Tribological Properties of API 10-Round Thread Connection During Make-and-Break Process  

作　　者：袁光杰 姚振强 林元华 王青华 

机构地区：[1]School of Mechanical and Power Engineering, Shanghai Jiao Tong University, Shanghai 200030, China [2]Petroleum Engineering Institute, Southwest Petroleum Institute, Chengdu 610500, China

出　　处：《Tsinghua Science and Technology》2004年第3期281-285,共5页清华大学学报（自然科学版（英文版）

基　　金：Supported by the Open Fund (PLN0403) of State Key Labora-tory of Oil and Gas Reservoir Geology and Exploitation; China

摘　　要：Galling is one of the most familiar failure forms for tubing and casing connections. It has been regarded as a key problem by metallurgy and petroleum systems all over the world. The theory of tribology and contact mechanics was used to analyze the contact force, plastic strain, and other parameters of API 10-round tubing connections in the process of makeup and breakout using the nonlinear finite element method. The stress states of the tubing thread connections were also analyzed for combined makeup and axial tensile loads. The results show that the main factors for tubing thread galling failure with thread grease are the normal contact force of the pin and box and the rigidity of the thread surface. The distribution of the contact force can be improved and the high contact force of the local thread can be reduced by optimizing the geometric parameters of the thread or using a small or varied pitch. The thread surface rigidity can be increased by improving the thread surface machining quality and by heat treatment. The chance of tubing thread galling failure can be reduced by designing hydraulic pressure tongs to avoid high speed and high torque makeup and by standardizing the operations of oilfield makeup and breakout.Galling is one of the most familiar failure forms for tubing and casing connections. It has been regarded as a key problem by metallurgy and petroleum systems all over the world. The theory of tribology and contact mechanics was used to analyze the contact force, plastic strain, and other parameters of API 10-round tubing connections in the process of makeup and breakout using the nonlinear finite element method. The stress states of the tubing thread connections were also analyzed for combined makeup and axial tensile loads. The results show that the main factors for tubing thread galling failure with thread grease are the normal contact force of the pin and box and the rigidity of the thread surface. The distribution of the contact force can be improved and the high contact force of the local thread can be reduced by optimizing the geometric parameters of the thread or using a small or varied pitch. The thread surface rigidity can be increased by improving the thread surface machining quality and by heat treatment. The chance of tubing thread galling failure can be reduced by designing hydraulic pressure tongs to avoid high speed and high torque makeup and by standardizing the operations of oilfield makeup and breakout.

关 键 词：tubing thread friction API thread connections thread galling 

分 类 号：TH131[机械工程—机械制造及自动化]