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工艺因素对铝双辊铸轧凝固过程的影响 总被引:1,自引:0,他引:1
利用铝双辊铸轧过程传热数学模型,系统分析了辊套材料、浇注温度等工艺因素对铝双辊铸轧过程凝固速率的影响及进一步提高铸轧机生产能力的途径,建立了钢和铜合金2种辊套材料的凝固壳厚度随时间变化的计算公式。 相似文献
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半固态镁合金板带双辊铸轧工艺参数研究 总被引:3,自引:0,他引:3
采用AZ91D镁合金为原料,以自行设计的双辊板带铸轧设备进行试验,研究半固态镁合金铸轧的工艺参数剪切速度、静置时间、浇铸温度对半固态组织的变化规律并对其形成机制作出分析。试验表明:剪切速度越大,浇铸温度越低,静置时间适中时半固态镁合金浆料制备的镁板带组织的固相颗粒越细小、均匀、圆整。但是由于试验各方面条件的限制剪切速度不可能太大、浇铸温度太低金属液不易流动,因此通过试验得到了最佳的工艺参数为:剪切速率为900 r.min-1、静置时间为15 min、浇铸温度565℃左右为宜。 相似文献
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结晶辊内部结构非常复杂,受热发生变形后,辊表面形状变得不规则,因此研究结晶辊温度场、热应力及热变形,掌握其分布规律,对于控制结晶辊的变形,得到均匀的铸带具有重要意义.以结晶辊为主要研究对象,采用热结构直接耦合方法计算结晶辊的温度场、热应力和热变形,为结晶辊的设计提供参考.结果表明,选用Be-Co-Cu作为结晶辊材质,辊转动30 s后,辊外表面温度和最大等效应力保持稳定,最高和最低温度分别为198和449℃,最大等效应力为1041 MPa;转动300 s后,辊内部温度及变形达到稳定状态,辊外表面径向位移都在0.4~0.5mm之间.通过对比Be-Co-Cu材质和钢材质的温度和最大等效应力,得出Be-Co-Cu材质更适合于制造双辊的结论. 相似文献
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Inthetwinrollstripcastingprocess ,themechanicalbehaviorofcastingmaterialcangreatlyinfluencerollingforce,whilerollingforceisrelevanttostripsurfacequali ty .Ifrollingforcesurpassesalimitedvalue ,theheattransferfromstriptocastingrollwillbecomeunevenalongstr… 相似文献
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The fluid flow in a twin‐roll strip caster is investigated by physical and numerical simulation on a 1:1‐scale water model. A laser‐optical measurement technique (Laser Doppler Anemometry ‐ LDA) is used to validate the numerical results for the water flow. The numerical simulations are then transferred to the melt flow in the strip caster. The investigations are focused on different SEN concepts (submerged entry nozzle), a single‐nozzle system with two outlet ports and a double‐nozzle system with one outlet port each. The Influence of these concepts on the velocity, turbulence, and temperature distribution inside the liquid pool between the casting rolls and on the solidification and growth of the strip shells are investigated by numerical simulations (Computational Fluid Dynamics ‐ CFD). The non‐isothermal melt flow is calculated considering the solidification enthalpy as well as the behaviour of the solidifying melt. In addition to the numerical simulations of the melt flow inside the pool the temperature distribution in the cast strip is simulated. The SEN concept directly correlates with the temperature distribution Inside the strip. Furthermore, the surface temperature of the strip below the outlet of the roll gap is measured using a line‐scanner and is compared with the CFD simulation. In order to simulate the shape of the free surface in the liquid pool, CFD simulations of the water flow in the physical model are carried out using a Volume of Fluid model (VoF). This two‐phase model is able to reproduce free surface waves. 相似文献
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A three‐dimensional mathematical model has been developed to simulate turbulent fluid flow, heat transfer and solidification in the pool of a twin‐roll strip caster. A Darcy‐porosity approach was used to study the fluid flow within the mushy solidification zone in the pool. The effect of the heat transfer coefficient and permeability constant on the flow and solidification was also predicted. It was shown that an even flow and temperature distribution of the pool can be obtained by using a suitable feeding system. The heat transfer between the rolls and the solidifying metal has a big influence on the location of the solidification end point. The permeability of the mushy zone is a key factor which affects the flow and solidification in the twin‐roll strip casting process. 相似文献
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Thetwinrollstripcastingprocess ,whichcancastmoltensteelinto 1- 5mmstripdirectly ,isat tractingtheattentionofthesteelproducersallovertheworld .Ithasmanyadvantagesoverconventionalstripproducingtechnology ,suchasreducedenergyconsumption ,lowerinvestmentandhigherflexibili ty .Comparedwiththinslabcasting process ,thistechnologycansave 70 %ofproductionandinvest mentcosts[1] ,and producestripswith poorform ability ,suchastoolsteelandsiliconsteelstrips . Thoughtwinrollstripcastinghasbeendevelop ing… 相似文献
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Achim R. Büchner 《国际钢铁研究》2006,77(11):809-817
Thin strip casting of steel through a twin‐roll caster demands the production of a perfectly homogeneous strip. This requirement is often not fulfilled due to non‐uniform heat contact between the solidifying strip and the rolls in the pool, which leads to temperature inhomogeneities visible at the strip behind the rolls (spottiness). The effect of spottiness is described from experimental observations in terms of contrast between dark and hot spots and of the mean diameter of the hot spots. The contrast is found to depend on roll material, surface roughness and roll velocity. A general dependence on the temperature difference between melt and rolls is observed. Calculations of heat transfer in the liquid and solid pool explain the hot‐dark‐temperature differences. The spottiness visible on the strip after leaving the rolls is initiated in the liquid pool, but it is enlarged by rolling contact differences in the solid pool. A model consideration based on thermally caused bending of the solidified material layers leads to a good coincidence with experimental data of the heat transfer coefficient at hot spots. 相似文献