堆焊技术在板带热连轧机支承辊上的应用

本文介绍堆焊技术在热连轧机支承辊再利用方面的试验和应用,叙述了堆焊材料的选择,堆焊工艺以及取得的效果和经济效益。     

精密力源多维模糊控制的探讨

针对比对式测力机源系统力值自动调节中存在参数变化的变速扰动环节和滞后量变化的滞后环节,从而给自动调节带来很大难度的问题,采用多维模糊模型进行预测和采用多维模糊控制作为调节的算法。有效地消除了扰动和滞后的影响,实现了高精度的力值调节控制。     

QAD-CGA—改进型组合几何点核程序

通过扩大 QAD-CG 程序的核数据库,克服了 QAD-CG 程序一次只能计算一个辐射源和选用一种积累因子的局限性,不仅形成了 QAD-CGA 版本,而且更加适应工程设计需要。     

FREQUENCY DEPENDENCE IN DIELECTROPHORESIS: TRAJECTORIES AND PARTICLE BUILDUP

A study of the effect of frequency of a sinusoidal field on dielectrophoretic capture is presented, using numerical analysis to compute particle trajectories. It is shown that at certain critical frequencies the trapping efficiency drops sharply due to weakening of the dielectrophoretic pull. Experiments in which the capture performance was visually recorded by photographing the particle buildup on a single rod at increasing frequencies are reported. Results are discussed in the light of the numerical analysis.     

炭黑和白炭黑对全钢载重子午线轮胎胎面胶生热和动态力学性能的影响

在全钢载重子午线轮胎胎面胶中加入不同用量炭黑N234,并将白炭黑与炭黑并用,考察炭黑用量和添加白炭黑对胶料性能的影响。结果表明:随着炭黑N234用量增大,不添加白炭黑的胶料Fmax和门尼粘度增大,门尼焦烧时间呈缩短趋势;密度、硬度和定伸应力提高,拉伸强度和回弹值降低,撕裂强度先提高后降低,耐磨性能提高,生热增大,炭黑用量不宜过大;在填料用量相当的条件下,添加白炭黑的胶料门尼粘度较小,门尼焦烧时间较短,撕裂强度和耐磨性能显著提高,生热明显降低;随着炭黑用量增大,不添加白炭黑的胶料弹性模量和损耗因子总体提高;总体来看,添加45份炭黑N234和10份白炭黑的胎面胶滞后损失和生热较低。     

Wind tunnel test of an unmanned aerial vehicle (UAV)

A low speed wind tunnel test was conducted for full-scale model of an unmanned aerial vehicle (UAV) in Korea Aerospace Research Institute (KARI) Low Speed Wind Tunnel (LSWT). The purpose of the presented paper is to illustrate the general aerodynamic and performance characteristics of the UAV that was designed and fabricated in KARI. Since the testing conditions were represented minor portions of the load-range of the external balance system, the repeatability tests were performed at various model configurations to confirm the reliability of measurements. Variations of drag-polar by adding model components such as tails, landing gear and test boom are shown, and longitudinal and lateral aerodynamic characteristics after changing control surfaces such as aileron, flap, elevator and rudder are also presented. To explore aerodynamic characteristics of an UAV with model components build-up and control surface deflections, lift curve slope, pitching moment variation with lift coefficients and drag-polar are examined. The discussed results might be useful to understand the general aerodynamic characteristics and drag pattern for the given UAV configuration.     

工程机械零件堆焊修复实例

一些工程机械零件在使用或加工过程中常常由于局部磨损、损伤和加工缺陷等原因而不能使用,损失相当大,若使用手工电弧焊堆的方法将这类损坏报废的零件及时修复,则不仅满足了使用的急需,而且能节约大量成本。     

中日20MN力基准机的力值比对

介绍并讨论中日两国在世界上首次进行的，力值上限达２０ＭＮ的大力值国际比对。比对结果表明，两国大力值一致性的水平为：在６ＭＮ以下，保持在±３．０×１０－４以内；在６ＭＮ到２０ＭＮ范围，保持在±１．５×１０－４以内     

卷取机夹送辊表面堆焊层组织性能研究

采用埋弧堆焊工艺在Q235B表面堆焊8-10mm的Cr8系列新型熔覆材料,测定其耐磨性和硬度变化,分析熔覆金属的组织形貌和高温工况下的合金元素扩散。研究结果表明,熔覆金属打底层主要是以铁素体为主,伴随着少量的贝氏体。盖面层的焊态组织主要为马氏体和残余奥氏体,伴有少量的回火马氏体,同时在枝晶马氏体间可见少量较小的碳化物。经550℃回火后其盖面层组织为回火马氏体和残余奥氏体,碳化物析出相均布较焊态呈增多趋势。焊态硬度值为530-580HV300,回火后硬度值为720-830HV300,磨损失重是45#淬火钢的0.31倍。在使用3个月后发现在熔覆层表面出现了元素偏移并形成了由Cr2O3、WO等组成的氧化膜,降低了夹送辊的粘钢倾向,提高使用寿命。     

工频有芯感应镀锌炉采用预制熔沟在液态下的修复

介绍了装配式预制熔沟工艺的特点及施工方法。采用该工艺不停电液态检修工频有芯感应固态起熔镀锌炉感应器,具有简便、安全、快速等优点。