Heat Transfer Simulations and Analysis of Joint Cross-Sectional Microstructure on Friction Stir Welding between Steel and Aluminium

2020 ◽  
Vol 863 ◽  
pp. 85-95
Author(s):  
Truong Minh Nhat ◽  
Truong Quoc Thanh ◽  
Tu Vinh Thong ◽  
Tran Trong Quyet ◽  
Luu Phuong Minh

This study presents conducted heat simulations and experimental jointing flat-plate of aluminum alloy 6061 and SUS 304. Temperature is simulated by the COMSOL software in three states: (1) Preheat the Friction Stir Welding (FSW) by TIG welding, (2) Thermal contact resistance between Aluminium and steel, and (3) The welding process using stiring friction is simulated. The simulations intended to predicting the temperature which is used for preheat and welding process to ensuring the required solid-state welding. The temperature is also determined and checked by a thermal imager comparing with simulation results. Besides, the results of tensile strength is carried out. The Box - Behnken method is used to identify the relationship between the welding parameters (rotation, speed and offset), temperature and tensile strength. The maximum tensile strength is 77% compared to the strength of aluminum alloy. The optimal set of parameters for the process is n = 676 rpm, v = 46 mm / min and x = 0.6 mm. The optimizing welding parameters to achieving good quality of welding process are described. SEM images to determine some properties of welding materials. This is also the basis for initial research to identify some defects in welding of two different materials (IMC thickness and interconnected pores) and the cause of these defects.

Author(s):  
Truong Minh Nhat ◽  
Truong Quoc Thanh ◽  
Tran Trong Quyet ◽  
Luu Phuong Minh

Friction stir welding exploits its solid-state process behavior to join aluminum to steel, which differs in thermal and mechanical properties, and where a combination of these metallic alloys by fusion welding prompts a deleterious reaction as a result of the melting and resolidification phases. Recently, hybrid techniques have been employed in FSW for several materials and alloys, particularly for steel–steel joining. These methods are generally aimed to pre-heat the steel plate materials. This study presents conducted heat simulations and experimental jointing flat-plate of aluminum alloy 6061 and SUS 304. Temperature is simulated by the COMSOL software in three states: (1) Preheat the Friction Stir Welding (FSW) by TIG welding, (2) Thermal contact resistance between aluminum and steel, and (3) The welding process using stirring friction is simulated. The simulations intended to predict the temperature, which is used for the preheating and welding process to ensuring the required solid-state welding. The temperature is also determined and checked by a thermal imager comparing with simulation results. Besides, the results of tensile strength are carried out. The Box - Behnken method is used to identify the relationship between the welding parameters (rotation, speed, and offset), temperature, and tensile strength. The maximum tensile strength is 77% compared to the strength of the aluminum alloy. The optimal set of parameters for the process is n = 676 rpm, v = 46 mm / min and x = 0.6 mm. The optimizing welding parameters to achieving a good quality of the welding process are described. SEM images to determine some properties of welding materials. This is also the basis for initial research to identify some defects in the welding of two different materials (IMC thickness and interconnected pores) and the cause of these defects.


2017 ◽  
Vol 37 (1) ◽  
pp. 6-21 ◽  
Author(s):  
C. Rajendrana ◽  
K. Srinivasan ◽  
V. Balasubramanian ◽  
H. Balaji ◽  
P. Selvaraj

AbstractAA2014 aluminum alloy (Al-Cu alloy) has been widely utilized in fabrication of lightweight structures like aircraft structures, demanding high strength to weight ratio and good corrosion resistance. The fusion welding of these alloys will lead to solidification problems such as hot cracking. Friction stir welding is a new solid state welding process, in which the material being welded does not melt and recast. Lot of research works have been carried out by many researchers to optimize process parameters and establish empirical relationships to predict tensile strength of friction stir welded butt joints of aluminum alloys. However, very few investigations have been carried out on friction stir welded lap joints of aluminum alloys. Hence, in this investigation, an attempt has been made to optimize friction stir lap welding (FSLW) parameters to attain maximum tensile strength using statistical tools such as design of experiment (DoE), analysis of variance (ANOVA), response graph and contour plots. By this method, it is found that maximum tensile shear fracture load of 12.76 kN can be achieved if a joint is made using tool rotational speed of 900 rpm, welding speed of 110 mm/min, tool shoulder diameter of 12 mm and tool tilt angle of 1.5°.


2012 ◽  
Vol 622-623 ◽  
pp. 323-329
Author(s):  
Ebtisam F. Abdel-Gwad ◽  
A. Shahenda ◽  
S. Soher

Friction stir welding (FSW) process is a solid state welding process in which the material being welded does not melt or 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 effects of process parameters include rotation speeds, welding speeds, and pin diameters on al.uminum weldment using double shoulder tools. Thermal and tensile behavior responses were examined. In this direction temperatures distribution across the friction stir aluminum weldment were measured, besides tensile strength and ductility were recorded and evaluated compared with both single shoulder and aluminum base metal.


2010 ◽  
Vol 44-47 ◽  
pp. 76-80
Author(s):  
Lei Wang ◽  
Jian Jun Zhu

Temperature distribution is the foundation to study friction stir welding technique, influence of welding parameters on temperature was studied through experiment measurement on AA2024-T4 aluminum alloy plates. An instantaneous relative linear velocity based heat source was utilized to build the FEM model of friction stir welding process, good agreement was observed between the measured and simulated thermal profiles. FEM model was also utilized to study effect of welding parameters on temperature distribution.


2019 ◽  
Vol 43 (2) ◽  
pp. 230-236
Author(s):  
Ashok S. Kannusamy ◽  
Ravindran Ramasamy

This paper addresses the effect of post weld heat treatment methods on the mechanical and corrosion characteristics of friction stir welded aluminum alloy AA2014-T6. Aluminum alloy AA2014 is mainly used in applications that demand high strength to weight ratios, such as aerospace, marine, and industrial applications. In this work, AA2014-T6 plates of 6 mm thick were butt welded using a tool with a square profile. Tensile strength, hardness, and corrosion characteristics were compared between the samples as welded and post weld heat treated. Welded samples that were heat treated for a shorter ageing period (8 h) showed improved tensile strength irrespective of welding process parameters, compared to as-welded samples. The samples heat treated for a longer ageing period (9 h) showed a decline in tensile strength for low tool rotation speed. Hardness increased in welded samples heat treated for 8 h. Welded samples heat treated for 9 h show high passivity in corrosion media.


Author(s):  
J.C. Verduzco Huarez ◽  
R. Garcia Hernandez ◽  
G. M. Dominguez Almaraz ◽  
J.J. Villalón López

This research work focuses on the study of the improvement of mechanical properties, specifically the tensile strength of 6061-T6 aluminum alloy on prismatic specimens with 9.5 mm thickness that has been subjected to friction stir welding process and two heat treatments; solubilized and aging before or after the welding process. Three cases studied and evaluated were, welding of the base material without heat treatment (BMW), solubilized heat treatment and partial aging of the base material before welding (HTBW), and heat treatment of solubilized and aging of the base material after welding (HTAW). The obtained results show an increase of about 10% (20 MPa) of tensile strength for the HTBW process, compared to BMW case. In addition, for the case of HTAW, the obtained tensile resistance presents a joint efficiency of 96%, which is close to the tensile strength of the base material (»310 MPa).


2014 ◽  
Vol 597 ◽  
pp. 253-256 ◽  
Author(s):  
Nurul Muhayat ◽  
Triyono ◽  
Bambang Kusharjanta ◽  
Radian T. Handika

The effects of preheat temperature on mechanical properties and the microstructure of friction stir welded (FSW) aluminum alloy 5052 joints were studied in the present work. Heated air from Hot Gun was applied in front of the FSW tool to give the preheat on friction stir welding process. Preheat temperature was set 150°C, 250°C and 300°C. Mechanical properties were correlated and analyzed according to tensile strength, macro and microstructure. Defect free weldswere obtained at all preheat variations. The increasing preheat temperature produced the coarser grain size, it influencedthe little decrease both the tensile strength and hardness of joints.


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