Numerical Simulation of the Effect of Process Parameters on Cooling Rate and Secondary Dendrite Arm Spacing in High-Speed Twin Roll Strip Casting of Al–15 wt % Cu Alloy

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Yuvaraj Ganpati Patil ◽  
Ajay Kumar Shukla

Abstract Twin roll casting is a process used to produce thin strips of metals by continuously pouring melt on to rotating rolls. In order to make the process more productive and economical, high roll speed is recommended. The numerical simulation of high-speed twin roll casting is performed by analyzing fluid flow, heat transfer, and solidification behavior of Al–Cu hypo-eutectic alloy. The flow field, temperature, liquid fraction distribution, and cooling rate are analyzed by solving governing transport equations of continuity, momentum, energy, and turbulence. The low-Re Turbulence model is used to capture turbulence effects in the process and enthalpy-porosity technique used to account for the rise in viscosity due to phase change. The effect of melt pool height and roll velocity on average cooling rate along the strip surface is investigated. It is found that the increase in melt pool height and roll speed increases the average cooling rate along strip surface due to rise in heat transfer up to certain roll velocity but beyond that process fails due to breakout. The average cooling rate of process affects the microstructure and properties of strips. It is found that higher cooling rates result in a decrement of secondary dendrite arm spacing (SDAS) of 1 mm thin strip along strip surface results in the fine and homogeneous microstructure.

2018 ◽  
Vol 382 ◽  
pp. 147-154
Author(s):  
Toshio Haga ◽  
Ryusuke Onishi ◽  
Hisaki Watari ◽  
Shinichi Nishida

Strip casting of Al-40%Sn-1%Cu, which is an aluminum alloy used for sliding bearings, was attempted using an unequal diameter twin roll caster. The conditions required to cast sound strips, including the roll speed, molten temperature, roll load, solidification length, melt head, and use of an upper plate, were investigated. The roll load required to make a stable strip surface was 0.01 kN/mm, and the porosity was minimum when the solidification time was less than 0.6 s. The solidification time was controlled by the roll speed and the solidification length. The casting temperature must be set below 670°C to properly solidify the molten metal, and the metal microstructure became finer as the melt head decreased.


2010 ◽  
Vol 154-155 ◽  
pp. 1544-1548 ◽  
Author(s):  
Kosuke Komeda ◽  
Ryoji Nakamura ◽  
Shinji Kumai

The disadvantages of the conventional twin-roll caster for aluminum alloy are low casting speeds and limited choices of alloys that are castable by this processing. It is known that strip casting of aluminum alloy 5182 is very difficult because of their wider freezing zones. The vertical-type high-speed twin-roll caster used in the present study was devised to overcome these disadvantages. Features of the high speed twin roll casters are as below. Mild steel rolls were used in order to increase the casting speed and to be made at a lower equipment cost. Roll coating is produced in casting of Al-Mg alloy. Therefore lubricant, that resists heat transfer, was not used in the present study. Heat transfer between melt and the roll was improved by hydrostatic pressure of the melt. Low superheat casting was carried out in order to improve microstructure of the strip. In the present study, effectiveness of a high-speed twin roll caster for recycling aluminum alloy was investigated. The effects of the high-speed twin roll caster on alleviating the deterioration of mechanical properties by impurities were investigated. Properties of the cast strip were investigated by metalography, a tension test, and a deep drawing test.


2011 ◽  
Vol 121-126 ◽  
pp. 4667-4670
Author(s):  
Toshio Haga ◽  
Kosuke Komeda ◽  
Kenta Mtsuoka ◽  
Shinji Kumai ◽  
Hisaki Watari

Roll casting of the model alloy of recycled AA5182 aluminum alloy was investigated. Fe up to 0.6% was added to the AA5182 to make the model alloys of recycled AA5182. Increase of 0.6% of Fe means that the recycle was three times operated. A vertical type high speed twin roll caster was used. Some devices were operated on the twin roll caster to increase the cooling rate in order to make impurity fine. The roll speed could be increased up to 80m/min. The roll-castability did not become worse by the addition of the Fe. The LDR (limiting Drawing Ratio) was 1.9 when the Fe addition was 0.6. The deterioration of the mechanical properties by the addition of impurity Fe was very small.


2018 ◽  
Vol 382 ◽  
pp. 160-166 ◽  
Author(s):  
Toshio Haga ◽  
Ryusuke Onishi ◽  
Hisaki Watari ◽  
Shinichi Nishida

Among the problems encountered when roll casting Al-405Sn-1%Cu, which is an aluminum alloy used for sliding plate bearings in large maritime diesel engines, are solidified chips embedded in the strip and scratch marks on the lower roll contact surface. In this study, three different improvement methods aimed at eliminating these particular defects—vibrating the side plates and back dam plate, adding a vibrating plate, and varying the casting conditions—are examined. Vibrating the side plates and dam plate was found to be effective for preventing these defects, while adding another vibrating plate was comparatively less effective. As for casting conditions, it was also determined that the occurrence of these defects could be reduced by increasing the roll speed, and that the molten metal casting temperature had little or no influence on defect formation.


2021 ◽  
Author(s):  
Dongpo Xuan ◽  
cheng zhou ◽  
You Zhou ◽  
Tianliang Jiang ◽  
Biji Zhu ◽  
...  

Abstract Using the commercial finite element software ProCAST to predict the temperature field, the flow field, the turbulent kinetic energy, and melt-pool outlet temperature of the top side-pouring twin-roll casting (TSTRC) of 6.5 wt.% Si steel process, and the cellular automaton–finite element (CA-FE) method was used to simulate the melt-pool outlet microstructure. The effect of different process conditions on the TSTRC process was investigated through numerical simulation and a processing technic appropriate for the production of 6.5 wt.% Si steel was obtained. Meanwhile, the influence of violent stirring in the melt-pool on the microstructure under different process conditions was evaluated. It was found that vigorous stirring in the melt-pool was conducive to formate the equiaxed crystal structure. Not only realized the near-final shape of the metal sheet, but also realized the near-final shape of the microstructure. Chose the proper process to experiment, and from comparing the simulation and the experiment, the simulation and experimental results were in good agreement, which verified the simulation's feasibility and accuracy.


2010 ◽  
Vol 139-141 ◽  
pp. 477-480
Author(s):  
Ryoji Nakamura ◽  
Shuya Hanada ◽  
Shinji Kumai ◽  
Hisaki Watari

An inline hot rolling was operated on 5182 aluminum alloy strip cast using a vertical type high speed caster (VHSTRC) at the speed of 60 m/min. A porosity existing at center line of the thickness and a ripple mark on the surface, these are typical defects of the strip cast by the VHSTRC, could be improved by the inline rolling. The rolling speed was as same as the roll-casting-speed of 60m/min. The temperature of the strip, when the inline rolling was operated, was 450oC. The reduction of the strip of the inline rolling was 35%.


2012 ◽  
Vol 217-219 ◽  
pp. 1928-1933
Author(s):  
Yu Cheng Zhang ◽  
Tian Yang Han ◽  
Zheng Yi Jiang ◽  
Dong Bin Wei

The process of twin-roll casting including pouring, solidifying, rolling and cooling can be accomplished in a very short time. Consequently, some important process parameters in the twin-roll casting that are difficult to be obtained in experiment can be acquired using numerical simulation. In this paper, a numerical simulation based on a 2D finite element model of vertical twin-roll strip casting of magnesium alloy has been conducted, and the thermal stress fields are significantly discussed. The influences of key process parameters consisting of submerged nozzle depth and nozzle spray angle have been studied. The thermal cracks on the surface of the strip are analysed according to the thermal stress distribution.


Author(s):  
Shogo Imai ◽  
Shinichi Nishida ◽  
Kyohei Ogawa ◽  
Makoto Hagiwara ◽  
Daichi Uematsu ◽  
...  

Abstract Copper alloy C19210 have excellent corrosion resistance, heat resistance, and conductivity, and is used for precision electronic parts such as lead frame materials. Conventionally, copper alloy strips are manufactured by repeating heat treatment and cold rolling, and have a problem that it is multi-process and production cost is expensive. On the other hand, twin roll casting can improve the above problems because strips are made directly from molten metals. In this study, twin roll strip casting of copper alloy C19210 using commercial scale machine was operated. The aims of this study is to investigate the possibility of strip casting for copper alloy. The effect of the side dam and release agent was researched. The effect of rolls speed on the strip surface condition was researched. The improved side dam prevented molten metal leakage. The release agent prevented sticking of the manufactured strip to the roll surface. The strip produced at roll speed of 7 m/min and 10 m/min had a lot of metallic luster. Moreover, the strip produced at roll speed of 7 m/min had more metallic luster than the strip produced at roll speed of 10 m/min. The lower the roll speed is, the greater the rolling load is. At a roll speed of 7 m / min, the rolling load became the maximum rolling load of the equipment. For producing strips with copper alloy C19210, higher rolling loads are preferred.


Sign in / Sign up

Export Citation Format

Share Document