scholarly journals Mechanical and Formability Evaluation of ST14 Alloys Welded by Friction Stir Welding

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Mahmoud Afshari ◽  
Nima Fakhralmobasheri ◽  
Mohammad Reza Samadi ◽  
Amirhossein Alavi ◽  
Hossein Norozi Foroushani

Friction stir welding as one of the modern methods of solid-state welding of steel sheets and aluminum is a highly regarded industry. In these studies, the experimental design and response surface methodology were used. Optimization of experimental conditions and results which are compared with good agreement between the results was observed. The mechanical properties and ductility of welded plates under optimal conditions were studied. Microhardness testing, metallography, tensile testing, and limiting dome height were used to investigate the mechanical properties and formability limit diagram attached, respectively. The results showed that the heat-affected zone is very small and narrow and not easily distinguished from the base metal. In all tests, the failure of the dome height limit in the area was chaos. In all samples welded with the optimal parameters, tensile failure occurred in the base metal region. Turbulence in the region confirms the presence of WC particles. Experimental design and response surface methodology could introduce an optimal state, and the creation of common defects in the FSW process can prevent the binding strength of the guarantee. But due to the lack of proper stirring in the perturbation area in the samples welded with non-optimized parameters, the strength of the connection is not suitable, and samples were broken from the SZ region.

Author(s):  
Rajat Gupta ◽  
Kamal Kumar ◽  
Neeraj Sharma

This chapter presents the friction stir welding (FSW) of aluminum alloy AA-5083-O using vertical milling machine. In present FSW experimentation, effects of different process parameter namely tool rotation speed, welding speed, tool geometry, and tool shoulder diameter have been determined on welding quality of two pieces of AA-5083-O using response surface methodology (RSM). The optimal sets of process parameters have been determined for weld quality characteristics namely tensile strength (UTS) and percentage elongation (%EL). In present experimentations, a specially designed tool made of high carbon steel with different shoulder diameters (15mm, 17.5mm, and 20 mm) having constant pin length (6 mm) were used for FSW of two pieces of aluminum alloy. The ANOVA and pooled ANOVA were used to study the effect of FSW parameters on UTS and %EL. Multi response optimization has been carried out using desirability function in conjunction with RSM to obtain the optimal setting of process parameters for higher UTS and lower %EL.


Author(s):  
Morteza Ghaffarpour ◽  
Ahmad Aziz ◽  
Taha-Hossein Hejazi

Improving quality in today’s complicated industrial systems is gaining more and more importance every day. Since applying these systems costs a lot, companies should try to offer the best outcomes and processes possible. One of the products most applied is Tailor Welding Blanks, which is widely used in automobile, aerospace, and other industries. One of the best methods of producing Tailor Welding Blanks is Friction Stir Welding. Using this technology, sheets dissimilar in material and thickness can be joined. In this paper, the possibility of welding thin sheets of 5083-H12 and 6061-T6 aluminum alloy by Friction Stir Welding with the thickness of 1.5 mm is examined. To detect the impact of Friction Stir Welding parameters, i.e. rotational speed (r/min), linear speed (mm/ min), shoulder diameter (mm), and tilt angle (°), a Box-Behnken design was used and using multiple Response Surface Methodology values of robust optimization of tensile strength and elongation were derived. The optimization and experiment results were then compared. The results of the comparison showed a good correspondence.


2010 ◽  
Vol 667-669 ◽  
pp. 505-510
Author(s):  
Ilya Nikulin ◽  
Alla Kipelova ◽  
Sergey Malopheyev ◽  
Rustam Kaibyshev

Friction stir welding (FSW) was used to join the submicrocrystalline (SMC) grained Al-Cu-Mg-Ag sheets produced by equal channel angular pressing (ECAP) followed by hot rolling (HR). The effect of SPD and FSW on the microstructure and mechanical properties in the zone of base metal, as well as in the stirred zone (SZ) were examined. In addition, effect of standard heat treatment on microstructure and mechanical properties in these zones was considered. A refined microstructure with an average grain size of ~ 0.6 m and a portion of high-angle grain boundaries (HAGBs) of ~0.67 was produced in sheets by ECAP followed by HR at 250°C. The microcrystalline grained structure with average grain size of ~2.3 mm was found in joint weld. The moderate mechanical properties were revealed in SMC sheets and joint welds. Heat treatment considerably increases strength of the base metal as well as the joint welds. The higher strength of the alloy after T6 temper is attributed to the dense precipitations of  dispersoids having plate-like shape which are uniformly distributed within aluminum matrix. It was observed that FSW can produce full strength weld both in the tempered and in the un-tempered conditions.


2020 ◽  
Vol 22 (4) ◽  
pp. 110-123
Author(s):  
Alexey Ivanov ◽  
◽  
Valery Rubtsov ◽  
Evgeny Kolubaev ◽  
Vladimir Bakshaev ◽  
...  

Introduction. Friction stir welding conditions determines character of thermomechanical impact on welded material, so a critical alteration of even one of condition parameters can result in formation of defects and strength decrease of welded joint. Also an important factor is an orientation of welded material relative to a welding direction since it determines kinetics of material deformation and consequently its final structure and properties. Research efforts of friction stir welding properties generally consist in analysis of final properties of obtained weld joints and its correlation with parameters of welding condition. But to solve a problem of obtaining of weld joints with strength and quality, it’s also important to estimate a welded material resistance to deformation from welding tool impact which could be achieved by monitoring a number of parameters directly in process of welding. The purpose of the work is to research an impact of welding condition parameters and an orientation of welded material’s structure on friction stir welding process behavior and also on structure and strength of weld joints of 2024 aluminum alloy. Results and discussion. By monitoring the torque and welding force, it is shown that as the tool penetration force increases, the material's resistance to deformation increases. When welding is longitudinal to the direction of base metal rolling a torque and a welding force parameters decreases in value of 5-20%. An increase of welding speed provides a growing of material resistance to welding tool movement, at that, a direction of welding doesn’t have a significant impact. With an increase of welding tool rotational speed, a material resistance to deformation decreases, a welding temperature grows and it results in growing of material’s plasticization degree and in improvement of its mass transfer conditions. It is also shown that the welding conditions, which allows welding the 2024 alloy at a temperature of 450 – 500 ºС, provides the degree of plasticization of the material, at which welded joints with a high-quality structure and high mechanical properties are obtained. In this conditions a direction of welding in relation to the direction of base metal rolling has an impact: when welding is longitudinal to the direction of rolling the tensile strength of weld joints reaches a value of 92%, and when welding is transverse - 95% of base material tensile strength.


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