A Literature Review on Effect of Laser Welding Parameters on Mechanical Properties and Microstructure (original) (raw)
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The impact of laser welding parameters on the mechanical properties of the weld
This paper discusses the effect of selected parameters of laser welding on the mechanical properties of welds. Two parameters were analysed: the welding speed and the laser power. The properties of the material in the fusion zone and the heat affected zone were determined by performing static tensile tests, hardness tests and microscopic analysis. The welding was carried out using a TRUMPF Lasercell 1005 CO2 laser (wavelength =10.6 m). The specimens were 0.8 mm in thickness and they were made of DC04 steel. The static tensile tests were conducted by means of a LabTest 5.20SP1 universal testing machine designed to determine the tensile and compressive strengths. The material hardness was measured with a NEXUS 4304 Vickers hardness tester. The microscopic analysis was performed with a Joel JSM-5400 scanning electron microscope. The results indicate that welds produced at different welding parameters have similar mechanical properties.
Research Developments in Laser Welding -A Review
Laser welding is considered as a sophisticated, high precision and high speed joining process. In this process, laser beam is used as a heat source to join variety of materials such as aluminum, titanium, carbon steels, HSLA steels and stainless steels etc. Laser welding is currently being utilized in joining of miniature electronic components, steel structures, engine parts, transmission parts, alternators, solenoids, fuel injectors, fuel filters, air conditioning equipment and air bags etc. The present research paper discusses the recent research developments, process parameters, optimization techniques and applications of laser welding.
Use of laser welding in welding thin-walled sheet metal parts
Implementation of lightweight low-ductility materials such as ultra-high strength steels, has become urgently needed for automotive manufacturers to improve the competitiveness of their products. Automotive industry is focusing on lightweight and high strength materials. The aim of the research was to evaluate the influence of the parameters of steel laser welding on the qualitative indicators of butt welds. A tensile test and yeld strength test were performed on selected samples, where the strength of welded joints was determined.
Microstructure and Mechanical Properties of Laser Beam Welds of 15CDV6 Steel
The present study is concerned with laser beam welding of 15CDV6 steel, that is in the hardened (quenched and tempered) condition before welding. Autogenously butt-welded joints are made using carbon dioxide laser with a maximum output of 3.5 kw in the continuous wave mode. Weld microstructure, microhardness measurement across the weldment, transverse tensile properties, and room temperature impact properties of the weldment have been evaluated. The fusion zone exhibits a epitaxial grain growth. The microstrutural features of heat-affected zone and fusion zone vary, due to different thermal cycles for which these were subjected during welding. The average weld metal hardness was 480 Hv. The observed hardness distribution across the welds were correlated with the micro structures. The welds exhibited lower toughness of 50 joules as compared to parent metal of 55 joules and the tensile strength values of the welded specimens are close to that obtained for sheet specimens.
A Study on Behavior of Materials Under The Influence of Laser Joining
IJRAME PUBLICATIONS, 2022
Laser welding will be an important welding process for different applications in aerospace , aircraft , automotive, electronics and other industries, due to its capabilities like minimum heat affected zone, welding of various thicknesses, adoptability to welding of various materials possessing widely varying physical properties like melting point, absorption, reflectivity etc. It utilizes laser source as a non contact heat generation technology to weld different materials so as to achieve welds of high quality narrow width and high penetration depths without the need of filler wires. It may be necessary to understand the effect of process parameters on the weldability of materials for successful welding. Laser welding popularly uses two types of lasers like CO2 and Nd:YAG (neodymium doped yttrium – aluminium – garnet) with different powers. Nd:YAG lasers are used to weld materials of different thicknesses involving powers upto 5 kW. Whereas, CO2 lasers are used for applications which involve higher powers upto 20 kW. Laser welding allows a direct transition from light energy into heat energy. This technique is involved with the process of laser - matter interaction in which various parameters such as pulse energy, pulse duration, spot size, welding speed, laser power, weld width, penetration depth, reflectivity, absorption coefficient, thermodynamic properties etc. are used for analysis. This paper presents a review of the different parameters including process as well as materials on the weldability of various materials like carbon steels, stainless steels, magnesium alloys, aluminium alloys, refractory materials such as vanadium, titanium, zirconium, tantalum etc. The selection of appropriate parameter for welding of specified material is discussed. The prominent weld defects common to the laser welding such as porosity, oxide inclusions, cracking, loss of alloying elements etc., are discussed as related to the microstructure as well as mechanical properties such as hardness, tensile strength and fatigue strength etc.
Surman Journal for Science and Technology, 2023
During laser beam welding focused high-capacity laser beam moved over the seam of the parts to be welded. The high intensity of the laser beam causes both parts to highly melt. In the melting bath a so-called keyhole formed, which enables the deep penetration of the laser beam. The melting bath solidifies quickly after the laser beam has passed, where strong connection with good metallurgical characteristics is the result. For this research, the laser sources applied for laser welding are mainly the CO2 laser. This research aimed to an attempt to investigate the microhardness changes of the welding area to unsimilar metals and which occur during the welding processes between unsimilar metals (304 stainless steel & low carbon steel), where the surface of laser beam welding offers deepness up to (3mm), The variables studied, which may have an effect on the welding processes, discussing the relationship between the welding parameter and Microhardness of welded joint and explaining the major effected of these variables (power) on the welding area.
2020
The joints of dissimilar metals have several problems because they have different mechanical properties and microstructures. This problem can be solved by using laser welding because the resulting energy focus and hot zone around the welding joint is minimal. The parameters that are important in welding either using welding laser or other welding process is the current. Thus, this study examined the joint of dissimilar metals i.e low carbon steel (mild steel A36) and stainless steel (stainless steel 304) using laser welding. The result of the laser welding joint with a strong variation of current tested its mechanical properties with tensile test and seen its micro structure with photo Scanning Electron Microscopy (SEM). Tensile test results on the current variable 410 - 440 Ampere obtained fracture is on the side of mild steel A36, while at 450 Ampere current strength obtained a fault on the laser welding joints, where the point of the break is below the point of broken mild steel ...
Study on laser welding of austenitic stainless steel by varying incident angle of pulsed laser beam
In the present work, AISI 304 stainless steel sheets are laser welded in butt joint configuration using a robotic control 600 W pulsed Nd:YAG laser system. The objective of the work is of twofold. Firstly, the study aims to find out the effect of incident angle on the weld pool geometry, microstructure and tensile property of the welded joints. Secondly, a set of experiments are conducted, according to response surface design, to investigate the effects of process parameters, namely, incident angle of laser beam, laser power and welding speed, on ultimate tensile strength by developing a second order polynomial equation. Study with three different incident angle of laser beam 89.7 deg, 85.5 deg and 83 deg has been presented in this work. It is observed that the weld pool geometry has been significantly altered with the deviation in incident angle. The weld pool shape at the top surface has been altered from semispherical or nearly spherical shape to tear drop shape with decrease in incident angle. Simultaneously, planer, fine columnar dendritic and coarse columnar dendritic structures have been observed at 89.7 deg, 85.5 deg and 83 deg incident angle respectively. Weld metals with 85.5 deg incident angle has higher fraction of carbide and d-ferrite precipitation in the austenitic matrix compared to other weld conditions. Hence, weld metal of 85.5 deg incident angle achieved higher micro-hardness of $280 HV and tensile strength of 579.26 MPa followed by 89.7 deg and 83 deg incident angle welds. Furthermore, the predicted maximum value of ultimate tensile strength of 580.50 MPa has been achieved for 85.95 deg incident angle using the developed equation where other two optimum parameter settings have been obtained as laser power of 455.52 W and welding speed of 4.95 mm/s. This observation has been satisfactorily validated by three confirmatory tests.
Structure – Properties Evaluation In Laser Beam Welds Of High Strength Low Alloy Steel
The present investigation reports on a study that has been taken up to develop an 9elseunderstanding of the Laser beam welding characteristics of similar combination of high strength low alloy steel which is in the hardened condition .i.e in a quenched and tempered condition before welding. The joint characterization studies include microstrutural examination, micro hardness measurement across the weldment and evaluation of tensile and impact toughness properties. The fusion zone exhibits a epitaxial grain growth. The microstrutural features of heat affected zone and fusion zone vary, due to the different thermal cycles for which they are subjected during welding. The observed hardness distributions across the welds are correlated with the observed microstructures. The welds exhibited lower toughness data compared to parent metal and the tensile strength values of the welded specimens are close to that obtained for sheet specimens
2006
Laser Aided Manufacturing Process (LAMP) can be applied to repair steel die/molds which are currently repaired using traditional welding process in industry. In order to fully understand the advantages of laser deposition repair process over traditional welded-repair process, the mechanical properties such as tensile strength and hardness of H13 tool steel samples produced by these two processes were investigated. The microstructure and fracture surface of the samples were analyzed using optical microscope and SEM (Scanning Electron Microscope). Moreover, depositions on substrates with different shapes were studied to evaluate the performance of LAMP on damaged parts with complicated geometric shape.