Developing an Empirical Relationship to Predict Tensile Strength of Friction Stir Welded AA2219 Aluminum Alloy

AA2219 aluminum alloy (Al-Cu-Mn alloy) has gathered wide acceptance in the fabrication of lightweight structures requiring a high strength-to-weight ratio and good corrosion resistance. Friction stir welding (FSW) process is an emerging solid state joining process in which the material that is being welded does not melt and recast. This process uses a nonconsumable tool to generate frictional heat in the abutting surfaces. The welding parameters such as tool rotational speed, welding speed, axial force, etc., and tool pin profile play a major role in deciding the joint strength. An attempt has been made to develop an empirical relationship between FSW variables to predict tensile strength of the friction stir welded AA2219 aluminum alloy. To obtain the desired strength, it is essential to have a complete control over the relevant process parameters to maximize the tensile strength on which the quality of a weldment is based. Therefore, it is very important to select and control the welding process parameter for obtaining maximum strength. To achieve this various prediction methods such as response surface method (RSM), analysis of variance (ANOVA), Student’s t-test, coefficient of determination, etc., can be applied to define the desired output variables through developing mathematical models to specify the relationship between the output parameters and input variables. Four factors, five levels central composite design have been used to minimize number of experimental conditions. The developed mathematical relationship can be effectively used to predict the tensile strength of FSW joints of AA2219 aluminum alloy at 95% confidence level.     

Influences of tool pin profile and welding speed on the formation of friction stir processing zone in AA2219 aluminium alloy

AA2219 aluminium alloy has gathered wide acceptance in the fabrication of light weight structures requiring a high strength to weight ratio. Compared to the fusion welding processes that are routinely used for joining structural aluminium alloys, friction stir welding (FSW) process is an emerging solid state joining process in which the material that is being welded does not melt and recast. This process uses a non-consumable tool to generate frictional heat in the abutting surfaces. The welding parameters and tool pin profile play major roles in deciding the weld quality. In this investigation, an attempt has been made to understand the effect of welding speed and tool pin profile on FSP zone formation in AA2219 aluminium alloy. Five different tool pin profiles (straight cylindrical, tapered cylindrical, threaded cylindrical, triangular and square) have been used to fabricate the joints at three different welding speeds. The formation of FSP zone has been analysed macroscopically. Tensile properties of the joints have been evaluated and correlated with the FSP zone formation. From this investigation it is found that the square pin profiled tool produces mechanically sound and metallurgically defect free welds compared to other tool pin profiles.     

Establishing empirical relationships to predict grain size and tensile strength of friction stir welded AA 6061-T6 aluminium alloy joints

AA 6061-T6 aluminium alloy(Al-Mg-Si alloy) has gathered wide acceptance in the fabrication of light weight structures requiring a high specific strength and good corrosion resistance.Compared with the fusion welding processes that are routinely used for joining structural aluminium alloys,friction stir welding(FSW) process is an emerging solid state joining process in which the material welded does not melt and recast.Joint strength is influenced by the grain size and tensile strength of the weld nugget region.Hence,an attempt was made to develop empirical relationships to predict grain size and tensile strength of friction stir welded AA 6061-T6 aluminium alloy joints.The empirical relationships are developed by response surface methodology(RSM) incorporating FSW tool and process parameters.A linear regression relationship was also established between grain size and tensile strength of the weld nugget of FSW joints.     

Comparison of RSM with ANN in predicting tensile strength of friction stir welded AA7039 aluminium alloy joints

Friction stir welding(FSW) is an innovative solid state joining technique and has been employed in aerospace, rail, automotive and marine industries for joining aluminium, magnesium, zinc and copper alloys. The FSW process parameters such as tool rotational speed, welding speed, axial force, play a major role in deciding the weld quality. Two methods, response surface methodology and artificial neural network were used to predict the tensile strength of friction stir welded AA7039 aluminium alloy. The experiments were conducted based on three factors, three-level, and central composite face centered design with full replications technique, and mathematical model was developed. Sensitivity analysis was carried out to identify critical parameters. The results obtained through response surface methodology were compared with those through artificial neural networks.     

AA2219铝合金搅拌摩擦焊接工艺窗口的建立

建立AA2219铝合金搅拌摩擦焊接的工艺窗口。采用不同的工艺参数如旋转速度和焊接速度来焊接该铝合金。通过对焊接接头的宏观形貌分析,建立搅拌摩擦焊的工艺窗口。通过拉伸试验、显微组织观察,对工艺窗口不同区域的接头强度进行分析。焊接接头断裂的位置与最低硬度分布相关。所建立的工艺窗口可以用来选择适当的工艺参数来获得高质量的AA2219铝合金搅拌摩擦焊接。     

Process parameters optimization for friction stir welding of RDE-40 aluminium alloy using Taguchi technique

Taguchi approach was applied to determine the most influential control factors which will yield better tensile strength of the joints of friction stir welded RDE-40 aluminium alloy. In order to evaluate the effect of process parameters such as tool rotational speed, traverse speed and axial force on tensile strength of friction stir welded RDE-40 aluminium alloy, Taguchi parametric design and optimization approach was used. Through the Taguchi parametric design approach, the optimum levels of process parameters were determined. The results indicate that the rotational speed, welding speed and axial force are the significant parameters in deciding the tensile strength of the joint. The predicted optimal value of tensile strength of friction stir welded RDE-40 aluminium alloy is 303 MPa. The results were confirmed by further experiments.     

Multi-Response Optimization of Friction-Stir-Welded AA1100 Aluminum Alloy Joints

AA1100 aluminum alloy has gathered wide acceptance in the fabrication of light weight structures. Friction stir welding process (FSW) is an emerging solid state joining process in which the material that is being welded does not melt and recast. The process and tool parameters of FSW play a major role in deciding the joint characteristics. In this research, the relationships between the FSW parameters (rotational speed, welding speed, axial force, shoulder diameter, pin diameter, and tool hardness) and the responses (tensile strength, hardness, and corrosion rate) were established. The optimal welding conditions to maximize the tensile strength and minimize the corrosion rate were identified for AA1100 aluminum alloy and reported here.     

搅拌摩擦焊工艺参数对铸态A356铝合金抗拉强度的影响(英文)

A356是一种高强度铝硅铸造态合金,广泛用于食品、化工、船舶、电器和汽车行业。熔焊这种铸造合金时存在许多问题,如孔隙、微裂隙、热裂等。然而,用搅拌摩擦焊(FSW)来焊接这种铸造态合金可以避免上述缺陷发生。研究了搅拌摩擦焊工艺参数对铸造态A356铝合金抗拉强度的影响;对旋转速度、焊接速度和轴向力等工艺参数进行优化;从宏观和微观组织分析角度对焊接区的质量进行分析;对焊接接头的抗拉强度进行了测定,并对抗拉强度与焊缝区硬度和显微组织的相关性进行了研究。在旋转速度1000r/min、焊接速度75mm/min和轴向力5kN的条件下得到的焊接接头具有最高的抗拉强度。     

焊接方法对AA2219铝合金接头性能的影响(英文)

使用钨电极惰性气体保护焊接、电子束焊接和搅拌摩擦焊接技术制备无填充金属的AA2219铝合金对焊接头。研究三种焊接工艺对材料拉伸、疲劳和腐蚀行为的影响。使用光学和电子显微镜研究显微结构。结果表明,与钨电极惰性气体保护焊和电子束焊接相比,搅拌摩擦焊制备的接头具有较高的拉伸和疲劳性能与较低的耐蚀性能,这主要是由于其中的细化晶粒和均匀分布的强化析出相所引起的。     

7A52铝合金搅拌摩擦焊工艺优化

接头强度是搅拌摩擦焊接头性能的一个重要指标,通过搅拌头旋转频率、焊接速度和轴肩下压量等焊接工艺参数的不同组合制备了35个7A52焊接试板,对试板进行拉伸试验检测了接头的抗拉强度,建立并分析了焊接接头抗拉强度与焊接工艺参数之间的回归模型,搅拌头旋转频率n,焊接速度v和轴肩下压量d<,ta>单独变化时,接头抗拉强度都有峰值...     

Multi-objective optimization of friction stir welding parameters using desirability approach to join Al/SiCp metal matrix composites

Silicon carbide particulate (SiC_p) reinforced cast aluminium (Al) based metal matrix composites (MMCs) have gained wide acceptance in the fabrication of light weight structures requiring high specific strength, high temperature capability and good wear resistance. Friction stir welding (FSW) process parameters play major role in deciding the performance of welded joints. The ultimate tensile strength, notch tensile strength and weld nugget hardness of friction stir butt welded joints of cast Al/SiC_p MMCs (AA6061 with 20% (volume fraction) of SiC_p) were investigated. The relationships between the FSW process parameters (rotational speed, welding speed and axial force) and the responses (ultimate tensile strength, notch tensile strength and weld nugget hardness) were established. The optimal welding parameters to maximize the mechanical properties were identified by using desirability approach. From this investigation, it is found that the joints fabricated with the tool rotational speed of 1370 r/min, welding speed of 88.9 mm/min, and axial force of 9.6 kN yield the maximum ultimate tensile strength, notch tensile strength and hardness of 265 MPa, 201 MPa and HV114, respectively.     

Impact of Friction Stir Welding (FSW) Process Parameters on Thermal Modeling and Heat Generation of Aluminum Alloy Joints

Friction stir welding(FSW)is a solid-state joining process,where joint properties largely depend on the amount of heat generation during the welding process.The objective of this paper was to develop a numerical thermomechanical model for FSW of aluminum–copper alloy AA2219 and analyze heat generation during the welding process.The thermomechanical model has been developed utilizing ANSYS~ APDL.The model was verified by comparing simulated temperature profile of three different weld schedules(i.e.,different combinations of weld parameters in real weld situations)from simulation with experimental results.Furthermore,the verified model was used to analyze the effect of different weld parameters on heat generation.Among all the weld parameters,the effect of rotational speed on heat generation is the highest.     

Analysis of process parameters effects on dissimilar friction stir welding of AA1100 and A441 AISI steel

Abstract

A prominent benefit of friction stir welding process is to join plates with dissimilar material. In this study, an attempt is made to find effects of tool offset, plunge depth, welding traverse speed and tool rotational speed on tensile strength, microhardness and material flow in dissimilar friction stir welding of AA1100 aluminium alloy and A441 AISI steel plates. Here, one factor at a time experimental design was utilised for conducting the experiments. Results indicated the strongest joint obtained at 1·3?mm tool offset and 0·2?mm plunge depth when the tool rotational speed and linear speed were 800?rev min^??1 and 63?mm min^??1 respectively. The maximum tensile strength of welded joints with mentioned optimal parameters was 90% aluminium base metal. Fracture locations in tensile test at all samples were in aluminium sides. Owing to the formation of intermetallic compounds at high tool rotational speed, the microhardness of joint interface goes beyond that of A441 AISI steel.     

Optimization of friction stir welding process to maximize tensile strength of AA6061/ZrB<Subscript>2</Subscript> in-situ composite butt joints

A variety of ceramic particles is added to aluminum alloys to produce aluminum matrix composites (AMCs). Establishing the joining procedure for AMCs is an essential requirement prior to extending their applications. Friction stir welding (FSW) is an emerging solid state welding which eliminates all the defects associated with fusion welding of AMCs. An attempt has been made to friction stir weld AA6061/ ZrB₂ in-situ composite. A four factor, five level central composite rotatable design has been used to minimize the number of experiments. The four factors considered are tool rotational speed, welding speed, axial force and weight percentage of ZrB₂. A mathematical model has been developed incorporating the FSW process parameters to predict the ultimate tensile strength (UTS) and FS process is optimized using generalized reduced gradient method (GRG) to maximize the UTS. The effect of process parameters on UTS was analyzed. It was observed that the process parameters independently influence the UTS over the entire range studied in this work.     

Development of processing windows for friction stir spot welding of aluminium Al5052 /copper C27200 dissimilar materials

Friction stir spot welding technique was used to join dissimilar combinations of aluminium alloy (Al5052) with copper alloy (C27200) and friction stir spot welding windows such as tool rotational speed–dwell time and tool rotational speed–plunge depth diagrams for effective joining of these materials were developed. Using a central composite design model, empirical relations were developed to predict the changes in tensile shear failure load values and interface hardness of the joints with three process parameters such as tool rotational speed, plunge depth and dwell time. The adequacy of the developed model was verified using ANOVA analysis at 95% confidence level. Response surface methodology was used to optimize the developed model to maximize tensile strength and minimize interface hardness. A high tensile shear failure load value of 3850 N and low interface hardness value of HV 81 was observed for joints made under optimum conditions, and validation experiments confirmed the high predictability of the developed model with error less than 2%. The operating windows developed shall act as reference maps for future design engineers in choosing appropriate friction stir spot welding process parameter values to obtain good joints.     

Shear localisation modelling of friction stir weld formation process

This paper presents a shear localisation model for studying friction stir welding (FSW) formation process. With this model, shear band (SB) width, SB formation time, and SB propagation speed can be theoretically estimated. The SB propagation speed in this context serves as a theoretical estimate of the maximum welding speed possible for a given material and prescribed welding conditions, such as stir pin rotation speed and torque level. The model is shown to provide reasonable estimates of shear localisation parameters against a set of recent experimental data on FSW of titanium alloy Ti–6Al–4V. With this model, titanium alloy Ti–6Al–4V, high strength low-alloy steel 4340, and aluminium alloy 2024 are compared in terms of shear localisation parameters, such as maximum SB propagation speeds (or welding speeds).     

Development of Ir based tool for friction stir welding of high temperature materials

Abstract

A friction stir welding (FSW) tool with high strength and high wear resistance at elevated temperature is needed to perform FSW of high temperature materials. The purpose of this study is to develop a welding tool suited for FSW of high temperature materials. It has been clarified that Ir is little oxidised at elevated temperatures and that the addition of Re within the solubility limit to Ir increases the recrystallisation temperature, the high temperature strength and the high temperature hardness of the Ir alloy. SUS304 stainless steel was successfully friction stir welded by an Ir–10?at‐%Re welding tool without significant wear.     

Influences of process parameters on tensile strength of friction stir welded cast A319 aluminium alloy joints

Fusion welding of cast A319 (Al-Si-Cu) alloy will lead to many problems including porosity, micro-fissuring, and hot cracking. Friction Stir Welding (FSW) can be used to weld A319 alloy without these defects. In this investigation, an attempt has been made to study the effect of FSW process parameters on the tensile strength of A319 alloy welded joints. Joints were made using different combinations of tool rotation speed, welding speed, and axial force, each at four levels. The quality of weld zone was analyzed using macrostructure and microstructure analysis. Tensile strength of the joints were evaluated and correlated with the weld zone microstructure. The joint fabricated with a 1200 rpm tool rotation speed, 40 mm/min welding speed, and 4 kN axial force showed superior tensile strength compared with the other joints.     

搅拌摩擦焊AA7075-T651铝合金接头的疲劳裂纹扩展(英文)

研究12 mm厚AA7075-T651铝合金板搅拌摩擦焊接头的疲劳裂纹扩展行为。从搅拌摩擦焊接头以及母材中截取试样,对试样进行疲劳裂纹扩展实验。对搅拌摩擦焊接头以及母材的横向拉伸性能进行评估。用光学显微镜和透射电镜分析焊接接头的显微组织。用扫描电镜观察试样的断裂表面。与母材相比,焊接接头的ΔKcr降低了10×10-3 MPa·m1/2。搅拌摩擦焊AA7075-T651接头的疲劳寿命明显低于母材的,其原因可归结于焊缝区的析出相在搅拌摩擦焊接过程中的溶解。     

Friction stir welding of AZ31 magnesium alloy

Friction stir welding (FSW) is an new solid-phase joining technology which has more advantages over fusion welding methods in welding of aluminum and other non-ferrous metals. The effects of welding parameters on mechanical properties and microstructure during friction stir welding of AZ31 magnesium alloy were studied in this paper. Microstructures and mechanical properties of the joints were investigated by means of optical microscopy, scanning electric microscopy ( SEM ) , micro-hardness analysis, and tensile test. Experimental results show that the magnesium alloy can be successfully welded by FSW method, and the ultimate tensile strength (UTS) of FSW joint reaches up to 90 percent of base metal. The microstructures of welded joints exhibit the variation from dynamically recrystallized fine grains to greatly deformed grains. Hardness in nugget zone was found lower than the base metal but not too obvious.