WEAR MECHANISMS DUE TO DIFFERENT ROCK DRILLING CONDITIONS

Abstract

Depending on the type of rock and on the drilling procedure used in rock drilling, cemented carbide is exposed to greatly differing mechanical and thermal conditions. These influence the properties of the cemented carbide required. By means of metallographical examination of rock drill inserts used under different conditions, it has been possible to determine what type of wear mechanism is critical in each case. Two kinds of mechanisms in particular were found to have a great influence on performance. When a drill is run under conditions of high mechanical stress and high temperature, which is the condition present when drilling in highly abrasive rocks, a major factor influencing performance is the creep resistance of the cemented carbide. One way of improving this property appears to be to increase the grain size. Percussive drilling in low-abrasive rock, where the mechanical stress is moderate, gives rise to another wear mechanism. In this, high thermal stresses are induced which lead to the formation of cracks and sometimes to rupture. Thus for this kind of application good thermal-crack resistance is important. During percussive drilling in rocks, with intermediate abrasivity, both mechanisms are active, making the choice of cemented carbide for this application more difficult.     

世界硅材料工业发展概况

文中以详尽的数据和事实分析了近几年世界半导体硅材料工业的发展及未来趋势。指出：欧、美、日各国的硅材料工业近几年产量增加、效益看好，仍然是各国的投资热点，大直径化的发展速度非常快，估计1998年Φ200mm硅片的产量将达到380万片／月，而且Φ300mm和Φ400mm硅片的研制已经在国际大协调的局面下启动。与此相适应，为了满足亚微米器件的需求，硅片的质量水平也在不断提高，从世界各地区的发展趋势看，存在着明显的不平衡，亚太地区显著地优于其他地区，此外，对多晶硅的大量需求与多晶硅生产能力不足的矛盾正成为硅材料工业发展的瓶颈，估计这种局面要到1997年后才能有所改观。     

美国及日本浸渍成型（Dig Forming）设备概况

详细介绍了美国及日本生产无氧铜杆的浸渍成型设备及工艺流程。该法整个过程均封闭在保护气氛中进行，采用自动控制。优点是设备占地面积小，投资小，生产能力达３．６～１０ｔ／ｈ，产品表面光亮，拉丝断裂少，质量高。     

凿岩用奇数边中空钢的轧制工艺研究

针对目前钎杆用中空钢的使用寿命短问题,设计了横截面为奇数边形的正七边形中空钢。然后借助ABAQUS软件,建立了其轧制计算模型,给定中空钢在轧制过程中的一系列工艺参数,进行了热力耦合的非线性数值模拟。所得数值模拟结果变形合理,应力场和温度场分布均匀。     

论网络环境下专业图书馆文献资源建设

随着网络信息技术的发展，给专业图书馆文献资源建设带来了许多影响。阐述了网络环境下专业图书馆文献资源建设的变化以及相应的建设内容。     

我国锰矿业的生产发展概况

文章回顾了建国４４年来锰矿业生产发展的进程，并对锰矿产品产量、质量进行了分析，指出了锰矿石当前生产存在的问题与对策。     

THE WEAR RATE OF CARBIDE CUTTING TOOLS

Abstract

The stress, strain, and temperature at the interface between tool and work material during metal cutting are such as to promote seizure. Conditions of seizure normally exist over part of the interface during most metal-cutting operations. The wear processes that are significant on those parts of the interface where seizure is complete are considered separately from those in areas where contact is localized and intermittent. Examination of worn tools suggests that two major wear processes take place on cemented carbide under each of these sets of conditions. It is believed to be unlikely that abrasion plays a major role in the wear of cemented carbide tools except in special circumstances.

The influence of powder-metallurgical processing variables in the production of cemented carbide tools is considered in relation to each of the main wear processes.     

大硐室软弱围岩变形特征及其监测预报

阐述了软弱岩体内开挖大型硐室过程中，围岩的变形特征及其规律，根据位移速度和最大位移量的极限值，成功地进行了监测预报，取得了满意的结果。对矿山地下工程有一定的指导意义。     

CONSIDERATIONS ON THE THEORY OF FRICTION: FRICTION WITHOUT WEAR

Abstract

From studies of the friction between metal surfaces it has been possible to form a new concept of friction in relation to wear. Its basis is the fact that certain intermetallic compounds are unlikely to stick on common metals. Friction can be produced by adding a small amount of metal to the intermetallic compound and it is shown theoretically that the condition of friction without wear is then achieved. The elastic vibrations produced in the metals lead to the necessary sticking followed by shearing to cause friction. Practical results are given where the lives of clutches have been prolonged by factors of up to 100; similar improvements are gained for the brakes of trains and aircraft. New phenomena are explained that limit the life of the friction materials even though wear is negligible.     

邢隆石膏矿巷道围岩松动圈的超声波测试分析

本文介绍了超声波探测技术在邢隆石膏矿工业试验中的应用,通过对围岩松动圈的测试分析,给工业试验提供了可靠的依据,在实践中被证明是一种成功的方法。     

EMPIRICAL RESEARCH ON THE BASES AND CORRELATES OF MANAGERIAL MOTIVATION: A REVIEW OF THE LITERATURE.

REVIEWS THE LITERATURE SINCE 1959 RELATING TO THE CORRELATES AND BASES OF MANAGERIAL MOTIVATION. 2 THEORETICAL PERSPECTIVES ARE USED AS A FRAMEWORK: A NEED-HIERARCHY MOTIVATIONAL SCHEME, AND THE MOTIVATION-HYGIENE DICHOTOMY. EVALUATIONS OF THESE FRAMEWORKS ARE MADE IN THE LIGHT OF THE SUPPORTIVE AND NONSUPPORTIVE LITERATURE TO DATE. THEORETICAL AND METHODOLOGICAL OBSTACLES ARE SUGGESTED AS LIMITING UNDERSTANDING OF MANAGERIAL MOTIVATION. SUGGESTIONS ARE MADE FOR IMPROVING THE EMPIRICAL BASE AND THEORETICAL RICHNESS THROUGH: (1) THE DEVELOPMENT OF SYSTEMATIC THEORETICAL STATEMENTS ABOUT MANAGERIAL ATTITUDES AND MOTIVATION, (2) THE USE OF MORE RIGOROUS STUDY DESIGNS AND IMPROVED MEASURING DEVICES, AND (3) THE INCORPORATION OF AN INCREASED VARIETY OF POSSIBLE MODERATOR VARIABLES. (2 P. REF.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

冷轧轧辊磨损数学模型研究

针对我国某厂1420mm冷轧生产线，研究了轧辊磨损的数学模型。结合实测磨损数据，用轮廓曲线对比法修正模型并进行了模拟计算。计算结果与实测值十分吻合，显著提高了模型的计算精度。     

炉卷轧机轧辊磨损与辊型设计探讨

通过对轧辊磨损模型的分析,探讨了适合本生产线的轧辊磨损回归模型,初步介绍了轧辊磨损模型的解析原理,在分析轧辊磨损状态的基础上初步解析设计轧辊辊型的原则和方法.     

铬铁矿粉造块方法综述

分析了铬铁矿资源情况及当前电炉冶炼铬铁合金所面临的主要问题(块矿减少、廉价的粉矿比例增加)。但是过多的粉矿入炉将恶化电炉的技术经济指标，采用造块工艺处理铬铁矿粉被认为是解决这一问题的根本途径。本文列举了铬铁矿粉造块的常用方法，并分析了各种方法的优缺点，指出烧结法是有效利用铬铁矿粉、降低铬铁合金生产成本的有效措施之一。     

扇形中深孔采矿中凿岩爆破参数的试验确定及其应用

在扇形中深孔采矿中 ,采用单孔爆破漏斗试验 ,变孔距多孔同段爆破试验与斜面台阶爆破试验相结合 ,确定凿岩爆破参数。实践表明 ,大块率低 ,爆破效果好 ,出矿能力大 ,经济效益明显 ,试验确定的凿岩爆破参数准确、实用     

锻造对飞机刹车副动片钢对偶材料摩擦性能与组织的影响

研究了锻造对飞机刹车副动片钢对偶材料摩擦磨损性能与组织的影响,结果表明:锻造提高了动片钢对偶材料的耐磨性和抗收缩性。     

国内外凿岩用球齿合金的现状、前景与发展趋势

本文叙述了凿岩用球齿合金的选择原则,国内外凿岩用球齿合金的现状(包括牌号、齿型)、前景及发展趋势,指出了不同牌号、不同齿型合金所适用的地层,为合理选择凿岩用球齿合金提供了技术依据。     

庙沟铁矿边坡结构面调查与岩体质量评价研究

应用奥地利结构面数字识别系统Shape MetriX3D对庙沟铁矿边坡进行结构面调查分析,获得了结构面的详细信息,为边坡稳定性研究提供数据支持。     

混合机传动胶轮的磨损分析与改造

针对充气胶轮传动混合机胶轮磨损严重的问题，从设计，使用和维护几方面进行了分析，并在此基础上对混合机的传动系统和胶轮进行了改造，使胶轮的使用寿命延长到16个月。