Solid State Welding Process for Aerospace Components

2015 ◽  
Vol 1119 ◽  
pp. 597-600
Author(s):  
Hyun Ho Jung ◽  
Ye Rim Lee ◽  
Jong Hoon Yoon ◽  
Joon Tae Yoo ◽  
Kyung Ju Min ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Solid State ◽  
Structural Integrity ◽  
Welding Process ◽  
Diffusion Welding ◽  
Intimate Contact ◽  
Friction Stir ◽  
Base Materials ◽  
Welding Processes ◽  
And Diffusion

Since solid state welded joint is formed from an intimate contact between two metals at temperatures below the melting point of the base materials, the structural integrity of welding depends on time, temperature, and pressure. This paper provides some of examples of friction stir welding and diffusion welding process for aerospace components. Friction stir welding process of AA2195 was developed in order to study possible application for a large fuel tank. Massive diffusion welding of multiple titanium sheets was performed and successful results were obtained. Diffusion welding of dissimilar metals of copper and stainless steel was necessary to manufacture a scaled combustion chamber. Diffusion welding of copper and steel was performed and it is shown that the optimum condition of diffusion welding is 7MPa at 890°C, for one hour. It is shown that solid state welding processes can be successfully applied to fabricate lightweight aerospace parts.

A Study on Solid State Welding of Aerospace Materials

2018 ◽  
Vol 762 ◽  
pp. 343-347
Author(s):  
Ho Sung Lee ◽  
Jong Hoon Yoon ◽  
Joon Tae Yoo
Keyword(s):  
Solid State ◽  
Diffusion Bonding ◽  
Structural Integrity ◽  
Welding Process ◽  
Aerospace Materials ◽  
Intimate Contact ◽  
Friction Stir ◽  
Foreign Materials ◽  
Press Bonding ◽  
Solid State Joining

Since solid state welding is formed from an intimate contact between two metals at temperatures below the melting point of the base materials, the structural integrity of welded zone is maintained without presence of foreign materials or temporary liquid phase. This paper provides some of examples for solid state joining of aerospace materials. Diffusion bonding process was developed for a titanium alloy for lightweight sandwich panels. Diffusion bonding of copper and stainless steel was also demonstrated to manufacture a combustion chamber. HIP (Hot Isostatic Press) bonding and friction stir welding process of aluminum alloy was developed in order to study possible application for a large launcher fuel tank. It is shown that solid state joining processes can be successfully applied to various aerospace materials and provide innovative solution for lightweight structures.

Numerical Study of the Tool Rake Angle Effect on the Material Flow in Friction Stir Welding Process

2007 ◽  
Author(s):  
Hosein Atharifar ◽  
Radovan Kovacevic
Keyword(s):  
Friction Stir Welding ◽  
Material Flow ◽  
Numerical Study ◽  
Welding Process ◽  
Rake Angle ◽  
Heat Transfer Analysis ◽  
Tool Geometry ◽  
Friction Stir ◽  
Tool Pin ◽  
Welding Processes

Minimizing consumed energy in friction stir welding (FSW) is one of the prominent considerations in the process development. Modifications of the FSW tool geometry might be categorized as the initial attempt to achieve a minimum FSW effort. Advanced tool pin and shoulder features as well as a low-conductive backing plate, high-conductive FSW tools equipped with cooling fins, and single or multi-step welding processes are all carried out to achieve a flawless weld with reduced welding effort. The outcomes of these attempts are considerable, primarily when the tool pin traditional designs are replaced with threaded, Trifiute or Trivex geometries. Nevertheless, the problem remains as to how an inclined tool affects the material flow characteristics and the loads applied to the tool. It is experimentally proven that a positive rake angle facilitates the traverse motion of the FSW tool; however, few computational evidences were provided. In this study, numerical material flow and heat transfer analysis are carried out for the presumed tool rake angle ranging from −4° to 4°. Afterwards, the effects of the tool rake angle to the dynamic pressure distribution, strain-rates, and velocity profiles are numerically computed. Furthermore, coefficients of drag, lift, and side force and moment applied to the tool from the visco-plastic material region are computed for each of the tool rake angles. Eventually, this paper confirms that the rake angle dramatically affects the magnitude of the loads applied to the FSW tool, and the developed advanced numerical model might be used to find optimum tool rake angle for other aluminum alloys.

Modeling Damage Evolution in Friction Stir Welding Process

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Youliang He ◽  
Paul R. Dawson ◽  
Donald E. Boyce
Keyword(s):  
Friction Stir Welding ◽  
Void Growth ◽  
Evolution Equations ◽  
Volume Fraction ◽  
Welding Process ◽  
Three Dimensions ◽  
Element Formulation ◽  
Operational Parameters ◽  
Friction Stir ◽  
Welding Processes

The evolution of voids (damage) in friction stir welding processes was simulated using a void growth model that incorporates viscoplastic flow and strain hardening of incompressible materials during plastic deformation. The void growth rate is expressed as a function of the void volume fraction, the effective deformation rate, and the ratio of the mean stress to the strength of the material. A steady-state Eulerian finite element formulation was employed to calculate the flow and thermal fields in three dimensions, and the evolution of the strength and damage was evaluated by integrating the evolution equations along the streamlines obtained in the Eulerian configuration. The distribution of internal voids within the material was qualitatively compared with experimental results, and a good agreement was observed in terms of the spatial location of voids. The effects of pin geometry and operational parameters such as tool rotational and travel speeds on the evolution of damage were also examined.

Numerical Modeling of Thermal Field Distribution during Friction Stir Welding (FSW) of Dissimilar Materials

2016 ◽  
Vol 254 ◽  
pp. 261-266
Author(s):  
Bogdan Radu ◽  
Cosmin Codrean ◽  
Radu Cojocaru ◽  
Cristian Ciucă
Keyword(s):  
Numerical Modeling ◽  
Friction Stir Welding ◽  
Solid State ◽  
Thermal Field ◽  
Welding Process ◽  
Dissimilar Materials ◽  
Dissimilar Joints ◽  
Element Analysis ◽  
Friction Stir ◽  
The Cost

Friction Stir Welding (FSW) is an innovative solid state welding process, relatively new in industry, which allow welding of two or more materials which have very different properties, particularly thermal properties as fusion temperature, thermal expansion coefficient, specific heat and thermal conduction and have a predisposition to form intermetallic brittle phases, neither one of the components to be weld reach to the melting point. Being a solid state welding process temperature field is very important for the quality of the welded joint, and a lot of researches focused on this topic. This paper presents some results in modeling and estimation of thermal field developed during FSW of dissimilar joints, using Finite Element Analysis. Numerical modeling of thermal field allows engineers to predict, in advance, the evolution of temperature and to estimate the behavior of the welded materials during the welding process. This will reduce significantly the time and number of experiments that have to be carried out, in the process of establishing a good FSW technology, as well as reducing significantly the cost of the tests.

Modeling of the Plastic Characteristics of AA6082 for the Friction Stir Welding Process

2015 ◽  
Vol 639 ◽  
pp. 309-316
Author(s):  
Sergio Pellegrino ◽  
Livan Fratini ◽  
Marion Merklein ◽  
Wolfgang Böhm ◽  
Hung Nguyen
Keyword(s):  
Friction Stir Welding ◽  
Strain Rate ◽  
Elevated Temperatures ◽  
Flow Behavior ◽  
Welding Process ◽  
Rate Sensitivity ◽  
Tensile Tests ◽  
Friction Stir ◽  
Friction Stir Welding Process ◽  
Welding Processes

Focus of this paper is to model the plastic forming behavior of AA6082, in order to develop the numerical FE analysis of the friction stir welding processes and the simulation of subsequent forming processes. During the friction stir welding process, the temperatures reached are until 500 °C and have a fundamental role for the correct performance of the process so the material data has to show a temperature dependency. Because of the tool rotation a strain rate sensitivity of the material has to be respected as well. In this context, the general material characteristics of AA6082 were first identified for different stress states. For the uniaxial state the standard PuD-Al used in the automotive industry was applied, for the shear state the ASTM B831-05 was used and for biaxial states the ISO 16842 was exploited. To characterize the plastic flow behavior of the AA6082 at elevated temperatures tensile tests were performed according to DIN EN ISO 6892-2 from 25 °C until 500 °C with a strain rate from 0.1 s-1up to 6.5 s-1.

scholarly journals A Multi-attribute Control Chart for Monitoring Friction Stir Welding Process Considering Small Sample Sizes

2018 ◽  
Vol 23 (4) ◽  
pp. 474-484
Author(s):  
Esmeralda Ramírez-Méndez ◽  
Mario Cantu-Sifuentes ◽  
David Salvador González-González ◽  
Argelia Fabiola Miranda-Pérez ◽  
Rolando Javier Praga-Alejo
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
Control Chart ◽  
Welding Process ◽  
Small Sample ◽  
Sample Sizes ◽  
Process Data ◽  
Friction Stir ◽  
Small Sample Sizes ◽  
Welding Processes

Abstract Often, welding processes used in the industry affect the mechanical properties of materials and quality of a manufactured product. There is, however, an alternative process named Friction Stir Welding (FSW), which is an solid state welding process developed to weld light alloys without compromising their mechanical properties. It is of interest to monitor the performance of FSW process to detect loss of quality. In practice, superficial and internal defects can be found; they can be identified through simple visual inspection and through visual recognition on destructive testing respectively, both procedures represent inspection by attributes. Therefore a multi-attribute control chart is assessed to monitor the process. Commonly, multi-attribute control charts involve high sampling rates to ensure accurate monitoring. In this paper, a multi-attribute control chart is proposed, considering the use of empirical control limits, instead of the theoretical ones, in order to improve its accuracy and lessen the small sample sizes effect. The performance of proposed approaches is analyzed by means of Monte Carlo simulation. The results suggest that the performance of the empirical designs is better than the theoretical ones in all tested cases. Finally, the results of monitoring FSW process data are detailed.

An Experimental Study of Process Parameters on Friction Stir Welded Aluminum Alloy 2219 Joint Properties

2017 ◽  
Vol 863 ◽  
pp. 3-7
Author(s):  
Koo Kil No ◽  
Joon Tae Yoo ◽  
Jong Hoon Yoon ◽  
Ho Sung Lee
Keyword(s):  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Solid State ◽  
Process Parameters ◽  
Process Condition ◽  
Welding Process ◽  
Frictional Heat ◽  
Friction Stir ◽  
Joint Properties ◽  
Aluminum Alloy 2219

Aluminum alloy 2219 is widely used in aerospace applications since it has a unique combination of good weldability and high specific strength. Furthermore, it can provide a high strength after heat treatment with superior properties in cryogenic environment so they have been widely used for cryogenic fuel tank of space launch vehicles. It is known that solid state welding like friction stir welding can improve the joint properties of this alloy. Friction stir welding is a solid state welding technology which two materials are welded together by the frictional heat due to the rotation of the tool. In this study, friction stir welding was performed on aluminum alloy 2219 sheets. The range of welding parameter is four rotation speeds from 350 to 800 rpm and six travel speeds from 120 to 420 mm/min. The results include the microstructural change after friction stir welding. The microstructure was characterized and material in the stirred zone experience sufficient deformation and heat input which cause the complete dynamic recrystallization. The present work represents the strength at each process condition and the optimum friction stir welding process parameters. The optimum weld efficiency obtained in this study was 76.5 %.

Empirical Dynamic Modeling of Friction Stir Welding Processes

2007 ◽  
Author(s):  
Xin Zhao ◽  
Prabhanjana Kalya ◽  
Robert G. Landers ◽  
K. Krishnamurthy
Keyword(s):  
Steady State ◽  
Friction Stir Welding ◽  
Process Parameters ◽  
Dynamic Models ◽  
Welding Process ◽  
Recursive Least Squares ◽  
Finite Difference Schemes ◽  
Power Relationship ◽  
Friction Stir ◽  
Welding Processes

Current Friction Stir Welding (FSW) process modeling research is concerned with the detailed analysis of local effects such as material flow, heat generation, etc. These detailed thermo-mechanical models are typically solved using finite element or finite difference schemes and require substantial computational effort to determine temperature, forces, etc. at a single point in time. Dynamic models describing the total forces acting on the tool throughout the entire welding process are required for the design of feedback control strategies and improved process planning and analysis. In this paper, empirical models relating the process parameters (i.e., plunge depth, traverse rate, and rotation speed) to the process variables (i.e., axial, traverse, and lateral forces) are developed to understand their dynamic relationship. First, the steady-state relationship between the process parameters and variables is constructed, and the relative importance of each process parameter on each process variable is determined. Next, the dynamic process response characteristics are determined using Recursive Least-Squares. The results indicate that the steady-state relationship between the process parameters and variables is well characterized by a nonlinear power relationship, and the dynamic responses are well characterized by low-order linear equations. Experiments are conducted that validate the developed FSW dynamic models.

Friction Stir Welding of Composite Materials with Metallic Matrix: A Brief Review

2015 ◽  
Vol 809-810 ◽  
pp. 449-454 ◽  
Author(s):  
Ana Boşneag ◽  
Marius Adrian Constantin ◽  
Eduard Niţu ◽  
Monica Iordache ◽  
Alin Rizea
Keyword(s):  
Composite Materials ◽  
Friction Stir Welding ◽  
Welded Joint ◽  
Metallic Matrix ◽  
Welding Process ◽  
Fusion Welding ◽  
Industrial Environment ◽  
Friction Stir ◽  
Current State ◽  
Welding Processes

Composite materials with metallic matrix are increasingly require more than traditional materials metallic, being lighter, more reliable and with their superior properties like: rigidity, tensile strength, flexural strength, fatigue strength, modulus of elasticity, hardness, etc. Due to these advantages, above mentioned, this process has largely penetrated industrial environment. Despite these advantages, there are restrictions on their combination through traditional fusion welding methods so that was passed at the solid-state welding processes, respectively at Friction Stir Welding (FSW). Our researches presents in this brief review: some general ideas about composite materials with metallic matrix and Friction Stir Welding process, appearance and benefits, basic information about the process and composite materials welded by this process, shows the current state of the research with respect to behaviour macrostructure, microstructure, microhardness, tensile properties and defects of the welded joint between composite materials with metallic matrix.

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