Effect of electric current pulse on flow behaviour of Al melt in parallel electrode process

This paper investigated the effect of coupling of direct current (DC) and pulling rate on dendrites and cooling behaviours of directionally solidified Pb–50Sn alloy. Experimental results indicated that the secondary dendritic arm spacing (SDAS) decreased and temperature gradient increased as increasing current densities. Moreover, temperature rise and SDAS under positive DC were higher than those under negative DC. It was speculated that Joule heating and electromigration were obviously induced by the present DC. The effect of DC on the microstructure and solidification parameters was weakened as the pulling rate increases. The coarsening rate reduced from tf1/3 toward a value of tf0.29 when DC of ±200 A cm–2 were applied. The refinement mechanism of SDAS was discussed.

Section: The Relationship Between Sdas and Solidification Parameters ...mentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Effect of medium-density direct current on dendrites of directionally solidified Pb–50Sn alloy

Zhang

et al. 2016

“…Electromagnetic force and flow field in the SPMO treated melt were simulated using ANSYS (a commercial FEM software). 16 Electromagnetic force distribution is shown in Fig. 9.…”

Section: Analysis Of Flow Field In Melt Treated With Spmomentioning

confidence: 99%

Structure of slowly solidified 30Cr2Ni4MoV casting with surface pulsed magneto-oscillation

Zhao

et al. 2015

Large scale 30Cr2Ni4MoV ingots play a crucial role in nuclear power plants. Shrinkage and carbon segregation are the most common defects in the manufacture of these large scale ingots. Large scale ingots have very low cooling rates. In the present work, an experimental method was employed to achieve similarly low cooling rates with the aim of simulating the solidification process of large ingots in smaller 30Cr2Ni4MoV ingots.Thus, we examined the effect of surface pulsed magneto-oscillation (SPMO)on solidification structure in a laboratory setting. Our experimental results showed an SPMO treated ingot with less carbon segregation and a smaller shrinkage cavity than in an untreated one. Finally, the action mechanism was analysed by numerical simulation.

“…In 1995, Bamak et al found that the pulse current greatly reduced the eutectic cells of Sn-Pb alloy [3][4][5][6][7]. In recent years, pulsed electromagnetic field has become an emerging technology in the area of electromagnetic coagulation [4,[8][9][10][11][12][13][14][15][16][17]. By fixing the pulse current of an isolated network, Liao et al [18] found that the refining effect was the most remarkable in the nucleation stage.…”

Section: Introductionmentioning

confidence: 99%

Effect of flow on solidification structure of pure aluminium under pulse magneto-oscillation

Cheng

Zhong

et al. 2018

This paper reports on the processing of aluminium melt by pulse magneto-oscillation (PMO) technology. The melt is divided into five layers using a layered isolation device and, after grinding and corrosion, the refining effects of equiaxed crystals are observed to decrease from the centre outwards. The electromagnetic force and flow velocity of the melt were simulated using the ANSYS package, and found to decrease in the same manner as crystal size; i.e. from the centre outwards. It was also found that the melt, treated by PMO, possessed an optimum characteristic length at which the flow velocity reaches a maximum value, thus improving the refining effect of the solidification structure of the melt.