Investigation of the effect of argon protection behavior in the ingot casting process

With the continuous improvement of product quality and function,the quality control of mold steel is becoming increasingly stricter. Argon protection is essential for ensuring casting quality during ingot casting. The development of argon protection in ingot casting and the production process of enclosed argon protection in 40 t line is discussed,w ith particular focus given the factors affecting the flow of oxygen in the argon protection cover are discussed. The influence of some related factors on the oxygen content is analyzed. On the basis of the online measurements of the oxygen content,the optimized operational approaches for improving the effect of argon protection are developed. This can decrease the liquid steel via secondary oxidation,and improve the quality of the ingots.

Research and application of numerical simulation to optimization of ingot casting process

During the ingot casting process, the parametric changes of the molten steel pouring process often cause both ingot surface and internal quality defects. With the increasingly wide application of computers in industrial technology ,numerical simulations of the molten steel pouring process enable predictions of the defects that will arise during the pouring and solidification process, especially for the molten steel flow during the early stages of casting. In addition,using a computer to simulate the casting process of a 40 t ingot and solidification can prevent many defects. The simulation results indicate that controlling the pouring speed to less than 80 kg/s, hanging the casting powder in a mold with the hanging height maintained at 100-150 mm, and controlling the taper angle of the mold brick outlet to a suitable level can reduce the probability of slag entrapment and improve the internal and surface quality of the ingot.

Teeming stream protection using an argon shroud during casting of steel ingots

Two kinds of argon shroud protection devices with two different basic structures were designed and investigated. Industrial experiments and numerical simulations were used to examine the protection effect, and the mechanism of air entrapment during the casting of steel ingots was analyzed. The influence of the structure of the argon shroud protection device on the protection effect was investigated. An argon shroud protection device mounted to the nozzle holder on the bottom of the ladle does not provide a good protection effect because air can easily flow into the teeming system and cause reoxidation of molten steel during teeming. By contrast, an argon shroud protection device seated on the top of the central trumpet provides an excellent protection effect, where air has little chance of flowing into the teeming system during casting. The feasibilities of the argon shroud protection devices are discussed.

Inclusions in Runner Steel During Ingot Casting

This paper reported the observation of inclusions in the steel of an ingot runner. Thermodynamic modeling was performed to study the formation mechanism and sources of inclusions. CFD modeling on fluid flow, heat transfer, solidification of molten steel was carried out and the entrapment of inclusions in runner steel was predicted and compared with the measurement. Al2O3-based inclusions were the main ones in the steel samples. MgO?Al2O3 mainly stemmed from the lining refractory. The high MnO inclusions in the runner steel came from the runner slag. The effect of natural convection was very important for the cooling and solidification of the steel in the runner. Both the observation and the modeling show that 】 50μm inclusions more accumulated on the upper area in the runner and 【 50μm inclusions dispersed well and more accumulated on the lower area of the runner.

Volume-averaged modeling of multiphase solidification with equiaxed crystal sedimentation in a steel ingot

Macrosegregation is a critical factor that limits the mechanical properties of materials.The impact of equiaxed crystal sedimentation on macrosegregation has been extensively studied,as it plays a significant role in determining the distribution of alloying elements and impurities within a material.To improve macrosegregation in steel connecting shafts,a multiphase solidification model that couples melt flow,heat transfer,microstructure evolution,and solute transport was established based on the volume-averaged Eulerian-Eulerian approach.In this model,the effects of liquid phase,equiaxed crystals,columnar dendrites,and columnar-to-equiaxed transition(CET)during solidification and evolution of microstructure can be considered simultaneously.The sedimentation of equiaxed crystals contributes to negative macrosegregation,where regions between columnar dendrites and equiaxed crystals undergo significant A-type positive macrosegregation due to the CET.Additionally,noticeable positive macrosegregation occurs in the area of final solidification in the ingot.The improvement in macrosegregation is beneficial for enhancing the mechanical properties of connecting shafts.To mitigate the thermal convection of molten steel resulting from excessive superheating,reducing the superheating during casting without employing external fields or altering the design of the ingot mold is indeed an effective approach to control macrosegregation.

Chemical composition analysis on industrial scale ingots and castings of TiAl alloys

The chemical composition variation of the TiAl-4722 alloys was examined in a batch of the industrial scale master ingots,and in the corresponding castings prepared by conventional vacuum arc remelting(VAR)combined with induction skull melting(ISM)and investment casting processes.The content changes of major elements and interstitial elements were evaluated based on the chemical analysis at the top and bottom of the ingots and castings.Results show that the contents of C,N,H,Fe and Si have almost no change in the ingots and castings,suggesting that the chemical analysis on these elements can be based on the batch analysis.The O content keeps almost the same in different ingots,but exhibits relatively large differences in castings,which was probably influenced by the reaction between the shell mold and the molten alloy,and the spalling of face coat of the shell mold during casting.For the major elements of Al,Nb and Cr,the composition difference between the top and the bottom of the ingots is less than that of the castings.But for the O element,the trend is different,especially for the castings,suggesting that the investment casting is a homogenization process for Cr and Nb,but a differentiation process for O.The contents of major elements in castings fluctuate mainly in the same range as that in the ingots,indicating that the contents of the major elements are controllable during investment casting.

Optimizing casting parameters of steel ingot based on orthogonal method

The influence and signification of casting parameters on the solidification process of steel ingot were discussed based on the finite element method (FEM) results by orthogonal experiment method. The range analysis, analysis of variance (ANOVA) and optimization project were used to investigate the FEM results. In order to decrease the ingot riser head and improve the utilization ratio of ingot, the casting parameters involved casting temperature, pouring velocity and interface heat transfer were optimized to decrease shrinkage pore and microporosity. The results show that the heat transfer coefficient between melt and heated board is a more sensitive factor. It is favor to decrease the shrinkage pore and microporosity under the conditions of low temperature, high pouring velocity and high heat transfer between melt and mold. If heat transfer in the ingot body is quicker than that in the riser, the position of shrinkage pore and microporosity will be closer to riser top. The results of optimization project show that few of shrinkage pore and microporosity reach into ingot body with the rational parameters, so the riser size can be reduced.

Technological investigation of electromagnetic casting for double ingot

The double ingot equipment of electromagnetic casting that consists of inductor, cooling water box, etc, was designed. The effects of inductor current and screen position on magnetic field distribution were investigated according to the measured results of series connection inductor. From these results, the solidification front of melt should be controlled to the bottom of inductor. The key parameters such as casting speed, liquid column height and flow rate of cooling water are about 0.6～1.5 mm/s, 30～45 mm and 1.5～2.5 m 3/h, respectively. And the round double ingot with a diameter of 240 mm and a length of 400 mm was cast.[

基于AnyCasting的长细钢锭铸造成型数值仿真

为了获得力学性能、表面质量、内部组织优良的某型电极坯用长细钢锭,分析了其铸造原理及工艺。运用有限元铸造仿真软件AnyCasting建立了长细钢锭铸造成型的数值仿真模型,对其在铸造成型过程中的钢液流动速度、温度、缺陷概率及碳偏析变化趋势及分布规律进行了数值仿真。结果表明：在长细钢锭铸造成型过程中,钢液流动速度由中心向两侧逐渐减小;温度和碳偏析最大值主要分布在钢锭中心位置,分布区域呈沿长度方向的长椭圆状;缺陷主要分布在上端中心位置处,区域呈沿长度方向的细长椭圆状。该研究结果能为细长钢锭铸造产品质量提升提供参考。

基于Procast的Φ650mm电极锭浇注方案优化研究

针对某钢厂Φ650 mm电极锭原浇注方案内部质量较差的问题,对电极锭浇注方案进行优化,利用有限元计算软件Procast对相应浇注方案下钢锭的内部质量进行了预测,最后得出了优化的浇注方案,即提高锭身浇注速度、降低冒口浇注速度。

Production and Characterization of Zr Based Bulk Metallic Glass Matrix Composites (BMGMC) in the Form of Wedge Shape Ingots

Bulk metallic glass matrix composites (BMGMC) are unique materials of future having excellent mechanical properties (such as high hardness, strength and profound elastic strain limit). However, they exhibit poor ductility and suffer from catastrophic failure on the application of force. The reasons behind this are still not very well understood. In this study, an effort has been made to overcome this pitfall by solidification processing. Zr based BMGMCs are produced in the form of “as cast” wedges using vacuum arc melting and suction casting button furnace. The idea is to study the effect of cooling rate and inoculation on formability during solidification. Adjustment, manipulation and proper control of processing parameters are observed to reflect upon the quality of ingots such as improved castability, proper mold filling and defect free casting as characterized by NDT. Further, thermal analysis, optical microscopy and hardness measurement confirmed the formation and evolution of in-situcomposite structure. This is first footprint of pathway towards sustainable manufacturing of these alloys in future.

Experience in the Production of Horizontal Ingots of Platinum Metals and Alloys

The quality of semi-products of platinum metals and alloys, produced by way of plastic working, essentially depends on or, in many cases, is completely determined by the quality of ingots. Plastic working does not make it possible to eliminate or localize metallurgical defects. In many cases it promotes the occurence thereof. Low-rate casting with directional crystallization can ensure the production of dense ingots free of non-metallic inclusions, shrinkage and gas weakness, with observance of certain temperature/rate modes. After comparative tests of vertical and horizontal molds, preference has been given to horizontal water-cooled molds, allowing to cast all alloys in the conditions of directional crystallization.

C70600白铜空心锭立式连铸工艺参数对凝固过程的影响

为了获得Ф260×Ф80 C70600白铜空心锭立式连铸合理的工艺参数,通过数值模拟定量分析了各种工艺参数对温度场和应力场的影响。结果表明:浇铸温度每提高20℃,液穴深度增加10 mm;拉坯速度每提高10 mm/min,液穴深度增加20 mm;液穴深度随着石墨芯管冷却强度的增大而减小。基于正交试验和方差分析发现,F_(A)>F_(0.01)(3,3),F_(B)>F_(D)>F_(0.1)(3,3),F_(C)<F_(0.1)(3,3),因此,拉坯速度对液穴深度的影响最显著,一冷强度对其影响不显著。根据模拟结果提出了合理工艺参数为:一冷强度24 m^(3)/h、拉坯速度80 mm/min、浇铸温度1280℃、芯管采用空冷。在此基础上成功试制出了合格的C70600白铜空心锭成品。

锌铝合金铸锭设备自动化进程研究

锌铝合金铸锭设备,是将锌和铝熔合成合金并铸造成锭的关键设备。该设备核心环节在于将阴极锌片和铝元素在熔炼装置中进行加热熔融,形成合金液体,随后将其浇铸到模具中,待冷却后形成高品质的成品锭。整个生产过程涉及加料、熔炼、合金化、浇铸、冷却、脱模、称重、标识等多个环节。鉴于锌锭市场价格疲软,而锌铝合金的高附加值及需求量的日益增长,未来锌铝合金锭有望取代锌锭,成为锌冶炼企业的主打产品。本文深入探讨了锌铝合金锭的应用场景、生产工艺流程以及国内铸锭设备的现状。同时,对国内外锌铝合金铸锭自动化设备的发展动态和自动化进程进行了系统梳理,并重点介绍了直线式和圆盘式两种高自动化程度的铸锭设备,展现了锌铝合金铸锭设备的广阔前景。

特殊钢模铸生产中钢锭模组合优化研究

针对特殊钢的生产特点,提出求解特殊钢模铸生产过程中的钢锭模组合优化问题的方法,该方法将钢锭模组合优化问题抽象为背包问题,并使用动态规划算法和递归回溯算法进行求解,能快速计算具有最优锻造比的钢锭模组合方案,还能计算所有满足要求的钢锭模组合,同时考虑了出钢量与电炉生产能力是否匹配的问题。通过对生产实例进行试验,验证了该方法的有效性,能够在一定程度上满足特殊钢企业的实际应用需求,对实际生产具有一定的指导意义。

高成材率钢锭缺陷控制技术及其研究进展

钢锭凝固过程中将不可避免地产生各类缺陷,严重制约了钢锭成材率,直接影响后续加工工艺和最终产品质量。抑制缺陷形成、探索创新并有效改进模铸工艺对提高钢锭成材率具有重要意义。通过探讨和分析关于提高钢锭成材率的研究现状和最新进展,包括锭型设计、工艺参数优化、先进铸造技术等,展望了多相流动控制、微观结构调控和冷却速率精准管理等未来模铸与凝固技术研究发展方向,为实现高成材率钢锭的稳定生产提供了合理化建议。

铁路轴箱轴承用8620钢3 t钢锭轧制产品研发

针对中国铁路客车和货车轴箱轴承用钢主要使用电渣钢的现状,采用铁水+废钢→70 t电弧炉→LF→RH→3 t钢锭→均热坑→1350+750/650轧机轧制的流程生产规格ϕ60~ϕ120 mm 8620钢(质量分数/%:0.18~0.22 C,0.15~0.30 Si,0.75~0.95 Mn,0.45~0.65 Cr,0.45~0.70 Ni,0.15~0.25 Mo,≤0.020 P,≤0.015 S,0.020~0.050 Al)。通过控制出钢留钢留渣、炉后造渣和合金化,真空处理时间≥25 min,氩气弱搅拌,控制钢水过热度,全过程Ar气保护,模铸自动浇注,轧制后控制冷却等工艺措施,生产的产品宏观夹杂物检测含量≤10 mm/dm3,晶粒度8~8.5级,密度达到7.854 g/cm^(3),钢材各项指标满足标准要求。

加工用高纯钒锭的制备工艺研究

鉴于金属钒具有储氢、高温超导、快中子吸收截面小及对液态钠有耐蚀性等特性,市场对金属钒制品的需求不断增加,而这些钒制品必须使用满足要求的高纯钒锭来加工制作,重点从制备原料、工艺原理及流程、生产影响因素等方面对高纯钒锭的研制工艺进行详细阐述。

自动化银锭熔铸技术在生产线的应用实践

介绍了银锭熔铸的工艺技术现状,包括传统熔铸工艺和全自动熔铸工艺技术的特点和不足。以500 t/a铸银规模为设备选型基准,对比分析了无火焰隧道式和腔体式熔铸工艺在主要设备投资和经营成本方面的差异,为银锭熔铸工艺改造方案的选择提供参考和建议。

航空集装箱用7021铝合金大扁锭产生裂纹的原因及对策

7021铝合金以其优良的特性广泛应用于航空集装箱.随着产品尺寸增加,所需的超大规格扁锭易出现裂纹缺陷.本试验观察了7021铝合金扁锭裂纹形貌,系统分析了合金熔铸过程中的化学成分、熔体质量、铸造工具和工艺对裂纹的影响,提出了解决7021铝合金扁锭裂纹的工艺优化方向以及有效控制措施.