钻杆溶解氧腐蚀影响因素分析

溶解氧腐蚀是钻杆使用寿命下降的最重要的原因。通过试验研究和文献分析,论述了钻井施工过程中服役环境、溶解氧浓度、泥浆pH值、井下温度、压力、钻井液、钻杆材质等诸多因素对钻杆溶解氧腐蚀的影响。分析认为,氧浓度对钻杆腐蚀起主导作用,钻杆腐蚀速度随着氧浓度的增加而加快;防止钻杆氧腐蚀最简便的措施是提高钻井液的pH值,最有效的办法是采用除氧剂对钻井液进行除氧。     

Chisel edge and cutting lip shape optimization for improved twist drill point design

This paper investigates the optimization of twist drill point geometries in order to minimize thrust and torque in drilling. A point geometry parameterization based on the drill grinding parameters is used to ensure manufacturability of the optimized geometry. Three commonly used drill point geometries, namely, conical, Racon^® and helical, are optimized for drilling forces while maintaining the inherent characteristics of each of the profiles. A significant reduction is shown in the drilling forces for the optimized drills. Drills with the optimized conical point profile are produced and tests run to validate the reduction in thrust and torque.     

Accuracy estimation of drilled holes with small diameter and influence of drill parameter on the machining accuracy when drilling in mild steel sheet

The miniaturization of component parts has advanced in the modern industrial product sector. Corresponding with this new wave, there is a strong demand for the establishment of minute-scale techniques to manufacture products with high quality involving the drilling of small holes. Non-traditional machining techniques such as electro discharge machining can be applied to make small holes. However, there is much practical value if small holes can be made by the traditional drilling process. In this paper, a method for estimating the drilled hole accuracy using a Fourier series analysis is proposed and this method is applied to small holes 1 mm in diameter drilled in mild steel for machine structure use. As a result, it is clarified that the bending rigidity of drill and the thinning of the drill point exert a large influence on the drilled hole accuracy.     

深孔加工切削液造成BTA钻杆涡动分析

利用BTA钻杆内切削液的Reynolds方程,得出钻杆所受流体力与钻杆转速、涡动和挤压效应之间的关系。分析深孔加工钻杆产生涡动的原理,指出促进钻杆正进动的流体分力是钻杆发生涡动的根本原因。模拟并分析了在不同时刻钻杆圆涡动形态,指出在只受到流体力时,钻杆可以稳定地运动。研究钻杆的反进动,揭示挤压油膜阻尼器的工作原理。利用MATLAB软件模拟分析添加挤压油膜阻尼器前、后钻杆的运动情况,证明挤压油膜阻尼器可以显著减小钻杆涡动。     

Thrust force, torque, and tool wear in drilling the bulk metallic glass

The thrust force, torque, and tool wear in drilling of Zr-based bulk metallic glass (BMG) material are investigated. Drilling the BMG at high speed generates the chip light emission, high tool temperature, and severe tool wear. At low spindle speed, the BMG work-material builds up at the major and margin cutting edges and may break the drill. A range of feasible spindle speed and feed rate for the efficient drilling of BMG without the detrimental chip light emission and cutting edge work-material build-up has been identified in this study. Under the same drilling condition, the WC-Co tool generally requires less thrust force and about the same torque than the high-speed steel tool. The progressive wear of the major and margin cutting edges for BMG drilling is examined. Severe drill wear is associated with the bright BMG chip light emission. Without chip light emission, the drill wear is visible but not severe. This study concluded that precision holes in BMG could be generated with proper selection of tooling and process parameters.     

基于回归正交试验的浅孔钻钻削的有限元仿真

基于回归正交试验法设计钻削模拟方案,利用最小二乘法原理得到钻削力的经验公式;基于有限元软件Deform3D平台,建立了用浅孔钻钻削加工45钢的有限元模型,动态模拟浅孔钻钻削过程,获得了浅孔钻钻削加工过程中工件的等效应力和温度,分析预测了加工过程中硬质合金刀具所受的主切削力、径向力以及两刀片所受的扭矩,并评估刀片的磨损情况。     

钢丝绳摩擦白层的研究

模拟钻井钢丝绳工作时承受的高压、高速摩擦条件，研究６５Ｍｎ钢和２０Ｍｎ２ＷＮｂＢ钢钢丝摩擦区的显微组织和性能。结果得出：６５Ｍｎ钢丝出现的摩擦白层是摩擦生热发生相变自淬火形成的硬度很高、脆性极大的高碳马氏体层；２０Ｍｎ２ＷＮｂＢ钢丝虽然也会因摩擦生热发生相变形成自硬化层，但其脆性较小，因而可望作为防止钻井钢丝绳单丝断裂的一种新材料     

The application of acoustic emission for precision drilling process monitoring

Precision drilling is a process where a close tolerance hole can be produced with a special drill bit without subsequent reaming. Producing a hole without reaming results in less overall processing time during hole preparation. Precision drilling is best accomplished by a robot with a computer controlled drilling end effector due to the high degree of process control required. Some aspects of the process, such as spindle speed, feed rate, and peck cycles, can easily be controlled by a computer controlled end effector. Other variables, such as drill bit wear, chipping, and point geometry variation, cannot be controlled with the end effector. These variables affect the diameter of the hole but cannot be detected unless the hole or the drill bit is manually inspected. It is not practical to stop the process and check the diameter after every hole. Therefore, a means to perform real time drilling process monitoring is required to detect if an oversized hole is being drilled. The primary objective of this research was to correlate the diameter of a hole drilled in steel with any acoustic emission (AE) signal measurement parameter. The secondary objective was to correlate drill bit lip height variation, which has a significant influence on the diameter of a hole, with any AE signal measurement parameter. The results of this study showed that acoustic emission could only be correlated to hole diameter variations if those variations were related to the lip height variations. However, AE energy and RMS were correlated to lip height variations under a wide variety of conditions.     

Chip thickening in deep-hole drilling

In conventional turning and milling cutting process models, chips are free of external forces after leaving the cutting area. However, in a drilling process, chip flowing is constrained by the drill flute, causing the change of chip shape and drilling forces. In this research, it is found that when drilling deep holes, the chip thickness increases as drilling progresses deeper into the workpiece. It is also found that during a deep-hole drilling process a significant part of the drilling force increase is due to the chip thickening effect. An analytical model was developed to predict the force increase caused by chip thickening. Experiments have been carried out to verify the model.     

高锰钢钻削用机夹式硬质合金刀具研究

为克服传统的焊接固定式钻头的不易更换、工艺性差的缺点,设计开发了机械夹持式的硬质合金钻削群钻。利用遗传算法给出了基于最大生产率的钻削参数优化结果,并进行新型机夹式刀具的钻削高锰钢的试验研究,得出了机夹式刀具的设计是可行的结论。同时,采用新型刀具加工,切削力和扭矩都相应的有所下降,其中轴向力下降了20%左右,扭矩下降了15%左右,切削效率也就得到了提高。     

方钻杆对接焊缝的超声波检测及缺陷分析

方钻杆在石油钻井过程中主要是传递扭矩并承受钻柱悬挂重量,因此需要对其对接焊缝进行超声波检测。介绍了方钻杆的超声波检测方法、步骤、缺陷定位方法以及质量判定时的注意事项。同时介绍了焊缝典型缺陷（如未焊透、裂纹和气孔）的形成原因及波形特点。多年的检测实践证明,采用超声波检测方法检测方钻杆是切实可行的。     

45钢超声振动钻削加工机理及其试验研究

通过超声振动加工技术对45钢进行钻削加工试验,研究超声振动加工技术的钻削机理、加工孔的表面微观形貌、切屑形态,以及超声振幅和主轴转速对加工孔表面粗糙度的影响规律。结果表明:在普通车床CA6140上利用超声振动发生器、换能器、变幅杆连接钻头对45钢进行钻削,可实现传统钻削加工与超声振动钻削加工的良好结合,有效改善孔内表面的形貌,降低表面粗糙度值,且切屑形态规整;同时,超声振幅控制在20μm最佳,主轴转速在320~400 r/min范围内的加工效果较好。     

回火温度对V150钻杆钢的强韧性匹配的影响

对V150钻杆钢进行了系统的回火温度优化试验,大幅度提高了钻杆钢的冲击韧性。并通过第二相析出物的形态及数量统计,对钻杆钢的强韧性匹配规律进行了微观机理解释。结果表明,在回火温度的拐点温度以下,钻杆钢在保持V150钢级基础上,冲击韧性随回火温度升高提高了近50%。随着回火温度的升高,第二相粒子的体积分数先升后降,为钻杆钢保持高强度级别提供了优化空间,而第二相粒子由棒状趋于球化和材料基体的逐渐软化,是韧性提高的主要原因。     

A standard conical point drill grinding machine

This paper describes a drill grinding machine that can produce conical twist drill points with very accurately specified point shapes. The machine is adjusted by precise orthogonal movements using shims and gages to make sure that the drill parameters are set precisely. The confidence in the point shape produced is high enough that inspection of the points produced is not necessary.     

陆地钻机钻具自动运移装置研制

针对目前国内传统的钻井工艺下人工运移钻具所存在的问题,设计了陆地钻机钻具自动运移系统。对于陆地50型钻机,该自动运移系统可实现钻杆、套管及钻铤在钻台和地面排放架之间安全、高效地自动运移。文中对该系统各部分结构进行了具体设计,对所用材料、焊接工艺进行了选择和制定;对系统的核心——起升装置设计进行了力学性能计算及相应的液压缸选型。设计结果能够满足目前钻井工艺对自动化的需求。     

超声振动钻削减摩机制研究与试验分析

在振动钻削加工原理的基础上建立振动钻削过程中平均摩擦力的数学模型,分析动载荷对平均摩擦力的影响规律。在超声振动钻削试验装置上对0Cr17Ni4Cu4Nb不锈钢进行了普通钻削和超声振动钻削试验,对比分析了孔壁表面粗糙度、钻头磨损形貌和切屑形状。结果表明:超声振动钻削能够减少平均摩擦力;通过观察加工后钻头与孔的表面形貌,超声振动钻削钻头磨损程度低,孔壁表面粗糙度值小,具有更好的断屑、排屑性能。     

苏里格地区钻具失效机理及预防措施

对2010年上半年苏里格地区所发生的钻具失效事故进行了数据收集和统计分析。统计表明,该地区最为常见的钻具失效类型依次为钻杆的疲劳/腐蚀疲劳失效、钻铤螺纹接头的疲劳/腐蚀疲劳失效和钻杆管体过载断裂失效3种。简单分析了导致这3种失效的原因,并提出了有效的预防措施。     

自动化钻杆输送设备液压系统设计

煤矿井下钻孔施工时,作业人员频繁地装卸钻杆不仅劳动强度高,同时存在一定的安全隐患。为解决该问题,根据该自动化钻杆输送设备的机械结构和要求功能,设计出一套配套该设备的具有防爆功能的高精度电液比例控制液压系统。依据设备中各液压执行元件的负载、速度和动作要求,依次计算其压力和流量,从而确定液压系统的功率、各控制元件和液压原理。为了验证所设计液压系统是否符合工作要求,根据原理图制作了自动化钻杆输送设备的液压系统样机。实验结果表明：该样机能够将钻杆从输送设备的料仓移动到钻机的料框中,满足钻杆输送设备的工作要求。     

A study of high-performance plane rake faced twist drills.: Part I: Geometrical analysis and experimental investigation

A study of a modified drill point design with plane rake faces for drilling high-tensile steels is presented. A geometrical analysis has shown that the modified drill point design yields positive normal rake angle on the entire lips and point relieving in the vicinity of the chisel edge. This drill geometry can be expected to reduce the cutting forces and torque, and hence reduce the possible drill breakages when drilling high-tensile steels. An experimental study of drilling an ASSAB 4340 high-tensile steel with 7–13 mm titanium nitride (TiN) coated high-speed steel (HSS) drills has shown that the modified drills can reduce the thrust force by as much as 46.9%, as compared to the conventional twist drills under the corresponding cutting conditions, while the average reduction of torque is 13.2%. Drill-life tests have also been carried out and confirmed the superiority of the modified drills over the conventional twist drills. In some cases, the conventional drills were broken inside the workpiece, while the modified drills performed very well under the same cutting conditions. To mathematically predict the drilling performance and optimise the drilling process using the plane rake faced drills, predictive models for the cutting forces, torque and power will be developed in the second part of this investigation.     

和田青玉超声波深孔高速钢麻花钻钻削试验研究

基于和田玉特殊的物理性能,采用直径为2、1.5、1 mm的高速钢麻花钻,在其主轴转速为700、1500、1800r/min;进给量为3μm/r和5μm/r的情况下;分别进行附加超声波振动和不附加超声波振动加工试验;在钻削加工过程刀具磨损,扩孔量、孔内表面粗糙度三个方面进行对比分析,超声振动波钻削能获得更好的加工质量和效率,并能减少钻头的磨损和破坏,为和田玉精密加工提供了一种新的深孔加工工艺方法。