MINIMUM WALL THICKNESS OF HOLLOW THREADED PARTS IN THREE-DIE COLD THREAD ROLLING

Abstract

The cold thread rolling technology was developed rapidly in recent years due to its high efficiency, low cost and perfect mechanical properties of its production. However, researches on the precise thread rolling of the hollow parts were very few. Traditionally, the minimum thickness of the thin-walled threaded parts by thread rolling was mainly determined by the empirical (trial and error) methods. In this study, the forming process of thin-walled thread parts rolled with three thread rolling dies was analyzed. The stress state of the hollow work piece was obtained by solving the statically indeterminate problems. Then, the equations for the minimum wall thickness were derived. Experiments are also performed. The experimental results are generally in good agreement with those by the current theoretical analysis. It could be concluded that the analysis presented in this study can provide a good guidance for the thread rolling of hollow parts.