大型汽轮机末级动叶片高效精密六轴联动数控砂带磨床完成用户终验收

重庆三磨海达磨床公司为了适应市场需求,最新研制出国内第一台具有自主知识产权的高效率、高精度、大规格六轴联动数控砂带磨床正式通过东方汽轮机厂终验收,本磨床为CNC控制,可实现六轴联动磨削加工,主要用于各类汽轮机叶片、航空发动机叶片等复杂曲面的高效精密磨削,也可实现如船用螺旋桨、叶轮等复杂型面零件的磨削和抛光。通过在东汽近半年的工程试用,该机先后实现了40英寸、43英寸和57英寸不同规格大型叶片的稳定磨削工艺试验验证,     

基于UG的叶片数控砂带磨削刀位数据的计算

介绍了一种在UG环境下使用Open API编程计算叶片砂带磨削刀位点的方法,并开发了磨削加工仿真模块,对计算结果进行了仿真验证。该方法可省略编程建模的复杂过程,计算结果精度高,为叶片数控砂带磨削的后置处理奠定了基础。     

三自由度柔性砂带磨床各关节轴的刚度和角位移对机器人磨削加工轨迹的影响

介绍用于机器人磨削加工的3自由度柔性砂带磨床的组成.采用Denavit-Hartenberg法建立该磨床的运动学模型,推导出磨削力作用点的法向挠度与各关节轴刚度和角位移的关系.通过数值仿真,分析各关节轴的刚度和角位移对磨削力作用点的法向挠度的定性和定量关系并得出一些结论.这些结论可用于3自由度柔性砂带磨床的设计和机器人磨削加工轨迹的在线修正,以提高机器人砂带修形磨削加工的精度.     

基于ACIS的叶片型面数控砂带磨削刀位计算及精度控制方法

提出了叶片型面六轴联动磨削的刀位点的计算方法,探讨了走刀步长、行距与磨削加工误差之间的关系,开发了基于ACIS的叶片型面磨削加工仿真软件.对某叶片型面的刀位点进行了计算和走刀轨迹仿真,验证了叶片型面砂带磨削加工刀位点以及轨迹计算的正确性.     

基于ADAMS的五轴数控工具磨床磨削力仿真分析

利用计算机三维建模与虚拟样机仿真技术建立自主研发的五轴数控工具磨床虚拟样机模型,对五轴数控工具磨床加工过程中砂轮磨削力的受力大小和变化趋势进行仿真,利用磨削力的理论计算公式验证了所建立的虚拟样机模型的有效性。研究了砂轮线速度、磨削深度、进给量对磨削力的影响,为五轴数控工具磨床的设计提供参考。     

汽轮机叶片数控砂带磨削工艺分析与磨床结构设计

文章介绍了汽轮机叶片材质和形状特点及砂带磨削特性,进行了叶片砂带磨削工艺分析,在对叶片磨削运动分析的基础上,进行了叶片数控砂带磨床的结构设计,并对砂带磨床的关键结构件进行了力学性能有限元分析。     

VERICUT虚拟机床技术在五轴加工中的应用研究

根据BV100双转台(A-C)五轴数控机床结构参数,基于VERICUT建立该机床的虚拟机床模型,构建仿真加工环境;并应用该虚拟机床对叶片进行数控仿真加工,不仅验证数控程序的正确性,而且通过仿真消除试切中的碰撞、干涉和超程等问题。通过系列实验验证了虚拟机床技术在五轴加工中的重要性。     

发动机连杆小端孔口倒角砂带磨床的研制

针对发动机连杆小端孔口倒角加工的技术难题,在分析传统机械加工方法缺陷的基础上,提出了利用砂带磨削技术进行连杆小端孔口倒角加工的新方法,详细介绍了该砂带磨床的结构设计,最后经试验证明了该砂带磨床的实用性.     

杭机集团自主研发数控砂带磨床通过预验收

杭州机床集团日前表示，其自行设计制造、拥有自主知识产权的首台大型SDM-1数控叶片叶顶砂带磨床业已完成。这台专为哈尔滨汽轮机厂磨削叶片叶顶度身订制的砂带磨床，已于7月初在杭州通过用户方预验收，并将在进一步完善数控加工程序和机床防护装置之后出厂。     

HPM 1850U虚拟机床的构建与多轴数控加工仿真验证

HPM 1850U机床是一种能进行高速高精度加工的五轴联动加工中心,由于其结构复杂,主轴灵活且还可进行立卧转换,所以在数控加工过程中存在无法人为判断数控程序的正确性和刀轴的干涉碰撞等问题。为解决此问题,利用三维软件搭建了1850U机床实测尺寸模型,并在数控虚拟仿真加工软件VERICUT中构建该机床的虚拟仿真环境,以某叶轮为例,验证了该虚拟仿真环境的正确性。结果表明:该机床的虚拟仿真环境可实现数控加工过程动态仿真,也可以验证刀具轨迹和数控程序的正确性,并同时检验刀轴干涉的碰撞,从而缩短产品生产周期,提高生产效率,并且为其他同类型多轴机床虚拟仿真提供技术支持,也为数字化集成制造提供了虚拟仿真机床和技术。     

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.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

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.     

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.     

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.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.