Dissertation > Industrial Technology > Metallurgy and Metal Craft > Metal pressure processing > Rolling > Rolling process > Rolling method > Special rolling

Numerical Simulation and Optimization of Radial-axial Ring Rolling Process for Titanium Alloy Ti40

Author LiBin
Tutor WangKeLu
School Nanchang University of Aeronautics and
Course Materials Processing Engineering
Keywords Burn resistant titanium alloy Ti40 Radial-axial ring rolling Numericalsimulation Process parameter of ring rolling
CLC TG335.19
Type Master's thesis
Year 2011
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Burn resistant titanium alloy Ti40is the key structure material needed in advancedaircraft engine combining excellent burn-resistance performance and comprehensivemechanical properties.while many defects are likely to appear in ring rolling process ofTi40alloy such as sunken end face,poly-rowed,elliptical and crack,because of highplastice deformation resistance, bad hot-forming property and the characteristics of ringrolling, such as nonlinear, time-varying and unsteady. In this paper, the radial-axial ringrolling process of Ti40alloy was numerically simulated and the parameters wereoptimized by using DEFORM-3D software. The results are beneficial to providetechnical support for actual production of Ti40alloy ring.The motion computing model of axial roll, core roll and guide roll have beenestablished based on the rolling theorety and the radial-axial ring rolling principle.Beside, the material model of Ti40alloy was established based on the data of constanttemperature and strain rate compression test. The radial-axial ring rolling process ofTi40alloy had been simulated by using FEM DEFORM-3D software. The changerules of temperature field, equivalent strain field and rolling force had been analyzed.The results show that the highest-temperature zone is the center area, and thetemperature of outside surface is lower and distribute nonuniform. In the outside surface,the temperature of the end face is higher than side face because of the effects of axialrolling, and the temperature of corner edge is the lowest. The results also indicate thatthe maximum equivalent strain appears in the outer-layer of ring, the smallest oneappears in the mid-layer,and the inner-layer is between the two extrems, The core rollrolling force increases to maximum value rapidly with time at the beginning stage, thenthe rolling force decreases slightly. The roll torque changes as the same rule as the rollforce.The size of Ti40alloy ring finished product is Φ724×Φ611×300mm, and thesize of ring billet is Φ486×Φ300×310mm. Ti40alloy ring radial-axial rolling processunder the different process conditions had been simulated, and the effects of rollingprocess parameters, the drive roll rotation speed, core roll speed, angle of guide roll,temperature of ring billet on ring rolling process have been analyzed. The researchresults indicates that rolling temperature, core roll feed speed and drive roll rotationalspeed have tremendous influences on the core roll force. when the rolling temperature are990℃、1040℃、1090℃,the maximum roll force are2.7x106N,2.1x106N and2.0×106N,respectively. With the enhancement of the rolling temperature,the core rollforce is increasing. when the core roll feed rate are0.8mm/s,1mm/s and1.5mm/s,themaximum roll force are2.1x106N,2.2x106N and2.5x106N,respectively.The drive rollrotational speed and core roll feed speed are the main parameters that have major impacton temperature field. When the drive roll rotational speed are1.27rad/s,1.82rad/s and2.36rad/s, the temperature ranges of ring are955℃~1055℃,974℃~1054℃and975℃~1056℃,respectively. With the enhancement of the drive roll rotational speed, thebulk temperature is increasing. when core roll speed are0.8mm/s,1mm/s, and1.5mm/s,the ring temperature are955℃~1052℃,960℃~1055℃and975℃~1055℃,respectively.Based on the simulation results, the optimal parameters are obtained as follows:starting rolling temperature is1040℃, and drive roll rotational speed is set as1.27rad/s, and core roll feed speed takes piecewise values0.8-1-0.8mm/s, and guideroll position angle is set as60o, and drive roll friction factor value should be higher,and axial roll friction factor value is preferable to be lower.

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