基于精确建模的微线段齿轮弯曲强度理论分析

提出了一种微线段齿轮精确建模方法。该方法通过建立齿轮轮廓方程和齿根过渡曲线方程,编程求出微线段全齿廓的坐标点,并利用PRO/E建立微线段齿轮的齿形模型,最后导入到Ansys中进行齿根弯曲强度分析。结果表明,齿根过渡曲线对齿轮齿根的弯曲强度大小有直接影响。该文所述方法提高了微线段齿轮齿根弯曲强度计算的准确性。     

斜齿微线段齿轮的重合度研究

论文简要介绍了斜齿微线段齿轮的基本原理，分析了其啮合过程，应用齿轮啮合的基本原理导出了斜齿微线段齿轮端面重合度及纵向重合度的计算方法，应用文中的公式编制了应用程序，并给出了计算实例。     

内斜微线段齿轮电解加工工艺及装备研发

针对常规机械加工难以解决的内斜微线段齿轮加工问题,提出了一种脉冲电解加工方法。利用可编程控制器(PLC)进行电解加工机床控制系统的设计,实现机床主轴和数控转台的联动。设计制造电解加工工装及片状阴极,优选电解液,选择合适的加工参数进行齿轮加工试验。齿轮精度满足要求,表面质量好,无机械残余应力,无须进行后续加工。     

渐开线零齿差内啮合齿轮机构的可靠性设计

文章指出了用传统的齿轮强度校核公式来校核渐开线零齿差齿轮副的不合理性,建立了新的、适用于零齿差机构的校核方程式.在此基础上,应用摄动方法和可靠性设计理论,探讨了零齿差内啮合齿轮的可靠性设计方法.文中方法可以定量地给出齿轮的可靠度并根据可靠度对齿轮进行可靠性设计,是对齿轮可靠性问题研究的一次重要探索.     

基于威布尔分布和极限状态理论的齿轮传动可靠性设计

针对现行的齿轮可靠性设计中多将影响齿轮的随机因素及齿轮应力和强度分布简单假定为正态或对数正态分布，与实际分布差异较大的情况。论文探讨一用威布尔分布描述影响齿轮的随机因素，应用极限状态理论进行齿轮传动可靠性设计方法；由于威布尔分布的灵活性，使其描述的分布状态与实际情况更接近从而设计更可信。文中对渐开线圆柱齿轮进行了可靠性设计，并开发了计算机应用程序，可以迅速准确地给圆柱齿轮的可靠性设计信息。     

血液透析机中的微齿轮注射模设计

利用Pro/E对微齿轮制件进行建模并加以分析,设计出一副应用于微注射齿轮加工的模具.结构上利用型腔镶块,模板材料上选用透气钢解决了微齿轮加工中排气的难点,四杆机构的使用合理地避免了顶出过程中有可能产生的缺陷.     

铝合金微型齿轮等温精密微成形工艺研究

利用自行研制的精密微塑性成形设备,对铝合金微型齿轮的等温精密成形工艺进行了研究,成功地获得了质量良好的节圆直径为Φ1mm的5A02铝合金微型齿轮.金相分析表明,微型齿轮的齿部流线沿齿形轮廓分布,有利于提高齿轮的承载能力和抗疲劳强度.纳米硬度分析表明微型齿轮的纳米硬度分布也有利于提高齿轮的抗疲劳强度.使用等温精密微成形技术可以制造出质量良好的微型齿轮.     

船用齿轮传动系统的可靠性方法

船用齿轮传动装置是船舶主机与螺旋桨之间实现功率和转速匹配的重要传动设备。本文从船舶系统的角度，研究了可靠性分配原理，讨论了轴系、柴油机和机座对齿轮传动可靠性的影响，提出了改进齿轮箱输入端轴系结构和联接方式，对称设计箱体和独立布置机座，调整中间轴承高度位置的方法，有效地提高了船用齿轮传动系统的工作可靠性。     

齿轮小无飞边模锻

以齿轮小无飞边模锻为研究对象,介绍了齿轮小无飞边模锻的类型及其应用实例,说明了齿轮小无飞边模锻具有技术上的可行性、质量上的可靠性和经济上的合理性,达到了齿轮模锻优质、高效和低耗的效果。     

采煤机重载齿轮的制造及其热处理工艺

介绍了采煤机重载齿轮的加工制造工艺和热处理工艺,提出了一系列提高和改善齿轮性能的措施,以保证采煤机工作的安全可靠性,延长其使用寿命.     

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.