Demirorer ◽  
Wojciech Suder ◽  
Supriyo Ganguly ◽  
Simon Hogg ◽  
Hassam Naeem
Keyword(s):  
Laser Beam ◽  
Laser Welding ◽  
Heat Input ◽  
Thermal Cycle ◽  
Laser Beam Welding ◽  
Base Material ◽  
High Strength ◽  
Cooling Rates ◽  
Aa 2024 ◽  
Welding Processes

An innovative process design, to avoid thermal degradation during autogenous fusion welding of high strength AA 2024-T4 alloy, based on laser beam welding, is being developed. A series of instrumented laser welds in 2 mm thick AA 2024-T4 alloys were made with different processing conditions resulting in different thermal profiles and cooling rates. The welds were examined under SEM, TEM and LOM, and subjected to micro-hardness examination. This allowed us to understand the influence of cooling rate, peak temperature, and thermal cycle on the growth of precipitates, and related degradation in the weld and heat affected area, evident as softening. Although laser beam welding allows significant reduction of heat input, and higher cooling rates, as compared to other high heat input welding processes, this was found insufficient to completely supress coarsening of precipitate in HAZ. To understand the required range of thermal cycles, additional dilatometry tests were carried out using the same base material to understand the time-temperature relationship of precipitate formation. The results were used to design a novel laser welding process with enhanced cooling, such as with copper backing bar and cryogenic cooling.

Characterization of Fusion Lines Obtained with Laser Welding on Ductile Iron Plates

2016 ◽  
Vol 254 ◽  
pp. 33-42
Author(s):  
Ioan Catalin Mon ◽  
Mircea Horia Tierean ◽  
Eugen Cicala ◽  
Michel Pilloz ◽  
Iryna Tomashchuk ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Laser Welding ◽  
Welding Speed ◽  
Ductile Iron ◽  
Continuous Laser ◽  
Welding Defects ◽  
Criteria For Selection ◽  
Selection Of ◽  
Melted Metal

This paper studies the ductile iron (DI) weldability using laser welding. For performing an Yb:YAG continuous laser was used, with a maximum power of 6 kW. The parametrical window power (P) - welding speed (S) was explored by carrying out the fusion lines on ductile iron plates without preheating, to determinate areas of weldability (complete penetration, correct geometry) to allow further characterization. The criteria for selection of focus areas were the geometry of the fusion lines and the absence of the welding defects. The unsatisfactory domains were characterized by: collapse of the melted metal, incomplete penetration, low fusion lines quality (geometry, compactness). In present study, several values of power and welding speed have been tested to identify their influence on geometry, compactness of the joints and mechanical properties. As result, the power-welding speed diagram for feasible domains of laser welding was generated.

Analysis of Roughness and Heat Affected Zone of Steel Plates Obtained by Laser Cutting

2014 ◽  
Vol 974 ◽  
pp. 169-173 ◽  
Author(s):  
Imed Miraoui ◽  
Mohamed Boujelbene ◽  
Emin Bayraktar
Keyword(s):  
Surface Roughness ◽  
Laser Beam ◽  
Heat Affected Zone ◽  
Laser Power ◽  
Laser Cutting ◽  
Major Effect ◽  
Steel Plates ◽  
Beam Diameter ◽  
Laser Beam Diameter ◽  
Cut Surface

In the present study, high-power CO2 laser cutting of steel plates has been investigated and the effect of the input laser cutting parameters on the cut surface quality is analyzed. The average roughness of the cut surface of the specimens, produced by different laser beam diameter and laser power, were measured by using roughness tester. The scanning electron microscopy SEM is used to record possible metallurgical alterations on the cut edge. The aim of this work is to investigate the effect of laser beam diameter and laser power on the cut surface roughness and on the heat affected zone width HAZ of steel plates obtained by CO2 laser cutting. An overall optimization was applied to find out the optimal cutting setting that would improve the cut surface quality. It was found that laser beam diameter has a negligible effect on surface roughness but laser power had major effect on roughness. The cut surface roughness decreases as laser power increases. Improved surface roughness can be obtained at higher laser power. Also, laser beam diameter and laser power had major effect on HAZ width. It increases as laser power increases.

Numerical Analysis of Solidification Behavior during Laser Welding Nickel-Based Single-Crystal Superalloy Part: II Crystallography-Dependent Supersaturation of Liquid Aluminum

2021 ◽  
Vol 1018 ◽  
pp. 13-22
Author(s):  
Zhi Guo Gao
Keyword(s):  
Laser Welding ◽  
Single Crystal ◽  
Weld Pool ◽  
Welding Speed ◽  
Heat Input ◽  
Laser Power ◽  
Liquid Aluminum ◽  
Dendrite Growth ◽  
Solidification Cracking ◽  
Solid Liquid Interface

The thermal metallurgical modeling of liquid aluminum supersaturation was further developed through couple of heat transfer model, dendrite selection model, multicomponent dendrite growth model and nonequilibrium solidification model during three-dimensional nickel-based single-crystal superalloy weld pool solidification. The welding configuration plays more important role in supersaturation of liquid aluminum, morphology instability and nonequilibrium partition behavior. The bimodal distribution of liquid aluminum supersaturation along the solid/liquid interface is crystallographically symmetrical about the weld pool centerline in (001) and [100] welding configuration. The distribution of liquid aluminum supersaturation along the solid/liquid interface is crystallographically asymmetrical throughout the weld pool in (001) and [110] welding configuration. Optimum low heat input (low laser power and high welding speed) with (001) and [100] welding configuration is more favored to predominantly promote epitaxial [001] dendrite growth to reduce the metallurgical factors for solidification cracking than that of high heat input (high laser power and slow welding speed) with (001) and [110] welding configuration. The lower the heat input is used, the lower supersaturation of liquid aluminum is imposed, and the smaller size of vulnerable [100] dendrite growth region is incurred to ameliorate solidification cracking susceptibility and vice versa. The overall supersaturation of liquid aluminum in (001) and [100] welding configuration is beneficially smaller than that of (001) and [110] welding configuration regardless of heat input, and is not thermodynamically relieved by gamma prime γˊ phase. (001) and [110] welding configuration is detrimental to weldability and deteriorates the solidification cracking susceptibility because of unfavorable crystallographic orientations and alloying aluminum enrichment. The mechanism of asymmetrical solidification cracking because of crystallography-dependent supersaturation of liquid aluminum is proposed. The eligible solidification cracking location is particularly confined in [100] dendrite growth region. Moreover, the theoretical predictions agree well with the experiment results. The useful modeling is also applicable to other single-crystal superalloys with similar metallurgical properties for laser welding or laser cladding. The thorough numerical analyses facilitate the understanding of weld pool solidification behavior, microstructure development and solidification cracking phenomena in the primary γ phase, and thereby optimize the welding conditions (laser power, welding speed and welding configuration) for successful crack-free laser welding.

Modeling of Weld Lap-Shear Strength for Laser Transmission Welding of Thermoplastic Using Artificial Neural Network

2012 ◽  
Vol 445 ◽  
pp. 454-459 ◽  
Author(s):  
M.R. Nakhaei ◽  
N.B. Mostafa Arab ◽  
F. Kordestani
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Shear Strength ◽  
Laser Welding ◽  
Process Parameters ◽  
Welding Speed ◽  
Laser Power ◽  
Laser Transmission Welding ◽  
Lap Shear Strength ◽  
Lap Shear

Laser welding of plastic materials has a wide range of applications in the packaging, medical, electronics and automobile industries provided it can predict high quality welds compared with other joining methods. Laser welding process parameters can affect the quality of welds. In this paper, Artificial Neural Network (ANN) is used to model the effects of laser power, welding speed, clamp pressure and stand-off distance on weld lap-shear strength in laser transmission welding (LTW) of acrylic (polymathy methacrylate). A set of experimental data on diode laser weld lap-shear strengths was used to train and test the ANN from which the neurons relations were gradually extracted to develop a model. The developed ANN model can be used for the analysis and prediction of the complex relationships between the above mentioned process parameters and weld lap-shear strength. The results indicated that increase in laser power and clamp pressure increases the weld lap-shear strength whereas welding speed and stand off distance had a decreasing affect on shear strength at high value.

Simulation and Experimental Based Analysis of the Laser Beam Welding of DP Steels

2020 ◽  
Vol 1157 ◽  
pp. 73-82
Author(s):  
Raghawendra Pratap Singh Sisodia ◽  
Marcell Gáspár ◽  
Béla Fodor ◽  
László Draskóczi
Keyword(s):  
Laser Beam ◽  
Heat Affected Zone ◽  
Physical Simulation ◽  
Welded Joint ◽  
Laser Beam Welding ◽  
Base Material ◽  
Hardness Tests ◽  
Welding Thermal Cycle ◽  
Diode Laser Beam ◽  
Gleeble 3500

In this paper, heat affected zone characteristics of DP1000 steels was investigated during diode laser beam welding (LBW). A butt-welded joint of specimen in dimension of 300 x 150 mm each (according to EN15614-11:2002) with 1 mm thickness is used for the experimental purpose. The welding thermal cycle and the cooling circumstances in the HAZ was determined by real experiment and the physical simulation. A Gleeble 3500 thermo-physical simulator was used to physically simulate the coarse grain heat affected zone (CGHAZ) on the base material specimens by the utilization of the thermal cycles for t8/5 =2.5 s. The results of the physical simulation were validated by real welding experiments. The properties of the simulated and the real HAZ was examined by optical microscopic, scanning electron microscope and hardness tests.

scholarly journals The Study on Mechanical Strength of Titanium-Aluminum Dissimilar Butt Joints by Laser Welding-Brazing Process

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 712 ◽  
Author(s):  
Xiongfeng Zhou ◽  
Ji’an Duan ◽  
Fan Zhang ◽  
Shunshun Zhong
Keyword(s):  
Tensile Strength ◽  
Laser Welding ◽  
Welding Speed ◽  
Laser Power ◽  
Butt Joint ◽  
Interface Fracture ◽  
Welding Parameters ◽  
Fracture Roughness ◽  
Joint Properties ◽  
5A06 Aluminum Alloy

Laser welding–brazing of 5A06 aluminum to Ti6Al4V titanium in a butt configuration was carried out to discuss the influences of welding parameters on dissimilar joint properties. The effects of laser offset, welding speed, and laser power on the spreading length of the molten aluminum liquid, interface fracture zone width (IFZW), fracture roughness, intermetallic compounds (IMCs) thickness, and tensile strength were also investigated. The microstructure and fracture of the joint were also studied. The results show that the tensile strength of the joint is not only influenced by the thickness and type of IMCs, but also influenced by the spreading ability of the aluminum liquid, the fracture area broken at the Ti/fusing zone (FZ) interface, and the relative area of the brittle and ductile fracture in FZ. A dissimilar butt joint with an IMC thickness of 2.79 μm was obtained by adjusting the laser offset, welding speed, and laser power to 500 μm, 11 mm/s and 1130 W, respectively. The maximum tensile strength of the joint was up to 183 MPa, which is equivalent to 83% of the tensile strength of the 5A06 aluminum alloy.

Laser Welding Simulations of Stainless Steel Joints Using Finite Element Analysis

2011 ◽  
Vol 383-390 ◽  
pp. 6225-6230
Author(s):  
K.R. Balasubramanian ◽  
T. Suthakar ◽  
K. Sankaranarayanasamy ◽  
G. Buvanashekaran
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Laser Beam ◽  
Laser Welding ◽  
Laser Beam Welding ◽  
Welding Process ◽  
Weld Bead ◽  
Heat Of Fusion ◽  
T Joints ◽  
Finite Element Software

Laser beam welding (LBW) is a fusion joining process that uses the energy from a laser beam to melt and subsequently crystallize a metal, resulting in a bond between parts. In this study, finite element method (FEM) is used for predicting the weld bead profile of laser welding butt, lap and T-joints. A three-dimensional finite element model is used to analyze the temperature distribution weld bead shape for different weld configurations produced by the laser welding process. In the model temperature-dependent thermo physical properties of AISI304 stainless steel, effect of latent heat of fusion and convective and radiative boundary conditions are incorporated. The heat input to the FEM model is assumed to be a 3D conical Gaussian heat source. The finite element software SYSWELD is employed to obtain the numerical results. The computed weld bead profiles for butt, lap and T-joints are compared with the experimental profiles and are found to be in agreement.

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