铝合金熔铸标准化快速配料法

论述了铝合金熔铸生产中配料工作涉及的一些专业技术问题,正确地配料是实现用低成本生产高品质铝合金铸锭的基础。分析了当前铝加工企业配料工作的现状和存在的一些问题。作者在多年生产实践中积累丰富经验的基础上,研究出铝合金熔铸标准化快速配料方法,在2×××、3×××、4×××、5×××、6×××、7×××和8×××系铝合金中各例举一个牌号的合金,作为典型配料实例,来阐述标准化快速配料法的应用。     

SPF model applications for aluminum

A closed-form, plane strain model (PS2) is compared with a finite element model (SUPFORM3) in analyzing the forming of rectangular pans from 2090-OE16 aluminum sheet. The errors introduced by improperly using a plane strain model are quantified. Some preliminary verification of SUPFORM3 is shown, and the effect of friction on the distribution of thickness in the superplastic forming (SPF) of a rectangular pan is presented. SUPFORM3 is used to predict thickness distribution of male formed access doors, selecting proper starting gauges, assessing producibility, estimating forming time, and developing pressure time cycles. SUPFORM3 will be used to form complex parts and flat-bottomed pans such that post-SPF properties samples can be cut from the flat areas of the flat-bottomed pans, yet have the same strain and strain rate history as the critical areas in the complex part. It is concluded that SUPFORM3 is a useful tool for predicting thickness distributions resulting from and pressurization schedules for superplastic forming.     

A dislocation-density-based 3D crystal plasticity model for pure aluminum

A dislocation-density-based crystal plasticity finite-element model (CPFEM) is developed in which different dislocation densities evolve. Based upon the kinematics of crystal deformation and dislocation interaction laws, dislocation generation and annihilation are modeled. The CPFEM model is calibrated for pure aluminum using experimental stress–strain curves of pure aluminum single crystal from the literature. Crystallographic texture predictions in plane-strain compression of aluminum are validated against experimental observations in the literature. The framework is implemented in ABAQUS with user interface UMAT subroutine.     

2A97铝锂合金蠕变本构模型的建立

对2A97新型铝锂合金在温度180℃不同应力水平条件下进行多组蠕变试验,通过数值拟合,建立了经典蠕变本构模型与基于双曲正弦函数的等温蠕变本构模型。结果表明,采用基于双曲正弦函数的等温蠕变本构模型得到的拟合曲线与试验值吻合较好,能准确描述蠕变时效成形过程。     

A mathematical model for the distribution balance of extraction processes from waste batteries

The experiments of metal Cd extraction were carried out three times at oil phase/aqueous phase (O/A)=1 and pH 2.2 by using 1.3 mol/L di(2-ethylhexyl)phosphoric acid (DEHPA) as the agent,with an extraction rate of 99.5%.Experiments on metal Co extraction were done three times at O/A=0.5 and pH 4.7 by using 0.4 mol/L Cyanex 272 as the agent,with an extraction rate of 99.2%.By using equilibrium data and massive calculations to analyze and predict the interaction among the extraction systems,this paper came out with the polynomials of the empirical model as well as their parameter values for the equilibrium concentration of the above two extraction loops.     

棕刚玉熔炼系统的新设计

介绍了国内首次实现的全机械化运行的刚玉分包接液新工艺,介绍了接液包的防爆措施;废除了传统的耐火砖拱顶而采用耐热混凝土天花板热保护,节约大量投资;采用了小巧的全保温炉缸,从而使冶炼炉具有较先进的节能效果。该设计在节能、节省电极材料消耗以及劳动保护方面显示出极大的优越性。     

A356铝合金的高温流变行为及本构模型研究

A356铝合金的高温流变特性和本构模型对其应力状态起着重要的作用,为铝合金流变成形过程的有限元模拟奠定了重要的基础.从A356铝合金轮毂铸造坯料上制取拉伸试样,利用Instron 3369型实验机进行等温拉伸实验,实验温度为300～375℃,应变速率为0.001～0.1 s-1.由此得到的真应力-真应变曲线表明,温度和...     

日本废钢业发展透视:废钢回收业如何实现“绿色重生”

<正>中国钢铁工业经历了数十年的快速发展,钢铁积蓄量不断增加,今后将有大量的废钢资源产生。如何有效利用、管理这些资源或将是未来中国钢铁工业需要解决的一个重大问题。相关资料显示,短流程炼钢比长流程炼钢可减少废气86%、废水76%和废渣97%,与长流程炼钢相比,用废钢炼1吨钢可减少近1.6吨碳排放,因此废钢生产更加清洁和有利于排废减量化,鼓励能耗低、污染小的电炉炼钢发展无疑有利于环境保护。日本钢铁业的发展与中国有很多类似之处,而且日     

Recrystallization model for hot-rolling of 5182 aluminum alloy

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Electrochemical etching model in aluminum foil for capacitor

A novel tunnel growth model is proposed to reveal how hydrogen is transported out of tunnels and explain the phenomena during etching process of aluminum foil for capacitor. Experimental results indicated that tunnel density increased and tunnel width decreased with temperature increasing at the temperature range of 70–80 °C. The pressure in electrolyte had an effect on the tunnel density. The tunnel density after etching at 0.2 atm was larger than that at 1 atm. A pulse electrochemical etching process is described according to the novel tunnel growth model. It considers that hydrogen bubble of nanometer dimension is absorbed on the tunnel’s walls surface during the pulse electrochemical etching process, and the saturated hydrogen at the end of the tunnel is accumulated to be a large bubble before hydrogen is transported out of the tunnel. The large bubble will emanate from the end of tunnel when the pressure in the bubble is equal to that outside. The wall surface passivation phenomena is explained by this model; the naturally corrugated texture with ripples of about 0.1 μm in tunnel’s walls surface is regarded to be produced by the potential periodical changes, which are caused by the large hydrogen bubble at the end of the tunnel. At the same time, the effect of temperature and pressure on the morphology of the tunnel is also investigated by use of the model. The pressure of the large hydrogen bubble in the tunnel is calculated according to the date in other references when the period of the pulse electrochemical etching is inferred to be 3 ms at their experimental conditions. The proposed process of pulse electrochemical etching could explain well the calculation results and the SEM images of etched tunnels under the same experimental conditions.     

混杂铝基复合材料的摩擦系数模型

建立了碳化硅、石墨粒混杂增强铝基复合材料的摩擦系数模型。将混杂复合材料摩擦系数处理成无碳化硅时的石墨－铝基复合材料摩擦系数分量,碳化硅对钢的刮擦从而引起摩擦分量两部分之和。对两部分分量分别进行了建和计算。然后相加得到混杂复合材料的总摩擦系数模型。通过与实验数据的比较,表明该模型能够较准确地计算同石墨含一的混杂铝基复合材料的摩擦系数。     

A mathematical model coupled to CALPHAD to predict precipitation kinetics for multicomponent aluminum alloys

A mathematical model was developed to simulate the precipitation kinetics during heat treatment of multicomponent aluminum alloys. The model is based on the general numerical framework proposed by Kampmann and Wagner, and features a full coupling with CALPHAD software for the evaluation of the Gibbs–Thomson effect. It also does not rely on the assumption that precipitate phase composition is stoichiometric or uniform, and is therefore applicable for predicting complex precipitation kinetics encountered in industrial practices. Applications of the model to various aging treatments of binary Al–Sc alloys and a ternary Al–Sc–Zr alloy were conducted. It was found that the model predictions for extended time coarsening kinetics are in good agreement with the analytical Lifshitz–Slyozov–Wagner coarsening theory. Its ability to reproduce the complex precipitation pathways in multicomponent alloys was demonstrated by simulation of the precipitation kinetics for an Al–0.09 at.% Sc–0.03 at.% Zr alloy. Comparison of the simulation results with experimental measurement has also highlighted research directions that require further effort.     

焊接热循环和变形历史相关的A7N01-T6本构关系

建立了与焊接热循环温度和热变形历史相关的铝合金本构关系,利用MSC.MARC二次开发接口和Fortran语言,以塑性变形有限元计算增量理论为基础,开发了适用于焊接过程的材料本构关系用户子程序.采用弹塑性(混合硬化)和蠕变性质(应变软化)描述低温应变硬化特征和高温动态回复及再结晶引起的应变软化特征,不同温度的本构关系形式一致而参数不同.结果表明,焊件的残余应力和应变结果与理论结果吻合良好.与采用理想弹塑性本构关系相比,采用新开发的本构关系,高温应变软化和低温应变硬化导致等效残余应力基本不变,纵向残余压缩塑性应变较大,相应的焊接残余变形也较大.     

A thermal model of friction stir welding in aluminum alloys

A thermal model of friction stir welding was developed that utilizes a new slip factor based on the energy per unit length of weld. The slip factor is derived from an empirical, linear relationship observed between the ratio of the maximum welding temperature to the solidus temperature and the welding energy. The thermal model successfully predicts the maximum welding temperature over a wide range of energy levels but under predicts the temperature for low energy levels for which heat from plastic deformation dominates. The thermal model supports the hypothesis that the relationship between the temperature ratio and energy level is characteristic of aluminum alloys that share similar thermal diffusivities. The thermal model can be used to generate characteristic temperature curves from which the maximum welding temperature in an alloy may be estimated if the thermal diffusivity, welding parameters and tool geometry are known.     

6082铝合金热变形的本构模型

利用Gleeble-1500热模拟机,研究6082锅合金在变形温度为300～500℃以及应变速率为0.01-10/s下高温单道次压缩过程的热变形流变应力行为.结果表明:6082铝合金高温单道次压缩下的热变形经历了从应变硬化阶段过渡到稳态变形阶段的过程,其软化机制主要为动态回复.该合金流变应力的大小受变形温度、应变速率的强烈影响,它随变形温度升高而降低,随应变速率提高而增大,说明该合金足一个正应变速率敏感的材料.该合金高温流变应力σ可采用Zener-Hollomon参数的函数来描述,函数表达式中参数A,a和n的值分别为3.97×1011s-1、0.011MPa-1、9.16;其热变形激活能Q为143.89kJ/mol.     

A material removal model for polishing glass–ceramic and aluminum magnesium storage disks

In this paper, a model is proposed to more closely describe the relationships between polishing parameters and the material removal rate for the commonly used storage disks in PC. Experiments were conducted to verify this model. It is shown that the proposed model predicts the material removal rate more accurately than existing models. The proposed model is expected to apply to different materials polished by similar processes. The FEM analysis of the applied polishing pressure well explained the current empirical results.     

An improved finite-element model for electromagnetic analysis in aluminum cells

This article presents the use of an improved finite-element model to calculate the static electromagnetic field for an aluminum reduction cell. Consisting of three solid cells and their surrounding bus bars, the model can evaluate the non-uniformity of the current distribution in the inside conductors and bus bar system and couple the current into the sequential magnetic analysis through a conversion routine. Voltage potential distribution in the molten aluminum was investigated based on one industrial 320 kA aluminum cell with two designed bus bar arrangements. Characteristics of magnetic components’ distributions were also given.