高瓦斯矿井开采层瓦斯抽采技术研究

针对不同煤层构造区,分析了煤层物理性质对水力扩孔钻孔和煤矿瓦斯抽放的影响,得出结论:液压钻孔扩孔可以不同程度地提高瓦斯抽采效率;水力钻孔扩孔的水射流压力主要取决于煤的结构,当煤层基本一体化时,喷射压力增大,泄放变得相对容易实现,对瓦斯抽采的阻碍作用减小,扩孔过程后瓦斯抽采明显增加。     

前混合磨料连续水射流钢材除鳞除锈系统分析

钢材在深度加工前有的需要对钢材表面除鳞、除锈及污垢清洗,这对钢材的质量有着重要的影响。介绍一种新型前混合磨料连续水射流除鳞除锈系统,对前混合磨料连续水射流的工作原理、组成、磨料水射流流动原理及前混合磨料连续水射流除鳞除锈系统进行了分析。     

60kg汽车用热轧高扩孔钢生产与应用

针对传统60 kg高强钢无法满足特殊用户使用要求的现状,宝钢采用低碳低硫的成分及特定的精炼方式,结合特殊的热轧工艺,开发出一种新型60 kg高扩孔钢。通过比较分析60 kg高扩孔钢和传统60 kg高强钢的化学成分、生产工艺、金相组织、力学性能,发现高扩孔钢具有更好的综合力学性能。扩孔裂纹传播特征及扩孔裂纹扩展的机理分析表明,由于传统高强钢存在珠光体及带状特征,加速了扩孔裂纹的萌生及快速扩展;而高扩孔钢以多边形铁素体为主,有效阻碍了裂纹的扩展,因此组织均匀性是获得高扩孔率的关键因素之一。最后,以车轮轮辐为例介绍60 kg高扩孔钢的应用,60 kg高扩孔钢冲压轮辐中心孔及螺栓孔等关键部位成形良好,并通过用户成形认证。     

水射流切割技术

水射流切割作为一种冷加工工艺一直受到国内外学者的关注。本文在论述水射流切割机理基础上，讨论了切割性能及其特点，并简述了水射流切割技术的应用领域。     

高压水射流技术综述

水射流是一项迅速崛起的新技术、新工艺,同时又是以射流为核心,集泵、阀、密封、液压、自动化控制为一体的综合学科.文章主要介绍了水射流的起源、发展概况及其应用,并对其发展趋势进行了展望.     

炼钢转炉出钢口扩孔机技术改造实践

介绍了转炉专用设备扩孔机的改造方案,通过升级改造扩孔机的发动机,根据发动机功率相应匹配新主泵,使其系统工作压力提高了1.5倍.     

汽车摆臂用高级别扩孔钢的开发

介绍了河钢邯钢汽车摆臂用高级别扩孔钢HR600/780HE的成分体系、冶炼连铸工艺、热轧及酸洗工艺控制要点,并进行了显微组织及力学性能、扩孔性能、冷弯性能检测。结果表明,HR600/780HE显微组织主要为铁素体和贝氏体,晶粒大小及分布较均匀;组织中可见细小弥散的碳化物析出及部分TiN颗粒;拉伸性能及扩孔性能指标均满足国标要求,且具有良好的冷弯性能。此扩孔钢已成功应用于汽车摆臂生产。     

测试条件对汽车高强钢扩孔率的影响

钢材的扩孔性能一般可用扩孔试验求出的扩孔率来评价,同种材料,由于试验条件的不同,测得的扩孔率存在显著差别。研究了不同的孔加工方式及毛刺朝向对扩孔率的影响,钻孔方式获得的扩孔率高于冲压孔方式获得的扩孔率,毛刺朝向与凸模运动方向相反时冲压孔获得的扩孔率,大于毛刺朝向与凸模运动方向相同时的冲压孔获得的扩孔率。     

偏心刮刀钻头在扩孔中的运用

本文以某机场载荷试验反力系统的锚标语扩孔为例介绍了偏心刮刀钻头的结构，工作原理及应用。实践证明，偏心刮刀钻头适用于土层和软弱、半坚硬岩石，具有低成本，高效率的优点，是一种值得推广的钻具。     

高压水采矿方法在黄金薄矿脉矿床中的应用

简述了高压水采矿方法的应用与发展，提出了回采黄金矿床薄矿脉的两种新采矿方法──磨料水射流掘进采矿方法与磨料水射流切割采矿法，并对以在我国的应用提出一些建议。     

Scour due to Crossing Jets at Fixed Vertical Angle

Plunge pool scour is an important topic in hydraulic structures design. Numerous studies have been done in past years to understand the scour phenomenon due to plunging jets. These studies finally aimed at reducing the risk of structural undermining and collapse. Scour holes created under various hydraulic and geometrical conditions were analyzed for both two-dimensional and three-dimensional cases, and methods to reduce the scour were also investigated. In the current study, an attempt was made to quantify the feasibility of using crossing jets. The scour process was analyzed, and various relationships were presented to predict the main geometrical parameters, i.e., maximum scour hole depth, scour hole length, and scour hole width. Scour profiles were also compared with those due to an equivalent single jet. The main parameters on which the scour geometry depends were found as the densimetric Froude number of the jet, the crossing angle between the jets, the distance between the crossing point and the water surface level, and the water depth. All experiments have been carried out for a fixed vertical angle of 45°.     

小孔法测量残余应力

介绍了小孔释放法测量残余应力的原理,以及用来提高测量精度的释放系数修正方法,包括形状改变比能的应变释放系数修正法、应变释放系数分级使用修正法、误差迭代计算修正法、误差曲线修正法等。并分别介绍了钻孔开孔法、喷砂开孔法、高速透平铣孔法等几种常用的开孔方法及其优缺点。还介绍了其他影响小孔法测试结果的因素。     

Experimental Investigation on Influence of Aeration on Plane Jet Scour

A series of experiments was conducted to investigate the influence of aeration on plane jet scour. The scour holes caused by the aerated and the nonaerated jets were compared under the same conditions of jet velocity, water discharge per unit width, and tailwater depth. A quantitative relationship between the air concentration of jet and the relative scour depth was established, which is not affected by jet velocity and water discharge per unit width. The profile of the scour hole was found to mainly depend on the scour depth under the same conditions of bed material and tailwater depth and affected very little by the air concentration itself in the test range. The aeration influences the shape of the scour hole mainly through decreasing the scour depth. The scour holes formed under aerated and nonaerated conditions are self-similar.     

聚合射流氧枪射流特性的实验研究

利用带有中心主孔的Laval喷管和16个副孔的聚合射流氧枪喷头的氧枪射流检测系统研究氧枪射流中心速度的衰减规律,测试常温氦气代替高温燃烧的保护气体作为伴流而产生的聚合射流,以及高温以主孔通空气,两副孔分别通入氧气和丙烷来产生保护气体模拟的聚合射流。结果表明,聚合射流特性优于传统射流特性,常温下随氦气入口压力增加,中心射流的轴向衰减变缓,获得比传统超音速射流更长的超声速区域;高温下通过调节燃气和氧气流量可改变环状火焰长度,同时可以根据生产实际情况变化主射流长度,满足冶炼工艺要求。     

50 t转炉四孔变角氧枪射流融合距离的数值模拟

采用Fluent软件模拟了50 t转炉四孔变角和非变角氧枪气体射流,研究了喷孔倾角对氧气射流流场和流股融合距离的影响。结果表明,在距喷头出口距离较近时,各流股独立为自由射流,随着距喷头出口距离的增加,各流股不断扩张,并在一定距离时融合成单股射流;非变角喷头A的流股融合距离为1.3 m,与冷态水模实验得出枪位1.3 m时炉口溅出量最大是一致的;变角氧枪B至I的对角喷孔倾角不同,射流流股融合了两次,大大降低了炉口溅出量;变角氧枪对角喷孔倾角相差0.5°较对角喷孔倾角相差1°时更有利于射流融合距离的增加;在研究喷孔倾角10.5°~11.5°/12.5°的9个喷头中,倾角11°/11.5°的喷头H射流融合距离最长,其理论炉口喷溅量最少。     

集束氧枪射流特性对转炉炼钢过程的影响

从宝钢现有转炉氧气喷枪的技术参数计算了多孔集束流的速度衰减规律并分析其喷射特性，表明集束流对熔池产生极大的冲击深度和反应接触面积，达到比常规自由射流更好的脱碳条件和化渣效果。     

Erosion of Sand by Circular Impinging Water Jets with Small Tailwater

This technical note presents the results of an experimental study of the erosion of loose cohesionless sand beds by impinging circular water jets with a minimum depth of tailwater. Measurements were made of both the maximum dynamic and static scour depths and the radius of the scour hole. It was found that the dynamic scour depth is about three times that of static scour at the asymptotic state. Dimensional arguments and experimental results are used to show that the main dimensions of the scour hole at the asymptotic state are a function of the densimetric Froude number F0′ = U0′/, where U0′ = velocity of the jet at the original level of the sand bed; g = acceleration due to gravity; D = mean diameter of the sand particles; ρ = density of the eroding fluid; and Δρ = difference between particle and fluid densities. Useful correlations have been developed to estimate the size of the scour holes. Also included is a comparison between the erosion caused by submerged and unsubmerged impinging circular jets.     

圆形冲击射流对水层的穿透深度研究

要使中厚板淬火控冷装置获得最佳的冷却能力,必须要保证冲击射流可以穿透钢板表面的滞留水层。通过实验和数值模拟的方法,研究了圆形冲击射流对水层的穿透深度与射流速度、射流直径和射流高度的关系,并给出了穿透深度与射流出口弗鲁德数Fr的拟合曲线关联式。     

260 t转炉用双角度六孔氧枪的射流特性研究

通过CFD数值模拟研究了260 t转炉用双角度氧枪的倾角变化对射流偏移程度和融合距离的影响,比较了双角度六孔氧枪在喷孔倾角12°-15°～14°-17°下的射流特性,明确了双角度氧枪的射流偏移系数A。研究结果表明：对于双角度六孔氧枪的两股不同射流,倾角越大,射流偏移程度和融合距离越大;与射流偏移程度相比,喷孔倾角对融合距离的影响占主导地位;一组倾角相同时,另外一组倾角越大,融合距离越大,偏移程度越小,聚并现象发生得越晚,射流偏移系数A的变化范围在(3.38～4.12)×10^-3。