旋压机控制原理的分析与应用

分析了旋压瞬时主轴与成形辊及板材接触点的速度变化状态。首次成功地应用了力反馈控制原理，设计出恒功率自适应同步控制系统，从而满足了旋压过程中啮合点任意瞬时、任意位置的同步要求。     

一种新型的旋压辊装置设计

本文就FWX2 0封头旋压机旋压加工中啮合点处转速瞬间同步的必要性 ,提出了一种同步转速系统装置。实践证明 ,设计的旋压辊系统装置结构简单、合理、运行平稳     

强力旋压计算机辅助工艺设计

讨论了强力旋压工艺CAD／CAM系统设计中零件图的绘制、强力旋压毛坯尺寸设计计算、旋压道次划分等计算机辅助工艺设计问题。系统开发过程中采用B祥条曲线表示经验数据和道次曲线，借鉴模糊数学的思想，利用经验数据生成任意中间道次曲线，解决了旋压加工工艺设计的关键性技术难题，并给出了道次划分实例。为系统开发提供基本的强力旋压工艺设计方法。     

摩擦生热旋压成型加工

在车床加工中,旋压成型方法已被推广应用。但是,对于型面简单和壁厚较小的零件旋压时,冷旋法需多次旋压才能逐步成型;热旋法需要外加热源才能逐点成型。前者效率低,后者工艺复杂。所以,产生一种利用旋压工具和工件相互接触的摩擦生热旋压成型加工。高速旋转的工件同移动进给的型模相互接触,由于挤压力的作用,工件表面会产生很大的摩擦力,并在瞬时内形成900°左右的高温,使金属塑性     

一种新型刚性同步装置的研究与开发

基于对细长、厚壁、变断面工件的强力旋压机床的同步装置分析，提供了一种新型机械式刚性同步装置，从而使相应的设备造价、维修等成本降低，且同步性能稳定。     

圆柱螺旋板式换热器双螺旋板同步拉伸—旋压成型工艺

在圆柱螺旋板式换热器双螺旋板的加工中,采用压制法效率低、成本高,而一次性拉伸成型法又存在螺距误差与翘曲变形。文中提出了双螺旋板同步拉伸—旋压成型工艺,并就下料尺寸精确计算、起始螺距误差校正、三次拉伸与旋压校正等解决方案进行了详述。     

20t立式数控带轮旋压机床

该机床是制造钣制旋压皮带轮的专用设备。它采用微机数控和光栅位移检测系统,实现速度拟合以控制带轮的旋压过程,工艺调整方便,实现准确的重复定位和监测旋压过程,解决了控制带轮产品尺寸精度的难题。它采用特有的上、下主轴同步回转机构,解决了表面划伤和材料粘结的问题,保证了带轮的表面质量。它采用三工位旋轮     

强力旋压反旋自动跟踪装置

强力旋压是具有无切削、材料利用率高、表面光洁度好、尺寸精度高和能够细化晶粒、提高零件强度等优点的压力加工新工艺。强力旋压按金属轴向流动方向,又可分为正旋和反旋两种。在机械加工行业中,有大量不带底多台阶的薄壁筒形件或任意曲     

旋压机滚珠丝杠驱动进给速度和预紧相关性

在介绍全新的旋压成型技术-同步旋转模环旋压可根据张力驱动系统实现自适应的要求和特点基础上,提出了双驱动螺母旋转型滚珠丝杠副的进给方案;结合滚珠丝杠副的设计标准,初选了滚珠丝杠副的关键参数。通过对滚珠丝杠的预压和寿命进行分析,最终得出预紧力的大小取决于进给速度的大小的结论。     

有色金属(铝合金)旋压零件的工艺研究

阐述了旋压零件结构、材料及旋压工艺特点,并阐述了旋压工艺参数的选定、旋压设备的选型以及旋压零件质量的保证。     

不同温度下镍基单晶高温合金的低周疲劳性能

研究了Ni-Cr-Co-Mo-W-Ta-Nb-Re-Al-Hf-C系镍基单晶高温合金在不同温度(800,980℃)下的低周疲劳性能.结果表明:与800℃下相比,980℃下合金的塑性变形量更大,损伤更严重,疲劳强度更低,寿命更短;2种温度下合金的疲劳断裂均为类解理断裂;800℃时,裂纹萌生于疏松组织处,沿{111}平面扩...     

焊趾疲劳裂纹扩展统计模型

本文通过试验获得了焊趾疲劳裂纹扩展特性,应用概率统计方法建立了焊趾疲劳裂纹扩展的统计模型,分析了焊趾疲劳裂纹扩展的统计分布规律。     

X射线衍射测定经各种处理后粉煤灰物相组成的研究

将粉煤灰分别经如下条件处理:115℃烘干、700℃焙烧、700℃焙烧加硫酸(1+3)活化处理、700℃焙烧加入一定量碳酸钠(2+1)、700℃焙烧加入一定量碳酸钠(2+1)后经1000℃煅烧再加入硫酸(1+3)。将经处理后的粉煤灰进行X射线衍射(XRD)分析,分析其物相组成,了解经不同条件处理后粉煤灰的组成变化,从而防止粉煤灰资源的浪费,减少粉煤灰对环境的污染。     

Shear strength of ball studs according to the resistance welding conditions & reliability testing based on the weibull distribution function

As a kind of bolt having a spherical head, the ball stud is widely used as part of a ball joint in steering or suspension sys-tems of automobiles. Generally, the production process of ball studs consists of multi-step cold forging and screw making. This study evaluated the shear strength of joints by varying the welding current and welding pressure in the resistance welding of ball studs. The ball was made with SS400, and the stud was made with SCM435. The sample welded at current of 10.3 kA and welding pressure of 367.7 kPa was tested for its shear strength under different cooling methods. The room temperature cooling of the sample was left at about 293 K for 12 hours after heat treatment. The pressurized air cooling of the sample was subjected to a stream of air at pressure of 490 kPa for 7 seconds. Shear strength test was performed at room temperature with speed setting of 5 mm/min. The shear strength was analyzed by Weibull probability distribution. The scale parameter increased with increasing welding current at welding pressure of 367.7 kPa. The shear strength showed the least dispersion and distribution at welding current of 10.3 kA and welding pressure of 367.7 kPa.     

Particle erosion behaviour of boiler tube materials at elevated temperature

The particle erosion behaviour of typical boiler tube materials, including carbon steel, low alloy steels and austenitic steels, at elevated temperatures up to 650 °C was studied using irregularly shaped silica particles. Using 304 steel, the influence of various factors, namely particle concentration, velocity and impingement angle, was examined. The erosion behaviour did not seem to differ significantly from that obtained at room temperature. The erosion rate was a linear function of the particle concentration. The velocity exponents obtained at 300 and 650 °C were both approximately 2.8. The peak impingement angle was at acute angles of 20° – 30°, with a tendency for the peak angle to be slightly higher at 300 °C than at 650 °C. However, the temperature effect was clearly observed in that the erosion rate at acute impingement angles increased significantly with the temperature suggesting that the steel tends to show a behaviour more typical of ductile materials as the temperature is increased. The erosion morphologies at low angles indicated cutting for every temperature used and the lengths of the cutting tracks obtained at 20° also increased with temperature.The erosion rate varied significantly between materials, e.g. the alloy (Incoloy) 800 eroded the most and the 12Cr-1Mo-V steel eroded the least at every temperature used, although every material showed an increase in the erosion rate with temperature. From an attempt to compare the erosion rate data obtained at 20° for every material at every temperature with the tensile properties of the steels, it was found that the yield strength of materials correlates reasonably well with the erosion rate. The erosion rate was apparently proportional to the reciprocal of the yield strength, suggesting that the flow stress included in Finnie's cutting theory may be conveniently substituted by the yield strength multiplied by a constant.     

奥氏体不锈钢脉冲电流止裂处的晶间腐蚀性能及其评价方法

采用草酸电解浸蚀试验和恒电位极化试验研究了敏化处理前后304不锈钢脉冲电流止裂处的晶间腐蚀性能,得到适合评价裂纹止裂处晶间腐蚀性能的方法。结果表明:经脉冲电流止裂后,止裂处的凝固区、细晶区、形变马氏体区晶界处均未析出碳化物,而经恒电位极化后,晶界处的钝化膜完整,未发生晶间腐蚀;经草酸电解后,敏化试样止裂处不同区域的晶界处均发生了腐蚀,说明草酸电解法不能区分脉冲止裂后不同微区晶间腐蚀性能的差异;经恒电位极化后,敏化试样止裂处凝固区和细晶区晶界处的钝化膜稳定性较好,具有一定的耐晶间腐蚀能力,形变马氏体区发生了严重的晶间腐蚀;恒电位极化法是评价奥氏体不锈钢脉冲电流止裂处晶间腐蚀性能的一种有效方法。     

Contact Stress Distribution of a Pear Cam Profile with Roller Follower Mechanism

The problem of this paper is the high contact stress at the point of contact between the cam and the follower.A pear cam and roller follower mechanism were studied and analyzed for different position of the follower and different contact compression load.The objective of this paper is to study the effect of contact compression load on the contact stress distribution of the cam profile at the point of contact.Four different positions of the follower with the cam was considered(0°,90°,180°,and 270°).The theory of circular plate was applied to derive the analytic solution of the contact stress.The numerical simulation had been done using ANSYS Ver.19.2 package to determine the contact stress,while SolidWorks software was used to investigate follower displacement,velocity,and acceleration.Four distinct values of the compression contact load,such as 3.121 N,6.242 N,9.364 N,and 12.485 N,were used in the numerical simulation.In the experiment setup,a photo-elastic technique was carried out in the field of polarized light to exhibit the stress distribution on the cam specimen.The annealed PSM-4 backalate material was used in the experiment setup.The experimental value of contact stress was checked and verified analytically and numerically at the point of contact.The innovation in this paper the use of spring-damper system which reduce the value of contact stress at the point of contact.The contact stress was maximum 2.136 MPa when the follower located at 270° with the cam,while the contact stress was minimum 1.802 MPa when the follower located at 180°at compression load 12.485 N.     

渗铝层对一种定向凝固镍基高温合金拉伸性能的影响

研究了渗铝层对一种定向凝固镍基高温合金在不同温度下拉伸性能的影响。结果表明:在较低温度(<870℃),渗铝层使合金的拉伸强度和塑性有所降低,但降低的幅度较小;在1 030℃时对强度基本没有影响,但塑性明显降低;在较低的拉伸温度下,渗铝层脆性断裂引起的缺口效应是其拉伸性能降低的主要原因。     

非设计工况下斜流泵叶轮进出口环量变化分析

基于RNG k-ε湍流模型对斜流泵内部三维流场进行了数值计算,重点针对非设计工况下的斜流泵叶轮进出口环量分布特征进行了分析。研究结果显示,在设计点附近的叶轮进口环量受叶片进口边影响较大,不同采样线的环量分布具有一定差异,小流量工况下受到叶轮进口回流的影响,不同采样线的环量分布趋于一致。叶轮出口环量分布受采样线位置影响较小,在设计流量点时,叶轮出口呈等环量分布。在小流量工况点,受到叶轮出口回流的影响,叶轮出口外缘处的环量数值显著增大。通过研究还发现,从叶轮出口流道通过轮毂一侧回流进入叶轮的流体微团具有与叶轮旋转方向相反的圆周速度分量,其环量数值甚至低于同工况下的叶轮进口环量值。     

Variable thermal loading analysis on (111) plane of single crystal gold

The temperature response on the properties of single crystal gold (111) plane at elevated temperatures was considered in this work. The ability to perform nanoindentation experiments at elevated temperatures opens up significant new possibilities in nanotechnology. The experiments are performed at various temperatures of 373 K, 473 K and 573 K with tailor made Berkovitch tip of radius 100 nm to study the behavior of single crystal gold. The new phenomenon of material bouncing back under the indenter at the end of unloading was clearly noted, due to the accumulation of high energy. The results for different temperatures were compared. Our experiments clearly show the onset of the first burst of dislocation glide, which is indicated by a sudden increase of displacement with no increase of loading, the onset of plastic deformation in connection with the periodic bursts, and the strain hardening, softening and release effects. Pile up was also observed. The complete elastic range was found. There was significant drop in the hardness, elastic modulus and the increase in depth with increasing temperature. The elastic recovery was reduced at higher temperatures.