灰色系统建模理论在机床主轴疲劳寿命设计中的应用研究

运用灰色系统的理论及方法，将疲劳应力与寿命的相互制约关系看成一个灰色系统，将疲劳试验的应力水平均匀分成数级，并找出与之对应的安全寿命的白化值。通过对安全寿命值数列的一次累加，生成一个光滑离散函数。据此建立灰色系统模型，并求解灰色系统的微分方程 。通过残差模型的修正，提高模型精度，再运用灰色系统模型的还原模型，可计算出任一应力水平下的安全寿命值。为机床主轴的安全寿命计算提供了新的途径，具有较大的推广应用价值。     

机床圆柱结合部的动态特性解析方法

在机床图纸设计阶段，预测机床整机的动态特性具有十分重要的意义，进行机床整机动态特性预测的难点在于如何确定结合部的刚度和阻尼参数，本文以机床结构中应用较普遍的圆柱结合部为例，研究了基于结合面基础特性参数的圆柱结合部动态特性解析方法，并编制相应解析软件，给出应用实例，证明本文的方法及软件是正确的。     

机床电力拖动脉冲宽度调制技术的研究

本文重点介绍用于机床电力拖动系统中的电机脉冲调制(PWM)技术，在分析现有脉冲宽度调制技术的基础上，提出一种采用优化技术生成PWM调制波的方法，推导了优化PWM调制波的求解过程，给出了其计算公式。     

吹喷氧化物质点改善铁基合金的高温耐磨性

为了节省能源,国内外广泛开展了煤的流化床燃烧技术的研究。然而,流化床中埋管材料及其上面所焊鳍片材料耐高温磨蚀性能的提高,是推广这一技术的关键。采用共沉法或机械合金化方法已成功地制成氧化物弥散强化高温合金,不仅高温强度可以维持到合金的熔点附近,而且可以改善高温耐磨性,但这类合金制造工艺复杂、成本高,不适宜大量用于能源工业。向钢水中吹喷氧化物质点可以明显提高镇静钢的室温和高温强度,而且价     

超音速微粒轰击表面纳米化及其对耐磨性的影响

采用超音速微粒轰击技术对20钢进行表面纳米化处理。研究了表面纳米化工艺对材料流失与形貌变化的影响，并采用往复磨损试验机研究了纳米化表面的磨损性能。结果表明：超音速微粒轰击在表面形成纳米层过程中使材料发生流失和表面粗糙度增大。在干摩擦和油润滑条件下，微粒轰击样品的磨损率分别是未轰击样品的2．77和1．83倍，轰击抛光样品的磨损率则比未轰击样品分别降低了26％和42％。对其影响耐磨性的原因作了初步讨论。     

机床的静压系统及润滑

对机床的静压系统及其发展过程进行了综述 ,介绍了静压系统的基本结构、特点及其在机床中的各种运用。     

Characterization and wear behavior of modified silicon nitride

Silicon nitride-based materials are applied to many tribological components because of their superior thermal and mechanical properties and corrosion resistance. The purpose of this study is to investigate the wear performance of modified silicon nitride which contained 3 wt.% La₂O₃ and 3 wt.% Y₂O₃. The relationships between microstructure and mechanical properties have been also addressed. Vickers microhardness and toughness were measured, the later being determined by means of the direct crack measurement method (DCM). Scanning electron microscopy technique (SEM) coupled with energy dispersive X-ray spectroscopy (EDS) was used for the morphological characterization of the samples as well as for the characterization of the wear scars. Wear properties were studied under a load of 10 N by using the ball-on-disk tribometer. AISI 52100 steel balls and balls of WC + 6% Co (6 mm diameter) were used as static counterparts, respectively. Steady state friction coefficients of 0.66 and 0.62 were measured for the tribological pairs WC + 6 % Co/Si₃N₄ and AISI 52100/Si₃N₄, respectively. The wear mechanism was determined in each case, and comparison between the wear performance of the traditional and modified silicon nitride is also presented.     

Microstructure and Sliding Wear Behaviour of Ni(Cr)-TiB_2 Coatings Deposited by HVOF Spraying of SHS Powders

THERMAL SPRAYING provides a large range ofcoatings,which increase the wear resistance ofsubstrates[1].One of the major coating families is thecermet,composed of hard ceramic particles with ametallic binder.The most commonly used cermetcoatings in industrial applications are based on eitherthe WC-Co or the Cr3C2-Ni(Cr)systems with WC-17wt%Co and Cr3C2-25wt%Ni(Cr)being typicalcompositions[2,3].Although WC-Co deposits are hardand wear resistant at ambient temperatures their rangeof ap…     

Wear resistance of ceramic coating on AZ91 magnesium alloy by micro-arc oxidation

The ceramic coating formed on AZ91 magnesium alloy by micro-arc oxidation （MAO） was characterized. The results show that the ceramic coating （3.4-23 μm in thickness）on the surface ofAZ91 alloy was attained under different micro-arc oxidation treatment conditions, which consist mainly of MgO, Mg2SiO4 and MgSiO3 phases. Nano-hardness in a cross-sectional specimen was determined by nano-indentation experiment. The MAO coatings exhibit higher hardness than the substrate. Dry sliding wear tests for the MAO coatings and AZ91 alloy were also carded out using an oscillating friction and wear tester in a ball-on-disc contact configuration. The wear resistance of the MAO coatings is improved respectively under different treatment time as a result of different structures of ceramic coatings formed on AZ91 alloy.     

X6125铣床数控化改造

通过对我院教学实习基地的一台X6125铣床结构和性能的研究，针对盘式凸轮加工的特点，并结合现有条件，确定了铣床的数控化改造方案，介绍了滚珠丝杠、步进电动机的选择设计以及数控系统软硬件的设计。改造后的铣床可提高生产效率，保证产品质量和减轻工人的劳动强度。