模锻锤打击能量的计算机控制

介绍了在普通双作用模锻锤上采用锻锤打击能量教学反馈演示系统,可减小锻造能量波动,提高锻件厚度尺寸精度,延长模具寿命.并使操作简便,降低工人的劳动强度,提高劳动生产率,效果显著.     

直驱式打击液压阀及其液压系统特性分析

打击液压阀控制着数控全液压模锻锤的主要动作,其动态性能的好坏也就直接影响着模锻锤的工作性能。通过用SimulationX软件来仿真分析数控全液压模锻锤的液压系统,得到模锻锤的工作性能曲线和相关参数,与实际情况进行比对,进而得出打击液压阀的工作参数,为打击液压阀的结构设计和优化打下了基础。     

直驱式打击液压阀及其控制的研究

打击液压阀控制着数控全液压模锻锤的主要动作，其动态性能的好坏也就直接影响着模锻锤的工作性能。通过用SimulationX软件来仿真分析数控全液压模锻锤的液压系统，得到模锻锤的工作性能曲线和相关参数，与实际情况进行比对，进而得出打击液压阀的工作参数，为打击液压阀的结构设计和优化打下了基础。     

液压模锻锤液压控制系统研究

阐述了液压模锻锤的结构及工作原理。通过动量定理建立了全液压模锻锤液压缸的数学模型,为设定打击能量和打击次数的大小提供了依据,同时为实现模锻锤运行过程的精确控制提供了理论参考。并对锤头速度、位移、动能变化情况进行了试验仿真,通过仿真分析为其进一步实现模锻锤打击工序和打击能量的数控化和柔性化奠定了基础。     

数控全液压模锻锤的能量控制与仿真

在对63 kJ数控全液压模锻锤系统分析的基础上,提出通过建立数学模型,并应用Simulink进行仿真分析,从而直观地求出打击阀的开启时间t与打击能量e之间的能量仿真关系,实现比较精确的能量控制.通过对打击阀的开启时间t与打击能量e之间的仿真结果分析,为数控全液压的反馈控制提供了参考,该方法目前已在模锻锤开环控制方面取得...     

大齿轮锻件的成形新工艺

我厂３ｔ自由锻锤对于大齿轮类锻件，若采用传统的套模工艺锻造，由于其模具专用性强，且锻造力大，常有力不从心，且锻件质量差的弊端。为此，经反复研究，提出了一种充分利用锻锤打击能量的新工艺方法。１工艺设计（１）胎模设计根据锻造工艺过程及毛坯图尺寸，确定胎模...     

减振器外体模锻成形工艺与设计改进

针对减振器外体在相对打击能量较小的30kN模锻锤上极难模锻成形的不利因素,对预锻模进行了3次改进设计,改进后的最终结果表明:减振器外体在30kN模锻锤上模锻成形的省时省力效果优于在50kN模锻锤上模锻成形,模锻效率至少提高3倍,模锻生产周期由原来超过7天300件减少到2~3天300件,锻件合格率由92%提高到99%,锻件成本降低了30%。     

396柴油机连杆模锻成形工艺研究

以396柴油机连杆为研究对象,针对该连杆在相对打击能量较小的30kN模锻锤上的模锻成形工艺进行分析,比较了396柴油机连杆分别在30kN模锻锤和50kN模锻锤上的模锻成形效果,并对连杆锻模设计的相关内容:模锻工步、预锻热锻件形状、终锻热锻件形状、预锻和终锻的冲孔连皮、压凹连皮以及飞边槽等进行优化设计与实验验证。实验结果表明:连杆锻件合格品率由原94%提高到98%,减少锻造生产周期至少6天/300件,提高模锻效率至少1倍,锻造成本至少降低40%。     

直驱式电液伺服模锻锤控制系统AMESim仿真及控制研究

传统模锻锤采用定转速液压泵、蓄能器和打击阀方案实现对锤头的打击能量控制,存在打击能量可控性差、精确差,打击阀易损坏、寿命短等问题,提出一种采用交流伺服电机驱动定量泵的模锻锤打击能量控制方案,称为直驱式电液伺服模锻锤。针对这种新型模锻锤控制系统的精确控制问题,采用AMESim和Simulink仿真分析,提出了合适的解决方法。首先,建立交流永磁同步伺服电机和液压系统联合仿真模型,仿真分析出锤头速度和位移、泵流量及电机转速曲线,结果表明,锤头打击能量可以通过电机转速实现精确控制。针对传统PID对非线性控制的局限性,提出了一种小波神经网络PID模锻锤压力与速度的控制策略。利用c SPACE系统控制原型,通过半实物物理仿真,验证了控制方法的有效性。     

50kJ液压模锻锤打击能量仿真研究

在建立了50kJ液压模锻锤打击能量的数学模型的基础上,经过仿真分析,得出了在一定充气压力及装模高度下的打击行程与打击能量的关系曲线,并对仿真计算结果进行了实验验证.通过分析对比,确定了这一数学模型可以用于液压模锻锤打击能量的数据控制,为液压模锻锤的程序控制提供了依据.     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.