Proper Welding Parameters Research Articles

Parametric optimization for hardness of tig welded duplex stainless steel

Achieving optimal mechanical properties in welding joints hinges on employing precise parametric conditions. This is particularly crucial for Tungsten Inert Gas (TIG) welding of ASTM/UNS 2205 Duplex Stainless Steel (DSS), where attributes like hardness, ultimate tensile strength, and yield strength are paramount. Maintaining high Hardness Value (HV) demands proper welding parameters such as welding current, gas flow rate, and welding speed. To enhance DSS welding quality, especially hardness, this study utilizes the Taguchi method to optimize welding process parameters. The importance of each factor is assessed through Annova statistical analysis. The outcomes highlight the positive impact of parametric optimization on HV, as evidenced by the analysed data. Parametric optimization proves to be a potent approach for refining industrial processes like welding, with particular relevance in TIG welding of duplex stainless steel due to its mechanical robustness and corrosion resistance. Nevertheless, challenges arise due to the material's elevated hardness and low thermal conductivity, resulting in potential defects like cracks and porosity. The identification of optimal welding parameters, encompassing current, voltage, speed, and gas flow rate, helps address these challenges and advances high-quality welds. Through systematic variations and analysis of these parameters, researchers and engineers can pinpoint the optimal combination that mitigates defects while maximizing desired joint attributes. Within the realm of TIG welding of duplex stainless steel, metric optimization holds the potential to elevate welding quality, curtail costs and waste, and heighten productivity and safety. Consequently, organizations can attain enhanced performance, efficiency, and profitability within their welding processes

Development of Mathematical Model for Percentage of Elongation of TIG Welded Duplex Stainless Steel

Quality strongly depends on good mechanical properties of any manufacturing material. Similarly, quality of Tungsten Inert Gas (TIG) welding of Duplex Stainless Steel (DSS) depends on good mechanical properties like percentage of elongation, ultimate tensile strength etc. Better Percentage of Elongation (PE) is produced using proper welding parameters and their values at the time of TIG welding. In this study, TIG welding has been done on ASTM/UNS 2205 duplex stainless steel materials. A new mathematical model is developed using non-linear regression analysis for the prediction of percentage of elongation. The variables used in the prediction models are selected welding parameters like welding current, gas flow rate and speed of welding. A residual plot for PE has been developed to validate the mathematical model. Calculation of percentage deviation for PE has been made. Comparison of measured and predicted PE value has been done by graphical representation. The relationship between percentage of elongation and the welding parameters has been illustrated graphically by surface plots and contour plots as well. Combined effects of any pair of input parameters on PE are represented graphically with the help of three-dimensional surface plots. According to this analysis, the models provide good PE with the data used in this study.

To Investigate the Weld Bead Hardness at Various Current through TIG Welding

In the industrial industry, TIG welding is the most frequent method of putting metals together. The electrode is held at a 10°–15° angle to the vertical by the welder while he initiates the weld by striking an arc and creating a puddle. By moving the electrode and arc in tandem, the welder "pushes" the molten metal forward and toward weld. welder strength of a building is determined by the quality of its weld beads. The weld's mechanical qualities are mostly enhanced by the weld's quality. The writers of this article explain how to weld with high weld bead quality by using the proper welding parameters. In this research, it has been proven that the hardness of welded joints improves with the increase in welding current up to 110 A for 6 mm thick plates, and afterwards declines with the rise in welding current. Splash and damage to the workpiece could occur when the current is raised to an excessively high level. Because the workpiece is so thin, high current might cause the material gap to grow. This practise may result in an increased weld affected area and a longer time to deposit the same amount of filler material, as well as damage from high heat. Inverted microscopic analysis of the weld zone was performed in order to assess the effect of the welding parameters on the weld quality. As part of the TIG weld bead quality improvement process, dye penetration testing is performed.

Effect of friction stir welding parameters on the deep drawing of tailor-welded blanks (TWBs)

Friction stir welding is a method for joining dissimilar sheets and producing tailor-welded blanks (TWBs). An important issue in TWBs is their formability, as the material properties is not uniform across the welding line. In this method, the mechanical properties changing is a function of welding parameters such as traverse speed, rotational speed, and the shape of the tool. A common issue is choosing proper friction welding parameters to achieve the appropriate forming properties of the welded blanks. So in this paper, TWBs of AA2024-T3 and AA7075-T6 aluminum were prepared and welded using friction stir welding (FSW) method under various conditions, including three different tool shapes as conical, cylindrical, and square under various traverse speeds and rotational speeds. Tensile tests were carried out in order to obtain the best tensile strength conditions that are acceptable for deep drawing. The deep drawing procedure was simulated by using finite element method (FEM) to investigate the effect of weld line properties on thickness distribution and weld line movement. To verify the simulation results, the best joint was subjected to the deep-drawing process and its thickness distribution and welding line movement were compared with the simulation result. The simulation results revealed that the joint made with circular pin obtain gives the best results in deep drawing in terms of thickness distribution and weld line movement.

Friction welding of dissimilar metals (aluminium AL 6061 T6 and stainless steel AISI 304)

In friction welding, welding takes place due to exterior pressure applied on the cylindrical rods. Both the specimen to be welded are having a linear motion or a rotary motion. The main benefit of friction welding, is that it produces low distortion. The other advantage is absence of defects and comparatively high weld strength. It can also be employed to weld materials that are considered difficult to weld by older welding methods. Friction welded specimen do not require any external auxiliary such as tools or filler rods and thus helps to save cost. Also, this method requires relatively lesser welding times as compared to other welding processes. Using this technology, we can achieve welding of a large number of materials which have distinct mechanical properties and chemical composition. Friction Welding also helps to reduce the costs of process by a significant amount. This also has shown prominent reduction in overall weight of the component. This study encapsulates the work done in friction welding, presents the summary of the testing done in this field till date in brief. The identification of proper welding parameters such as Friction Load, Friction Time and Forge Load is an important task. The problem of obtaining good weldability as well as high weld strength is tackled and dealt with hereby. Friction welding could be a discovery in production technology, a leap which will profit a large variety of industries, as well as the aviation, naval industries. It also has use in manufacturing drilling tools.

Analysis of temperature and stress-strain fields during laser beam welding of a TRIP steel

Transformation Induced Plasticity (TRIP) steels belong to the group of Advanced High Strength Steels (AHSS) that are characterized by good strength-strain combination and formability required for special applications in the automotive industry. The excellent combination of strength, ductility and formability of TRIP steels is achieved by a careful control of microstructure development in the process of their production. The microstructure of multiphase TRIP steels typically consists of ferrite, carbide-free bainite and metastable retained austenite, which can be transformed into martensite by plastic deformation. Upon crash, this feature allows the TRIP steels to absorb more energy, ensuring greater passenger safety. In the automotive industry, TRIP steels are mainly joined by resistance spot welding, laser or electron beam welding. Generally, the thermal cycle of a fusion welding process destroys the sophistically designed microstructure of these steels in fusion and heat-affected zones resulting in deterioration of mechanical properties of the weld joint. Negative consequences of the welding process can be eliminated using proper welding parameters. The paper deals with numerical simulation and analysis of the temperature and stress-strain fields developed during the laser beam welding of a CMnSiNb TRIP steel sheets with the thickness of 2 mm. Simulation model takes into account non-linear temperature and phase dependent material properties. The heat input during the laser beam welding is modelled using the conical volumetric heat source. The optimal welding parameters for production of butt joints of CMnSiNb TRIP steel sheets using the TruDisk 4002 disc laser with the maximum power of 2 kW are designed.

Experimental research on CFRTP-Al alloy laser butt joining

Joining Al alloy with CFRTP has received significant attention because of its potential application in automobile, aviation industry. Lots of works have been carried out on CFRTP-metal lap welding. However, there is little work focused on CFRTP-Al alloy laser butt-welding. To improve the strength of the CFRTP-Al alloy butt joint, microtextures were prepared on the Al alloy surface by pulsed lasers and a PA resin layer with a proper thickness was added in the CFRTP-Al alloy interface. Six factors and five levels orthogonal experiments were designed and carried out. The joint strength with different welding parameters was examined and the joint fracture interface was detected. The result showed that with the proper welding parameters the melting PA resin flows into the microtextures of the Al alloy and a mechanical anchoring was produced, and a butt joint with the strength about 12MPa can be obtained.

Current Design Rules for Welding of Wind Energy Structures for Arctic Conditions

An article presents a review of current standards and guidelines in the field welding fabrication requirements for wind energy structures in arctic conditions. Extreme climatic conditions, such as Arctic, have a strong influence on the requirements for wind turbines structural characteristics, materials and fabrication methods. Special attention has to be paid for selecting steels with suitable mechanical properties, processing methods and delivery conditions. Additionally, it is highly important to select proper welding process and welding parameters, so that the structural integrity and reliable operation can be achieved.

Hybrid joining of a modular multi-material body-in-white structure

The production of pure steel and steel-aluminum (Al) bi-material body-in-white (BIW) in the same assembly line requires the use of joining techniques with high flexibility, and this is not currently possible with state-of-the-art mechanical joining techniques. This work therefore developed a hybrid joining technique, rivet resistance spot welding (RRSW). In this process, a special FEM-optimized rivet clamps the Al sheet on both sides, with one flat and one nearly flat surface. It functions as an adapter to weld the Al part with the other steel parts and separates the steel and Al parts to avoid contact corrosion. Experiments demonstrated that, with optimized rivet geometry and proper welding parameters, RRSW created steel-Al combinations in BIW that were of at least equal strength to, and usually stronger, than self-piercing riveting (SPR). RRSW’s corrosion resistance was also superior to SPR’s. To verify the sample level development, a steel roof was redesigned to use Al, and this was then welded to the adjacent steel parts using fully-automated spot welding unit. Using the same welding conditions as for the steel roof the RRSW quality was good. The same welding system can thus be used both for pure steel and for steel-Al multi-material BIW assembly. RRSW is therefore a flexible and economical joining method and a viable alternative to SPR.

Connection Status Research of the Resistance Spot Welding Joint Based on a Rectangular Terminal Electrode

Rectangular terminal electrode is adopted in this research to conduct a resistance spot welding (RSW) process on stainless steel plate. The connection status of RSW joints under different welding current, time, and pressure were studied, and revealed how the rectangular terminal electrode shape and its dimensions influence the RSW joint dimensions. The process analysis results showed that the RSW nuggets welded with rectangular terminal electrode are normally elliptical in shape, and the dimensions of the long axis direction and the short axis direction have a certain proportion. As the welding current increases, the nuggets dimensions in long direction increase first and then decrease, and the internal grain structure also varies. As the welding time increases, the nugget size in long direction increase first and then steady and rarely splash occurs. As the welding pressure increase, the nugget dimensions in long direction increase first and then decrease, and the splash easily occurs under large welding pressure. However, when the welding pressure is too small, the unique adjacent double fusion nugget formed. By adopting proper welding parameters, the nugget size and quality can be controlled. This provides an important basis for the application of rectangular terminal electrode in RSW welding process.

Construction of productivity windows for fillet welds using the FCAW process for thin ship panel manufacturing

The FCAW process used filler metal E71T-11 of Ø0.035” to apply fillet welds with a size of ~4mm on T-joints made of ASTM A36 steel, in a horizontal position, using 42 appropriate combinations of wire feed speeds -WFS- (between 50 and 540 ipm), voltages (13-33V) and welding speeds (4.2-24.5 ipm). The test welds applied with each combination were inspected visually and by macro-attack to establish their compliance with the acceptance criteria for naval panels provided by the American Bureau of Shipping - ABS. With these results, Voltage vs. WFS, Voltage vs. Amperage and Heat Input vs. WFS graphs were constructed, and productivity windows were drawn over them including the combinations of welding parameters capable of producing welds of acceptable quality. The productivity windows obtained with this method, called ARCWISE, allow proper welding parameters to be selected during the design of WPSs avoiding iterative processes of trial and error.

Lightweight Design and Welding Manufacturing of a Hydrogen Fuel Cell Powered Car’s Chassis

The development of the chassis for the hydrogen fuel cell powered car has been involved in the designing and manufacturing aspects, while taking into consideration the mass, strength, stiffness, centre of gravity (COG), and manufacturing cost requirements. Towards this direction, a chassis design is proposed employing a space frame structure and constructed by an aluminium alloy with great strength. The structural design has been derived through the lightweight engineering approaches in conjunction with the part consolidation, Design for Assembly (DFA) and Design for Manufacture methods. Moreover, it has been performed in compliance with the safety regulations of the Shell Eco Marathon racing competition. The material’s principal characteristics are the great strength, the low mass, as well as the great workability, machinability, and weldability. Following the national and global environmental issues, the recyclable characteristics of the aluminium alloy are an extra asset. Furthermore, the existence of aluminium alloy manufacturers around the fabricating area provides low cost supply and fast delivery benefits. The integration of the fuel cell powered vehicle is obtained through the designing and the manufacturing processes of the chassis and the parts fitted on the chassis. The manufacturing procedures are described thoroughly; mainly consisting of the cutting and welding processes and the assembling of the parts that are fitted on the chassis. Additionally, the proper welding parameters for the custom chassis design are investigated and are selected after deductive reasoning. The quality control of the weld joints is conducted by non-destructive methods (NDT) ensuring the required structural properties of the welds. A combination of the selected material, the specific type of the chassis, and the manufacturing processes lead to construction simplicity in a low manufacturing cost by using the existing laboratory equipment. Furthermore, the designing and manufacturing parameters lead to a stiff with a low centre of gravity, and the most lightweight chassis of the urban concept category at the Shell Eco Marathon race.

EXPERIMENTAL ANALYSIS OF RESISTANCE SPOT WELDING PARAMETERS FOR LOW CARBON STEEL SHEET

Resistance Spot Welding (RSW) is one of the most efficient fusion welding processes which known as a thermo – electric process used in joining metal by a combination of adjustable parameters (heat, pressure and time), it is high speed, flexible and highly productive process. It is extensively used for many industrial purposes in particular in the automotive industry. The aim of the present work is to study the effect of welding nugget area on the tensile strength of the resistance spot welded joints, the present discussion deals with effect of the parameters of resistance spot welding process (current, time, electrode force) on nugget formation and on failure load of the spot weld joints (the relation between nugget size and strength with input parameters). The test material of the specimens which used in this study is low carbon steel. The mechanical performance (peak load, failure mode) of the welded joints was determined by tensile testing, the testing results were analyzed which were obvious the effectiveness and the necessaries of the suitable or proper welding parameters for the strength of the spot weld joints

Metal Inert Gas (MIG) Welding Process Optimization using Teaching-Learning Based Optimization (TLBO) Algorithm

Welding parameters play a great significant role in determining the weld joint quality in terms of weld-bead geometry. To obtain a good quality weld, it is necessary to select the proper welding parameters. This study focuses on the optimization parameters for Metal Inert Gas (MIG) welding on AISI 1018 mild steel by Teaching-Learning Based Optimization (TLBO) algorithm. The input parameters considered are welding current, workpiece thickness, voltage and wire feed rate. Taguchi’s L27 orthogonal array have been used for design of experiment (DoE) and the mathematical models have been developed for output response using MINITAB16. Results show that welding current and voltage are statistical significance on overall MIG welding performance.

The Influence of Laser Welding on the Mechanical Properties of Dual Phase and Trip Steels

Nowadays, a wide range of materials is used for car body structures in order to improve both the passengers’ safety and fuel consumption. These are joined by laser welding and solid state fiber lasers being used more and more in present. The article is focused on the research of laser welding influence on the mechanical and deformation properties, microstructure and microhardness of advanced high-strength steels: high-strength low-alloyed steel HC340LA, dual phase steel HCT600X and multi-phase residual austenite steel RAK40/70. The proper welding parameters have been found based on weld quality evaluation. The specimens for tensile test with longitudinal laser weld were used to measure mechanical and deformation properties. Microstructure and microhardness of laser welds were evaluated in the base metal, heat affected zone and fusion zone. The higher values of strength and lower ones for deformation properties of laser-welded materials have been found for dual and multi-phase steel. The microhardness strongly depends on the carbon equivalent of steel. Deformation properties are more sensitive than strength properties to the change of microstructure in the fusion zone and heat affected zone.

Electron beam welding of thick-walled copper components

Electron beam welding facilitates a very high energy density, which is a significant advantage when welding materials with a high thermal conductivity like copper. Nevertheless, in EBW of copper, unique root defects are observed in full penetration welding of thick components. Therefore, it is of scientific interest and relevant for applications to determine the reason and to develop countermeasures. A novel attempt to address this problem is using filler material. First, with a copper–tin alloy filler metal in form of sheets, a sufficient solidification range can be established. Second, a pure tin plasma-sprayed layer is applied to achieve an alloyed weld zone. With these approaches and in combination with proper welding parameters, defect free joints are established.

Hybrid laser-metal active gas welding of S460ML steel plates: Weldability and consequences of dropping on weld quality

This work investigates the weldability of S460ML steel using a hybrid laser-metal active gas (MAG) process and the effect of dropping on material properties. Dropping is the creation of regularly scattered drops on the back side of thick plates during full penetration hybrid laser-MAG welding. As these drops can reach several millimeters in diameter, it is an unacceptable defect since it lowers esthetic properties. Besides the geometrical aspect, mechanical properties are also affected by dropping. In order to check the consequences of dropping on weld quality: metallographic, mechanical, and dilution analyses have been performed. Results confirm the good weldability of S460ML using hybrid welding with proper welding parameters. If dropping occurs, it enhances heterogeneity in chemistry and microstructure, and welding defects such as porosity and undercuts. However, these properties and defects remain tolerable. Drops can be removed by grinding, making the weld acceptable.

Effect of the welding process and filler material on the fatigue behavior of 960 MPa structural steel at a butt joint configuration

Ultrahigh-strength steels are being used more and more frequently in the engineering industry. Normally, the welding of these steels is more demanding. The welding requires a controlled heating and cooling rate. In this study, the S-N curves were determined for the laser, the laser-gas metal arc hybrid (Laser-GMA hybrid welding, LHW) and the gas metal arc welding (GMAW) welded joints according to the recommendations of the International Institute of Welding (IIW) by using a constant amplitude loading and a stress ratio of R = 0.1. The frequency of loading varied between 4 and 10 Hz. The tested material was direct quenched steel with a yield strength of 960MPa and a thickness of 6 mm. The total amount of tested specimens was 51. The fatigue test results have proven to be close to the IIW recommendations and the differences between various welding processes were minor. Instead of welding process or filler material, the main factor influencing the fatigue behavior was the geometry of the weld. Consequently, the proper welding parameters should be applied in every welding process in order to achieve a smooth joint geometry and, thus, a high fatigue resistance.

Experimental Analysis of Friction Stir Welding of Dissimilar Alloys AA6061 and Mg AZ31 Using Circular Butt Joint Geometry

The Aluminium alloy 6061 and Magnesium alloy AZ31 plates of 6mm thickness are welded in circular butt joint geometry by friction stir welding (FSW) process, using CNC vertical milling machine. Process parameters such as welding speed and tool rotational speed play an important role to obtain a better weld joint for dissimilar metals/materials. The friction stir welding tool is one of the critical components to the success of this process. It consists of a cylindrical shoulder and a pin with different geometry. In the experimental work, the said tool has been designed with cylindrical pin having four different geometries for friction stir welding of the dissimilar circular metal plates. Friction stir welding has been carried out at welding speed varying from 10 to 40mm/min and tool rotational speed from 800 to 2000rpm. Effects of process parameters on butt welded circular joint were investigated for weld strength. In this research work, it is found that welded joint between dissimilar metals alloys Al 6061 and Mg AZ31 can be formed using friction stir welding by selecting proper tool pin profile and welding parameters. It is suggested that friction stir welding of Aluminium alloy and Magnesium alloy with circular butt joint geometry would be useful in the future for automobile applications by getting the benefits from each material in a functional way.

Process parameter optimization in friction spot welding of AA5754 and Ti6Al4V dissimilar joints using response surface methodology

This study shows experimental and numerical results of friction spot welding of AA5754 and Ti6Al4V alloys. The determination of proper welding parameters plays an important role for the weld strength. Experimental tests, conducted according to combinations of process parameters such as tool rotational speed (RS) and dwell time (DT), were investigated with response surface methodology using a 3k factorial design of experiments. Sound joints with elevated shear strength were achieved and the influence of the main process parameters on joint strength evaluated. DT was the parameter with the largest influence on the joint shear resistance (58.9 %), followed by its interaction with RS (38.1 %). Higher strength was correlated to the thickness and morphology of the joint interface. A numerical model for predicting lap shear strength was successfully developed and used to optimize welding parameters in order to produce high-performance joints with less energy consumption and high efficiency.