The Influence of the Bottom Hole of Cold Extruding Internal Thread on Thread Quality

The diameter of the threaded bottom hole determines whether extrusion can proceed smoothly and fullness tooth shape after extrusion. height rate is an important indicator strength connection. In order to establish relationship between extruded internal thread, this paper takes aluminum alloy M8×1.25 mm thread as example, uses a method combining numerical simulation process test. Obtained changing law profile workpieces with different diameters. Using MATLAB fit results, prefabricated workpiece was obtained. reliability results feasibility fitting formula are verified through experiments. show that controlled within 7.33~7.39 when processed by cold process. high meets requirements connection strength, has forming quality good surface quality.