【摘要】 在对ＡＰＩ标准分析的基础上，通过系统试验，找出了螺距、锥度、中径、接箍不圆度等参数对ＡＰＩ８牙圆螺纹油套管密封性、连接强度及上扣扭矩—圈数相关性的影响，从而提出了内、外螺纹上扣配合的理想螺纹公差范围。更多还原

【Abstract】 Based on API standard and a sevies of tests, the relationship of influence each other about the thread parameters, such as the thread hitch, slope of thread, pitch diameter of thread and coupling roundness tolerance, with the API 8th knuckle thread casing pipe’s tightness, joint strength and tighten up torque with the number of turns are discovered, and the ideal thread tolerance suitable to the tighten up is pointed out.更多还原