国产分Φ139．7mm（5in）套管螺纹检测及误差分析

The Thread Check and Tolerance Analysis of Homemade 139. 7mm Casing Pipe

通过对国产Φ１３９．７ｍｍ（５）套管螺纹检测及误差分析发现，由于套管螺纹的锥度及螺距沿管子螺纹轴线的不均匀分布，使得配合螺纹的螺距、锥度突变值较大，造成内、外螺纹不合理匹配。受其影响，局部螺纹的中径偏差亦较大，造成上扣时较大的环向装配应力，发生粘扣，引起螺纹失效。

Through the thread check and tolerance analysis to homemade 139.7(5) casing pipe,it is realized that since the casing thread taper and pitch aren't well-distributed along the airection of casing,thread axis,the variations of the match thread taper and pitch are serious.So,the inner and the outer thread couldn't match properly.While the threads are screwed,due to the tolerance of the thread middle diameter is greater,a greater assembly stress at the thread cirde direction will be caused, the threads adhere to each other,and will invalid.