摘要
分析热压孕镶金刚石钻头的压制成形过程、钻头结构和钻具组合等3个方面对钻头内外径偏磨的影响。受力分析表明,不考虑压制成形过程中的摩擦因素时,压制压力在钻头端部均匀分布。离散元仿真模拟结果表明,金属粉末与加载模具之间的摩擦是导致压制试样出现密度差异的主要因素,试样内的局部密度还与压制前该位置的初始孔隙率密切相关;试样内部的密度差异会影响胎体对金刚石的包镶能力和胎体的耐磨性,从而导致钻头的偏磨。计算结果表明,钻头外径与内径的比值a,以及钻头水口宽度与周长的比值b是导致钻头内径磨损比外径严重的主要因素,当a大于1.2且b大于0.5时这一影响迅速加剧,内径磨损较外径更严重。此外,钻头在孔底钻进时产生旋转偏摆也是造成钻头内外径偏磨的主要原因之一。
Effects of pressing formation process,structure,and coordination of drilling tools assembly on lopsided wear of inner and outer diameter of hot-pressed impregnated diamond bit were studied.Force analysis demonstrates that,pressing stress distribution on bit bottom face will be uniformly under frictionless condition.Simulation results from discrete element method（DEM） indicate that,the friction between metal powder and loading mould is the key factor to cause different density of pressed sample,and the local density of the sample is related to the initial local porosity significantly.Different density will cause the difference of wrap inlay ability and abrasiveness of metal matrix to diamonds and influence the wear of bit work layer.Theoretical calculation indicates that,the ratio of bit outer diameter to inner diameter a and the ratio of bit water gap＇s total width to inner circumference b are the two main factors causing lopsided wear on bit inner diameter.This influence will be more seriously when a is larger than 1.2 and b is larger than 0.5.Besides,another reason for this phenomenon is the deflective rotation of bit in drilling process.
出处
《粉末冶金材料科学与工程》
EI
北大核心
2013年第4期609-614,共6页
Materials Science and Engineering of Powder Metallurgy
基金
中国地质调查局超深孔钻进技术预研究项目子项目(KZ10Z250)
中国地质大学(武汉)教学实验室开放基金资助项目(SKJ2011124)
关键词
受力分析
离散元法
磨损强度
钻头偏摆
force analysis
discrete element method
wear intensity
deflective rotation of bit
