Contact Mechanism of Rail Grinding with Open-Structured Abrasive Belt Based on Pressure Grinding Plate

The current research of abrasive belt grinding rail mainly focuses on the contact mechanism and structural design.Compared with the closed structure abrasive belt grinding,open-structured abrasive belt grinding has excellent performance in dynamic stability,consistency of grinding quality,extension of grinding mileage and improvement of working efficiency.However,in the contact structure design,the open-structured abrasive belt grinding rail using a profiling pressure grinding plate and the closed structure abrasive belt using the contact wheel are different,and the contact mechanisms of the two are different.In this paper,based on the conformal contact and Hertz theory,the contact mechanism of the pressure grinding plate,abrasive belt and rail is analyzed.Through finite element simulation and static pressure experiment,the contact behavior of pressure grinding plate,abrasive belt and rail under single concentrated force,uniform force and multiple concentrated force was studied,and the distribution characteristics of contact stress on rail surface were observed.The results show that under the same external load,there are three contact areas under the three loading modes.The outer contour of the middle contact area is rectangular,and the inner contour is elliptical.In the contact area at both ends,the stress is extremely small under a single concentrated force,the internal stress is drop-shaped under a uniform force,and the internal stress under multiple concentration forces is elliptical.Compared with the three,the maximum stress is the smallest and the stress distribution is more uniform under multiple concentrated forces.Therefore,the multiple concentrated forces is the best grinding pressure loading mode.The research provides support for the application of rail grinding with open-structured abrasive belt based on pressure grinding plate,such as contact mechanism and grinding pressure mode selection.

不烧滑板磨削加工用Fe-Ni-Cu-Sn金属基金刚石工具的制备与性能

Al_(2)O_(3)-C不烧滑板作为连铸功能耐火材料在炼钢领域中受到广泛应用,而金属结合剂金刚石工具在滑板磨削加工中起到关键作用。本工作通过热压烧结法制备Fe-Ni-Cu-Sn金属基胎体和Fe-Ni-Cu-Sn金属基金刚石工具,首先研究烧结温度、保温时间和烧结压力对金刚石工具胎体力学性能的影响,获得优化的胎体烧结工艺参数并为后续制备金刚石工具奠定基础;其次研究不同的金刚石磨料对金刚石工具力学性能及磨削不烧滑板性能的影响,通过研究金刚石的浓度、粒度、品级与加工工具磨削效率、寿命及锋利度的关系,从而得到磨削加工不烧滑板的金刚石工具中金刚石磨料的优化参数,通过SEM对金刚石工具表面胎体与金刚石磨料的结合状态、金刚石的磨损情况进行表征。实验结果表明:金刚石工具胎体的最佳烧结工艺参数是烧结温度、烧结压力和保温时间分别为785℃、170 MPa、240 s;金刚石工具中的金刚石磨料最优选择为金刚石浓度25%、粒度45/50、品级SMD35。

Study on magneto-elastic-plastic deformation characteristics of ferromagnetic rectangular plate with simple supports

In this paper, the magnetic-elastic-plastic deformation behavior is studied for a ferromagnetic plate with simple supports. The perturbation formula of magnetic force is first derived based on the perturbation technique, and is then applied to the analysis of deformation characteristics with emphasis laid on the analyses of modes, symmetry of deformation and influences of incident angle of applied magnetic field on the plate deformation. The theoretical analyses offer explanations why the configuration offer- romagnetic rectangular plate with simple supports under an oblique magnetic field is in-wavy type along the x-direction, and why the largest deformation of the ferromagnetic plate occurs at the incident angle of 45°for the magnetic field. A numerical code based on the finite element method is developed to simulate quantitatively behaviors of the nonlinearly coupled multi-field problem. Some characteristic curves are plotted to illustrate the magneto--elastic-plastic deflections, and to reveal how the deflections can be influenced by the incident angle of applied magnetic field. The deformation characteristics obtained from the numerical simulations are found in good agreement with the theoretical analyses.

Influences of Al and Si Powders on Microstructure and Hot Mechanical Properties of Al_2O_3-C Slide Plates

The basic formulation of Al2O3- C slide plates was65%（ in mass,the same hereinafter） white fused corundum particles,25% white fused corundum fines,6% active α-Al2O3 micropowder,4% carbon black and flake graphite, and additional 4% phenolic resin.Based on this formulation,3% Al powder,3% Si powder,and 3% Al ＋ 3% Si powder were used to substitute equivalent white corundum fines to improve the hot mechanical properties of Al2O3- C slide plates. The specimens with dimensions of 140 mm × 25 mm × 25 mm were pressed at 150 MPa,dried at 200 ℃ for 24 h,and hot treated at 1 400 ℃ for 3 h in carbon embedded condition. Then hot modulus of rupture and thermal shock resistance of the specimens were tested and the phase compositions and microstructure were analyzed. The results show that specimen with 3% Al powder has the higher hot modulus of rupture but lower residual modulus of rupture after thermal shock than the specimen with3% Si powder; the specimen with 3% Al ＋ 3% Si powders exhibits the highest hot modulus of rupture and the best thermal shock resistance; the change of mechanical property is closely related with the in-situ formed nonoxides： AlN in the form of bars is formed in specimens with Al powder; fibrous SiC whiskers are formed in specimens with Si powder; in the specimens with both Al and Sipowders,besides AlN and SiC whiskers,hexagonal tabular SiAlON is in-situ synthesized,which interlocks with each other.

The Influence of Preheat Temperature of Steel Plate on Steel-mushy Cu-graphite Bonding

The pressing bonding of steel plate to QTi3.5-3.5 graphite slurry was conducted. Under the conditions of 530 ℃ for the preheat temperature of dies, 45% for the solid fraction of QTi3.5- 3.5 graphite slurry, 50 MPa for the pressure and 2 min for the pressing time, the relationship between the preheat temperature of steel plate and interfacial mechanical property of bonding plate was studied. The results show that when the preheat temperature of steel plate is lower titan 618 ℃ , the interfacial shear strength of bonding plate increases with the increasing of the preheat temperature of steel plate. When the preheat temperature of steel plate is higher than 618 ℃ , the interfacial shear strength decreases with the increasing of the preheat temperature of steel plate. When the preheat temperature of steel plate is 618 ℃ , the highest interfacial shear strength of bonding plate of 127.8 MPa can be got.

基于交变磁场辅助磁力研磨中永磁极优化试验

钛合金是新兴的结构和功能材料,TC4钛合金表面的精密加工依旧是个难题。为提高钛合金表面质量,在交变磁场磁粒研磨加工中进一步优化了永磁极的排列方式。利用有限元软件分别对未优化的交变磁场以及优化后的交变磁场进行模拟分析对比,再通过试验对比优化前后的几个交变磁场下,磁粒研磨加工TC4钛合金的表面形貌和表面粗糙度的变化情况。研究表明:在未优化交变磁场下磁粒研磨加工10 min,磁粒研磨加工工件的表面粗糙度从1.28μm降至0.38μm;在优化后磁场强度最大的交变磁场作用下,磁粒研磨加工工件的表面粗糙度从1.28μm降至0.13μm。在辅助磁粒研磨过程中,优化后的交变磁场不仅提高了加工区域内的磁感应强度,而且磁性磨粒研磨轨迹更加复杂,促进了磁性磨粒的更新,使加工后工件的表面形貌更加平整。用优化后的交变磁场辅助磁粒研磨TC4钛合金表面,提高了研磨效率,进一步提高了工件的表面质量。

陶瓷水阀片自动上料单面研磨系统设计

针对传统陶瓷水阀片单面研磨工艺过度依赖人工的弊端和环保问题,设计一种自动上料单面研磨系统。该系统通过导入槽将被震动斗翻面后的陶瓷水阀片有序嵌入研磨行星轮。在主轴电机的带动下,研磨限位轮条将陶瓷水阀片进一步卡紧并限位,避免陶瓷水阀片在研磨过程中发生窜动。该系统实现了陶瓷水阀片自动上料研磨,有效解决了传统陶瓷水阀片生产过程中的问题,提高了生产效率与精度,同时有利于生产工艺的标准化。

采用CBN砂轮磨削气缸体Ni-SiC复合镀层

与离子溅射、火焰溅射、CVD等方法相比较,采用电沉积方法形成的复合镀层有着非常优越的性能,但同时复合镀层的精密加工亦成为制约其性能发挥的关键。某小型航空发动机气缸体中由于有Ni-SiC复合镀层,其内孔磨削的难加工是制约该型号发动机性能的关键工艺。针对该缸体的特殊结构及镀层特点,文中采用合理的装夹方式及磨削工艺参数,在精密内圆磨床上采用陶瓷结合剂CBN砂轮实现了对Ni-SiC复合镀层内孔的磨削。实践证明,该工艺方法解决了Ni-SiC弥散复合镀层的精密加工难题,提高了加工效率,改善了表面尺寸形状精度和表面粗糙度。

水轮发电机组镜板研磨装置的优化改进

镜板是水轮发电机组推力轴承的心脏部件,它的质量直接关系着水轮发电机组的安全运行,理想光滑的镜板与推力瓦配合是机组安全稳定运行的关键因素。在发电机组的A级检修过程中,使用镜板研磨装置对镜板面实施研磨和抛光处理,以使粗糙度、光洁度、表面硬度和波浪度达到相关技术要求,但相关研磨装置已使用近十年,在检修现场已暴露出一些不足,不能完全贴合使用需求。通过对现有镜板研磨装置各类问题分析,提出相应优化措施,成功设计并制作了一套高效、精准、安全的研磨装置。

抽水蓄能电站在役高强螺栓质量安全检测技术研究

对抽水蓄能电站机组在役高强螺栓质量安全检测技术进行了研究,提出了对螺栓内部质量超声波相控阵检测和超声波法检测螺栓轴向应力相结合的技术方法。采用相控阵检测螺栓内部质量能够精确地发现螺栓对比试样中的四个人工刻槽缺陷,采用超声波法检测螺栓轴向应力,检测精度误差在±2%以内,具有很高的检测精度。通过试验和数据分析结果表明,该检测方法能够快速地实现对水工金属结构在役高强螺栓的质量检测排除安全隐患,具有很高的工程应用价值。

泗阳站4#上机架镜板电蚀现象分析

该文旨在探讨水利工程中上机架镜板电蚀现象的成因及解决方案,以提升水利工程的安全性和运行效能。通过对镜板电蚀现象的机理分析,明确溶解腐蚀、电化学腐蚀和结构等因素综合导致电蚀现象的发生。研究方法包括现场实测、材料特性分析和电化学原理探讨,对泗阳站4#机组镜板进行深入研究。结果显示,电蚀现象会导致镜板表面受损,增加安全隐患,加重经济负担,并缩短使用寿命。为改善这种情况,该文采用针对性的解决措施,如选用抗蚀材料替换原有镜板材质,设计专门的镜板吊装翻转流程,采用研磨台精细化研磨处理,以及制定严格的定期维护和检查制度。经过这些技术改造与维护策略的实施,泗阳站4#机组的镜板电蚀现象得到有效控制,提高镜板工作面的质量要求,确保镜板与推力头间绝缘电阻值高于40 MΩ,导轴瓦与瓦背间电阻值高于50 MΩ,并符合设计粗糙度要求。综合来看,该研究提出的解决方案为类似水利工程中镜板电蚀问题的防治提供有价值的参考案例。

HRM3400B生料立磨的节能改造

某5000t/d水泥熟料生产线HRM3400B生料立磨系统存在耗电量高、阻力大、运行效率低、入磨物料综合水分高、系统漏风点多、漏风量大等问题。通过优化旋风筒进风口结构,加高旋风筒进风口及上壳体,加长旋风筒内筒,新增热风管道,增大入磨溜子角度,在排渣皮带机尾部增设缓冲箱,将磨辊密封罩更换为内部迷宫式新型密封罩,拆除旋风筒下部压力铰刀并更换为无动力翻板阀,将收尘器气缸全部更换为不锈钢材质等措施,生料立磨磨机压差降低183Pa,在线窑尾废气氧含量降低1.8%~2.0%,磨机电耗由16.33kW∙h/t降至13.70kW∙h/t,有效降低了生产成本,改造效果显著。

Vibration coupling effects and machining behavior of ultrasonic vibration plate device for creep-feed grinding of Inconel 718 nickel-based superalloy

Ultrasonic vibration-assisted grinding(UVAG)is an effective and promising method for machining of hard-to-cut materials.This article proposed an ultrasonic vibration plate device enabling the longitudinal full-wave and transverse half-wave(L2T1)vibration mode for UVAG.The characteristics of two-dimensional coupled vibration in different directions were analyzed on the basis of apparent elastic method and finite element method.Furthermore,a correction factor was applied to correct the frequency error caused by the apparent elastic method.Finally,the comparative experiments between the conventional creep-feed grinding and UVAG of Inconel 718 nickel-based superalloy were carried out.The results indicate that the apparent elastic method with the correction factor is accurate for the design of plate device under the L2T1 vibration mode.Compared with the conventional creep-feed grinding,the UVAG causes the reduction of grinding force and the improvement of machined surface quality of Inconel 718 nickel-based superalloy.Furthermore,under the current experimental conditions,the optimal ultrasonic vibration amplitude is determined as 6μm,with which the minimum surface roughness is achieved.

Study of Single Plated Principle on Large Diameter Circular Weft Knitting Machine

A new theory and method that differs from the tradition-al single plated weft - knitting theory and method hasbeen expounded after theoretical analyzing and experi-mental proving. If the new method is used when platingstitch is knitted on large diameter weft knitting machine,the thorny problem of long standing that ground yarn iseasy to appear on the face side of fabric is solved. Thenew method, i.e, the production of physical ability oftraining uniform for serviceman has been used.

Thermo-mechanical Properties of In-situ Formed Al_2O_3-SiC-SiAION Composites

Al2 O3 - SiC - SiAION composite specimens have been prepared using fused alumina, ultra fine α-Al2O3, Si and Al powders as starting materials and liquid phenol formaldehyde resin as binder and firing at 1 500 ℃ for 3 h in carbon embedded condition. Thermo-mechanical properties of Al2 O3 - SiC - SiAlON composites have been studied. The results show ： （ 1 ） Al2 O3 - SiC - SiAION composites can be prepared and sintered at 1 500 ℃ under carbon embedded condition. When Si/Al ratio is 8/0 and 7/1, the prepared composite is Al2O3 - SiC - O＇ -SiAlON; when Si/Al ratio is 5/3 and 3/5, the pre- pared composite is Al2 O3 - SiC - β-SiAION. （ 2 ） The composites possess high temperature strength properties. Hot modulus of rupture at 1 400 ℃ is 10 - 30 MPa. They are in elastic range up to 1 000 ℃, after which plastic deformation is observed; even at 1 400 ℃, amount of deformation is relatively low. （3） The com- posites possess good thermal shock resistance, their resid- ual strength ratio （AT = 1 100 ℃ ） is 65% - 80%. （4） The marked improvement in thermo-mechanical properties of Al2O3 - SiC - SiAlON composites may be at- tributed to the in-situ formation of SiC, SiAlON and AIN, the fibrous SiC, columnar SiAlON and tabular-like AlN fill in the corundum skeleton structure creating strengthening and toughening effects.

Dynamics of cantilever plates and its hybrid vibration control

Applying Lagrange-Germain＇s theory of elas- tic thin plates and Hamiltonian formulation, the dynamics of cantilever plates and the problem of its vibration control are studied, and a general solution is finally given. Based on Hamiltonian and Lagrangian density function, we can obtain the flexural wave equation of the plate and the relationship between the transverse and the longitudinal eigenvalues. Based on eigenfunction expansion, dispersion equations of propagation mode of cantilever plates are deduced. By satisfying the boundary conditions of cantilever plates, the natural frequencies of the cantilever plate structure can be given. Then, analytic solution of the problem in plate structure is obtained. An hybrid wave/mode control approach, which is based on both independent modal space control and wave control methods, is described and adopted to analyze the active vibration control of cantilever plates. The low-order （controlled by modal control） and the high-order （controlled by wave control） frequency response of plates are both improved. The control spillover is avoided and the robustness of the system is also improved. Finally, simulation results are analyzed and discussed.

Application of color structured light pattern to measurement of large out-of-plane deformation

Measurement of out-of-plane deformation is significant to understanding of the deflection mechanisms of the plate and tube structures.In this study,a new surface contouring technique with color structured light is applied to measure the out-of-plane deformation of structures with one-shot projection.Through color fringe recognizing,decoding and triangulation processing for the captured images corresponding to each deformation state,the feasibility of the method is testified by the measurement of elastic deflections of a flexible square plate,showing good agreement with those from the calibrated displacement driver.The plastic deformation of two alloy aluminum rectangular tubes is measured to show the technique application to surface topographic evaluation of the buckling structures with large displacements.

Rapid Expansion of Supercritical Solution of Poly (1,1,2,2- Tetrahy-droperfluorodecyl Acrylate)

Poly(1,1,2,2- tetrahydroperfluorodecyl acrylate) (poly (TA-N)) was synthesized in laboratory. The resulting morphology of rapid expansion of supercritical solution (RESS) sprays of poly(TA - N) was investigated. At apre - expansion temperature of 45℃), amorphous polymer was formed. At temperature around 60 ℃ to 80 ℃ , fibers were formed. Increase of temperature increasesparticle size slightly. At temperature of 105℃ , most of particles are spheres. The RESS is an attractive process. To apply the polymers desired for coating applications in an organic solvent - free process that is economically viable , and it will have implications for pollution prevention during polymer film

Multichip on Aluminum Metal Plate Technology for High Power LED Packaging

Multichip on Ahnnintnn Metal Plate（MOAMP） technology with simple structure and low thermal resistance is developed for effective heat reratrval of Light Emitting Diode（LED） p-n junction and LED lighting module to have high reliability. The thermal resistance of LED modules was numerical and experimental. Thermal resistance from the jtnction to aluminten metal plate, considering input power of IFD module using MOAMP technology, is 3.02 K/W, 3.23 K/W for the measured and calculated, respectively. We expect that the reported MOAMP technology with low thermal resistance will be a promising solution for high power LED fighting modules.

利用滑板磨制粉制备转炉挡渣Al2O3-C外水口砖

为了合理利用滑板磨制粉,节约资源,并降低转炉挡渣外水口砖的生产成本,以白刚玉颗粒和细粉、片状石墨、SiC细粉、α-Al2O3微粉、镁铝合金复合抗氧化剂为原料,加入质量分数分别为0、5%、10%、15%的滑板磨制再生粉(粒度≤0.045 mm),并以液体热固性酚醛树脂和固体树脂粉为结合剂,对比研究了经200℃固化和1 300℃埋焦炭热处理后试样的体积密度、显气孔率、常温抗折强度、常温耐压强度和抗热震性能。结果表明:引入滑板磨制再生粉后,试样经1 300℃热处理后的体积密度和显气孔率有所下降,常温耐压强度、抗折强度小幅下降,抗热震性变化不大。生产的转炉外水口砖在江苏某钢厂的100 t转炉使用15~17炉,平均每炉扩孔0.8~1.3 mm,满足了钢厂冶炼要求。