基于摆线旋分原理的飞刀加工及其刀具的结构设计

滑块槽和倒锥是汽车同步器齿套的主要部位,由于属于内表面且表面形状略复杂,因此属难加工表面。首先介绍了滑块槽加工的国内外加工现状和基于摆线旋分原理的加工方法,从数学模型上计算了其加工的理论误差。然后建立了切削滑块槽飞刀的数学模型,在拥有自主知识产权的旋分数控机床和市场上通用的可转位刀具基础上设计了加工齿套滑块槽部位的专用刀具。经过实践检验证明该刀具是适用的。     

汽车变速箱同步器齿套滑块槽表面飞刀切削数学模型的建立

为了解决汽车同步器齿套滑块槽的表面加工问题,应用飞刀切削的原理,并提出了采用复轨迹法加工汽车同步器齿套滑块槽的思想.通过对经典切削力指数模型进行变形,建立了一种包含切削前角新的切削力模型.设计了测量飞刀切削力试验.为判定模型中的各系数,用多元线性回归的方法处理试验数据,确定了切削力模型中的系数,得出了飞刀切削滑块槽的切削力数学模型.     

汽车同步器齿套飞刀切削数学模型的建立及其试验验证

为了解决汽车同步器齿套滑块槽的表面加工问题,论文应用飞刀切削的原理提出了用复轨迹法加工汽车同步器齿套滑块槽的思想。通过对经典切削力指数模型进行变形,建立了一种包含切削前角新的切削力模型。设计了测量飞刀切削力试验。为判定模型中的各系数,用多元线性回归的方法处理试验数据,确定了切削力模型中的系数,得出了飞刀切削滑块槽的切削力数学模型。     

飞刀加工汽车同步器齿套滑块槽的切削稳定性研究

简要介绍飞刀加工汽车同步器齿套滑块槽时存在的弊病,分析了导致切削颤振的原因.测量了飞刀加工时的主切削力,并以此建立其数学模型;通过改变进给量及切削速度的方法改着了切削振动,提高了生产质量和生产效率.     

汽车同步器齿套摆线加工数控机床结构总体方案设计

将传统的汽车同步器齿套倒锥及滑块槽的几种加工方法，与用摆线逼近法加工汽车同步器齿套倒锥及滑块槽的加工方法加以比较，阐明了这种新方法产生的背景和优势；介绍了用摆线加工滑块槽的原理；在此基础上设计了汽车同步器齿套摆线加工数控机床的总体结构；给出了机床的主要动力和运动参数，最后展望了这种方法的应用前景。     

滑动齿套拨叉槽的立方氮化硼刀具切削工艺试验研究

为了确定硬态切削代替磨削加工滑动齿套拨叉槽时各参数对其表面质量的影响,采用立方氮化硼刀具对20CrMnTi棒料进行切削,利用正交试验法对加工表面粗糙度进行了直观分析和方差分析,得出切削速度、进给量、背吃刀量对拨叉槽表面粗糙度的影响规律,并给出拨叉槽加工时合理的切削用量;同时也对加工过程中刀具的磨损进行分析,为滑动齿套拨叉槽的立方氮化硼切削工艺参数的选取提供了依据。     

基于有限元分析的汽车同步器齿套倒锥刀具安全校核

为了解决汽车同步器齿套的倒锥部分的表面加工问题,本文在分析传统加工缺陷的基础上,针对专用的摆线数控机床,从功能和结构上设计了加工倒锥部位的刀具.通过有限元对其进行强度、刚度及动力学模态的分析,并进行了安全校核.理论和实践证明该刀具是适用的.     

单点滑块油缸卡环槽机加新工艺

单点滑块油缸卡环槽的加工一般在数控立车上完成。如何在数控镗铣床上完成孔槽的加工并达到精度要求,本文通过理论实践探索,总结了一套工艺：先将滑块油缸部分尺寸焊前加工成品,然后对滑块油缸卡环槽用三面刃铣刀割出,再用铣刀精铣槽面,最后精镗油缸大孔至图纸要求。     

凹面齿圆柱蜗杆付蜗轮滚刀齿形的设计计算

鉴于目前加工凹面齿圈柱蜗杆的刀具只限于蜗轮飞刀的设计计算方法。本文提出蜗轮滚刀的设计计算方法,从滚刀参数的选择,滚刀齿形的检验,加工Ⅰ和Ⅱ型凹面齿圆柱蜗杆付蜗轮滚刀齿形的设计计算方法等方面论述,并建立了数学模型;最后举例验算了计算方法的正确性。可供设计蜗轮滚刀者参考。     

面齿轮车齿加工研究与试验验证

为了实现面齿轮的高精度、高效率加工,研究面齿轮的车齿加工技术。分析面齿轮车齿加工原理,建立刀具数学模型,根据车齿展成原理推导面齿轮的齿面及齿根过渡曲面方程。以配对渐开线圆柱齿轮共轭的面齿轮齿面作为基准齿面,构建车齿齿面的偏差齿面,分析不同刀具螺旋角、齿数和前角对车齿齿面的影响规律。使用YK2260MC数控车齿机床进行车齿加工,使用格里森650GMS齿轮检测中心,进行齿面误差检测。结果表明：左侧齿面和右侧齿面的误差最大分别为14.7、14.1 μm,验证了所提车齿加工数学模型的正确性,为提高面齿轮的加工精度和效率,进一步改进面齿轮车齿工艺提供了参考。     

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.