铝熔炼过程合金熔体温度场的数值模拟

根据物料平衡方程、能量守恒方程、动量方程建立熔炼炉内熔炼过程中熔体温度的数学模型;以能量平衡测试中得到的数据为边界条件,通过重油燃烧过程的概率密度函数(PDF)仿真提供相关信息,运用Fluent6.3流体力学软件,对熔炼过程铝合金熔体温度场进行数值模拟,模拟结果与实际情况相符.     

旋流数对铝熔炼炉熔炼过程的影响

针对现有的圆形铝熔炼炉,结合铝熔炼炉熔炼过程的特点,在铝熔炼炉热平衡测试的基础上,建立了合理的铝熔炼炉数学模型,并运用计算流体力学软件FLUENT实现燃烧空间和熔池的耦合物理场的数值模拟。同时分析了不同旋流数对铝熔炼炉熔炼过程的影响,依据提出的优化准则,确实旋流数大于0.6时能够获得最佳的熔炼性能。     

蓄热式铝熔炼炉熔炼过程的数值模拟

为了更好地研究和优化铝熔炼炉的性能,针对现有的蓄热式圆形铝熔炼炉,在建立合理的铝熔炼炉基本模型的基础上,通过耦合用户自定义熔化模型和氧化烧损模型,运用计算流体力学软件FLUENT实现燃烧空间和熔池的耦合物理场的数值模拟。着重研究不同固液区和不同孔隙率对铝及铝合金熔炼过程的影响。结果表明,该模型较好地反映铝熔炼炉的熔炼现象,可运用该模型进行铝熔炼炉熔炼过程工艺参数的优化研究。同时获得了固液区和孔隙率对熔炼参数影响规律:铝液温度在固液区上升缓慢,而离开固液相线时,铝液温度上升速度加快,炉膛温度和氧化层质量随着熔炼时间分别呈周期性增加和呈抛物线增加;随着氧化层厚度的增加,铝液温度随着孔隙率的增加而增加变得缓慢。     

烧嘴对蓄热式铝熔炼炉熔炼过程的影晌

结合蓄热式铝熔炼炉熔炼过程的特点,运用FLUENTUDF和FLUENTScheme混合编程,耦合用户自定义熔化模型和燃烧器换向及燃烧量变化模型,实现了蓄热式铝熔炼炉熔炼过程的数值模拟。依据优化原则,获得了熔炼时间随影响因子的变化规律：熔炼时间随着旋流数、燃烧器倾角、空气预热温度或天然气流量的增加而缩短;熔炼时间随着燃烧器间水平夹角或空燃比的延长,先减小而后增加：熔炼时间随着燃烧器高度的增加而延长。     

1235铝合金铸轧精炼过程中气液相流场模拟

应用Fluent软件对熔炼炉中精炼过程进行了模拟,模拟结果表明氮气口的位置变化对熔炼炉中氮气的分布影响很大。通过增加进气口可以改善型腔中铝液流动,使熔炼炉中氮气的分布更为均匀。氮气与铝熔体的接触面积得到了有效的增大,降低了铝液中氧化物颗粒数,使得铝箔产品品质提高。氮气流的搅拌作用促进了铝液成分和温度均匀,节约了熔炼所消耗的能量。     

图像处理技术的钢水熔炼终点识别及控制

结合企业实际生产条件，对用中频熔炼炉熔炼过程中测温和扒渣方法进行了改进。用数字图像处理技术对熔炼过程中钢水液面的图像进行分析处理，来检测钢水的温度以及表面是否存在钢渣，自动控制机械手扒渣以及自动控制中频炉的输入功率来达到钢水的升温和保温，最终判断熔炼过程的终点。该系统的应用使得熔炼过程的自动化程度大大提高。     

田口方法在优化铝熔炼炉工艺参数中的应用

为提升铝熔炼炉热效率、降低污染物排放和提高熔体质量,根据影响熔炼性能的特性要因,运用正交表安排数值模拟方案,通过田口方法进行铝熔炼炉的工艺参数优化,得到最优的铝熔炼炉工艺参数组合,并对最优参数进行验证,结果表明达到了节源减排的目的.     

Al-Si合金熔炼过程中Sr烧损的研究

通过对Al-Si合金锭、熔炼炉中熔体、浇包中熔体的Sr含量进行对比分析,研究了Sr元素在Al-Si合金熔炼过程中的烧损情况.研究结果表明,Al-Si合金中Sr在熔炼过程中烧损程度较大.对此,进行了原因分析,并提出了有效的改进措施.     

感应熔炼技术的发展及其在铸铁生产中的应用

结合国内外铸铁生产厂家应用熔炼设备的状况,对工频感应熔炼炉和中频感应熔炼炉的优缺点进行了较详细地论述,并指出工频感应熔炼炉间向大容量发展已经基本停止,而中频感应熔炼炉则以其电效率和热效率高、熔炼时间短、耗电较省、占地和投资较少、生产灵活和易于实现过程自动化等优点得到迅速发展和广泛应用。     

A356.2铝合金熔炼过程中锶烧损的研究

对A356.2铝合金锭、熔炼炉中熔体、浇包中熔体以及低压铸造机保温炉中熔体的锶含量进行了对比分析,研究了锶元素在A356.2铝合金熔炼过程中的烧损情况。结果表明,A356.2铝合金中锶在熔炼过程中烧损程度较大,在低压铸造机保温炉中的烧损比熔炼过程中的锶烧损要少,为达到工艺要求可在精炼除气前添加铝-锶合金来调整锶含量。     

取消铝熔体“静置时间”及优化净化相关工艺操作的探讨

铝合金熔炼铸造工序是生产铝材的基础,缩短熔铸的工艺流程有利于节能,提高熔体的洁净度有利于生产出高品质的铝材。作者基于长期在生产第一线工作中积累的经验,就取消熔体静置时间来缩短熔铸工艺流程,以及优化与熔体净化相关的工艺操作来提高熔体的洁净度进行了论述。     

Modeling of an aluminum melting process using constructive polynomial functions

Constantly increasing quality requirements and ever-stricter conditions pose difficult challenges for the foundry industry. They must produce the high-quality components demanded by the market at a reasonable cost. Modern technologies and innovative methods help to master this challenge. Until recently, production, from the design of the aluminum melting furnace to daily process, relied largely on traditional methods and experience. However, important data and information about the melting process—for example, the temperatures and the shape of the aluminum block in the furnace—can hardly be obtained with conventional experimental methods, as the temperatures exceed 700 °C. Therefore, this research project investigates the method of monitoring a melting process by means of optical sensors for the first time. The purpose of this paper is to predict the surface shape of the block during the melting process, as it is not possible to maintain a constant monitoring due to the heat and energy loss during measurement Behrens (Einsatz einer Lichtfeldkamera im Hochtemperaturbereich beim Schmelzvorgang von Aluminium, wt Werkstattstechnik online, 2016). To generate the necessary data, a 3D light-field camera is installed on top of an aluminum melting furnace in order to monitor the process. The basic idea is to find a general method for curve modeling from scattered range data on the aluminum surface in 3D space. By means of the (x, y, z) data from the 3D camera, the aluminum surface is modeled as a polynomial function with coefficient derived using various interpolation and approximation methods. This study presents an attempt to find the optimal polynomial function model that describes the aluminum surface during the melting process by interpolation or approximation methods. The best method for curve fitting will be extended and implemented for surface modeling. Based on this method, the melting process can be better controlled while the furnace operates continuously under stable conditions and the efficiency can therefore be increased. The proposed model can be modified for a wide variety of melting furnaces.     

Energy and bond strength development during ultrasonic consolidation

A process model was developed that couples the effects of the three adjustable ultrasonic consolidation (UC) process parameters (amplitude, force and speed) into a single term – thermal weld energy due to frictional and volumetric heat generation. Infrared thermography was used to evaluate weld energy during UC and a relationship was established between weld energy and the peel strength of ultrasonically consolidated aluminum. An optimum processing widow was identified for bonding Al 1100-0 and Al 3003-H14 based on UC processing temperature and weld time. Bonding occurred well below the material melting temperatures, confirming that thermal softening in the bulk of the material or melting are not the bonding mechanisms and that bonding takes place in the solid-state.     

搅拌摩擦焊接头的温度检测

利用了搅拌摩擦焊接头温度检测系统，测量了中、薄铝合金板搅拌摩擦焊缝在不同特征点上的温度变化过程及其峰值温度，证实了搅拌摩擦焊过程中没有熔化现象，并获得了温度分布的大致规律。检测结果表明：不同搅拌摩擦焊功率、扭矩等焊接过程参量对应了不同的温度分布。     

Impurities evaporation from metallurgical-grade silicon in electron beam melting process

The purification of metallurgical-grade silicon (MG-Si) has been investigated during electron beam melting (EBM) process. The results show that the phosphorus, calcium and aluminum contents decrease significantly after melting, and magnesium is partially removed. However, no significant change in content for boron and iron has been found. Langmuir’s equation and Henry law were used to derive the removal effi-ciency for each impurity element. The free surface temperature was estimated by the Hertz-Knudsen-Langmuir equation and silicon’s vapor pressure equation. Good agreement was found between measured and calculated impurities’ removal efficiency for phosphorus, calcium and aluminum, magnesium, boron and iron. The deviation between the two results was also analyzed in depth.     

重熔工艺对Al-Ti-C晶粒细化剂组织的影响

采用Lasertec1LMH21共焦扫描激光显微镜和光学显微镜,观察了Al-Ti-C晶粒细化剂在加热熔化过程中的组织变化与凝固后的组织。结果发现,在加热过程中,Al-Ti-C细化剂中Al基体首先熔化,随后片状Ti Al3和TiC相成为游离相,然后被熔断、破碎成细小的新质点,其破碎程度随着保温时间的延长与熔化温度的升高而加剧。重熔工艺可有效改善Ti Al3和TiC晶粒的形貌,低温对Ti Al3相的形貌影响较大,高温对TiC相的形貌影响较大。     

一种Al-Zn-Mg合金板材焊缝裂纹的原因分析及预防措施

Al-Zn-Mg合金板材在使用加工中焊接时焊缝处出现裂纹,分析了裂纹产生的原因,确认裂纹缺陷是因铸锭内部组织中存在粗大金属化合物聚集,该粗大化合物在板材轧制变形过程中产生分层所致.并从合金的元素含量、熔铸温度、搅拌方式、在线过滤等方面提出了避免该类缺陷的措施.     

LOW TEMPERATURE ALUMINUM ELECTROLYSIS IN NaF-AlF3-BaF2-CaF2 BATH SYSTEM

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