Ways to increase the strength of pipes of oil assortment

Shape sleeve ends and the ends of the pipes is chosen independently flat, conical, convex or concave. The conical shape of the end is different from a plane at an angle, the tangent of which does not exceed the value of the coefficient of friction between the sleeve and the pipe ends. Such performance contact sleeve ends and pipes allow forming most workable connection depending on the given conditions, sizes and materials of its connection details. Find ways to improve designs highly hermetic threaded joints to improve reliability casing is relevant and promising task