牙轮失效分析研究  

Failure Analysis of a Cone in Mining Tri-cone Bit

作　　者：伍翠兰[1] 陈汪林[1] 元敏[1] 

机构地区：[1]湖南大学材料科学与工程学院,湖南长沙410082

出　　处：《湖南大学学报（自然科学版）》2010年第2期50-55,共6页Journal of Hunan University:Natural Sciences

基　　金：国家973计划资助项目(2008CB617608);中国博士后基金资助项目(20070410979);湖南省自然科学基金资助项目(09JJ6002)

摘　　要：研究在使用过程中钻井牙轮提前断裂的原因.牙轮的材料为20Ni4Mo,热处理工艺为气体渗碳再进行780℃淬火+低温回火.利用化学分析、金相检验、硬度计及扫描电镜等方法对20Ni4Mo渗碳钢制矿用牙轮的断裂原因进行了分析.结果表明:牙轮断裂的主要原因为渗碳及热处理工艺不当,另一原因是牙轮基体存在硫化物等非金属夹杂物.为了检验牙轮的淬火工艺,将20Ni4Mo钢原材料分别在780和850℃进行淬火实验,结果证明780℃淬火工艺不合理.The failure analysis of a drilling cone, that was suddenly broken at work, was conducted. The cone was made of 20Ni4Mo steel and was carburized in Acetone gas. It was reheated to 780 ℃ and oil quenched for tempering at low temperature （200 ℃）. The failed （or failure） cone was investigated with chemical analysis, morphology examination, hardness measurement and scanning electron microscopy. The results showed that the main factor responsible for the cone fracture was the discontinuity of the microstructure and the hardness of the material, which was caused by improper carburizing and heat treatments. Besides, non-metal inclusions, such as sulphide particles in the matrix, might also lead to the fracture of the bit. In order to optimize the quenching process for the cone, 20Ni4Mo raw materials samples were quenched at different temperatures. It was shown that 780 ℃-quenching temperature was unreasonable.

关 键 词：牙轮 渗碳 淬火 断裂失效 

分 类 号：TG166.3[金属学及工艺—热处理]