超低速、大扭矩、宽调速电液伺服马达的综合分析

本文对超低速、大扭矩、宽调速电液同服马达进行了理论及实验研究。用辨识技术建立了该马达的教学模型,指出该马达的线性化适用范围,并对其动特性进行了全面的分析。同时提出该马达的测试标准问题。     

木材厂自动检尺及管理系统研究

本文介绍了新近研制成功的,利用CCD对木材尺寸进行动态测量的仪器,该仪器连同上级机组成了一个木材厂自动化管理系统。它在测试技术、信号处理及数据处理等方面都具有明显的特点,而且测量仪器具有较高的精度,适合工业现场使用。     

具有广义位移参数试解的杂交应力板单元

本文通过使用广义位移参数建立位移变量的新方法,推出了常力矩和线性力矩杂交应力三角形板单元。并且沿着两个单元的公共边界,将线性力矩单元的有关广义位移参数置零,能够使两个不同阶次的单元互相匹配。     

赤峰市暴雨强度公式的推导

根据赤峰地区的22年降雨资料和气象资料,对该市的暴雨强度公式进行了推导,使该市在设计雨水管道工程方面有一个完整的计算公式.     

直流自动协调系统的数字计算机辅助分析方法

由数字计算机对直流自动协调系统所做的辅助分析,其方法简单且具有较好的实用性.本文介绍了根据观测器原理设计的直流自动协调系统,阐述了数字计算机对该系统进行的辅助分析的具体方法.     

SiC涂层碳纤维增强铝复合丝的机械性能及其界面特性

研究了不同热处理温度对碳化硅涂层碳纤维增强铝复合丝的拉伸强度影响,结果表明:500℃热处理2h及550℃热处理1h后使复合丝的拉伸强度提高,600℃以上的热处理都使复合丝的拉伸强度下降,通过测量从复合丝中分离出来的纤维强度,表明碳化硅涂层对碳纤维具有良好的保护作用,用电子探针及能量损失谱分析了C/Al界面的稳定性。     

ON THE PRIMARY η-PHASE IN A HIGH-Ti Ni-Fe-Cr BASED SUPERALLOY

The precipitation and dissolution together with their control of the primary η-phase in ahigh-Ti Ni-Fe-Cr base superalloy have been investigated.The precipitation of primaryη-phase was found to be closely related to Ti or Al content and solidification rate of the alloy.The aggregation of blocky η-phase may remarkably reduce the tensile strength,ductility andrupture life of the alloy.The temperature-time relation of dissolution of the primary η-phaseobeys T=1370-86.1 lgt for as-cast superalloy.The formation of primary η-phase may beprevented by the reasonable control of Ti or Al content and smelting process.The adoption oftreatment under large hot deformation and homogenization may be the remedy forunfavorable influence of η-phase.     

EFFECT OF MICROSTRUCTURE ON MECHANICAL PROPERTIES OF INCOLOY 907

Effect of microstructure on the mechanical properties of a precipitation strengtheningFe-Ni-Co based low expansion alloy,Incoloy 907.has been investigated under different heattreatments.The dispersed γ-phase is found to be the principal strengthening phase in thealloy.The microstructure of the alloy with even dispersed fine γ′-phase seems to have the bestmechanical properties.However,it will be worsened if the alloy was aged at some higher tem-perature or overaged to precipitate needle-like ε-phase.     

MICROSTRUCTURE AND CORROSION RESISTANCE OF LASER SURFACE ALLOYING PLASMA SPRAYED Cr-Mo COATING

The precipitation of χ-phase,σ-phase and carbides may be restrained or eliminated by lasermelting the plasma sprayed Cr-Mo alloy coating,in which austenite of abundant block usual-ly occurred on medium carbon low alloying steels.The corrosion resistance of this coating to0.5mol/L H_2SO_4 was examined to be superior to that of 18-8 stainless steel.The laser al-loying Cr-Mo coating also has excellent resistance to pitting corrosion,and no pitting ap-peared even it immersed in a medium containing Cl~- ions.     

INFLUENCE OF RESIDUAL STRESS AND SURFACE MORPHOLOGY ON FATIGUE PROPERTIES OF STEEL 60Mn

Influence of residual stress and surface morphology induced by shot-peening on fatigue behav-ior of a medium temperature tempered spring steel 60 Mn has been studied.The compressiveresidual stress induced in the near-surface region may improve fatigue limit from 930 to 1010MPa,and the very high tensile residual stress in the interior may reduce it from 1010 to 940MPa,whereas the severe surface damage may cause a drop-off of it from 1010 down to 800MPa.Fatigue cracks initiated in such position where the equivalent Mises stress,includingresidual stress,exceeded the local strength of the material.The compressive residual stress,induced by shot-peening,may intensify the effect of crack closure,so as to decrease the crackgrowth rate.