Three-Dimensional Visualization of Material Flow During Friction Stir Welding of Steel and Aluminum

Morisada, Yoshiaki; Imaizumi, Tsutomu; Fujii, Hidetoshi; Matsushita, Muneo; Ikeda, Rinsei

doi:10.1007/s11665-014-1202-6

Cited by 37 publications

(18 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Previous experimental work by Schmidt et al [37] carried out on aluminium showed the same results of material flow, where marker foils of copper flowed around the tool, broken into pieces then reverted around the retreating side in the same direction of rotation. Morisada et al [38] used a W tracer with the aid of an XR transmission system to monitor the material flow during FSW of aluminium Al050 and low carbon steel. They found that in Al the W tracer can rotate many times around the probe, whereas, in steel the tracer moved along the rotating probe, passed through the retreating side and stopped at the back of the probe.…”

Section: Parent Materials Flow Around the Toolmentioning

confidence: 99%

“…The previous work found in [2,5,22] reported the wormhole defect in the same region of interest and they found that the occurrence of this defect increased as traverse speed increased due to inadequate material flow. Morisada et al [38] also suggested that the formation of a stagnant zone can lead to a defect in the SZ and that uniform material flow for steel is only achieved at low traverse speed. They interpreted the formation of a stagnant zone on the advancing side as being caused by a low heat input due to high traverse speed.…”

Section: W5 W6mentioning

confidence: 99%

See 1 more Smart Citation

Modelling of friction stir welding of DH36 steel

Al-moussawi

Smith

Young

et al. 2017

Int J Adv Manuf Technol

View full text Add to dashboard Cite

A 3-D computational fluid dynamics (CFD) model was developed to simulate the friction stir welding of 6-mm plates of DH36 steel in an Eulerian steady-state framework. The viscosity of steel plate was represented as a nonNewtonian fluid using a flow stress function. The PCBN-WRe hybrid tool was modelled in a fully sticking condition with the cooling system effectively represented as a negative heat flux. The model predicted the temperature distribution in the stirred zone (SZ) for six welding speeds including low, intermediate and high welding speeds. The results showed higher asymmetry in temperature for high welding speeds. Thermocouple data for the high welding speed sample showed good agreement with the CFD model result. The CFD model results were also validated and compared against previous work carried out on the same steel grade. The CFD model also predicted defects such as wormholes and voids which occurred mainly on the advancing side and are originated due to the local pressure distribution between the advancing and retreating sides. These defects were found to be mainly coming from the lack in material flow which resulted from a stagnant zone formation especially at high traverse speeds. Shear stress on the tool surface was found to increase with increasing tool traverse speed. To produce a "sound" weld, the model showed that the welding speed should remain between 100 and 350 mm/min. Moreover, to prevent local melting, the maximum tool's rotational speed should not exceed 550 RPM.

show abstract

Section: Parent Materials Flow Around the Toolmentioning

confidence: 99%

Section: W5 W6mentioning

confidence: 99%

Modelling of friction stir welding of DH36 steel

Al-moussawi

Smith

Young

et al. 2017

Int J Adv Manuf Technol

View full text Add to dashboard Cite

show abstract

“…The material flow during the FSW was observed by the three-dimensional visualization process [13][14][15]. The material flow has been studied using various approaches such as the tracer method [16][17][18][19][20], analysis of the crystallographic texture in a weld [21], measuring the eutectic Si distribution [22].…”

mentioning

confidence: 99%

Determination of strain rate in Friction Stir Welding by three-dimensional visualization of material flow using X-ray radiography

2015

View full text Add to dashboard Cite

Recrystallization, which is mainly caused by the induced strain, is one of the most important factors of Friction Stir Welding. In this study, strain and strain rate are directly obtained by the change in the material flow velocity which is observed by three-dimensional visualization of the material flow. The grain size of the pure aluminum in the stir zone estimated by the Zener-Hollomon parameter using the obtained strain rate shows good agreement with that observed by Electron Back-Scatter Diffraction mapping.Much attention has recently been paid to Friction Stir Welding (FSW) because of the low distortion and 20 excellent mechanical properties of the joint [1][2][3][4]. A rotating tool is inserted into the interface at the butt line of the metal plates and produces a highly plastically deformed zone. The metal plates are joined by the traveling of the rotating tool along the interface. Sever plastic deformation occurs and strain is induced in the stir zone (SZ). The interface of the two metal plates disappears by the material flow, and it is the main bonding mechanism of FSW. Generally, the SZ consists of recrystallized fine and equiaxed grains which are formed by the induced strain during the FSW 30 [5][6][7]. Therefore, the recrystallization is one of the most important factors of FSW. It is well known that the recrystallized grain size can be estimated by the strain rate [8,9]. However, it is difficult to measure the strain rate accurately during the FSW because the various changes in the SZ cannot be observed directly using conventional methods. Therefore, determination of the strain rate is very important for estimating the microstructure in the SZ.There are several reports related to the strain rate in the FSW. Chen et al. showed that the strain was $3.5 and the 40 strain rate was $85 s À1 before entering into the thread space during the FSW with a simple threaded pin at 740 rpm [10]. Arora et al. indicated that the computed strains and strain rates were in ranges of À10 to 5 and À9 to 9 s À1 , respectively [11]. However, the obtained results are computed values based on a three-dimensional coupled viscoplastic flow and heat transfer model. The strain rate of 34.8 ± 5.2 s À1 was estimated for magnesium alloy (AZ31) during FSW by the experimentally verified finite element model [12]. If it can be obtained these values by a direct 50 observation of the phenomenon, it should be very valuable to compare the other results.In this study, the strain rate was directly calculated by the change in the material flow velocity. The material flow during the FSW was observed by the three-dimensional visualization process [13][14][15]. The material flow has been studied using various approaches such as the tracer method [16][17][18][19][20], analysis of the crystallographic texture in a weld [21], measuring the eutectic Si distribution [22]. However, it is impossible to know the material flow velocity using 60 these approaches because the obtained results show only one part of the process. In this study, the material f...

show abstract

“…HAZ in Fig. 14 has been determined between the SZ and a peak temperature of 900 °C [31]. Figure 15 shows the relative velocity distribution in the workpiece which comes from the material affected by the tool rotation.…”

Section: Cfd Resultsmentioning

confidence: 99%

Thermo-Mechanical Effect on Poly Crystalline Boron Nitride Tool Life During Friction Stir Welding (Dwell Period)

Al-moussawi

Smith

2018

Met. Mater. Int.

View full text Add to dashboard Cite

Poly Crystalline Boron Nitride (PCBN) tool wear during the friction stir welding of high melting alloys is an obstacle to commercialize the process. This work simulates the friction stir welding process and tool wear during the plunge/dwell period of 14.8 mm EH46 thick plate steel. The Computational Fluid Dynamic (CFD) model was used for simulation and the wear of the tool is estimated from temperatures and shear stress profile on the tool surface. Two sets of tool rotational speeds were applied including 120 and 200 RPM. Seven plunge/dwell samples were prepared using PCBN FSW tool, six thermocouples were also embedded around each plunge/dwell case in order to record the temperatures during the welding process. Infinite focus microscopy technique was used to create macrographs for each case. The CFD result has been shown that a shear layer around the tool shoulder and probe-side denoted as thermo-mechanical affected zone (TMAZ) was formed and its size increase with tool rotational speed increase. Maximum peak temperature was also found to increase with tool rotational speed increase. PCBN tool wear under shoulder was found to increase with tool rotational speed increase as a result of tool's binder softening after reaching to a peak temperature exceeds 1250 °C. Tool wear also found to increase at probe-side bottom as a result of high shear stress associated with the decrease in the tool rotational speed. The amount of BN particles revealed by SEM in the TMAZ were compared with the CFD model.

show abstract

Three-Dimensional Visualization of Material Flow During Friction Stir Welding of Steel and Aluminum

Cited by 37 publications

References 26 publications

Modelling of friction stir welding of DH36 steel

Modelling of friction stir welding of DH36 steel

Determination of strain rate in Friction Stir Welding by three-dimensional visualization of material flow using X-ray radiography

Thermo-Mechanical Effect on Poly Crystalline Boron Nitride Tool Life During Friction Stir Welding (Dwell Period)

Contact Info

Product

Resources

About